(BLANK), Hokkaido University

(BLANK)

(BLANK)

粉体工学

資源リサイクル工学

鉱物処理工学

Powder Technology

Resources Recycling and Utilizatin

Mineral Processing

Energy Engineering, Earth resource engineering, Energy sciences

Manufacturing Technology (Mechanical Engineering, Electrical and Electronic Engineering, Chemical Engineering), Transport phenomena and unit operations

Bachelor's degree program, School of Engineering

Master's degree program, Graduate School of Engineering

Doctoral (PhD) degree program, Graduate School of Engineering

2000, 資源・素材学会 第25回奨励賞
Japan

(社)資源・素材学会, 第32回論文賞
硫酸溶液中での黄銅鉱浸出に対する活性炭と石炭の触媒作用
岡本秀征;中山良一;黒岩樹人;広吉直樹;恒川昌美

Influence of inorganic solid particles on the stability of water-in-crude oil emulsions: Evaluating the role of surface charge
Tokima Hattori; Yogarajah Elakneswaran; Xingjuan Hao; Mai Shimokawara; Naoki Hiroyoshi
Colloids and Surfaces A: Physicochemical and Engineering Aspects, 699, 134726, 134726, Elsevier BV, Oct. 2024, [Peer-reviewed]
Scientific journal

Exploring the reinforcing mechanism of graphene oxide in cementitious materials through microstructural analysis of synthesised calcium silicate hydrate
Mylvaganam Nithurshan; Yogarajah Elakneswaran; Yuya Yoda; Keiichi Yano; Ryoma Kitagaki; Naoki Hiroyoshi
Cement and Concrete Composites, 153, 105717, 105717, Elsevier BV, Oct. 2024, [Peer-reviewed]
Scientific journal

Microencapsulation-based surface modification for improving flotation separation of Cu-Zn mixed sulfide minerals
Ilhwan Park; Dai Uchida; Sanghee Jeon; Kosei Aikawa; Naoki Hiroyoshi; Mayumi Ito
Minerals Engineering, 213, 108756, 108756, Elsevier BV, Aug. 2024
Scientific journal

Influence of Reservoir Salinity, Mineralogy, Temperature, and Pressure on Geochemical Hydrogen Loss in Depleted Carbonates
Angelo Kennedy Lino Limaluka; Elakneswaran Yogarajah; Naoki Hiroyoshi; Moataz Abu-AlSaud; Dong Kyu Cha; Subhash C. Ayirala
SPE Journal, 29, 10, 5690, 5701, Society of Petroleum Engineers (SPE), 29 Jul. 2024, [Peer-reviewed]
Scientific journal, Summary

Underground hydrogen storage (UHS) is a cost-effective and safer system vital for the growth of the hydrogen market and its role as an essential transitional fuel. Presently, depleted hydrocarbon reservoirs (DHR) account for more than 75% of all UHS sites due to their higher prevalence and readiness for use. However, hydrogen (H2) loss primarily due to abiotic interactions poses a significant challenge to the integrity of DHR sites, and while the underlying conditions have been investigated in some studies, the conclusions have been inconsistent, particularly for carbonate reservoirs. In this study, we analyzed the impact of reservoir physical and chemical parameters, (i.e., salinity, mineralogy, temperature, and pressure) on H2-brine-mineral interactions and the extent of H2 loss in carbonate formations. Static batch simulations were performed using PHREEQC and MATLAB® for a 1-year storage cycle period with three different brine and rock samples at 50–130°C and 15–30 MPa. The results showed that the dissociation of H2 and formation of CH4 and H2S increased with increasing temperature, at a two times higher rate compared to pressure. Also, markedly, in various brine compositions and reactive mineralogy, a 20% or less H2 loss could be attained in temperatures <50°C and 115–130°C, with pressure below 17 MPa; meanwhile, the pressure condition 18 MPa and greater (at 50°C) would risk at least 50% loss, with >86% from 19 MPa. Second, H2 loss increased to 80% after about 50 days for all the brines, and pressure and temperature conditions in the mineral sample with the largest composition of reactive minerals (i.e., pyrite, anhydrite, etc.) suggested a 50% loss risk in such mineralogy during the storage cycle period of about 1 month. Lastly, in the mineral sample with >90 wt% calcite and 0–2 wt% reactive minerals composition, H2 molality increased at least fourfold on average across the storage period and reservoir brine/temperature/pressure conditions. This result further indicates that reactive mineralogy has a more significant effect on the stability of hydrogen relative to temperature and pressure in a carbonate UHS formation. In summary, the findings suggest that a minimal reactive mineral composition, 100°C or higher, and 17 MPa or lower constitutes a set of reservoir physical and chemical conditions with the potential for a limited risk of H2 loss (<20%) in carbonate DHR. However, the extension of the present work to the dynamic UHS conditions is necessary to further ascertain these conclusions.

Surface chemistry and radionuclide anion immobilisation potential of phosphoric acid-activated metakaolin-based geopolymers
Xiaobo Niu; Yogarajah Elakneswaran; Naoki Hiroyoshi
Cement and Concrete Research, 181, 107549, 107549, Elsevier BV, Jul. 2024, [Peer-reviewed]
Scientific journal

Role of Semiconductive Property on Selective Cementation Mechanism of Iron Oxides to Gold in Galvanic Interaction with Zero-Valent Aluminum from Gold–Copper Ammoniacal Thiosulfate Solutions
Joshua Zoleta; Kosei Aikawa; Nako Okada; Ilhwan Park; Mayumi Ito; Yogarajah Elakneswaran; Naoki Hiroyoshi
Metals, 14, 5, 550, 550, MDPI AG, 07 May 2024
Scientific journal, Iron oxides (hematite, Fe2O3, and magnetite, Fe3O4), previously used as electron mediators in the galvanic system with zero-valent aluminum (ZVAl), have been shown to recover Au upon cementation in Au–Cu ammoniacal thiosulfate media selectively, and this warrants further investigation. This research is focused on investigating the role of the semiconductive properties of metal oxides by performing a cementation experiment by mixing 0.15 g of electron mediators (Fe3O4, Fe2O3, TiO2 (anatase and rutile)) and 0.15 g of zero-valent aluminum powder as an electron donor in various electrochemical experiments. The results revealed that upon the cementation experiment, synthetic Fe2O3 and Fe3O4 were consistently able to selectively recover Au at around 90% and Cu at around 20%. Compared to activated carbon (AC), TiO2, in anatase and rutile forms, obtained selective recovery of gold, but the recovery was utterly insignificant compared to that of iron oxides, obtaining an average of 93% Au and 63% Cu recovery. The electrochemical and surface analysis supports the results obtained upon the cementation process, where TiO2, upon cyclic voltammetry (CV), obtained two reduction peaks centered at −1.0 V and −0.5 V assigned to reducing Au and Cu ions, respectively. Furthermore, various electrochemical impedance spectroscopic analyses revealed that the flat band potential obtained in the Mott–Schottky plot is around −1.0 V and −0.2 V for iron oxides and titanium oxides, respectively, suggesting that the electrons travel from semiconductor interface to electrolyte interface, and electrons are accessible only to Au ions in the electrolyte interface (reduction band edge around −1.0 V). The determination of this selective cementation mechanism is one of a kind. It has been proposed that the semiconductive properties of Fe2O3, Fe3O4, and, by configuring their relative energy band diagram, the travel of electrons from the iron oxide–electrolyte interface facilitate the selective cementation towards Au(S2O3)23+ ions in gold–copper ammoniacal thiosulfate solutions.

Multiscale computational modelling of nano-silica reinforced cement paste: Bridging microstructure and mechanical performance
Mylvaganam Nithurshan; Yogarajah Elakneswaran; Yuya Yoda; Ryoma Kitagaki; Naoki Hiroyoshi
Construction and Building Materials, 425, 136047, 136047, Elsevier BV, Apr. 2024, [Peer-reviewed]
Scientific journal

Development of metakaolin-based geopolymer for selenium oxyanions uptake through in-situ ettringite formation
Xiaobo Niu; Yogarajah Elakneswaran; Raudhatul Islam Chaerun; Chuwei Fang; Naoki Hiroyoshi; John L. Provis; Tsutomu Sato
Separation and Purification Technology, 324, 124530, 124530, Elsevier BV, Nov. 2023
Scientific journal

N-methyldiethanolamine (MDEA) as an effective CO2 absorbent for direct air capture (DAC) in cement-based materials
Kirushnapillai Kopitha; Yogarajah Elakneswaran; Ryoma Kitagaki; Ryosuke Saito; Masato Tsujino; Akira Nishida; Hisanori Senboku; Naoki Hiroyoshi
Chemical Engineering Journal, 475, 146067, 146067, Elsevier BV, Nov. 2023
Scientific journal

Modified Diglycolamide Resin: Characterization and Potential Application for Rare Earth Element Recovery
Junnile L. Romero; Carlito Baltazar Tabelin; Ilhwan Park; Richard D. Alorro; Joshua B. Zoleta; Leaniel C. Silva; Takahiko Arima; Toshifumi Igarashi; Takunda Mhandu; Mayumi Ito; Steffen Happel; Naoki Hiroyoshi; Vannie Joy T. Resabal
Minerals, 13, 10, 1330, 1330, MDPI AG, 14 Oct. 2023
Scientific journal, Rare earth elements (REEs) are crucial for green energy applications due to their unique properties, but their extraction poses sustainability challenges because the global supply of REEs is concentrated in a few countries, particularly China, which produces 70% of the world’s REEs. To address this, the study investigated TK221, a modified extraction chromatographic resin featuring diglycolamide (DGA) and carbamoyl methyl phosphine oxide (CMPO), as a promising adsorbent for REE recovery. The elemental composition and functional groups of DGA and CMPO on the polystyrene-divinylbenzene (PS-DVB) support of TK221 were confirmed using scanning electron microscopy with energy dispersive X-ray spectroscopy (SEM-EDX), attenuated total reflectance Fourier transform infrared spectroscopy (ATR-FTIR), and X-ray photoelectron spectroscopy (XPS). The adsorption kinetics of neodymium (Nd), yttrium (Y), cerium (Ce), and erbium (Er) followed the pseudo-second-order kinetic model and Langmuir isotherm, indicating monolayer chemisorption. Furthermore, iron (Fe) adsorption reached apparent equilibrium after 360 min, with consistent Fe adsorption observed at both 360 min and 1440 min. The inclusion of Fe in the study is due to its common presence as an impurity in most REE leachate solutions. The Fe adsorption isotherm results are better fitted with the Langmuir isotherm, implying chemisorption. Maximum adsorption capacities (qmax) of the resin were determined as follows: Nd (45.3 mg/g), Ce (43.1 mg/g), Er (35.1 mg/g), Y (15.6 mg/g), and Fe (12.3 mg/g). ATR-FTIR analysis after adsorption suggested that both C=O and P=O bands shifted from 1679 cm−1 to 1618 cm−1 and 1107 cm−1 to 1142 cm−1 for Y, and from 1679 cm−1 to 1607 cm−1 and 1107 cm−1 to 1135 cm−1 for Ce, implying possible coordination with REEs. These results suggest that TK221 has a huge potential as an alternative adsorbent for REE recovery, thus contributing to sustainable REE supply diversification.

A novel recycling route for aluminum alloys: Synthesis of Fe/Al bimetallic materials and magnetic separation
Ilhwan Park; Mayumi Ito; Sanghee Jeon; Carlito Baltazar Tabelin; Theerayut Phengsaart; Marthias Silwamba; Naoki Hiroyoshi
Minerals Engineering, 201, 108202, 108202, Elsevier BV, Oct. 2023
Scientific journal

Role of pH and cations on emulsion formation and stability of crude oils
Xingjuan Hao; Yogarajah Elakneswaran; Sadia Afrin; Mai Shimokawara; Yoshitake Kato; Ryuta Kitamura; Naoki Hiroyoshi
Geoenergy Science and Engineering, 227, 211905, 211905, Elsevier BV, Aug. 2023, [Peer-reviewed]
Scientific journal

Functional modification of mussel adhesive protein to control solubility and adhesion property
Anju Pilakka Veedu; Kazunori Nakashima; Hayahide Shiga; Takahiro Sato; Kasun Godigamuwa; Naoki Hiroyoshi; Satoru Kawasaki
Journal of Bioscience and Bioengineering, 136, 2, 87, 93, Elsevier BV, Aug. 2023
Scientific journal

A Pretreatment of Refractory Gold Ores Containing Sulfide Minerals to Improve Gold Leaching by Ammonium Thiosulfate: A Model Experiment Using Gold Powder and Arsenic-Bearing Sulfide Minerals
Takunda Joseph Mhandu; Ilhwan Park; Sanghee Jeon; Sohta Hamatsu; Yogarajah Elakneswaran; Mayumi Ito; Naoki Hiroyoshi
Metals, 13, 8, 1357, 1357, MDPI AG, 28 Jul. 2023
Scientific journal, The use of thiosulfate to extract gold from refractory ores is promising because of its non-toxicity and high selectivity. Sulfide minerals (i.e., pyrite, arsenopyrite, chalcopyrite), major gold carriers in refractory gold ores, however, hinder gold extraction due to the high consumption of a lixiviant. In this study, a new method to improve gold extraction from sulfide bearing gold ores is proposed based on the model experiments using a mixture of gold powder and arsenopyrite-bearing sulfide (HAsBS) ore. The effects of HAsBS ore on gold leaching in ammonium thiosulfate solutions were investigated, and it was found that gold extraction in the presence of HAsBS ore was suppressed because of the unwanted decomposition of thiosulfate on the surface of sulfide minerals. To improve gold extraction in the presence of the sulfide minerals, this study investigated the effects of the pretreatment of HAsBS ore using ammonium solutions containing cupric ions and confirmed that HAsBS ore was oxidized in the pretreatment and its surface was covered by the oxidation products. As a result, thiosulfate consumption was minimized in the subsequent gold leaching step using ammonium thiosulfate, resulting in an improvement in gold extraction from 10% to 79%.

Selective Cementation of Gold Using an Iron Oxide and Zero-Valent Aluminum Galvanic System from Gold–Copper Ammoniacal Thiosulfate Solutions
Joshua Zoleta; Sanghee Jeon; Akuru Kuze; Nako Okada; Ilhwan Park; Mayumi Ito; Yogarajah Elakneswaran; Naoki Hiroyoshi
Metals, 13, 7, 1289, 1289, MDPI AG, 18 Jul. 2023
Scientific journal, Ammonium thiosulfate leaching is a promising alternative to the conventional cyanide method for extracting gold from ores. However, strategies for recovering gold from the leachate are less commercially used due to its low affinity to gold. The present study investigated the recovery of gold from the leachate using iron oxides (hematite, Fe2O3 or magnetite, Fe3O4). Cementation experiments were conducted by mixing 0.15 g of aluminum powder as an electron donor and 0.15 g of an electron mediator (activated carbon, hematite, or magnetite) in 10 mL of ammonium thiosulfate leachate containing 100 mg/L gold ions and 10 mM cupric ions for 24 h at 25 °C. The results of the solution analysis showed that when activated carbon (AC) was used, the gold was recovered together with copper (recoveries were 99.99% for gold and copper). However, selective gold recovery was observed when iron oxides were used, where the gold and copper recoveries were 89.7% and 21% for hematite and 85.9% and 15.4% for magnetite, respectively. An electrochemical experiment was also conducted to determine the galvanic interaction between the electron donor and electron mediator in a conventional electrochemical setup (hematite/magnetite–Al as the working electrode, Pt as the counter electrode, Ag/AgCl as the reference electrode) in a gold–thiosulfate medium. Cyclic voltammetry showed a gold reduction “shoulder-like” peak at −1.0 V using hematite/Al and magnetite/Al electrodes. Chronoamperometry was conducted and operated at a constant voltage (−1.0 V) determined during cyclic voltammetry and further analyzed using SEM-EDX. The results of the SEM-EDX analysis for the cementation products and electrochemical experiments confirmed that the gold was selectively deposited on the iron oxide surface as an electron mediator.

Carrier Flotation Using Coarse Pyrite for Improving the Recovery of Finely Ground Chalcopyrite: Development of Post-Process of Carrier Flotation to Separate Finely Ground Chalcopyrite Particles from Coarse Pyrite Particles
Muhammad Bilal; Ilhwan Park; Mayumi Ito; Fawad Ul Hassan; Kosei Aikawa; Sanghee Jeon; Naoki Hiroyoshi
Minerals, 13, 7, 916, 916, MDPI AG, 07 Jul. 2023
Scientific journal, Carrier flotation is a technique that can recover fine particles by using coarse carrier particles during the flotation process. In heterogeneous carrier flotation, coarse mineral particles of different minerals are used as carriers to recover fine mineral particles. By using Cu2+-treated pyrite particles as carriers, fine chalcopyrite particles recovery could be improved. However, a disadvantage of this heterogeneous carrier flotation is that it requires a post-flotation separation process to improve the grade of the final Cu concentrate. This study tested mechanical and chemical treatments to detach finely ground chalcopyrite (D50~3.5 µm) particles from Cu2+-treated coarse pyrite particles (−125 + 106 µm) after flotation. The results showed that the ultrasonic treatment was not effective to detach chalcopyrite fines from Cu2+-treated pyrite particles. However, acid treatment was effective to detach chalcopyrite fines from coarse pyrite particles. At pH 2, approximately 96% of chalcopyrite fines were detached from coarse Cu2+-treated pyrite particles. The acid treatment of flotation froth (mixture of chalcopyrite fines and Cu2+-treated pyrite particles) decomposed the collector KAX (potassium amyl xanthate) and dissolved the Cu precipitates adsorbed on the pyrite surface. This weakened the hydrophobic attraction force between the chalcopyrite fines and coarse pyrite particles, thus promoting the detachment of chalcopyrite fines from Cu2+-treated coarse pyrite particles.

Flotation of Copper Ores with High Cu/Zn Ratio: Effects of Pyrite on Cu/Zn Separation and an Efficient Method to Enhance Sphalerite Depression
Kosei Aikawa; Mayumi Ito; Nodoka Orii; Sanghee Jeon; Ilhwan Park; Kazutoshi Haga; Taro Kamiya; Tatsuru Takahashi; Kazuya Sunada; Taisuke Sakakibara; Tatsuhiro Ono; Refilwe S. Magwaneng; Naoki Hiroyoshi
Minerals, 12, 9, 1103, 1103, MDPI AG, 30 Aug. 2022
Scientific journal, Porphyry copper deposits are important sources of copper and typically processed by flotation to produce copper concentrates. As mining areas become deeper, the amounts of impurities, such as sphalerite, can be increased in copper ores, so the appropriate depression of sphalerite floatability should be achieved to obtain saleable copper concentrates. In this study, the flotation behaviors of chalcopyrite and sphalerite in model samples mimicking copper ores with high Cu/Zn ratios (i.e., the ratio of chalcopyrite/sphalerite = 13:1) were investigated with zinc sulfate as a depressant for sphalerite. In addition, the effect of pyrite—a major gangue mineral in copper ores—on the depression of sphalerite floatability with zinc sulfate was examined. When sphalerite and chalcopyrite coexisted, the floatability of the former was effectively depressed by zinc sulfate (Zn recovery: <12%), whereas the presence of pyrite promoted the release of Cu2+ due to the galvanic interaction with chalcopyrite, which resulted in the elimination of the effectiveness of zinc sulfate in depressing sphalerite floatability (Zn recovery: >90%). Despite the presence of much higher amounts of chalcopyrite and pyrite than sphalerite, the application of nitrogen (N2) gas limiting the galvanic interaction between pyrite and chalcopyrite by reducing the dissolved oxygen (DO) concentration in the system effectively depressed the floatability of sphalerite (Zn recovery: <30%).

Development of a Sustainable Process for Complex Sulfide Ores Containing Anglesite: Effect of Anglesite on Sphalerite Floatability, Enhanced Depression of Sphalerite by Extracting Anglesite, and Recovery of Extracted Pb2+ as Zero-Valent Pb by Cementation Using Zero-Valent Fe
Kosei Aikawa; Mayumi Ito; Atsuhiro Kusano; Sanghee Jeon; Ilhwan Park; Naoki Hiroyoshi
Minerals, 12, 6, 723, 723, MDPI AG, 06 Jun. 2022
Scientific journal, The presence of anglesite (PbSO4) in complex sulfide ores negatively affects the separation of Cu-Pb sulfides and sphalerite (ZnS) due to lead activation, and PbSO4 rejected to tailings dams contaminates the surrounding environment with lead. To address these problems, this study investigated the application of ethylene diamine tetra acetic acid (EDTA) pretreatment extracting PbSO4 to ZnS flotation and the recovery of the extracted Pb2+ as zero-valent Pb by cementation using zero-valent iron (ZVI). The application of EDTA pretreatment could extract ~99.8% of PbSO4, thus depressing ZnS floatability from 82% to 30%. In addition, cementation using ZVI could recover ~99.7% of Pb2+ from the leachate of EDTA pretreatment.

Alkaline Leaching and Concurrent Cementation of Dissolved Pb and Zn from Zinc Plant Leach Residues
Marthias Silwamba; Mayumi Ito; Naoki Hiroyoshi; Carlito Baltazar Tabelin; Ryota Hashizume; Tomoki Fukushima; Ilhwan Park; Sanghee Jeon; Toshifumi Igarashi; Tsutomu Sato; Imasiku Nyambe; Hokuto Nakata; Shouta Nakayama; Mayumi Ishizuka
Minerals, 12, 4, Apr. 2022
Scientific journal

Heterogenous carrier flotation technique for recovering finely ground chalcopyrite particles using coarse pyrite particles as a carrier
Muhammad Bilal; Mayumi Ito; Riku Akishino; Xiangning Bu; Fawad Ul Hassan; Ilhwan Park; Sanghee Jeon; Kosei Aikawa; Naoki Hiroyoshi
Minerals Engineering, 180, Apr. 2022
Scientific journal

A simple and efficient recovery technique for gold ions from ammonium thiosulfate medium by galvanic interactions of zero-valent aluminum and activated carbon: A parametric and mechanistic study of cementation
S. Jeon; S. Bright; I. Park; C.B. Tabelin; M. Ito; N. Hiroyoshi
Hydrometallurgy, 208, Feb. 2022, [Peer-reviewed]

A Kinetic Study on Enhanced Cementation of Gold Ions by Galvanic Interactions between Aluminum (Al) as an Electron Donor and Activated Carbon (AC) as an Electron Mediator in Ammonium Thiosulfate System
S. Jeon; S. Bright; I. Park; A. Kuze; M. Ito; N. Hiroyoshi
Minerals, 12, 1, Jan. 2022, [Peer-reviewed]

Development of the reverse hybrid jig: Separation of polyethylene and cross-linked polyethylene from eco-cable wire
Mayumi Ito; Ayumu Saito; Megumi Takeuchi; Nana Murase; Theerayut Phengsaart; Carlito Baltazar Tabelin; Naoki Hiroyoshi
Minerals Engineering, 174, Elsevier Ltd, 01 Dec. 2021
English, Scientific journal

Beneficiation of Low-Grade Rare Earth Ore from Khalzan Buregtei Deposit (Mongolia) by Magnetic Separation
I. Park; Y. Kanazawa; N. Sato; P. Galtchandmani; M. K. Jha; C.B. Tabelin; S. Jeon; M. Ito; N. Hiroyoshi
Minerals, 11, 12, Dec. 2021, [Peer-reviewed]

Addition of Fe3O4 as electron mediator for enhanced cementation of Cd2+ and Zn2+ on aluminum powder from sulfate solutions and magnetic separation to concentrate cemented metals from cementation products
S. Choi; S Jeon; I. Park; M. Ito; N. Hiroyoshi
Journal of Environmental Chemical Engineering, 9, 6, Dec. 2021, [Peer-reviewed]

Simultaneous extraction and recovery of lead using citrate and micro-scale zero-valent iron for decontamination of polluted shooting range soils
Marthias Silwamba; Mayumi Ito; Carlito Baltazar Tabelin; Ilhwan Park; Sanghee Jeon; MasaoTakada; Yasushi Kubo; Naohiro Hokari; Masami Tsunekawa; Naoki Hiroyoshi
Environmental Advances, 5, Oct. 2021, [Peer-reviewed]

Repurposing of aluminum scrap into magnetic Al0/ZVI bimetallic materials: Two-stage mechanical-chemical synthesis and characterization of products
C.B. Tabelin; V.J.T. Resabal; I. Park; M.G.B. Vilanueva; S. Choi; R. Ebio; P.J. Cabural; M.V. Tabelin; A. Orbecido; R.D. Alorro; S. Jeon; M. Ito; N. Hiroyoshi
Journal of Cleaner Production, 317, Oct. 2021, [Peer-reviewed]

A novel arsenic immobilization strategy via a two-step process: Arsenic concentration from dilute solution using schwertmannite and immobilization in Ca–Fe–AsO4 compounds
I. Park; T. Ryota; T Yuto; C.B. Tabelin; T. Phengsaart; S. Jeon; M. Ito; N. Hiroyoshi
Journal of Environmental Management, 295, Oct. 2021, [Peer-reviewed]

Agglomeration-flotation of finely ground chalcopyrite using surfactant-stabilized oil emulsions: Effects of co-existing minerals and ions
V. Horn; I. Park; M. Ito; H Shimada; T. Suto; C.B. Tabelin; S. Jeon; N. Hiroyoshi
Minerals Engineering, 171, Sep. 2021, [Peer-reviewed]

The Effects of Coexisting Copper, Iron, Cobalt, Nickel, and Zinc Ions on Gold Recovery by Enhanced Cementation via Galvanic Interactions between Zero-Valent Aluminum and Activated Carbon in Ammonium Thiosulfate Systems
S. Jeon; S. Bright; I. Park; C.B. Tabelin; M. Ito; N. Hiroyoshi
Metals, 11, 9, Aug. 2021, [Peer-reviewed]

Enhanced pyrite passivation by carrier-microencapsulation using Fe-catechol and Ti-catechol complexes
X. Li; I. Park; C.B. Tabelin; K. Naruwa; T. Goda; C Harada; S. Jeon; M. Ito; N. Hiroyoshi
Journal of Hazardous Materials, 416, Aug. 2021, [Peer-reviewed]

Copper and critical metals production from porphyry ores and E-wastes: A review of resource availability, processing/recycling challenges, socio-environmental aspects, and sustainability issues
C.B. Tabelin; I. Park; T. Phengsaart; S. Jeon; M.V. Tabelin; D. Alonzo; K. Yoo; M. Ito; N. Hiroyoshi
Resources, Conservation and Recycling, 170, Jul. 2021, [Peer-reviewed]

Development of a restraining wall and screw-extractor discharge system for continuous jig separation of mixed plastics
T. Phengsaart; M. Ito; S. Kimura; A. Azuma; K. Hori; H. Tanno; S. Jeon; I. Park; C.B. Tabelin; N. Hiroyoshi
Minerals Engineering, 168, Jul. 2021, [Peer-reviewed]

Enhanced cementation of Cd2+, Co2+, Ni2+, and Zn2+ on Al from sulfate solutions by activated carbon addition
S. Choi; S. Jeon; I. Park; C.B. Tabelin; M. I; N. Hiroyoshi
Hydrometallurgy, 201, May 2021, [Peer-reviewed]

Suppression of arsenopyrite oxidation by microencapsulation using ferric-catecholate complexes and phosphate
I. Park; K. Higuchi; C.B. Tabelin; S. Jeon; M. Ito; N. Hiroyoshi
Chemosphere, 269, Apr. 2021, [Peer-reviewed]

Flotation separation of chalcopyrite and molybdenite assisted by microencapsulation using ferrous and phosphate ions: Part II. flotation
Ilhwan Park; Seunggwan Hong; Sanghee Jeon; Mayumi Ito; Naoki Hiroyoshi
Metals, 11, 3, 1, 11, MDPI AG, 01 Mar. 2021
English, Scientific journal

Effects of coarse chalcopyrite on flotation behavior of fine chalcopyrite
M. Bilal; M. Ito; K. Koike; V. Hornn; F.U. Hassan; S. Jeon; I. Park; N. Hiroyoshi
Minerals Engineering, 163, Mar. 2021, [Peer-reviewed]

Flotation of Seafloor Massive Sulfide Ores: Combination of Surface Cleaning and Deactivation of Lead-Activated Sphalerite to Improve the Separation Efficiency of Chalcopyrite and Sphalerite
Kosei Aikawa; Mayumi Ito; Atsuhiro Kusano; Ilhwan Park; Tatsuya Oki; Tatsuru Takahashi; Hisatoshi Furuya; Naoki Hiroyoshi
Metals, 11, 2, 253, 253, MDPI AG, 02 Feb. 2021
Scientific journal, The purpose of this study is to propose the flotation procedure of seafloor massive sulfide (SMS) ores to separate chalcopyrite and galena as froth and sphalerite, pyrite, and other gangue minerals as tailings, which is currently facing difficulties due to the presence of water-soluble compounds. The obtained SMS ore sample contains CuFeS2, ZnS, FeS2, SiO2, and BaSO4 in addition to PbS and PbSO4 as Pb minerals. Soluble compounds releasing Pb, Zn2+, Pb2+, and Fe2+/3+ are also contained. When anglesite co-exists, lead activation of sphalerite occurred, and thus sphalerite was recovered together with chalcopyrite as froth. To remove soluble compounds (e.g., anglesite) that have detrimental effects on the separation efficiency of chalcopyrite and sphalerite, surface cleaning pretreatment using ethylene diamine tetra acetic acid (EDTA) was applied before flotation. Although most of anglesite were removed and the recovery of chalcopyrite was improved from 19% to 81% at 20 g/t potassium amyl xanthate (KAX) after EDTA washing, the floatability of sphalerite was not suppressed. When zinc sulfate was used as a depressant for sphalerite after EDTA washing, the separation efficiency of chalcopyrite and sphalerite was improved due to deactivation of lead-activated sphalerite by zinc sulfate. The proposed flotation procedure of SMS ores—a combination of surface cleaning with EDTA to remove anglesite and the depression of lead-activated sphalerite by using zinc sulfate—could achieve the highest separation efficiency of chalcopyrite and sphalerite; that is, at 200 g/t KAX, the recoveries of chalcopyrite and sphalerite were 86% and 17%, respectively.

Enhanced Cementation of Co2+ and Ni2+ from Sulfate and Chloride Solutions Using Aluminum as an Electron Donor and Conductive Particles as an Electron Pathway
S. Choi; S Jeon; I. Park; M. Ito; N. Hiroyoshi
Metals, 11, 2, Feb. 2021, [Peer-reviewed]

Flotation Separation of Chalcopyrite and Molybdenite Assisted by Microencapsulation Using Ferrous and Phosphate Ions: Part I. Selective Coating Formation
Ilhwan Park; Seunggwan Hong; Sanghee Jeon; Mayumi Ito; Naoki Hiroyoshi
Metals, 10, 12, Dec. 2020, [Peer-reviewed]

Solid-phase partitioning and release-retention mechanisms of copper, lead, zinc and arsenic in soils impacted by artisanal and small-scale gold mining (ASGM) activities
Carlito Baltazar Tabelin; Marthias Silwamba; Florifern C. Paglinawan; Alissa Jane S. Mondejar; Ho Gia Duc; Vannie Joy Resabal; Einstine M. Opiso; Toshifumi Igarashi; Shingo Tomiyama; Mayumi Ito; Naoki Hiroyoshi; Mylah Villacorte-Tabelin
Chemosphere, 260, 127574, 127574, Elsevier BV, Dec. 2020
Scientific journal

Estimation of hybrid jig separation efficiency using a modified concentration criterion based on apparent densities of plastic particles with attached bubbles
Mayumi Ito; Ayumu Saito; Nana Murase; Theerayut Phengsaart; Shoko Kimura; Naho Kitajima; Megumi Takeuchi; Carlito Baltazar Tabelin; Naoki Hiroyoshi
Journal of Material Cycles and Waste Management, 22, 6, 2071, 2080, Springer Japan, 01 Nov. 2020
English, Scientific journal

Acid mine drainage formation and arsenic mobility under strongly acidic conditions: Importance of soluble phases, iron oxyhydroxides/oxides and nature of oxidation layer on pyrite
Carlito Baltazar Tabelin; Ryan D. Corpuz; Toshifumi Igarashi; Mylah Villacorte-Tabelin; Richard Diaz Alorro; Kyoungkeun Yoo; Simit Raval; Mayumi Ito; Naoki Hiroyoshi
JOURNAL OF HAZARDOUS MATERIALS, 399, Nov. 2020
English, Scientific journal

Kinetic Analysis for Agglomeration-Flotation of Finely Ground Chalcopyrite: Comparison of First Order Kinetic Model and Experimental Results
Vothy Hornn; Mayumi Ito; Ryosuke Yamazawa; Hiromasa Shimada; Carlito Baltazar Tabelin; Sanghee Jeon; Ilhwan Park; Naoki Hiroyoshi
61, 10, Sep. 2020, [Peer-reviewed]

Detoxification of lead-bearing zinc plant leach residues from Kabwe, Zambia by coupled extraction-cementation method
Marthias Silwamba; Mayumi Ito; Naoki Hiroyoshi; Carlito Baltazar Tabelin; Tomoki Fukushima; Ilhwan Park; Sanghee Jeon; Toshifumi Igarashi; Tsutomu Sato; Imasiku Nyambe; Meki Chirwa; Kawawa Banda; Hokuto Nakata; Shouta Nakayama; Mayumi Ishizuka
Journal of Environmental Chemical Engineering, 8, 4, 104197, 104197, Elsevier BV, Aug. 2020, [Peer-reviewed]
Scientific journal

Agglomeration–Flotation of Finely Ground Chalcopyrite Using Emulsified Oil Stabilized by Emulsifiers: Implications for Porphyry Copper Ore Flotation
Vothy Hornn; Mayumi Ito; Hiromasa Shimada; Carlito Baltazar Tabelin; Sanghee Jeon; Ilhwan Park; Naoki Hiroyoshi
Metals, 10, 7, 912, 912, MDPI AG, 08 Jul. 2020, [Peer-reviewed]
Scientific journal, Flotation is the conventional method for processing porphyry copper deposits, one of the most economically important sources of copper (Cu) worldwide. The rapidly decreasing grade of this type of Cu ore in recent years, however, presents serious problems with fine particle recovery using conventional flotation circuits. This low recovery could be attributed to the low collision efficiency of fine particles and air bubbles during flotation. To improve collision efficiency and flotation recovery, agglomeration of finely ground chalcopyrite (CuFeS2) (D50 = 3.5 μm) using emulsified oil stabilized by emulsifiers was elucidated in this study. Specifically, the effects of various types of anionic (sodium dodecyl sulfate (SDS), potassium amyl xanthate (KAX)), cationic (dodecyl amine acetate (DAA)), and non-ionic (polysorbate 20 (Tween 20)) emulsifiers on emulsified oil stability and agglomeration–flotation efficiency were investigated. When emulsifiers were added, the average size of agglomerates increased, resulting in higher Cu recovery during flotation. This dramatic improvement in flotation efficiency could be attributed to the smaller oil droplet size in emulsified oil and their higher stability in the presence of emulsifiers. The utilization of emulsifiers during agglomeration–flotation not only lowered the required agitation strength for agglomeration but also shortened the agglomeration time, both of which made the process easier to incorporate in existing flotation circuits.

Depression of lead-activated sphalerite by pyrite via galvanic interactions: Implications to the selective flotation of complex sulfide ores
Kosei Aikawa; Mayumi Ito; Tatsuya Segawa; Sanghee Jeon; Ilhwan Park; Carlito Baltazar Tabelin; Naoki Hiroyoshi
Minerals Engineering, 152, 106367, 106367, Elsevier BV, Jun. 2020, [Peer-reviewed]
Scientific journal

Redox potential-dependent chalcopyrite leaching in acidic ferric chloride solutions: Leaching experiments
Nguyen Thi Phuong Thao; Shushi Tsuji; Sanghee Jeon; Ilhwan Park; Carlito Baltazar Tabelin; Mayumi Ito; Naoki Hiroyoshi
Hydrometallurgy, 194, 105299, 105299, Elsevier BV, Jun. 2020, [Peer-reviewed]
Scientific journal

Jig separation of crushed plastics: the effects of particle geometry on separation efficiency
Theerayut Phengsaart; Mayumi Ito; Arisa Azuma; Carlito Baltazar Tabelin; Naoki Hiroyoshi
Journal of Material Cycles and Waste Management, 22, 3, 787, 800, Springer, 01 May 2020
English, Scientific journal

Metal Recovery and Pb Removal by Melting Mixture of Lead Glass and Printed Circuit Board
Hiroyuki INANO; Keiichi TOMITA; Tatsumi TADA; Naoki HIROYOSHI
Journal of MMIJ, 136, 4, 25, 32, Mining and Materials Processing Institute of Japan, 30 Apr. 2020
Scientific journal

Agglomeration-Flotation of Finely Ground Chalcopyrite and Quartz: Effects of Agitation Strength during Agglomeration Using Emulsified Oil on Chalcopyrite
Vothy Hornn; Mayumi Ito; Hiromasa Shimada; Carlito Baltazar Tabelin; Sanghee Jeon; Ilhwan Park; Naoki Hiroyoshi
Minerals, 10, 4, 380, 380, MDPI AG, 23 Apr. 2020, [Peer-reviewed]
Scientific journal, In flotation, the size of mineral particles is one of the most important parameters: when the size becomes fine, collision efficiency of the particles and air bubbles becomes low, causing low flotation recovery. To improve the collision efficiency and flotation kinetics, agglomeration using the emulsified oil of finely ground chalcopyrite (D50 = 3.5 μm) was carried out before flotation. In this study, the effects of agitation strength during agglomeration, kerosene dosage and potassium amyl xanthate (KAX) dosage on the flotation were investigated. Agglomeration using emulsified oil improved Cu recovery because the median diameter of agglomerate increased. With increasing agitation strength, KAX and kerosene dosages, Cu recovery was further increased. Agglomeration-flotation of a mixture containing chalcopyrite and quartz with 1:1 ratio (w/w, weight by weight) showed that Si recovery in froth was low and did not change with varying conditions (agitation strength, KAX and kerosene dosages); however, Cu recovery was significantly improved with increasing agitation strength, KAX and kerosene dosages, and thus the separation efficiency was improved.

Recovery of Lead and Zinc from Zinc Plant Leach Residues by Concurrent Dissolution-Cementation Using Zero-Valent Aluminum in Chloride Medium
Marthias Silwamba; Mayumi Ito; Naoki Hiroyoshi; Carlito Baltazar Tabelin; Ryota Hashizume; Tomoki Fukushima; Ilhwan Park; Sanghee Jeon; Toshifumi Igarashi; Tsutomu Sato; Meki Chirwa; Kawawa Banda; Imasiku Nyambe; Hokuto Nakata; Shouta Nakayama; Mayumi Ishizuka
Metals, 10, 4, 531, 531, MDPI AG, 20 Apr. 2020, [Peer-reviewed]
Scientific journal, Zinc plant leach residues (ZPLRs) contain significant amounts of metal compounds of lead (Pb), zinc (Zn), iron (Fe), etc., hence, they are considered as a secondary source of metals. On the other hand, ZPLRs are regarded as hazardous materials because they contain heavy metals that pollute the environment. Resources and environmental concerns of ZPLRs were addressed in this study by removing/recovering Pb and Zn using a concurrent dissolution and cementation technique. To cement the dissolved Pb and Zn in leaching pulp, zero-valent aluminum (ZVAl) was added during ZPLRs leaching in the hydrochloric (HCl)–sodium chloride (NaCl) solution. The resulting cemented metals were agglomerated and separated by sieving. Lead removal increased with increasing both NaCl and HCl concentrations. However, when ZVAl was added, significant Pb removal was achieved at a low concentration. Zinc was not cemented out of the pulp using ZVAl and its recovery from ZPLRs was dependent on the HCl concentration only. By applying a concurrent dissolution and cementation technique, both Pb and Zn were removed using a low concentration of NaCl, and most importantly Pb—the most toxic metal in ZPLRs—was captured and separated before the solid-liquid separation, hence, eliminating the need for extensive washing of the generated residues to remove the inherent residual solution.

Agglomeration flotation of finely ground chalcopyrite: Comparison of model calculation vs. Experimental results
Vothy Hornn; Mayumi Ito; Hiromasa Shimada; Sanghee Jeon; Ilhwan Park; Carlito Baltazar Tabelin; Naoki Hiroyoshi; Shigeto Kuroiwa; Yuji Aoki
15th International Symposium on East Asian Resources Recycling Technology, EARTH 2019, The Korean Institute of Resources Recycling, 2020
English, International conference proceedings

Agglomeration-flotation of finely ground chalcopyrite: Effects of agitation strength in agglomeration on flotation separation efficiency
Vothy Hornn; Mayumi Ito; Hiromasa Shimada; Sanghee Jeon; Ilhwan Park; Carlito Baltazar Tabelin; Naoki Hiroyoshi; Shigeto Kuroiwa; Yuji Aoki
15th International Symposium on East Asian Resources Recycling Technology, EARTH 2019, The Korean Institute of Resources Recycling, 2020
English, International conference proceedings

Effects of flatness ratio on the particle motion during jig separation of plastic and improvement of jig separation efficiency using modified water pulsation
Theerayut Phengsaart; Daiki Kitayama; Arisa Azuma; Sanghee Jeon; Ilhwan Park; Carlito Baltazar Tabelin; Naoki Hiroyoshi; Mayumi Ito
15th International Symposium on East Asian Resources Recycling Technology, EARTH 2019, The Korean Institute of Resources Recycling, 2020
English, International conference proceedings

Development of discharge systems using restraining walls for continuous jig separation of plastics to improve purity of bottom layer products
Theerayut Phengsaart; Shoko Kimura; Arisa Azuma; Sanghee Jeon; Ilhwan Park; Carlito Baltazar Tabelin; Naoki Hiroyoshi; Mayumi Ito
15th International Symposium on East Asian Resources Recycling Technology, EARTH 2019, The Korean Institute of Resources Recycling, 2020
English, International conference proceedings

Lead removal in zinc leach residues from Kabwe, Zambia by carrier-in-pulp method using zero-valent iron
M. Silwamba; M. Ito; T. Fukushima; I. Park; S. Jeon; C. B. Tabelin; N. Hiroyoshi
15th International Symposium on East Asian Resources Recycling Technology, EARTH 2019, The Korean Institute of Resources Recycling, 2020
English, International conference proceedings

Estimation of settling velocity and jig separation efficiency of non-spherical plastics using flatness ratio
Theerayut Phengsaart; Arisa Azuma; Daiki Kitayama; Sanghee Jeon; Ilhwan Park; Carlito Baltazar Tabelin; Naoki Hiroyoshi; Mayumi Ito
15th International Symposium on East Asian Resources Recycling Technology, EARTH 2019, The Korean Institute of Resources Recycling, 2020
English, International conference proceedings

Effects of particle geometry on the bubble attachment during hybrid jig separation
Theerayut Phengsaart; Arisa Azuma; Daiki Kitayama; Shoko Kimura; Sumetas Rittiboon; Apiset Wongthanuwat; Dawan Wiwattanadate; Sanghee Jeon; Ilhwan Park; Carlito Baltazar Tabelin; Naoki Hiroyoshi; Mayumi Ito
15th International Symposium on East Asian Resources Recycling Technology, EARTH 2019, The Korean Institute of Resources Recycling, 2020
English, International conference proceedings

Improved pyrolysis behavior of ammonium polyphosphate-melamine-expandable (APP-MEL-EG) intumescent fire retardant coating system using ceria and dolomite as additives for I-beam steel application
Joshua B. Zoleta; Gevelyn B. Itao; Vannie Joy T. Resabal; Arnold A. Lubguban; Ryan D. Corpuz; Mayumi Ito; Naoki Hiroyoshi; Carlito Baltazar Tabelin
Heliyon, 6, 1, Elsevier Ltd, 01 Jan. 2020
English, Scientific journal

Enhanced cementation of gold via galvanic interactions using activated carbon and zero-valent aluminum: A novel approach to recover gold ions from ammonium thiosulfate medium
Sanghee Jeon; Carlito Baltazar Tabelin; Hirotaka Takahashi; Ilhwan Park; Mayumi Ito; Naoki Hiroyoshi
Hydrometallurgy, 191, Elsevier B.V., 01 Jan. 2020
English, Scientific journal

Effects of galvanic interactions between lead-activated sphalerite and pyrite on flotation
K. Aikawa; T. Segawa; S. Jeon; I. Park; C. B. Tabelin; N. Hiroyoshi; M. Ito
15th International Symposium on East Asian Resources Recycling Technology, EARTH 2019, 2020
International conference proceedings

Carrier-microencapsulation of arsenopyrite using Al-catecholate complex: nature of oxidation products, effects on anodic and cathodic reactions, and coating stability under simulated weathering conditions
Ilhwan Park; Carlito Baltazar Tabelin; Kensuke Seno; Sanghee Jeon; Hiroyuki Inano; Mayumi Ito; Naoki Hiroyoshi
Heliyon, 6, 1, e03189, e03189, Elsevier BV, Jan. 2020, [Peer-reviewed]
Scientific journal

Ammonium thiosulfate extraction of gold from printed circuit boards (PCBs) of end-of-life mobile phones and its recovery from pregnant leach solution by cementation
Sanghee Jeon; Carlito Baltazar Tabelin; Ilhwan Park; Yoshito Nagata; Mayumi Ito; Naoki Hiroyoshi
Hydrometallurgy, 191, 105214, 105214, Elsevier BV, Jan. 2020, [Peer-reviewed]
Scientific journal

Development of advanced pyrite passivation strategies towards sustainable management of acid mine drainage
C. B. Tabelin; I. Park; X. Li; S. Seng; M. Villacorte-Tabelin; T. Igarashi; M. Ito; N. Hiroyoshi
IOP Conference Series: Earth and Environmental Science, 351, 1, Institute of Physics Publishing, 28 Oct. 2019
English, International conference proceedings

Hematite-catalysed scorodite formation as a novel arsenic immobilisation strategy under ambient conditions
Tabelin Carlito Baltazar; Corpuz Ryan D; Iarashi Toshifumi; Villacorte-Tabelin Mylah; Ito Mayumi; Hiroyoshi Naoki
CHEMOSPHERE, 233, 946, 953, Oct. 2019, [Peer-reviewed]

A review of recent strategies for acid mine drainage prevention and mine tailings recycling
Park Ilhwan; Tabelin Carlito Baltazar; Jeon Sanghee; Li Xinlong; Seno Kensuke; Ito Mayumi; Hiroyoshi Naoki
CHEMOSPHERE, 219, 588, 606, Mar. 2019, [Peer-reviewed]

Suppressive effects of ferric-catecholate complexes on pyrite oxidation
Li Xinlong; Hiroyoshi Naoki; Tabelin Carlito Baltazar; Naruwa Kosuke; Harada Chie; Ito Mayumi
CHEMOSPHERE, 214, 70, 78, Jan. 2019, [Peer-reviewed]

Galvanic Microencapsulation (GME) Using Zero-Valent Aluminum and Zero-Valent Iron to Suppress Pyrite Oxidation
Seng Sophea; Tabelin Carlito Baltazar; Kojima Motoya; Hiroyoshi Naoki; Ito Mayumi
MATERIALS TRANSACTIONS, 60, 2, 277, 286, 2019, [Peer-reviewed]

Formation of surface protective coatings on arsenopyrite using Al-catecholate complex and its mode of inhibition of arsenopyrite oxidation
Park Ilhwan; Tabelin Carlito; Inano Hiroyuki; Seno Kensuke; Higuchi Kazuki; Ito Mayumi; Hiroyoshi Naoki
25TH REGIONAL SYMPOSIUM ON CHEMICAL ENGINEERING (RSCE 2018), 268, 2019, [Peer-reviewed]

Carrier-microencapsulation using Al-catecholate complex to suppress arsenopyrite oxidation: Evaluation of the coating stability under simulated weathering conditions
Seno Kensuke; Park Ilhwan; Tabelin Carlito; Magaribuchi Kagehiro; Ito Mayumi; Hiroyoshi Naoki
25TH REGIONAL SYMPOSIUM ON CHEMICAL ENGINEERING (RSCE 2018), 268, 2019, [Peer-reviewed]

Prediction of acid mine drainage formation and zinc migration in the tailings dam of a closed mine, and possible countermeasures
Tabelin Carlito; Sasaki Asuka; Igarashi Toshifumi; Tomiyama Shingo; Villacorte-Tabelin Mylah; Ito Mayumi; Hiroyoshi Naoki
25TH REGIONAL SYMPOSIUM ON CHEMICAL ENGINEERING (RSCE 2018), 268, 2019, [Peer-reviewed]

CeO2-dolomite as fire retardant additives on the conventional intumescent coating in steel substrate for improved performance
Zoleta Joshua; Itao Gevelyn; Joy Resabal Vannie; Lubguban Arnold; Corpuz Ryan; Tabelin Carlito; Ito Mayumi; Hiroyoshi Naoki
25TH REGIONAL SYMPOSIUM ON CHEMICAL ENGINEERING (RSCE 2018), 268, 2019, [Peer-reviewed]

Arsenic, selenium, boron, lead, cadmium, copper, and zinc in naturally contaminated rocks: A review of their sources, modes of enrichment, mechanisms of release, and mitigation strategies
Tabelin Carlito Baltazar; Igarashi Toshifumi; Villacorte-Tabelin Mylah; Park Ilhwan; Opiso Einstine M; Ito Mayumi; Hiroyoshi Naoki
SCIENCE OF THE TOTAL ENVIRONMENT, 645, 1522, 1553, 15 Dec. 2018, [Peer-reviewed]

Improvement of jig efficiency by shape separation, and a novel method to estimate the separation efficiency of metal wires in crushed electronic wastes using bending behavior and "entanglement factor"
Phengsaart Theerayut; Ito Mayumi; Hamaya Naoki; Tabelin Carlito Baltazar; Hiroyoshi Naoki
MINERALS ENGINEERING, 129, 54, 62, Dec. 2018, [Peer-reviewed]

Interference of coexisting copper and aluminum on the ammonium thiosulfate leaching of gold from printed circuit boards of waste mobile phones
Jeon Sanghee; Tabelin Carlito Baltazar; Takahashi Hirotaka; Park Ilhwan; Ito Mayumi; Hiroyoshi Naoki
WASTE MANAGEMENT, 81, 148, 156, Nov. 2018, [Peer-reviewed]

Simultaneous suppression of acid mine drainage formation and arsenic release by Carrier-microencapsulation using aluminum-catecholate complexes (vol 205C, pg 414, 2018)
Park Ilhwan; Tabelin Carlito Baltazar; Seno Kensuke; Jeon Sanghee; Ito Mayumi; Hiroyoshi Naoki
CHEMOSPHERE, 209, 1021, Oct. 2018, [Peer-reviewed]

Simultaneous suppression of acid mine drainage formation and arsenic release by Carrier-microencapsulation using aluminum-catecholate complexes
Ilhwan Park; Carlito Baltazar Tabelin; Kensuke Seno; Sanghee Jeon; Mayumi Ito; Naoki Hiroyoshi
Chemosphere, 205, 414, 425, 01 Aug. 2018, [Peer-reviewed]
English, Scientific journal

Lead generation and separation mechanisms from lead silicate glass by reduction-melting
Inano Hiroyuki; Tomita Keiichi; Tada Tatsumi; Hiroyoshi Naoki
JOURNAL OF THE CERAMIC SOCIETY OF JAPAN, 126, 8, 595, 601, Aug. 2018, [Peer-reviewed]
Scientific journal

Gold recovery from shredder light fraction of E-waste recycling plant by flotation-ammonium thiosulfate leaching
Sanghee Jeon; Mayumi Ito; Carlito Baltazar Tabelin; Rongrit Pongsumrankul; Naho Kitajima; llhwan Park; Naoki Hiroyoshi
Waste Management, 77, 195, 202, 01 Jul. 2018, [Peer-reviewed]
English, Scientific journal

Suppression of the release of arsenic from arsenopyrite by carrier-microencapsulation using Ti-catechol complex
Ilhwan Park; Carlito Baltazar Tabelin; Kagehiro Magaribuchi; Kensuke Seno; Mayumi Ito; Naoki Hiroyoshi
Journal of Hazardous Materials, 344, 322, 332, 15 Feb. 2018, [Peer-reviewed]
English, Scientific journal

Magnetic separation of rare earth ore from from Khalzan Burgedei peralkaline rare earth deposit, Mongolia
G. Purevdelger; M. Ito; N. Sato; C.B. Tabelin; N. Hiroyoshi; J. Sereenen
Proc. of the 4th International Conference and Exhibition (Mineral Processing 2018), 21, 23, 2018
English

Simultaneous leaching of arsenite, arsenate, selenite and selenate, and their migration in tunnel-excavated sedimentary rocks: II. Kinetic and reactive transport modeling
Carlito Baltazar Tabelin; Ryosuke Sasaki; Toshifumi Igarashi; Ilhwan Park; Shuichi Tamoto; Takahiko Arima; Mayumi Ito; Naoki Hiroyoshi
CHEMOSPHERE, 188, 444, 454, Dec. 2017, [Peer-reviewed]
English, Scientific journal

Simultaneous leaching of arsenite, arsenate, selenite and selenate, and their migration in tunnel-excavated sedimentary rocks: I. Column experiments under intermittent and unsaturated flow
Carlito Baltazar Tabelin; Ryosuke Sasaki; Toshifumi Igarashi; Ilhwan Park; Shuichi Tamoto; Takahiko Arima; Mayumi Ito; Naoki Hiroyoshi
CHEMOSPHERE, 186, 558, 569, Nov. 2017, [Peer-reviewed]
English, Scientific journal

Pyrite oxidation in the presence of hematite and alumina: II. Effects on the cathodic and anodic half-cell reactions
Carlito Baltazar Tabelin; Suchol Veerawattananun; Mayumi Ito; Naoki Hiroyoshi; Toshifumi Igarashi
SCIENCE OF THE TOTAL ENVIRONMENT, 581, 126, 135, Mar. 2017, [Peer-reviewed]
English, Scientific journal

Pyrite oxidation in the presence of hematite and alumina: I. Batch leaching experiments and kinetic modeling calculations
Carlito Baltazar Tabelin; Suchol Veerawattananun; Mayumi Ito; Naoki Hiroyoshi; Toshifumi Igarashi
SCIENCE OF THE TOTAL ENVIRONMENT, 580, 687, 698, Feb. 2017, [Peer-reviewed]
English, Scientific journal

Effects of pyrite and pyrrhotite on the flotation of lead-activated sphalerite
Mayumi ITO; Tatusya SEGAWA; Yoji Minoura; Tsuyoshi Horiguchi; Carlito Baltazar Tabelin; Naoki HIROYOSHI
the 28th International Mineral Processing Congress, 2016
English, Symposium

A Study on the Utilization of Magnetite for the Recovery of Platinum Group Metals from Chloride Solution
Peet Homchuen; Richard Diaz Alorro; Naoki Hiroyoshi; Ryo Sato; Hajime Kijitani; Mayumi Ito
MINERAL PROCESSING AND EXTRACTIVE METALLURGY REVIEW, 37, 4, 246, 254, 2016, [Peer-reviewed]
English, Scientific journal

Electrochemical Investigation of Gold Uptake From Chloride Solution by Magnetite
Richard Diaz Alorro; Naoki Hiroyoshi; Hajime Kijitani; Mayumi Ito; Masami Tsunekawa
MINERAL PROCESSING AND EXTRACTIVE METALLURGY REVIEW, 36, 5, 332, 339, Sep. 2015, [Peer-reviewed]
English, Scientific journal

Short and long term release mechanisms of arsenic, selenium and boron from a tunnel-excavated sedimentary rock under in situ conditions
Shuichi Tamoto; Carlito Baltazar Tabelin; Toshifumi Igarashi; Mayumi Ito; Naoki Hiroyoshi
JOURNAL OF CONTAMINANT HYDROLOGY, 175, 60, 71, Apr. 2015, [Peer-reviewed]
English, Scientific journal

Stability of As(V)-sorbed schwertmannite under porphyry copper mine conditions
Sengpasith HoungAloune; Naoki Hiroyoshi; Mayumi Ito
MINERALS ENGINEERING, 74, 51, 59, Apr. 2015, [Peer-reviewed]
English

The use of schwertmannite for arsenic immobilization in copper flotation tailings
Sengpasith Houngaloune; Naoki Hiroyoshi; Mayumi Ito; Masato Fujimura
Proceedings - European Metallurgical Conference, EMC 2015, 1, 161, 169, GDMB Verlag GmbH, 2015
English, International conference proceedings

Effect of Fe(II) and Cu(II) on transformation of schwertmannite to goethite
S. Houngaloune; N. Hiroyoshi; M. Ito
International Journal of Chemical Engineering and Applications, 6, 1, 32, 37, 2015, [Peer-reviewed]
English, Scientific journal

Influences of electrolyte concentration on subcritical crack growth in sandstone in water
Yoshitaka Nara; Ryo Nakabayashi; Megumi Maruyama; Naoki Hiroyoshi; Tetsuro Yoneda; Katsuhiko Kaneko
ENGINEERING GEOLOGY, 179, 41, 49, Sep. 2014, [Peer-reviewed]
English, Scientific journal

Study on schwertmannite production from copper heap leach solutions and its efficiency in arsenic removal from acidic sulfate solutions
Sengpasith HoungAloune; Takahiro Kawaai; Naoki Hiroyoshi; Mayumi Ito
HYDROMETALLURGY, 147, 30, 40, Aug. 2014, [Peer-reviewed]
English, Scientific journal

Preparation of Fe/Al Composite for Metal Recovery
M Ito; K Sukegawa; N Hiroyoshi
12th Int. Symp. East Asian Recycling Technology, 293, 296, 2013
English, International conference proceedings

Flotation of anode slime in copper electro-refining
M Ito; T Ikemoto; N Hiroyoshi
12th Int. Symp. East Asian Recycling Technology, 954, 957, 2013
English, International conference proceedings

Separation of polyethylene and cross-linked polyethylene using a reverse hybrid jig
M Ito; A Saito; N Murase; N Hamaya; M Takeuchi; N Hiroyoshi
ASEAN++2013, 2013
English, International conference proceedings

Application of reductive melting process of CRT glass for recovering valuable metals from PCB waste
N Hiroyoshi; H Prin; Y Takaya; M Ito
ASEAN++2013, 2013
English, International conference proceedings

Technological development in jig separation and approaches to adovance in separation
M Tsunekawa; M Ito; N Hiroyoshi
Journal of MMIJ, 129, 284, 289, 2013, [Peer-reviewed]
Japanese, Scientific journal

A method for determining optimum water pulsation parameter in jig separatiin using pressure and level sensors and its application to separation of fine particles
M Tusnekawa; J Akimoto; W Ogiko; S Ochi; N Hiroyoshi; M Ito
Journal of MMIJ, 129, 284, 289, 2013, [Peer-reviewed]
Japanese, Scientific journal

Advanced jig separation technology for resource recycling and mineral processing
Mayumi Ito; Naoki Hiroyoshi; Masami Tsunekawa
Proc. of The 5th Regional Conference on Geological Engineering, 13, 18, 2013, [Peer-reviewed]
English, International conference proceedings

SELECTIVE COMMINUTION AND MAGNETIC SEPARATION OF RARE-EARTH ORE FROM DONG PAO, VIETNAM
M Ito; M Takamatsu; K Asakura; C Nisikawa; N Hiroyoshi; M Tsunekawa
23rd World mining congress, 775, 2013, [Peer-reviewed]
English, International conference proceedings

STABILIZATION OF ARSENIC IN THE MINING AND METALLURGICAL INDUSTRIES? A REVIEW
S Houngaloune; N Hiroyoshi; M Ito; F Masato
23rd World mining congress, 777, 2013, [Peer-reviewed]
English, International conference proceedings

Coagulation flotation of anode slime in copper electro-refining
M Ito; T Ikemoto; N Hiroyoshi
Proc. of 3rd Joint seminar on Geo-environmental engineering & recycling, 54, 2013
English, International conference proceedings

Mineral processing of rare-earth ore from Kipawa, Canada
M Ito; M Takamatsu; K Ono; N Hiroyoshi
Proc. of 3rd Joint seminar on Geo-environmental engineering & recycling, 70, 2013
International conference proceedings

Recovery of the Platinum Group Metals from the Chloride Solution by Synthesized Magnetite and Slag Magnetite
N Hiroyoshi; R Sato; P Homchuen; M Ito
Proc. of 3rd Joint seminar on Geo-environmental engineering & recycling, 19, 2013
International conference proceedings

Preparation and Evaluation of Fe/Al composite for metal recovery
M Ito; K Sukegawa; N Hiroyoshi
Proc. of 3rd Joint seminar on Geo-environmental engineering & recycling, 48, 2013
English, International conference proceedings

Newly developed discharge device for jig separation of plastics to recover higher grade bottom layer product
Masami Tsunekawa; Riki Kobayashi; Kunihiro Hori; Hideaki Okada; Naka Abe; Naoki Hiroyoshi; Mayumi Ito
INTERNATIONAL JOURNAL OF MINERAL PROCESSING, 114, 27, 29, Nov. 2012, [Peer-reviewed]
English, Scientific journal

Influence of relative humidity on fracture toughness of rock: Implications for subcritical crack growth
Yoshitaka Nara; Kazuya Morimoto; Naoki Hiroyoshi; Tetsuro Yoneda; Katsuhiko Kaneko; Philip M. Benson
INTERNATIONAL JOURNAL OF SOLIDS AND STRUCTURES, 49, 18, 2471, 2481, Sep. 2012, [Peer-reviewed]
English, Scientific journal

Recovery and immobilization of lead in cathode ray tube funnel glass by a combination of reductive and oxidative melting processes
Takashi Okada; Hiroyuki Inano; Naoki Hiroyoshi
JOURNAL OF THE SOCIETY FOR INFORMATION DISPLAY, 20, 9, 508, 516, Sep. 2012, [Peer-reviewed]
English

Effect of particle shape on hydrocyclone classification
Kouki Kashiwaya; Takahiko Noumachi; Naoki Hiroyoshi; Mayumi Ito; Masami Tsunekawa
POWDER TECHNOLOGY, 226, 147, 156, Aug. 2012, [Peer-reviewed]
English, Scientific journal

Effect of water addition on centrifugal treatment to remove lead compounds from polyvinylchloride in electric wires and cables
Masami Tsunekawa; Mayumi Ito; Yoshiaki Nakamura; Yuta Sasaki; Tomoo Sakai; Naoki Hiroyoshi
SEPARATION AND PURIFICATION TECHNOLOGY, 89, 94, 97, Mar. 2012, [Peer-reviewed]
English, Scientific journal

Mineral processing of deep-sea ores ”, The 4th Regional Conference on Geological Engineering
M.Ito; S. Futakuchi; K. Asakura; N. Hiroyoshi
The 4th Regional Conference on Geological Engineering“Research-based Education in Geological and Geo-resources Engineering for Sustainable Development in ASEAN Region, 2012, [Peer-reviewed]
English, International conference proceedings

A Study on the Utilization of Magnetite for The Recovery of Platinum Group Metals from Chloride Solution
P. Homchuen; M. Ito; N. Hiroyoshi
The 4th Regional Conference on Geological Engineering“Research-based Education in Geological and Geo-resources Engineering for Sustainable Development in ASEAN Region, 2012, [Peer-reviewed]
English, Scientific journal

Plastic-plastic separation using advanced jig separation technology
Mayumi Ito; Megumi Takeuchi; Naoki Hiroyoshi
Proc of the 6th International Workshop and Conference on Earth Resources Technology, 2012, [Peer-reviewed]
English, Scientific journal

Hybrid jig separation of plastic particles-A case of a separation of Nylon and PVC-
Mayumi Ito; Megumi Takeuchi; Naoki Hiroyoshi
Proc. of Int. Symposium on earth science technology 2012, 315, 317, 2012, [Peer-reviewed]
English, International conference proceedings

SUPPRESSION OF PYRITE OXIDATION BY CARRIER MICROENCAPSULATION USING SILICON AND CATECHOL
Rani Kumari Thakur Jha; Jacqueline Satur; Naoki Hiroyoshi; Mayumi Ito; Masami Tsunekawa
MINERAL PROCESSING AND EXTRACTIVE METALLURGY REVIEW, 33, 2, 89, 98, 2012, [Peer-reviewed]
English, Scientific journal

Evaluation of entanglement properties of crushed automobile shredded residue and detachment of entrapped particles
Yutaka Kuwayama; Mayumi Ito; Maiko Akatsuka; Naoki Hiroyoshi; Masami Tsunekawa
JOURNAL OF MATERIAL CYCLES AND WASTE MANAGEMENT, 13, 2, 156, 163, Aug. 2011, [Peer-reviewed]
English, Scientific journal

Removal of lead compounds from polyvinylchloride in electric wires and cables using cation-exchange resin
Masami Tsunekawa; Mayumi Ito; Yuta Sasaki; Tomoo Sakai; Naoki Hiroyoshi
JOURNAL OF HAZARDOUS MATERIALS, 191, 1-3, 388, 392, Jul. 2011, [Peer-reviewed]
English, Scientific journal

Suppression of floatability of pyrite in coal processing by carrier microencapsulation
Rani Kumari Thakur Jha; Jacqueline Satur; Naoki Hiroyoshi; Mayumi Ito; Masami Tsunekawa
FUEL PROCESSING TECHNOLOGY, 92, 5, 1032, 1036, May 2011, [Peer-reviewed]
English, Scientific journal

Effects of humidity and temperature on subcritical crack growth in sandstone
Yoshitaka Nara; Kazuya Morimoto; Tetsuro Yoneda; Naoki Hiroyoshi; Katsuhiko Kaneko
INTERNATIONAL JOURNAL OF SOLIDS AND STRUCTURES, 48, 7-8, 1130, 1140, Apr. 2011, [Peer-reviewed]
English, Scientific journal

Gold Recovery from Clolide Solution Using Copper Convertor Slag
N. Hiroyoshi; H. Kijitani; R.D. Alorro; M. Ito; M. Tsunekawa
Proceedings of 11th Int. Symp. East Asian Recycling Technology, 442, 445, 2011, [Peer-reviewed]
English, International conference proceedings

Mineral Processing of Rare-Earth Ore from Dongpao
M. Ito; C. Nishikawa; N. Hiroyoshi; M. Tsunekawa
Proc of the 5th International Workshop and Conference on Earth Resources Technology, 40, 42, 2011, [Peer-reviewed]
English, International conference proceedings

Recovery and immobilization of lead in cathode ray tube funnel glass by a combination of reductive and oxidative melting processes
Takashi Okada; Hiroyuki Inano; Naoki Hiroyoshi
IDW'11: PROCEEDINGS OF THE 18TH INTERNATIONAL DISPLAY WORKSHOPS, VOLS 1-3, 617, 620, 2011, [Peer-reviewed]
English, International conference proceedings

Estimating the size distribution of anode and cathode activating agents in the crushed products of nickel metal hydride batteries from hybrid vehicles and its classification
Mayumi Ito; Kouki Kashiwaya; Naohiro Sumiya; Hisatoshi Furuya; Naoki Hiroyoshi; Masami Tsunekawa
INTERNATIONAL JOURNAL OF MINERAL PROCESSING, 97, 1-4, 92, 95, Nov. 2010, [Peer-reviewed]
English, Scientific journal

Reverse jig separation of shredded floating plastics separation of polypropylene and high density polyethylene
Mayumi Ito; Masami Tsunekawa; Emi Ishida; Koki Kawai; Tatsuru Takahashi; Naka Abe; Naoki Hiroyoshi
INTERNATIONAL JOURNAL OF MINERAL PROCESSING, 97, 1-4, 96, 99, Nov. 2010, [Peer-reviewed]
English, Scientific journal

Effects of relative humidity and temperature on subcritical crack growth in igneous rock
Yoshitaka Nara; Naoki Hiroyoshi; Tetsuro Yoneda; Katsuhiko Kaneko
INTERNATIONAL JOURNAL OF ROCK MECHANICS AND MINING SCIENCES, 47, 4, 640, 646, Jun. 2010, [Peer-reviewed]
English, Scientific journal

Effect of chloride ions on leaching rate of chalcopyrite
Kyoungkeun Yoo; Soo-kyung Kim; Jae-chun Lee; Mayumi Ito; Masami Tsunekawa; Naoki Hiroyoshi
MINERALS ENGINEERING, 23, 6, 471, 477, May 2010, [Peer-reviewed]
English, Scientific journal

Effect of temperature on precipitation of calcium carbonate using soil microorganisms
Kawasaki, S; Ogata, S; Hiroyoshi, N; Tsunekawa, M; Kaneko, K; Terajima, R
Journal of Japan Society of Engineering Geology, 51, 1, 10, 18, Japan Society of Engineering Geology, 2010, [Peer-reviewed]
Japanese, Scientific journal, We have been performing fundamental laboratory tests in order to develop a novel conceptual grout, hereafter called biogrout. Hardened biogrout consists primarily of calcium carbonate or silica, typical cement elements in soil and rock. These compounds can fill the voids and cracks in soil and rock using microbial metabolism. This paper reports some test results for biogrout using calcium carbonate and discusses them. We performed a series of precipitation tests on calcium carbonate in test tubes using soil microorganisms sampled from various parts of Japan, examining the effect of temperature on the precipitation of calcium carbonate when testing. As a result, it was indicated that precipitation of calcium carbonate using soil microorganisms occurred at temperatures ranging from 5 to 35°C. Furthermore, we measured the number of soil microorganisms used in the tests and conducted gene analyses of them. The phases of soil microorganisms before testing were compared to those after testing by determining the number of living soil microorganisms, the highest relative frequency of soil microorganisms, and their attributive taxonomical groups. In consequence, it is possible that fungi such as the Penicillium and Aspergillus species frequently metabolized organic nutrition, and at the same time their number increased via their metabolism.

Mineral processing of deep-sea hydrothermal deposit ores
M. Ito; T. Takahashi; S. Futakuchi; N. Hiroyoshi; M. Tsunekawa
Proc of the 4th International Workshop and Conference on Earth Resources Technology, 2010, [Peer-reviewed]
English, International conference proceedings

On the Use of Magnetite for Gold Recovery From Chloride Solution
Richard Diaz Alorro; Naoki Hiroyoshi; Hajime Kijitani; Mayumi Ito; Masami Tsunekawa
MINERAL PROCESSING AND EXTRACTIVE METALLURGY REVIEW, 31, 4, 201, 213, 2010, [Peer-reviewed]
English, Scientific journal

Development of a New Gravity Separator for Plastics -a Hybrid-Jig
Kunihiro Hori; Masami Tsunekawa; Masatsune Ueda; Naoki Hiroyoshi; Mayumi Ito; Hideaki Okada
MATERIALS TRANSACTIONS, 50, 12, 2844, 2847, Dec. 2009, [Peer-reviewed]
English, Scientific journal

Anode activating agent recovery by magnetic separation from the < 0.075 mm fraction of crushed nickel metal hydride batteries from hybrid vehicles
Mayumi Ito; Kouki Kashiwaya; Naohiro Sumiya; Naoki Hiroyoshi; Masami Tsunekawa
SEPARATION AND PURIFICATION TECHNOLOGY, 69, 2, 149, 152, Sep. 2009, [Peer-reviewed]
English, Scientific journal

Optimum water pulsation of jig separation for crushed plastic particles
Kunihiro Hori; Masami Tsunekawa; Naoki Hiroyoshi; Mayumi Ito
INTERNATIONAL JOURNAL OF MINERAL PROCESSING, 92, 3-4, 103, 108, Aug. 2009, [Peer-reviewed]
English, Scientific journal

Recovery of heavy metals from MSW molten fly ash by CIP method
Richard Diaz Alorro; Naoki Hiroyoshi; Mayumi Ito; Masami Tsunekawa
HYDROMETALLURGY, 97, 1-2, 8, 14, Jun. 2009, [Peer-reviewed]
English, Scientific journal

Subcritical crack growth in rocks in an aqueous environment
NARA Yoshitaka; TAKADA Masafumi; IGARASHI Toshifumi; HIROYOSHI Naoki; KANEKO Katsuhiko
Geophysical exploration, 62, 1, 163, 171, 物理探査学会, Mar. 2009, [Peer-reviewed]
Japanese, Scientific journal

Effect of temperature on rate of CaCO₃ precipitation for biogrouting process
Ogata, S; Kawasaki, S; Hiroyoshi, N; Tsunekawa, M; Kaneko, K; Terajima, R
Proceedings of 3rd International Workshop and Conference on Earth Resources Technology, 12, 17, 2009, [Peer-reviewed]
English, International conference proceedings

微生物代謝を利用したグラウトにおける炭酸カルシウム析出の温度依存性
小潟 暁; 川﨑 了; 広吉直樹; 恒川昌美; 金子勝比古; 寺島 麗
第38回岩盤力学に関するシンポジウム講演論文集, 120, 124, 2009
Japanese, Symposium

Removal of Lead from PVC in Electric Wires and Cables
M. Tsunekawa; J. Mimura; T. Sakai; Y. Nakamura; Y. Sasaki; M. Ito; N. Hiroyoshi
Proceedings of EcoDesign2009, OS-3A-9, 2009, [Peer-reviewed]
English, International conference proceedings

Physical Separation of Shredder Residue of Plastics used in Home Appliances -Gravity separation using advanced jig separation technology-
M. Ito; M. Akatsuka; Y. Kuwayama; K. Hori; E. Ishida; N. Hiroyoshi; M. Tsunekawa
Proceedings of EcoDesign2009, OS-3A-8, 2009, [Peer-reviewed]
English, International conference proceedings

Physical Separation of Crushed Nickel-metal Hydride Battery Components for Recycling
M. Ito; K. Kashiwaya; N. Sumiya; H. Furuya; N. Hiroyoshi; M. Tsunekawa
Proceedings of EcoDesign2009, OS-3A-7, 2009, [Peer-reviewed]
English, International conference proceedings

Characterization of ASR for Recovering Low Chloride Fuel and Metals by Physical Separation
Y. Kuwayama; M. Ito; M. Akatsuka; N. Hiroyoshi; M. Tsunekawa
Proceedings of 10th Int. Symp. East Asian Recycling Technology, 636, 639, 2009, [Peer-reviewed]
English, International conference proceedings

Review of Treatment of Ocean-floor Resources -Recovery Methods for Rare Metals
M. Ito; T. Takahashi; K. Sekimura; N. Hiroyoshi; Masami Tsunekawa
Proceedings of 10th Int. Symp. East Asian Recycling Technology, 302, 305, 2009, [Peer-reviewed]
English, International conference proceedings

Application of Electric Ddisintegration Method for Gold Containing Complex Waste Rocks of the Lepanto Mine
M. Ito; T. Hamano; N. Hiroyoshi; M. Tsunekawa
Proceedings of 10th Int. Symp. East Asian Recycling Technology, 270, 273, 2009, [Peer-reviewed]
English, International conference proceedings

Wet Treatment of ASR to Obtain Solid Fuel - Removal of Unburnable Fine Particles Entrapped in the Agglomerates and Their Characte
M. Ito; M. Akatsuka; Y. Kuwayama; N. Hiroyoshi; M. Tsunekawa
Proceedings of 10th Int. Symp. East Asian Recycling Technology, 640, 643, 2009, [Peer-reviewed]
English, International conference proceedings

A Hydrometallurgical Approach to Recover Metals from Primary and Secondary Sources
Richard D. Alorro; Naoki Hiroyoshi; Mayumi Ito; Masami Tsunekawa
Proceedings of 3rd International Workshop and Conference on Earth Resources Technology, 187, 196, 2009, [Peer-reviewed]
English, International conference proceedings

Carrier Micro Encapsulation (CME) for Coal Preparation
Rani Kumari; Thakur Jha; Jacqueline Satur; Naoki Hiroyoshi; Mayumi Ito; Masami Tsunekawa
Proceedings of 3rd International Workshop and Conference on Earth Resources Technology, 197, 203, 2009, [Peer-reviewed]
English, International conference proceedings

Electrical disintegration of gold containing complex waste rocks of the Lepanto mine
Mayumi Ito; Takatoshi Hamano; Naoki Hiroyoshi; Masami Tsunekawa
Proceedings of 3rd International Workshop and Conference on Earth Resources Technology, 204, 211, 2009, [Peer-reviewed]
English, International conference proceedings

Advanced jig separation of cobalt-rich ferromanganese ore
Mayumi Ito; Tatsuru Takahashi; Kengo Sekimura; Kunihiro Hori; Naoki Hiroyoshi; Masami Tsunekawa
Proceedings of 3rd International Workshop and Conference on Earth Resources Technology, 212, 217, 2009, [Peer-reviewed]
English, International conference proceedings

Subcritical crack growth in rocks in an aqueous environment
Yoshitaka Nara; Masafumi Takada; Toshifumi Igarashi; Naoki Hiroyoshi; Katsuhiko Kaneko
EXPLORATION GEOPHYSICS, 40, 1, 163, 171, 2009, [Peer-reviewed]
English, Scientific journal

Removal of Trace Impurity from Limestone Using Flotation Techniques
Masami Tsunekawa; Yugo Honma; Kyoungkeun Yoo; Naoki Hiroyoshi; Mayumi Ito
MATERIALS TRANSACTIONS, 50, 1, 171, 176, Jan. 2009, [Peer-reviewed]
English, Scientific journal

Recovery of heavy metals from MSW molten fly ash by carrier-in-pulp method: Fe powder as carrier
Richard Diaz Alorro; Shinichi Mitani; Naoki Hiroyoshi; Mayumi Ito; Masami Tsunekawa
MINERALS ENGINEERING, 21, 15, 1094, 1101, Dec. 2008, [Peer-reviewed]
English, Scientific journal

Carrier-microencapsulation using Si-catechol complex for suppressing pyrite floatability
Rani Kumari Thakur Jha; Jacqueline Satur; Naoki Hiroyoshi; Mayumi Ito; Masami Tsunekawa
MINERALS ENGINEERING, 21, 12-14, 889, 893, Nov. 2008, [Peer-reviewed]
English, Scientific journal

Immersion Behavior of Automobile Shredded Residue in Surfactant Solutions and Detachment of Particulate Matter
Mayurni Ito; Maiko Akatsuka; Yutaka Kuwayama; Kunihiro Hori; Naoki Hiroyoshi; Masami Tsunekawa
MATERIALS TRANSACTIONS, 49, 10, 2371, 2376, Oct. 2008, [Peer-reviewed]
English, Scientific journal

Attempts to Improve Education at Course of Sustainable Resources Engineering, Department of Socio-Environmental Engineering, Faculty of Engineering, Hokkaido University
FUJII Yoshiaki; HIROYOSHI Naoki; HARADA Shusaku; KANEKO Katsuhiko
Journal of Jsee, 56, 5, 36, 41, Japanese Society for Engineering Education, 20 Sep. 2008
Japanese, Department of Resources Engineering, Faculty of Engineering, Hokkaido University, which was renamed to Course of Sustainable Resources Engineering in 2005, was established in 1972 based on Department of Mining. Number of coal mines in Japan rapidly decreased at that time by the governmental policy and the department was not popular with students from the beginning. Students with very low GPA (Maximum GPA was 1.6 in 1981, for example) were distributed to the department and the department was filled with full of dull students. Teachers also lost eagerness for high quality education. A negative spiral was formed and the situation went worse and worse. As time goes, attempts were made to revolutionize the department. One is "Curriculum Petit Committee" . And the other is "Committee for Education System Improvement" . These two committees significantly improved the education in the department. As a result, the department was filled with full of vivid students, and teachers. For exampe, in 2007, students′ maximum, minimum and average GPA was 3.3, 2.0 and 2.5, respectively,

Engineering Education for All University First Year Students Using Playing in the Sand and Blowing Soap Bubbles
TSUNEKAWA Masami; HIROYOSHI Naoki; ITO Mayumi; HIRAJIMA Tsuyoshi
Journal of JSEE, 56, 5, 111, 114, Japanese Society for Engineering Education, 20 Sep. 2008
Japanese, Hokkaido University holds first year student seminars for promoting student ability in communication, presentation, design, and creativity. The authors have held this seminar to students of all faculties, where the research topics were determined by the students themselves from the phenomena or questions relating to children′s games such as playing in the sand and blowing soap bubbles. Then, they planned experimental procedures, discussed, summarized, and presented the results with minimal advice from teachers. After the student presentations the teachers introduced the techniques and equip...

Dispersion-Flocculation Behavior of Fine Lead Particles in an Organic Solvent
Masami Tsunekawa; Yuta Sasaki; Yoshiaki Nakamura; Mayumi Ito; Naoki Hiroyoshi; Kyoung Keun Yoo
MATERIALS TRANSACTIONS, 49, 9, 2119, 2123, Sep. 2008, [Peer-reviewed]
English, Scientific journal

Estimation of degree of liberation in a coarse crushed product of cobalt-rich ferromanganese crust/nodules and its gravity separation
Mayumi Ito; Masami Tsunekawa; Eiji Yamaguchi; Kengo Sekimura; Kouki Kashiwaya; Kunihiro Hori; Naoki Hiroyoshi
INTERNATIONAL JOURNAL OF MINERAL PROCESSING, 87, 3-4, 100, 105, Jul. 2008, [Peer-reviewed]
English, Scientific journal

Effect of solution composition on the optimum redox potential for chalcopyrite leaching in sulfuric acid solutions
Naoki Hiroyoshi; Hiroko Kitagawa; Masami Tsunekawa
HYDROMETALLURGY, 91, 1-4, 144, 149, Mar. 2008, [Peer-reviewed]
English

バイオグラウトにおける炭酸カルシウムの析出に及ぼす温度の影響
川﨑 了; 小潟 暁; 広吉直樹; 恒川昌美; 金子勝比古; 寺島 麗
地盤工学会北海道支部技術報告集, 48, 27, 30, 2008
Japanese, Symposium

Carrier-in-Pulp Method as a New Hydrometallurgical Route to Reject and Recover Heavy Metals from MSW Melting Fly Ash
R. D. Alorro; S. Mitani; N. Hiroyoshi; M. Ito; M. Tsunekawa
Proceedings of The 22nd International Conference on Solid Waste Technology and Management, 270, 276, 2008, [Peer-reviewed]
English, International conference proceedings

Selective crushing of cobalt-rich ferromanganese ores and flotation of the fine size product
M. Ito; K. Kashiwaya; E. Yamaguchi; K. Sekimura; T. Takahashi; N. Hiroyoshi; M. Tsunekawa
Proceedings of The 2nd International Workshop and Conference on Earth Resources Technology, 42, 45, 2008, [Peer-reviewed]
English, International conference proceedings

Optimization of Jig Separation with Fluidization of Particle Layer
K. Hori; M. Tsunekawa; N. Hiroyoshi; M. Ito
Proceedings of 24rd International Mineral Processing Congress, 841, 845, 2008, [Peer-reviewed]
English, International conference proceedings

Rejection and recovery of heavy metals from MSW melting fly ash by carrier-in-pulp method
R. D. Alorro; N. Hiroyoshi; S. Mitani; M. Ito
Proceedings of 24rd International Mineral Processing Congress, 3610, 3617, 2008, [Peer-reviewed]
English, International conference proceedings

Mineral processing of cobalt-rich ferromanganese crust and nodules
M. Ito; M. Tsunekawa; K. Sekimura; E. Yamaguchi; K. Kashiwaya; K. Hori; N. Hiroyoshi
Proceedings of 24rd International Mineral Processing Congress, 806, 812, 2008, [Peer-reviewed]
English, International conference proceedings

Carrier-microencapsulation for preventing pyrite oxidation
Jacqueline Satur; Naoki Hiroyoshi; Masami Tsunekawa; Mayumi Ito; Hideyuki Okamoto
INTERNATIONAL JOURNAL OF MINERAL PROCESSING, 83, 3-4, 116, 124, Sep. 2007, [Peer-reviewed]
English, Scientific journal

The recovery of electrode compounds from waste nickel metal hydride batteries by physical separation techniques
Masami Tsunekawa; Mayumi Ito; Hisatoshi Furuya; Naoki Hiroyoshi
MATERIALS TRANSACTIONS, 48, 5, 1089, 1094, May 2007, [Peer-reviewed]
English, Scientific journal

Carrier-Microencapsulation using Si-Catechol Complex for Suppressing Pyrite Floatability
R .K .T. Jha; J. Satur; N. Hiroyoshi; M. Ito; M. Tsunekawa
Proceedings of MEI's Intern. Flotation '07 Conf, 1, 14, 2007, [Peer-reviewed]
English, International conference proceedings

Development of Wet Recycling Process for Automobile Shredded Residue - Effect of Surfactants on the Wettability of Autmobile Shredded Residue
M. Ito; M. Akatsuka; Y. Kuwayama; K. Hori; N.Hiroyoshi; M. Tsunekawa
Proceedings of 9th Int. Symp. East Asian Recycling Technology, 237, 2007, [Peer-reviewed]
English, International conference proceedings

Dispersion-Floccuration Behavior of Fine Pb Powder in Organic Solvent
M. Tsunekawa; Y. Sasaki; Y. Nakamura; M. Ito; N. Hiroyoshi; K. K. Yoo
Proceedings of 9th Int. Symp. East Asian Recycling Technology, 503, 2007, [Peer-reviewed]
English, International conference proceedings

Physical Separation of Anode and Cathod Activating Agents from Waste Nickel Metal Hydride Batteries
M. Ito; K. Kashiwaya; N. Sumiya; H. Furuya; N.Hiroyoshi; M. Tsunekawa
Proceedings of 9th Int. Symp. East Asian Recycling Technology, 439, 2007, [Peer-reviewed]
English, International conference proceedings

Classification of Fine Hydrophobic Particles Using Hydrocyclone
K. Kashiwaya; T. Noumachi; M. Ito; N.Hiroyoshi; M. Tsunekawa
Proceedings of 9th Int. Symp. East Asian Recycling Technology, 503, 2007, [Peer-reviewed]
English, International conference proceedings

New Washing Method of Lead Contaminated Soil
M. Ito; N. Hokari; M. Takada; N.Hiroyoshi; M. Tsunekawa
Proceedings of 9th Int. Symp. East Asian Recycling Technology, 576, 2007, [Peer-reviewed]
English, International conference proceedings

Development of a New Gravity Concentration Machinery - a Hybrid Jig
K. Hori; M. Tsunekawa; N.Hiroyoshi; M. Ito
Proceedings of 9th Int. Symp. East Asian Recycling Technology, 466, 2007, [Peer-reviewed]
English, International conference proceedings

Development of Wet Recycling Process for Automobile Shredded Residue - Evaluation of Entanglement Properties of Automobile Shredded Residue Crushed Product
M. Ito; Y. Kuwayama; M. Akatsuka; K. Hori; N.Hiroyoshi; M. Tsunekawa
Proceedings of 9th Int. Symp. East Asian Recycling Technology, 187, 2007, [Peer-reviewed]
English, International conference proceedings

Mineral Processing of Cobalt-Rich Manganese Crust and Nodules - Establishment of treatment flow for removal of substrate rock from deep sea mined ore
M. Ito; K. Kashiwaya; E. Yamaguchi; K. Sekimura; K. Hori; N. Hiroyoshi; M. Tsunekawa
Proceedings of 37th Underwater Mining Institute, 2007, [Peer-reviewed]
English, International conference proceedings

Carrier-Microencapsulation for Suppressing Flotability and Oxidation of Pyrite in Copper Mineral Processing
J. Satur; N. Hiroyoshi; M. Ito; M. Tsune
Proceedings of the 6th International Copper-Cobre Conference, 3, 9, 2007, [Peer-reviewed]
English, International conference proceedings

Fundamental study on novel grout cementing due to microbial metabolism
Kawasaki, S; Murao, A; Hiroyoshi, N; Tsunekawa, M; Kaneko, K
Journal of Japan Society of Engineering Geology, 47, 1, 2, 12, Japan Society of Engineering Geology, 2006, [Peer-reviewed]
Japanese, Scientific journal, Natural soil contains approximately 10^7 to 10^9 microorganisms per gram. Considering this large number of microorganisms, it is expected that soil and rock engineering, especially the field of mechanics, may be able to develop a novel eco-friendly technology to improve the scalability of soil and rock. We performed fundamental laboratory tests in order to develop a novel conceptual grout, hereafter denoted as biogrout. Biogrout consists primarily of calcium carbonate, one of the typical cement elements in soil and rock. This compound can fill the voids and cracks in soil and rock using microbial metabolism. We performed separation tests on calcium carbonate in test tubes, examining the effects of several test conditions, including temperature, organic nutrition, and different buffering conditions, on the separation of calcium carbonate when challenged with commercially available dry yeast and microorganisms naturally living in soil. Furthermore, we examined the improvements in the sealability of sand and clay following biogrout improvement, confirming that coefficients of permeability of both soil types decreased by approximately one order of magnitude from those seen for normal soils. Although a number of problems will need to be addressed, these test results indicate that biogrout is a promising candidate to improve ground properties. The development of such a compound has been successful using microbial metabolism.

The recovery of electrode materials from waste nickel metal hydride batteries in a hybrid vehicle
Tsunekawa M; Furuya H; Hiroyoshi N; Ito M; Kitamura O; Ichimura R; Kikuta K
Proceedings of 3rd Japan-Korea International Symposium of Resources Recycling and Materials Science, 59, 73, 2006, [Peer-reviewed]
English, International conference proceedings

Technological Developments in Wet Gravity Separation Processes
TSUNEKAWA Masami; HORI Kunihiro; HIROYOSHI Naoki; ITO Mayumi
Shigen-to-Sozai, 121, 10/11, 467, 473, The Mining and Materials Processing Institute of Japan, 25 Nov. 2005
Japanese, Gravity separation is one of the ancient technologies for mineral processing and is still in widespread use. In recent years, many kinds of machinery for wet gravity separation have been developed and applied to process fine particles and solid waste.<BR>The authors have reviewed newly developed machineries, in addition to the principle of wet gravity separation and conventional machineries. Most of them are conducted in gravitational fields or films of flowing water. The former harnesses the settling behavior of particles in water and the later the movement of particles in films of flowi...

微生物代謝により固化する新しいグラウトに関する基礎的検討
村尾彰了; 川﨑 了; 広吉直樹; 恒川昌美; 金子勝比古
第34回岩盤力学に関するシンポジウム講演論文集, 417, 422, 2005
Japanese, Symposium

Upgrading of Crystalline Limestone by Carrier Flotation
Tsunekawa M; Honma Y; Yoo K; Hiroyoshi N; Ito M
Proceedings of 8th Int. Symp. East Asian Recycling Technology, 221, 224, 2005, [Peer-reviewed]
English, International conference proceedings

The Recovery of Useful Materials from Scrapped Secondary Batteries by Physical Separation Techniques
Tsunekawa M; Furuya H; Hiroyoshi N; Ito M; Kitamura O; Ichimura R; Kikuta K
Proceedings of 8th Int. Symp. East Asian Recycling Technology, 382, 385, 2005, [Peer-reviewed]
English, International conference proceedings

Catalytic Effect of Activated Carbon and Coal on Chalcopyrite Leaching in Sulfuric Acid Solutions
OKAMOTO Hideyuki; NAKAYAMA Ryoichi; KUROIWA Shigeto; HIROYOSHI Naoki; TSUNEKAWA Masami
Journal of MMIJ, 120, 10, 600, 606, The Mining and Materials Processing Institute of Japan, 25 Nov. 2004
Japanese, Activated carbon is known as a catalyst for chalcopyrite leaching in sulfuric acid solutions. This paper compares the effects of six different activated carbon samples on copper extraction from a chalcopyrite concentrate by shaking flask leaching experiments at 303 K under atmospheric conditions. Eight different coals were also evaluated as an alternative to activated carbon.
Except for one activated carbon sample, activated carbon addition enhanced copper extraction. Increases in the weight ratio of activated carbon to the chalcopyrite concentrate caused increases in copper extraction.
The effects of the coals on copper extraction were related to the rank of the coals: Low rank coals like brown coal, which have low fixed carbon contents and high contents of volatile matter, suppress copper extraction, and high rank coals, which contain more fixed carbon and less volatile matter, enhance copper extraction. High rank coals stored under atmospheric conditions over long periods (more than 7 months) suppressed copper extraction, implying that oxidation of the coal surface and its products cause the suppression in copper extraction.
The experimental results are analyzed and discussed with a reaction model for the redox potential dependence of chalcopyrite leaching, which assumes the formation of intermediate Cu₂S by chalcopyrite reduction and a subsequent oxidation of the Cu₂S.

Iron Dissolution Behavior from High Sulfur Refuse and Flotation of High Sulfur Coal in the Leachate of the Refuse
ITO Mayumi; TSUNEKAWA Masami; HIRAJIMA Tsuyoshi; HIROYOSHI Naoki; YAMADA Ryuichi; YUKAWA Kentaro
Shigen-to-Sozai, 117, 12, 961, 966, The Mining and Materials Processing Institute of Japan, 25 Dec. 2001
Japanese, The effects of inhibitors to iron-oxidizing bacteria (Thiobacillus ferrooxidans) on the dissolution of iron species from high sulfur coal refuse (5.75 db% S) were studied in acidic solutions with the bacteria, using sodium lauryl sulfate (SDS) and tannic acid as inhibitors. Flotation experiments of high sulfur coal (4.27 dafb% S) in leachates from the refuse were conducted to remove sulfur.<BR>Compared with tannic acid, SDS inhibited the iron-oxidizing activity of Thiobacillus ferrooxidans more and dissolution of pyrite in high sulfur coal refuse, but SDS did not prevent dissolution of solu...

Recycling. Extraction and Recovery Techniques. Microbiological Treatment.
広吉 直樹; 恒川 昌美
Journal of MMIJ, 113, 12, 958, 961, The Mining and Materials Processing Institute of Japan, 25 Dec. 1997
Japanese

Macroscale Modeling of Geochemistry Influence on Polymer and Low-Salinity Waterflooding in Carbonate Oil Reservoirs
Angelo Kennedy Lino Limaluka; Yogarajah Elakneswaran; Naoki Hiroyoshi, ACS Omega, 05 Apr. 2024
[Image: see text] The enhancement of oil recovery (EOR) through low-salinity waterflooding (LSWF) and the emerging hybrid with a polymer (LSP) has proven to be effective at microscale investigations and cost-effective with ease of operation at field-scale tests. Their application in carbonate oil reservoirs, which typically occur oil-wet, presents a particularly essential capacity given that over half of the global oil reserves are hosted in carbonate formation. However, modeling the mechanisms involved to predict and evaluate the performance of low salinity-based EOR at a large scale is complex and requires the integration of geochemistry in reservoir simulation to upscale the interfacial interactions of crude oil, brine, and rock observed at the micrometer scale. This study presents an integrated approach that combines MRST’s polymer model with PHREEQC geochemical modeling to simulate LSWF at the reservoir scale. Using single-phase and multiphase experimental flooding data for validation, the coupled model was shown to accurately predict effluent ionic and oil recovery profiles. The simulation of LSWF and LSP both exhibited additional tertiary oil recovery, with LSWF and LSP showing 3 and 2%, respectively, which are consistent with previously reported field and core flooding results. Furthermore, the sequential application of formation water (FW), LSWF, and LSP flooding in secondary mode showed a high increase in oil recovery, with oil recovery percentages of 61, 20, and 19%, respectively. However, the FW results were 50% lower compared to regular core flooding due to upscaling limitations. The modeling of vertical and anisotropic permeability heterogeneity effects showed a positive synergy with low-salinity floodings, resulting in a 4% drop and 3 and 1% increase in FW, LSWF, and LSP, respectively. These findings demonstrate the potential of the coupled MRST-PHREEQC model in accurately simulating hydrogeochemical interactions during LSWF/LSP at the reservoir scale, providing valuable insights for the optimization of low salinity-based EOR strategies in carbonate reservoirs., American Chemical Society (ACS)

Concurrent treatment combining extraction and cementation of anglesite for depression of sphalerite floatability
相川公政; 伊藤真由美; 草野敦大; JEON Sanghee; PARK Ilhwan; 広吉直樹, 資源・素材(Web), 2021, 2021

A review of recent advances in depression techniques for flotation separation of cu–mo sulfides in porphyry copper deposits
Ilhwan Park; Seunggwan Hong; Sanghee Jeon; Mayumi Ito; Naoki Hiroyoshi, Metals, 10, 9, 1, 26, 01 Sep. 2020
MDPI AG, English, Book review

Effects of pyrite on the floatability of lead-activated sphalerite in flotation
相川公政; 瀬川達也; JEON Sanghee; PARK Ilhwan; TABELIN Carlito; TABELIN Carlito; 広吉直樹; 伊藤真由美, 資源・素材学会春季大会(Web), 2020, 2020

鉛イオンで活性化された閃亜鉛鉱の浮遊性に及ぼす亜硫酸ナトリウムの影響
草野敦大; 相川公政; JEON Sanghee; PARK Ilhwan; 広吉直樹; 伊藤真由美, 資源・素材学会春季大会(Web), 2020, 2020

銅・亜鉛硫化鉱の浮選における閃亜鉛鉱の浮遊抑制
折井のどか; 相川公政; JEON Sanghee; PARK Ilhwan; 広吉直樹; 伊藤真由美, 資源・素材学会春季大会(Web), 2020, 2020

Effects of several depressants on the floatability of sphalerite in the flotation of copper-zinc sulfides
伊藤真由美; 折井のどか; 相川公政; JEON Sanghee; PARK Ilhwan; 広吉直樹; MAGWANENG Refilwe; 工藤賢太郎; 砂田和也; 高橋達, 資源・素材(Web), 2020, 2020

Effects of lead ion and sodium sulfite concentrations on sphalerite flotation
伊藤真由美; 草野敦大; 相川公政; JEON Sanghee; PARK Ilhwan; 広吉直樹, 資源・素材(Web), 2020, 2020

Improvement of flotation and suppression of pyrite oxidation using phosphate-enhanced galvanic microencapsulation (GME) in a ball mill with steel ball media
Sophea Seng; Carlito Baltazar Tabelin; Yuta Makino; Monyneath Chea; Theerayut Phengsaart; Ilhwan Park; Naoki Hiroyoshi; Mayumi Ito, Minerals Engineering, 143, 01 Nov. 2019

Development of suitable product recovery systems of continuous hybrid jig for plastic-plastic separation
Mayumi Ito; Ayumu Saito; Nana Murase; Theerayut Phengsaart; Shoko Kimura; Carlito Baltazar Tabelin; Naoki Hiroyoshi, Minerals Engineering, 141, 01 Sep. 2019

A physical separation scheme to improve ammonium thiosulfate leaching of gold by separation of base metals in crushed mobile phones
Sanghee Jeon; Mayumi Ito; Carlito Baltazar Tabelin; Rongrit Pongsumrankul; Shinya Tanaka; Naho Kitajima; Ayumu Saito; Ilhwan Park; Naoki Hiroyoshi, Minerals Engineering, 138, 168, 177, 01 Jul. 2019

Suppression of pyrite oxidation by ferric-catecholate complexes: An electrochemical study
Xinlong Li; Min Gao; Naoki Hiroyoshi; Carlito Baltazar Tabelin; Tetsuya Taketsugu; Mayumi Ito, Minerals Engineering, 138, 226, 237, 01 Jul. 2019

複雑硫化鉱浮選における閃亜鉛鉱の浮遊性低下のメカニズム
相川公政; 瀬川達也; 得田敦博; TABELIN Carlito; 広吉直樹; 伊藤真由美, 資源・素材学会春季大会(Web), 2019, 2019

鉛で活性化された閃亜鉛鉱の浮遊性に及ぼすガルバニック相互作用の影響
伊藤真由美; 相川公政; 瀬川達也; JEON Sanghee; PARK Ilhwan; TABELIN Carlito; 広吉直樹, 資源・素材学会北海道支部春季講演会講演要旨集, 2019, 2019

Effects of physical separation as a pretreatment for ammonium thiosulfate leaching of gold from waste mobile phones
S. Jeon; M. Ito; R. Pongsumrankul; S. Tanaka; N. Kitajima; C. B. Tabelin; N. Hiroyoshi, IMPC 2018 - 29th International Mineral Processing Congress, 690, 698, 01 Jan. 2019

Effects of physical separation as a pretreatment for ammonium thiosulfate leaching of gold from waste mobile phones
Jeon; M. Ito; R. Pongsumrankul; S. Tanaka; N. Kitajima; C. B. Tabelin; N. Hiroyoshi, IMPC 2018 - 29th International Mineral Processing Congress, 3790, 3798, 01 Jan. 2019

Improvement of hybrid jig separation efficiency using wetting agents for the recycling of mixed-plastic wastes
Mayumi Ito; Megumi Takeuchi; Ayumu Saito; Nana Murase; Theerayut Phengsaart; Carlito Baltazar Tabelin; Naoki Hiroyoshi; Masami Tsunekawa, Journal of Material Cycles and Waste Management, 01 Jan. 2019

The characterization of crushed printed circuit boards of waste mobile phone and recovery of gold components by hybrid-jig separation
S. Jeon; M. Ito; S. Tanaka; N. Kitajima; C.B. Tabelin; N. Hiroyoshi, Proc. of the 17th Global Joint Seminar on Geo-environmental Engineering,, 192, 197, 2018
English, Summary international conference

Suppression of the release of arsenic from arsenopyrite by titanium- and aluminum-based carrier-microencapsulation
I. Park; C.B. Tabelin; K. Seno; K. Magaribuchi; M. Ito; N. Hiroyoshi, Proc. of the 17th Global Joint Seminar on Geo-environmental Engineering,, 305, 311, 2018
English, Summary international conference

Comparison of electrochemical properties of various metal-catecholate complexes for carrier-microencapsulation
X. Li; C. Harada; I. Park; N. Hiroyoshi; C.B. Tabelin; M. Ito, Proc. of the 17th Global Joint Seminar on Geo-environmental Engineering,, 344, 348, 2018
English, Summary international conference

The roles of soluble phases in the release of geogenic arsenic and selenium from tunnel-excavated rocks of marine origin
C.B. Tabelin; R. Sasaki; T. Igarashi; I. Park; S. Tamoto; T. Arima; M. Ito; N. Hiroyoshi, Proc. of the 17th Global Joint Seminar on Geo-environmental Engineering,, 312, 319, 2018
English, Summary international conference

The effects of particle geometrical properties on the settling velocity of plastic particles in jig separation
T. Phengsaart; A. Azuma; M. Ito; D. Kitayama; S. Kimura; C.B. Tabelin; N. Hiroyoshi, Mining in Asia International Symposium, Bandung, Indonesia, 2018
English, Summary international conference

Improvement of bottom product purity in a continuous jig using a restraining wall
T. Phengsaart; M. Ito; A. Azuma; S. Kimura; K. Hori; H. Tanno; C.B. Tabelin; N. Hiroyoshi, Mining in Asia International Symposium, Bandung, Indonesia, 2018
Japanese, Summary international conference

Effects of iron-catecholate complexes on pyrite oxidation.
X. Li; N. Hiroyoshi; K. Naruwa; C. Harada; C.B. Tabelin; M. Ito, The 6th Joint Seminar on Geo-environment Engineering and Recycling (GER 2018), 2018
English, Summary international conference

Recent advances in jig separation technologies for resources recycling
T. Phengsaart; M. Ito; S. Jeon; A. Azuma; D. Kitayama; S. Kimura; C.B. Tabelin; N. Hiroyoshi, The 6th Joint Seminar on Geo-environment Engineering and Recycling (GER 2018), 2018
English, Summary international conference

Characterization of zinc leaching residue in Kabwe area, Zambia.
M. Silwamba; M. Ito; T. Fukushima; S. Takakuwa; K. Minatogawa; C.B. Tabelin; N. Hiroyoshi; M. Chirwa; K.E. Banda; I. Nyambe, Proc. of 2nd International Kabwe Mine Pollution Amelioration Initiative (KAMPAI) Symposium, Lusaka, Zambia, 2018
English, Summary international conference

Decontamination of zinc leach plant residues: recovery of extracted lead in leach pulp by cementation on ZVI
M. Silwamba; M. Ito; T. Fukushima; C.B. Tabelin; S. Takakuwa; N. Hiroyoshi; M. Chirwa; K.E. Banda; I. Nyambe, Proc. of 2nd International Kabwe Mine Pollution Amelioration Initiative (KAMPAI) Symposium, Lusaka, Zambia, 2018
English, Summary international conference

he effects of geometrical properties of particles on recycling treatment by physical separation techniques: A review
T. Phengsaart; M. Ito; N. Kitajima; A. Azuma; C.B. Tabelin; N. Hiroyoshi, Proceedings of the 10th AUN/SEED-net Regional Conference on Geo-Resource and Geological Engineering, 446, 459, 2017
English, Summary international conference

Effects of metal ions on flotation of sulfide minerals
M. Ito; A. Tokuda; T. Segawa; T Horiguchi; C.B. Tabelin; N. Hiroyoshi, Proceedings of International Symposium on Earth Resources and Management, 2017
English, Summary international conference

Electrochemical studies of chalcopyrite dissolution in acidic chloride solutions
T.T. Nguyen; S. Tsuji; C.B. Tabelin; M. Ito; N. Hiroyoshi, the 14th International Symposium on East Asian Resources Recycling Technology and the Mining and Materials Processing Institute of Japan Fall Meeting, 3, 6, 2017
English, Summary international conference

Distribution of different metals in gravity separation of printed circuit boards from mobile phones using jig separator and Knelson concentrator
S. Tanaka; S. Jeon; N. Kitajima; C.B. Tabelin; N. Hiroyoshi; M. Ito, the 14th International Symposium on East Asian Resources Recycling Technology and the Mining and Materials Processing Institute of Japan Fall Meeting, 23, 28, 2017
English, Summary international conference

Carrier-microencapsulation using Al-catechol complex for suppressing arsenic release from arsenopyrite
I. Park; K. Seno; K. Magaribuchi; C.B. Tabelin; M. Ito; N. Hiroyoshi, the 14th International Symposium on East Asian Resources Recycling Technology and the Mining and Materials Processing Institute of Japan Fall Meeting, 10, 15, 2017
English, Summary international conference

Redox properties of metal complexes with catechol and its derivatives
X. Li; K. Naruwa; C.B. Tabelin; M. Ito; N. Hiroyoshi, the 14th International Symposium on East Asian Resources Recycling Technology and the Mining and Materials Processing Institute of Japan Fall Meeting, 4, 9, 2017
English, Summary international conference

Effects of mechanochemical treatment on the stability of arsenic-loaded schwertmannite
Y. Takeuchi; N. Hiroyoshi; R.D. Alorro; M. Ito; C.B. Tabelin, the 14th International Symposium on East Asian Resources Recycling Technology and the Mining and Materials Processing Institute of Japan Fall Meeting, 16, 21, 2017
English, Summary international conference

Effects of zinc ions and their precipitates on flotation of sulfide minerals under alkaline condition
A. Tokuda; M. Ito; T. Segawa; T. Horiguchi; C.B. Tabelin; N. Hiroyoshi, the 14th International Symposium on East Asian Resources Recycling Technology and the Mining and Materials Processing Institute of Japan Fall Meeting, 2, 4, 2017
English, Summary international conference

Enhanced passivation of pyrite in phosphate solution using ferric-catechol complex and zero-valent iron
C.B. Tabelin; X. Li; S. Seng; M. Kojima; T. Igarashi; M. Ito; N. Hiroyoshi, the 14th International Symposium on East Asian Resources Recycling Technology and the Mining and Materials Processing Institute of Japan Fall Meeting, 8, 13, 2017
English, Summary international conference

Heterocoagulation anf galvanic interaction in mineral processing: A review.
S. Seng; C.B. Tabelin; M. Kojima; Y. Kontani; M. Ito; N. Hiroyoshi, Proceedings of 1st International Kabwe Mine Pollution Amelioration Initiative (KAMPAI) Symposium, 32, 2017
English, Summary international conference

Recovery of gold ions from ammonium thiosulfate solution by aluminum and other conductive particles
S. Jeon; T. H. Takahashi; R. Pongsumrankul; S. Tanaka; C.B. Tabelin; M. Ito; N. Hiroyoshi, Proceedings of 1st International Kabwe Mine Pollution Amelioration Initiative (KAMPAI) Symposium, 32, 2017
English, Summary international conference

Suppressive effects of aluminum-catechol complexes on the release of arsenic from arsenopyrite
I. Park; K. Seno; K. Magaribuchi; C.B. Tabelin; M. Ito; N. Hiroyoshi, Proceedings of 1st International Kabwe Mine Pollution Amelioration Initiative (KAMPAI) Symposium, 31, 2017
English, Summary international conference

Characterization of zinc contaminated mine waste in Kabwe area, Zambia
M. Ito; T. Fukushima; S. Takakuwa; K. Minatogawa; C.B. Tabelin; N. Hiroyoshi, Proceedings of 1st International Kabwe Mine Pollution Amelioration Initiative (KAMPAI) Symposium, 29, 2017
English, Summary international conference

Effects of additional organic functional groups on the redox properties of metal-catecholate complexes
X. Li; K. Naruwa; C.B. Tabelin; M. Ito; N. Hiroyoshi, Proceedings of 1st International Kabwe Mine Pollution Amelioration Initiative (KAMPAI) Symposium, 28, 2017
English, Summary international conference

Effects of particle size and shape during jig separation
T. Phengsaart; M. Ito; A. Azuma; C.B. Tabelin; N. Hiroyoshi, Proceedings of 1st International Kabwe Mine Pollution Amelioration Initiative (KAMPAI) Symposium, 27, 2017
English, Summary international conference

Advanced separation techniques for coarse size fraction of cesium-contaminated soil: Effects of soil particle morphology of soil washing.
M. Ito; S. Takakuwa; K. Minatogawa; C.B. Tabelin; N. Hiroyoshi; Y. Tomida, Proceedings of 1st International Kabwe Mine Pollution Amelioration Initiative (KAMPAI) Symposium, 23, 26, 529, 2017
[地盤工学会], English, Summary international conference

Gravity separation and its application in coal cleaning and resources recycling: A review
T. Phengsaart; M. Ito; C.B. Tabelin; G.C. Eliseo; Y. Makino; A. Azuma; N. Hiroyoshi, Proceedings of Coal Mining and Utilization for Sustainable Development International Conference, Chiang Mai, Thailand, 301, 308, 2017
English, Summary international conference

Development of gold recovery method from ammonium thiosulfate solution using aluminum and activated carbon
S. Jeon; H. Takahashi; C.B. Tabelin; M. Ito; N. Hiroyoshi, Proceedings of International Symposium on Earth Science and Technology, 608, 610, 2017
English, Summary international conference

Redox potential dependence of chalcopyrite leaching in ferric-chloride solution: Effects of temperature and solution composition
N. Hiroyoshi; S. Tsuji; T.T. Nguyen; M. Ito; C.B. Tabelin, Proceedings of International Symposium on Earth Science and Technology, 615, 618, 2017
English, Summary international conference

Effects of aluminum-catechol complexes on pyrite oxidation
I. Park; C.B. Tabelin; K. Seno; K. Magaribuchi; M. Ito; N. Hiroyoshi, Proceedings of International Symposium on Earth Science and Technology, 611, 614, 2017
English, Summary international conference

Suppression of pyrite oxidation using zero-valent iron powder
S. Seng; C.B. Tabelin; M. Kojima; Y. Kontani; M. Ito; N. Hiroyoshi, Proceedings of International Symposium on Earth Science and Technology,, 619, 622, 2017
English, Summary international conference

Synergistic effects of calcium ion and anionic flocculants on coal flotation
M. Ito; Y. Makino; G.C. Eliseu; C.B. Tabelin; N. Hiroyoshi, Proceedings of International Symposium on Earth Science and Technology, 623, 626, 2017
English, Summary international conference

Attachment of iron oxyhydroxides on pyrite and its effects on pyrite oxidation
S. Seng; C.B. Tabelin; Y. Kontani; M. Kojima; M. Ito; N. Hiroyoshi, Proceedings of International Symposium on Earth Science and Technology, 600, 604, 2017
English, Summary international conference

Characterization of rare earth ore from Khaldzan Burgedei Peralkaline Deposit and its beneficiation by magnetic separation
M. Ito; P. Galtchandmani; N. Sato; C.B. Tabelin; T. Otake; N. Hiroyoshi, Proceedings of International Symposium on Earth Science and Technology, 98, 199, 2017
English, Summary international conference

Effects of flatness ratio on the jig separation of crushed plastic particles
Theerayut Phengsaart; Arisa Azuma; Carlito Baltazar Tabelin; Naoki Hiroyoshi; Mayumi Ito, 14th International Symposium on East Asian Resources Recycling Technology, EARTH 2017, 01 Jan. 2017

Kinetic modeling of agglomeration-flotation of finely ground chalcopyrite
Vothy Hornn; Ryosuke Yamazawa; Carlito Baltazar Tabelin; Naoki Hiroyoshi; Imaizumi Yuji; Mayumi Ito, 14th International Symposium on East Asian Resources Recycling Technology, EARTH 2017, 01 Jan. 2017

A review of heterocoagulation and galvanic interaction of sulfide minerals
Sophea Seng; Motoya Kojima; Kontani Yusuke; Carlito Baltazar Tabelin; Mayumi Ito; Naoki Hiroyoshi, 14th International Symposium on East Asian Resources Recycling Technology, EARTH 2017, 01 Jan. 2017

Synergistic effects of aluminum and other conductive particles on the cementation of gold ions from ammonium thiosulfate solutions
Sanghee Jeon; Hirotaka Takahashi; Rongrit Ponsumrankul; Shinya Tanaka; Carlito Baltazar Tabelin; Mayumi Ito; Naoki Hiroyoshi, 14th International Symposium on East Asian Resources Recycling Technology, EARTH 2017, 01 Jan. 2017

Advanced soil washing of coarse size fraction containing cesium : Removal of vermiculite by magnetic separation
伊藤 真由美; 湊川 和貴; Tabelin Carlito Baltazar; 広吉 直樹, 地下水・土壌汚染とその防止対策に関する研究集会講演集, 22, 389, 391, 23 Jun. 2016
[地盤工学会], Japanese

Recent Studies in Laboratory of Mineral Processing and Resources Recycling in Hokkaido University : Applications of Carrier Microencapsulation for Preventing Acid Mine Drainage Formation and Pyrite Flotation in Coal Cleaning
広吉 直樹; 伊藤 真由美; Tabelin Carlito Baltazar, 環境資源工学 = Resources processing : 資源処理技術, 63, 2, 61, 64, 2016
環境資源工学会, Japanese

Electrochemical insights on pyrite dissolution in the presence of alumina
S. Veerawattananun; D. Wiwattanadate; C.B. Tabelin; M. Ito; N. Hiroyoshi; T. Igarashi, the 9th International Conference on Earth Resources Technology, 906, 917, 2016
English, Summary international conference

Suppression of arsenopyrite oxidation by carrier microencapsulation using Ti-catechol complex.
I. Park; K. Magaribuchi; S. Veerawattananum; C.B. Tabelin; M. Ito; N. Hiroyoshi; T. Igarashi, the 9th International Conference on Earth Resources Technology,, 918, 928, 2016
English, Summary international conference

Recovery methods for valuable metals from used printed circuit boards: A review.
S. Jeon; M. Ito; Y. Nagata; N. Kitajima; S. Tanaka; R. Pongsumrankul; T. Yamamoto; C.B. Tabelin; N. Hiroyoshi, the 9th International Conference on Earth Resources Technology, 564, 579, 2016
English, Summary international conference

A review of approaches to enhance sulfide-fines recovery by flotation
V. Hornn; M. Ito; M. Kameya; T. Segawa; R. Yamazawa; C.B. Tabelin; N. Hiroyoshi, the 9th International Conference on Earth Resources Technology, 461, 473, 2016
English, Summary international conference

Fundamental electrochemical studies of carrier micro-encapsulation on pyrite: The stability of metal-organic complexes
S. Veerawattananun; D. Wiwattanadate; C.B. Tabelin; M. Ito; N. Hiroyoshi; T. Igarashi, Proceedings of the 15th Japan-Korea-France-Canada Joint Seminar on Geo-environmental Engineering,, 141, 150, 2016
English, Summary international conference

The interplay between pyrite and hematite and its implications in acid mine drainage control
C.B. Tabelin; S. Veerawattananum; M. Ito; N. Hiroyoshi; T. Igarashi, Proceedings of the 15th Japan-Korea-France-Canada Joint Seminar on Geo-environmental Engineering, 141, 150, 2016
English, Summary international conference

Formation of schwertmannite-like and scorodite-like coatings on pyrite and its implications in acid mine drainage control
C. B. Tabelin; R. D. Corpuz; S. Veerawattananun; M. Ito; N. Hiroyoshi; T. Igarashi, IMPC 2016 - 28th International Mineral Processing Congress, 2016-September, 01 Jan. 2016

Sequestration of boron, arsenic and selenium leached from tunnel-excavated rocks through adsorption
C.B. Tabelin; A. Hashimoto; T. Igarashi; M. Ito; N. Hiroyoshi, Proc. of the 14th Global Joint Seminar on Geo-environmental Engineering, 5, 2015
English, Summary international conference

The effects of colloidal α-Fe2O3 on pyrite oxidative dissolution and their implications in the formation of acid mine drainage
C.B. Tabelin; N. Hiroyoshi; M. Ito; T. Igarashi, Proc. of the 8th International Conference on Geological and Geo-resources Engineering and 7th Mineral Symposium, 17, 2015
English, Summary international conference

The effects of ferric-catechol on pyrite oxidation,
X. Li; S. Veerawattananun; C.B. Tabelin; N. Hiroyoshi; M. Ito, the 13th International Symposium on East Asian Resources Recycling Technology,, 80, 87, 2015
English, Summary international conference

Acid Mine Drainage: Sources, environmental impacts and mitigation approaches
C.B. Tabelin; M, Ito; N. Hiroyoshi; T. Igarashi, Proc. of the 2nd International Symposium Integrated Research and Education Center for Energy Conversion, Storage, Saving, and Transport Technologies,, 13, 14, 2015
English, Summary international conference

Effects of water recirculation on the flotation of Kushiro and Mozambique Coals
Mayumi Ito; Geraldo Conde Eliseu; Carlito Baltazar Tabelin; Naoki Hiroyoshi, EARTH 2015 - Proceedings of the 13th International Symposium on East Asian Resources Recycling Technology, 88, 94, 01 Jan. 2015

Effect of copper wires on the recovery of valuable metals and plastics from crushed small home appliances by JIG separation
Theerayut Phengsaart; Dawan Wiwattanadate; Mayumi Ito; Naoki Hamaya; Tabelin Carlito; Naoki Hiroyoshi, EARTH 2015 - Proceedings of the 13th International Symposium on East Asian Resources Recycling Technology, 765, 770, 01 Jan. 2015

Recovery of valuable components from crushed mobile phones using JIG separation
Mayumi Ito; Naho Kitajima; Ayumu Saito; Surang Khanchang; Carlito Baltazar Tabelin; Naoki Hiroyoshi, EARTH 2015 - Proceedings of the 13th International Symposium on East Asian Resources Recycling Technology, 748, 753, 01 Jan. 2015

Novel method to recover gold from printed circuit boards using ammonium thiosulfate media
Naoki Hiroyoshi; Yoshito Nagata; Mayumi Ito; Carlito Baltazar Tabelin, EARTH 2015 - Proceedings of the 13th International Symposium on East Asian Resources Recycling Technology, 742, 747, 01 Jan. 2015

Bubble attachment on plastic particles during hybrid JIG separation: Measurements during water pulsation
Mayumi Ito; Nana Murase; Ayumu Saito; Carlito Baltazar Tabelin; Naoki Hiroyoshi, EARTH 2015 - Proceedings of the 13th International Symposium on East Asian Resources Recycling Technology, 754, 761, 01 Jan. 2015

Leachability of arsenic from tunnel-excavated rock under free- and controlled-flow conditions,
C.B. Tabelin; T. Igarashi; M. Ito; N. Hiroyoshi, Proc. of the 13th Global Joint Seminar on Geo-Environmental Engineering,, 31, 37, 2014
English, Summary international conference

Immobilization of arsenic by schwertmannite synthesized from copper heap leach solutions,
S. Houngaloune; N. Hiroyoshi; M. Ito; M. Fujimura, Proc. of the 6th international seminar on process hydrometallurgy (Hydroprocess2014), 3, 2014
English, Summary international conference

The leaching and speciation behaviors of arsenic and selenium in tunnel-excavated rocks under flow-through conditions,
C.B. Tabelin; R. Sasaki; T. Igarashi; S. Tamoto; M. Ito; N. Hiroyoshi, Proc. of the 3rd International Conference on Advances in Mining and Tunneling, 573, 581, 2014
English, Summary international conference

Enhanced encapsulation of pyrite using colloidal “micro-seeds”: Visualization and attachment experiments,
C.B. Tabelin; N. Hiroyoshi; M. Ito; T. Igarashi, Proc. of the 7th AUN/SEED-Net Geological Engineering Conference and the 2nd AUN/SEED-Net Natural Disaster Conference,, 20, 2014
English, Summary international conference

Gold leaching from waste printed circuit boards by ammonium thiosulfate leaching
N. Hiroyoshi; Y. Nagata; M. Ito; C.B. Tabelin, Proc. of the 8th International Conference on Earth Resources Technology,, 19, 23, 2014
English, Summary international conference

Tunnel-excavated rock: An invisible threat to the environment
C. B. Tabelin; T. Igarashi; M. Ito; N. Hiroyoshi, ISRM International Symposium - 8th Asian Rock Mechanics Symposium, ARMS 2014, 2554, 2560, 01 Jan. 2014

Treatment of cobalt-rich ferromanganese ore
M. Ito; K. Asakura; S. Futakuchi; N. Hiroyoshi, 26th International Mineral Processing Congress, IMPC 2012: Innovative Processing for Sustainable Growth - Conference Proceedings, 2242, 2252, 01 Dec. 2012

Hybrid jig separation of plastic particles and surface modification of the plastics
M. Ito; M. Takeuchi; E. Ishida; N. Hiroyoshi; M. Tsunekawa, 26th International Mineral Processing Congress, IMPC 2012: Innovative Processing for Sustainable Growth - Conference Proceedings, 2235, 2241, 01 Dec. 2012

ハイブリッドジグ選別のためのプラスチックの表面改質
伊藤真由美; 竹内愛; 広吉直樹, 資源・素材, 2012, 25, 11 Sep. 2012
Japanese

各種比重選別によるコバルトリッチクラストと脈石の分離
伊藤真由美; 朝倉賢; 広吉直樹; 恒川昌美, 資源・素材, 2012, 19, 11 Sep. 2012
Japanese

Subcritical crack growth of Shirahama sandstone in water with various electrolyte concentrations
Yoshitaka Nara; Naoki Hiroyoshi; Tetsuro Yoneda; Katsuhiko Kaneko, Zairyo/Journal of the Society of Materials Science, Japan, 61, 7, 662, 667, Jul. 2012
Japanese

Lead Recovery from Waste CRT Glass by Reduction Melting/Chloride Volatilization Hybrid Method
INANO Hiroyuki; TADA Tatsumi; OKADA Takashi; HIROYOSHI Naoki, Ceramics Japan : Bulletin of the Ceramic Society of Japan, 47, 2, 96, 100, 01 Feb. 2012
日本セラミックス協会, Japanese

回分式ジグ選別過程の圧力計測に基づく解析
広吉直樹; 河合孝樹; 武田良介; 伊藤真由美, 資源・素材学会春季大会講演集, 2012, 214, 215, 2012
Japanese

選択的電析・磁化を用いたAl合金の選別技術の開発
伊藤真由美; 中村啓一郎; ALORRO Richard Diaz; 広吉直樹, 資源・素材学会春季大会講演集, 2012, 45, 46, 2012
Japanese

ベトナム・ドンパオ鉱石中のレアアース鉱物の選択粉砕と磁選
伊藤真由美; 高松慎; 朝倉賢; 広吉直樹, 資源・素材学会北海道支部春季講演会講演要旨集, 2012, 45, 46, 2012
Japanese

PVC/Nylonのハイブリッドジグ選別~プラスチックの濡れ性に及ぼすAOT添加の影響~
伊藤真由美; 竹内愛; 広吉直樹; 恒川昌美, 資源・素材学会春季大会講演集, 2012, 216, 217, 2012
Japanese

銅電解スライム浮選に関しての基礎的研究
伊藤真由美; 池本貴志; 朝倉賢; 広吉直樹, 資源・素材学会北海道支部春季講演会講演要旨集, 2012, 43, 44, 2012
Japanese

ブラウン管ガラス熔融処理残渣からの鉛の溶出機構
広吉直樹; 高谷佳寛; 岡田敬志; 伊藤真由美; 稲野浩行, 資源・素材学会北海道支部春季講演会講演要旨集, 2012, 49, 50, 2012
Japanese

合成マグネタイトによる塩化物溶液からの白金族の回収
広吉直樹; 佐藤遼; HOMCHUEN Peet; 雉子谷東; 伊藤真由美, 資源・素材学会北海道支部春季講演会講演要旨集, 2012, 41, 42, 2012
Japanese

低品位銅鉱ヒープリーチング溶液からのシュベルトマナイト生成に関する基礎的研究
広吉直樹; 河合崇泰; 伊藤真由美; 岡本秀征, 資源・素材学会春季大会講演集, 2012, 190, 191, 2012
Japanese

金属回収のためのFe/Al複合粒子の調製
伊藤真由美; 祐川香太; 小杉正人; 広吉直樹, 資源・素材学会北海道支部春季講演会講演要旨集, 2012, 47, 48, 2012
Japanese

Subcritical crack growth in sandstone in water with various electrolyte concentrations
Y. Nara; R. Nakabayashi; N. Hiroyoshi; T. Yoneda; K. Kaneko; S. Murata; T. Ishida, Near Surface Geoscience 2012, 01 Jan. 2012

Influence of humidity and rock fabric on subcritical crack growth in rock
Y. Nara; K. Kaneko; T. Yoneda; N. Hiroyoshi; K. Morimoto, HARMONISING ROCK ENGINEERING AND THE ENVIRONMENT, 757, 760, 2012
English

磁性と還元力を持つ粒子を用いた貴金属の選択的抽出 : 都市鉱山技術開発の一例として
広吉 直樹, ぶんせき, 442, 593, 596, 05 Oct. 2011
日本分析化学会, Japanese

Jig separation of crushed automobile shredded residue and its evaluation by float and sink analysis
Yutaka Kuwayama; Mayumi Ito; Noki Hiroyoshi; Masami Tsunekawa, JOURNAL OF MATERIAL CYCLES AND WASTE MANAGEMENT, 13, 3, 240, 246, Oct. 2011
English

ジグ内粒子運動の圧力計測に基づく解析
広吉直樹; 河合孝樹; 武田良介; 伊藤真由美; 恒川昌美, 資源・素材, 2011, 2, 197, 198, 26 Sep. 2011
Japanese

銅製錬スラグを用いた塩化物溶液からの金回収
広吉直樹; 雉子谷東; ALORRO Richard Diaz; 伊藤真由美, 資源・素材, 2011, 2, 135, 136, 26 Sep. 2011
Japanese

銅製錬所鉛澱物の鉛濃縮に関する研究
広吉直樹; 大山史織; 伊藤真由美, 資源・素材, 2011, 2, 203, 204, 26 Sep. 2011
Japanese

Fe/Al複合粒子を用いた金属溶液からの金属回収
伊藤真由美; 小杉正人; 祐川香太; 広吉直樹, 資源・素材, 2011, 2, 141, 142, 26 Sep. 2011
Japanese

ベトナム・ドンパオ鉱石中のレアアース鉱物の回収~粉砕・分級特性~
恒川昌美; 西川千尋; 伊藤真由美; 広吉直樹; SATUR Jacqueline Vidal, 資源・素材, 2011, 2, 137, 138, 26 Sep. 2011
Japanese

海底熱水鉱床鉱石中の閃亜鉛鉱の浮選挙動
伊藤真由美; 二口修吏; 朝倉賢; 高橋達; 広吉直樹; 恒川昌美, 資源・素材, 2011, 2, 139, 140, 26 Sep. 2011
Japanese

2-331 Faculty Development at Course of Sustainable Resources Engineering, Faculty of Engineering, Hokkaido University
FUJII Yoshiaki; IGARASHI Toshifumi; HIROYOSHI Naoki, 工学教育研究講演会講演論文集, 23, 59, 538, 539, 22 Aug. 2011
Japanese Society for Engineering Education, Japanese

7-326 Internship Programs in the Course of Sustainable Resources Engineering, School of Engineering, Hokkaido University
ITO Mayumi; HIROYOSHI Naoki; IGARASHI Toshifumi, 工学教育研究講演会講演論文集, 23, 59, 620, 621, 22 Aug. 2011
Japanese Society for Engineering Education, Japanese

ヒ素含有銅鉱石のヒープリーチングに関する基礎的研究
広吉直樹; 河合崇泰; 伊藤正樹; 伊藤真由美, 資源・素材学会北海道支部春季講演会講演要旨集, 2011, 41, 42, 2011
Japanese

ベトナム・ドンパオ鉱石中のレアアース鉱物の回収~粉砕・分級特性~
恒川昌美; 西川千尋; 伊藤真由美; 広吉直樹; SATUR Jacqueline Vidal, 資源・素材学会春季大会講演集, 2011 (CD-ROM), ROMBUNNO.2123, 2011
Japanese

海底熱水鉱床鉱石の選鉱に関する基礎的研究~加温浮選とKnelson Concentratorを用いた銅・鉛・亜鉛鉱物の分離~
伊藤真由美; 朝倉賢; 二口修吏; 高橋達; 広吉直樹; 恒川昌美, 資源・素材学会北海道支部春季講演会講演要旨集, 2011, 39, 40, 2011
Japanese

海底熱水鉱床鉱石のジグによる比重選別
伊藤真由美; 二口修吏; 朝倉賢; 高橋達; 広吉直樹, 海洋工学シンポジウム(CD-ROM), 22nd, ROMBUNNO.OES22-008, 2011
Japanese

ジグ内粒子運動の圧力計測に基づく解析
広吉直樹; 河合孝樹; 武田良介; 伊藤真由美; 恒川昌美, 資源・素材学会春季大会講演集, 2011 (CD-ROM), ROMBUNNO.2103, 2011
Japanese

銅製錬スラグを用いた塩化物溶液からの金回収
広吉直樹; 雉子谷東; ALORRO Richard Diaz; 伊藤真由美, 資源・素材学会春季大会講演集, 2011 (CD-ROM), ROMBUNNO.2110, 2011
Japanese

ジグ内粒子運動の圧力損失に基づくセンシング
広吉直樹; 河合孝樹; 武田良介; 伊藤真由美, 資源・素材学会北海道支部春季講演会講演要旨集, 2011, 33, 34, 2011
Japanese

海底熱水鉱床鉱石中の閃亜鉛鉱の浮選挙動
伊藤真由美; 二口修吏; 朝倉賢; 高橋達; 広吉直樹; 恒川昌美, 資源・素材学会春季大会講演集, 2011 (CD-ROM), ROMBUNNO.2121, 2011
Japanese

プラスチックのハイブリッドジグ選別に及ぼす濡れ性制御の影響~PVC/NylonとHDPS/PPGFの選別~
伊藤真由美; 竹内愛; 石田絵美; 赤塚真依子; 広吉直樹; 恒川昌美, 資源・素材学会北海道支部春季講演会講演要旨集, 2011, 35, 36, 2011
Japanese

Al合金リサイクルのための選択的電析・磁化技術の開発~銅含有Al合金とその他のAlの選別~
伊藤真由美; DIAZ ALORRO Richard; 中村啓一郎; 広吉直樹, 資源・素材学会北海道支部春季講演会講演要旨集, 2011, 37, 38, 2011
Japanese

Temperature dependence of calcium carbonate precipitation for biogrout
S. Ogata; S. Kawasaki; N. Hiroyoshi; M. Tsunekawa; K. Kaneko; R. Terajima, Rock Engineering in Difficult Ground Conditions - Soft Rocks and Karst - Proceedings of the Regional Symposium of the International Society for Rock Mechanics, EUROCK 2009, 339, 344, 01 Dec. 2010

Recovery of precious metals from chloride solution by magnetite
R. Alorro; N. Hiroyoshi; M. Ito; M. Tsunekawa, XXV International Mineral Processing Congress 2010, IMPC 2010, 1, 263, 271, 01 Dec. 2010

Advanced Jig separation of shredded plastics
M. Ito; M. Akatsuka; E. Ishida; K. Hori; N. Hiroyoshi; M. Tsunekawa, XXV International Mineral Processing Congress 2010, IMPC 2010, 2, 843, 850, 01 Dec. 2010

Carrier micro encapsulation (CME) for suppressing pyrite floatability and oxidation in coal preparation
R. Jha; J. Satur; N. Hiroyoshi; M. Ito; M. Tsunekawa, XXV International Mineral Processing Congress 2010, IMPC 2010, 3, 2025, 2033, 01 Dec. 2010

混合プラスチックの湿式比重選別―RETAC JIGの原理と応用
堀邦紘; 恒川昌美; 阿部中; 広吉直樹; 伊藤真由美; 岡田敦志; 丹野秀昭, 高分子学会予稿集(CD-ROM), 59, 2 Disk1, ROMBUNNO.3Z03, 01 Sep. 2010
Japanese

複雑希土類鉱石中のバストネサイトの浮選分離(第2報)
恒川昌美; 西川千尋; 伊藤真由美; 広吉直樹; SATUR Jacqueline Vidal, 資源・素材学会春季大会講演集, 2, 53, 54, 30 Mar. 2010
Japanese

液晶パネルのリサイクルに関する基礎的研究
恒川昌美; 朝比奈遼; 広吉直樹; 伊藤真由美; 浜野孝俊; 志村一美, 資源・素材学会春季大会講演集, 2, 177, 178, 30 Mar. 2010
Japanese

硫化鉱物の浮遊性に及ぼすキャリアマイクロエンカプセレーションの効果
広吉直樹; 川代晋太郎; JHA Rani; Kumari Thakur; 恒川昌美; 伊藤真由美, 資源・素材学会春季大会講演集, 2, 51, 52, 30 Mar. 2010
Japanese

黄銅鉱浸出のためのマグネタイト利用に関する研究
広吉直樹; 伊藤正樹; 竹原裕生; 恒川昌美; 伊藤真由美, 資源・素材学会春季大会講演集, 1, 29, 30, 30 Mar. 2010
Japanese

電線被覆PVCからの鉛除去~三塩基性硫酸鉛と金属酸化物の凝集・分散~
広吉直樹; 酒井智生; 三村隼生; 恒川昌美; 伊藤真由美, 資源・素材学会春季大会講演集, 2, 179, 180, 30 Mar. 2010
Japanese

Effect of surrounding environment on subcritical crack growth index and long-term strength for rock
Yoshitaka Nara; Toshifumi Igarashi; Naoki Hiroyoshi; Tetsuro Yoneda; Katsuhiko Kaneko, Zairyo/Journal of the Society of Materials Science, Japan, 59, 3, 180, 185, Mar. 2010
Japanese

深海底鉱物資源開発のための選鉱法の確立
伊藤真由美; 恒川昌美; 広吉直樹, 資源・素材, 2010, 1, 245, 246, 2010
Japanese

リバースジグの選別性に及ぼす各種要因の検討
恒川昌美; 河合孝樹; 石田絵美; 広吉直樹; 伊藤真由美; 阿部中, 資源・素材学会北海道支部春季講演会講演要旨集, 2010, 45, 46, 2010
Japanese

マグネタイトによる塩化物溶液からの金吸着
広吉直樹; 雉子谷東; DIAZ ALORRO Richard; 恒川昌美; 伊藤真由美, 資源・素材学会北海道支部春季講演会講演要旨集, 2010, 41, 42, 2010
Japanese

メッキ廃水汚泥の安定性評価と資源化に関する研究
恒川昌美; 大山史織; 広吉直樹; 伊藤真由美, 資源・素材学会北海道支部春季講演会講演要旨集, 2010, 27, 28, 2010
Japanese

カーシュレッダーダストからの低塩素分・低灰分可燃物の回収
恒川昌美; 小杉正人; 桑山豊; 広吉直樹; 伊藤真由美, 資源・素材学会北海道支部春季講演会講演要旨集, 2010, 29, 30, 2010
Japanese

海底熱水鉱床鉱石の選鉱
伊藤真由美; 二口修吏; 高橋達; 広吉直樹; 恒川昌美, 資源・素材学会北海道支部春季講演会講演要旨集, 2010, 43, 44, 2010
Japanese

Effect of water on subcritical crack growth index and long-term strength for rock
Y. Nara; T. Igarashi; N. Hiroyoshi; T. Yoneda; K. Kaneko, 72nd European Association of Geoscientists and Engineers Conference and Exhibition 2010: A New Spring for Geoscience. Incorporating SPE EUROPEC 2010, 6, 4386, 4390, 01 Jan. 2010

Removal of mn ions by biological co-precipitation of fe ions
Kyoungkeun Yoo; Naoki Hiroyoshi; Masami Tsunekawa, Geosystem Engineering, 13, 3, 91, 96, 2010
English

Surface modification of shredder residue plastics for hybrid jig processing
M. Ito; M. Akatsuka; Y. Kuwayama; K. Hori; N. Hiroyoshi; M. Tsunekawa, The Minerals, Metals and Materials Society - 3rd International Conference on Processing Materials for Properties 2008, PMP III, 1, 315, 320, 01 Dec. 2009

レパント金鉱山廃石の電気パルス粉砕処理特性
伊藤真由美; 浜野孝俊; 広吉直樹; 恒川昌美, 資源・素材学会春季大会講演集, 2, 83, 84, 26 Mar. 2009
Japanese

微粒子のジグ選別
恒川昌美; 扇子渉; 堀邦紘; 小林利輝; 伊藤真由美; 広吉直樹, 資源・素材学会春季大会講演集, 2, 169, 170, 26 Mar. 2009
Japanese

非水/水溶液界面への鉛含有微粒子の捕捉現象
恒川昌美; 三村隼生; 酒井智生; 広吉直樹; 伊藤真由美, 資源・素材学会春季大会講演集, 2, 115, 116, 26 Mar. 2009
Japanese

綿状物を含むASR粉砕産物中の不燃物,塩素の物理選別による除去
桑山豊; 伊藤真由美; 赤塚真依子; 広吉直樹; 恒川昌美, 資源・素材学会春季大会講演集, 2, 105, 106, 26 Mar. 2009
Japanese

圧力センサーを用いたジグ選別のモニタリング
恒川昌美; 秋元淳希; 堀邦紘; 小林利輝; 広吉直樹; 伊藤真由美, 資源・素材学会春季大会講演集, 2, 173, 174, 26 Mar. 2009
Japanese

コバルトリッチクラストの細粒群のジグ選別
伊藤真由美; 高橋達; 關村健吾; 広吉直樹; 恒川昌美, 資源・素材学会春季大会講演集, 2, 85, 86, 26 Mar. 2009
Japanese

家電プラスチックのアドバンストジグ選別
伊藤真由美; 赤塚真依子; 石田絵美; 高橋達; 桑山豊; 広吉直樹; 恒川昌美, 資源・素材, 2009, 38, 2009
Japanese

コバルトリッチクラストの選鉱法の確立
伊藤真由美; 恒川昌美; 広吉直樹, 資源・素材, 2009, 1, 235, 238, 2009
Japanese

硫酸溶液中での黄銅鉱浸出に対するマグネタイトの影響
広吉直樹; 伊藤正樹; 竹原裕生; 恒川昌美; 伊藤真由美, 資源・素材学会北海道支部春季講演会講演要旨集, 2009, 49, 50, 2009
Japanese

複雑希土類鉱石の選鉱
恒川昌美; 西川千尋; SATUR Jacqueline Vidal; 伊藤真由美; 広吉直樹, 資源・素材学会北海道支部春季講演会講演要旨集, 2009, 47, 48, 2009
Japanese

コバルトリッチクラストの選鉱と希少金属の回収
伊藤真由美; 高橋達; ALORRO Richard D; 關村健吾; 広吉直樹; 恒川昌美, 資源・素材, 2009, 32, 2009
Japanese

電線被覆PVCからの鉛含有微粒子の除去
広吉直樹; 酒井智生; 三村隼生; 恒川昌美; 伊藤真由美, 資源・素材, 2009, 41, 2009
Japanese

各種センサーを用いたジグ選別特性の把握
恒川昌美; 秋元淳希; 広吉直樹; 伊藤真由美, 資源・素材, 2009, 37, 2009
Japanese

Lepanto金鉱山廃石の電気パルス粉砕
伊藤真由美; 浜野孝俊; 広吉直樹; 恒川昌美, 資源・素材, 2009, 31, 2009
Japanese

複雑希土類鉱石中のバストネサイトの浮選分離
恒川昌美; 西川千尋; VIDAL SATUR Jacqueline; 伊藤真由美; 広吉直樹, 資源・素材, 2009, 35, 2009
Japanese

焼却灰の脱塩素特性に関する研究
恒川昌美; 朝比奈遼; 広吉直樹; 伊藤真由美, 資源・素材学会北海道支部春季講演会講演要旨集, 2009, 55, 56, 2009
Japanese

微粒子ジグ選別における諸要因の影響
扇子渉; 恒川昌美; 広吉直樹; 伊藤真由美, 資源・素材, 2009, 36, 2009
Japanese

カテコール類似物質による酸化鉱物の選択的表面改質
広吉直樹; 川代晋太郎; JHA Rani; Kumari Thakur; 恒川昌美; 伊藤真由美, 資源・素材学会北海道支部春季講演会講演要旨集, 2009, 51, 52, 2009
Japanese

非水溶媒中に懸濁する鉛含有微粒子の固体表面への吸着除去
広吉直樹; 酒井智生; 三村隼生; 恒川昌美; 伊藤真由美, 資源・素材学会北海道支部春季講演会講演要旨集, 2009, 53, 54, 2009
Japanese

Physical separation of crushed product of waste nickel-metal hydride batteries from hybrid vehicles
M. Ito; M. Tsunekawa; K. Kashiwaya; N. Sumiya; H. Furuya; N. Hiroyoshi, Proceedings of the 2008 Global Symposium on Recycling, Waste Treatment and Clean Technology, REWAS 2008, 3, 8, 01 Dec. 2008

Improved chalcopyrite leaching through optimization of redox potential
N. Hiroyoshi; M. Tsunekawa; H. Okamoto; R. Nakayama; S. Kuroiwa, CANADIAN METALLURGICAL QUARTERLY, 47, 3, 253, 258, Jul. 2008
English

コバルトリッチクラストの選鉱に関する基礎的研究 第二報
恒川昌美; 伊藤真由美; 關村健吾; 山口英志; 高橋達; 柏谷公希; 広吉直樹, 資源・素材学会春季大会講演集, 2, 197, 198, 27 Mar. 2008
Japanese

ジグ選別における粒子の沈降挙動と選別パターン
堀邦紘; 恒川昌美; 広吉直樹; 伊藤真由美, 資源・素材学会春季大会講演集, 2, 109, 110, 27 Mar. 2008
Japanese

連続式網下気室型ジグ(RETAC Jig)選別の高度化に関する基礎的研究
恒川昌美; 小林利輝; 堀邦紘; 岡田英明; 広吉直樹; 伊藤真由美, 資源・素材学会春季大会講演集, 2, 107, 108, 27 Mar. 2008
Japanese

鉛汚染土壌からの鉛分リーチングおよび鉛濃縮に関する基礎的研究 第4報
伊藤真由美; 高田政雄; 帆苅直弘; 恒川昌美; 広吉直樹, 資源・素材学会春季大会講演集, 2, 189, 190, 27 Mar. 2008
Japanese

黄銅鉱のカラムリーチング
広吉直樹; 竹原裕生; 桑澤毅成; 恒川昌美; 伊藤真由美, 資源・素材学会北海道支部春季講演会講演要旨集, 2008, 43, 44, 2008
Japanese

非水/水溶液界面への微粒子の捕捉現象とそのメカニズム
恒川昌美; 三村隼生; 佐々木勇太; 広吉直樹; 伊藤真由美, 資源・素材学会北海道支部春季講演会講演要旨集, 2008, 47, 48, 2008
Japanese

コバルトリッチクラスト・ノジュールと脈石のJIG選別~大型JIG処理試験と最適運転条件の検討~
伊藤真由美; 高橋達; 關村健吾; 広吉直樹; 恒川昌美, 資源・素材学会北海道支部春季講演会講演要旨集, 2008, 45, 46, 2008
Japanese

鉛汚染土壌からの鉛分の溶解およびセメンテーション~セメンテーションの検討~
伊藤真由美; 高田政雄; 帆苅直弘; 恒川昌美; 広吉直樹, 資源・素材, 2008, 44, 2008
Japanese

ジグ選別プロセスにおける粒子流動化現象と最適条件
恒川昌美; 秋元淳希; 堀邦紘; 広吉直樹; 伊藤真由美, 資源・素材学会北海道支部春季講演会講演要旨集, 2008, 7, 8, 2008
Japanese

微粒子用ジグ選別機に関する基礎的研究
恒川昌美; 扇子渉; 堀邦紘; 小林利輝; 広吉直樹; 伊藤真由美, 資源・素材学会北海道支部春季講演会講演要旨集, 2008, 5, 6, 2008
Japanese

湿式サイクロンにおける微粒子の挙動に及ぼす粒子形状の影響
柏谷公希; 能町聖彦; 伊藤真由美; 広吉直樹; 恒川昌美, 資源・素材, 2008, 32, 2008
Japanese

コバルトリッチクラストの選鉱に関する基礎的研究 第三報
關村健吾; 恒川昌美; 伊藤真由美; 高橋達; 広吉直樹, 資源・素材, 2008, 17, 2008
Japanese

プラスチックの表面改質とハイブリットジグへの適用
赤塚真依子; 伊藤真由美; SATUR Jacqueline; 桑山豊; 広吉直樹; 恒川昌美, 資源・素材, 2008, 34, 2008
Japanese

Effects of coexisting metal ions on the redox potential dependence of chalcopyrite leaching in sulfuric acid solutions
N. Hiroyoshi; S. Kuroiwa; H. Miki; M. Tsunekawa; T. Hirajima, HYDROMETALLURGY, 87, 1-2, 1, 10, Jun. 2007
English

メタ珪酸ナトリウムを用いたバイオグラウト
小林 元; 川崎 了; 広吉 直樹; 恒川 昌美; 金子 勝比古; 島田 俊介, 春季大会講演集. I, 資源編, 19, 2, 73, 74, 29 Mar. 2007
Japanese

水溶液中での岩石のサブクリティカルき裂進展に関する研究
奈良 禎太; 高田 雅史; 五十嵐 敏文; 広吉 直樹; 金子 勝比古, 春季大会講演集. I, 資源編, 19, 1, 47, 48, 29 Mar. 2007
Japanese

Recovery of Heavy Metals from MSW Melting Fly Ash by Carrier-in-Pulp Method
ALORRO Richard D.; HIROYOSHI Naoki; ITO Mayumi; TSUNEKAWA Masami, 春季大会講演集. I, 資源編, 19, 2, 161, 162, 29 Mar. 2007
English

鉛汚染土壌からの鉛分リーチングおよび鉛濃縮に関する基礎的研究 第3報
伊藤真由美; 帆苅直弘; 高田政雄; 恒川昌美; 広吉直樹, 資源・素材学会春季大会講演集, 1, KIKAKU.85-KIKAKU.86, 29 Mar. 2007
Japanese

鉛汚染土壌からの鉛分リーチングおよび鉛濃縮に関する基礎的研究 第3報
伊藤 真由美; 帆苅 直弘; 高田 政雄; 恒川 昌美; 広吉 直樹, 春季大会講演集. I, 資源編, 19, 2, "企画, 85"-"企画-86", 29 Mar. 2007
Japanese

カーシュレッダーダスト(ASR)の有価物湿式回収プロセスの開発 : 界面活性剤溶液中でのASR浸漬・解砕挙動
伊藤 真由美; 赤塚 真依子; 桑山 豊; 堀 邦紘; 広吉 直樹; 恒川 昌美, 春季大会講演集. I, 資源編, 19, 2, 21, 22, 29 Mar. 2007
Japanese

カーシュレッダーダスト(ASR)の有価物湿式回収プロセスの開発 : ASRのジグ選別における繊維状物質の挙動
伊藤 真由美; 桑山 豊; 赤塚 真依子; 堀 邦鉱; 広吉 直樹; 恒川 昌美, 春季大会講演集. I, 資源編, 19, 2, 23, 24, 29 Mar. 2007
Japanese

ハイブリッドジグ選別におけるプラスチック表面の濡れ性の影響
恒川 昌美; 岡田 英明; 堀 邦紘; 越智 大司; 小林 利輝; 上田 将経; 広吉 直樹; 伊藤 真由美, 春季大会講演集. I, 資源編, 19, 2, 25, 26, 29 Mar. 2007
Japanese

プラスチック微粒子の湿式サイクロンによる分級
柏谷 公希; 能町 聖彦; 伊藤 真由美; 山本 康彰; 広吉 直樹; 恒川 昌美, 春季大会講演集. I, 資源編, 19, 2, 29, 30, 29 Mar. 2007
Japanese

廃Ni-MH電池リサイクルプロセスにおける破砕微粉の物理選別
伊藤 真由美; 角谷 直宏; 柏谷 公希; 広吉 直樹; 恒川 昌美, 春季大会講演集. I, 資源編, 19, 2, 31, 32, 29 Mar. 2007
Japanese

黄銅鉱浸出の電位制御による最適化
桑澤 毅成; 恩田 真吾; 広吉 直樹; 恒川 昌美; 伊藤 真由美, 春季大会講演集. I, 資源編, 19, 2, 45, 46, 29 Mar. 2007
Japanese

微量の水分を含む有機溶媒中での疎水性微粒子の分散・凝集
恒川 昌美; 佐々木 勇太; 中村 孔亮; 伊藤 真由美; 広吉 直樹; YOO Kyoung Keun, 春季大会講演集. I, 資源編, 19, 2, 51, 52, 29 Mar. 2007
Japanese

JIGを用いたコバルトリッチクラストの選鉱
恒川 昌美; 伊藤 真由美; 山口 英志; 關村 健吾; 柏谷 公希; 広吉 直樹, 春季大会講演集. I, 資源編, 19, 2, 53, 54, 29 Mar. 2007
Japanese

硫化鉱物からのヒ素の溶出とその除去
富岡 祐一; 広吉 直樹; 恒川 昌美, 硫酸と工業, 60, 2, 23, 28, Feb. 2007
硫酸協会, Japanese

P42. Fundamental study on biogrout using sodium metasilicate
KOBAYASHI Gen; KAWASAKI Satoru; HIROYOSHI Naoki; TSUNEKAWA Masami; KANEKO Katsuhiko; TERAJIMA Rei; SHIMADA Shunsuke, 研究発表会講演論文集, 19, 229, 230, 2007
日本応用地質学会, Japanese

疎水性プラスチック微粒子の湿式サイクロンによる分級
柏谷公希; 能町聖彦; 伊藤真由美; 山本康彰; 広吉直樹; 恒川昌美, 資源・素材学会北海道支部春季講演会講演要旨集, 2007, 47, 48, 2007
Japanese

Leaching&Cementation法による鉛汚染土壌の浄化~処理プロセスの検討~
伊藤真由美; 高田政雄; 帆苅直弘; 広吉直樹; 恒川昌美, 地下水・土壌汚染とその防止対策に関する研究集会講演集(CD-ROM), 13th, ROMBUNNO.S5-5, 2007
Japanese

カーシュレッダーダスト(ASR)の有価物湿式回収プロセスの開発~ASRの溶液浸漬性評価と浸漬機構の解明~
伊藤真由美; 赤塚真依子; 桑山豊; 堀邦紘; 広吉直樹; 恒川昌美, 資源・素材学会北海道支部春季講演会講演要旨集, 2007, 49, 50, 2007
Japanese

Leaching&Cementation法による鉛汚染土壌の浄化~鉛の除去率に及ぼす各種因子の影響~
伊藤真由美; 帆苅直弘; 高田政雄; 広吉直樹; 恒川昌美, 地下水・土壌汚染とその防止対策に関する研究集会講演集(CD-ROM), 13th, ROMBUNNO.S5-4, 2007
Japanese

鉛汚染土壌からの鉛除去に関する研究~クエン酸による土中鉛浸出と鉄粉濃縮挙動の把握~
伊藤真由美; 高田政雄; 帆苅直弘; 恒川昌美; 広吉直樹, 資源・素材学会北海道支部春季講演会講演要旨集, 2007, 27, 28, 2007
Japanese

連続式ジグのプラスチック選別特性~回分式ジグとの比較~
恒川昌美; 小林利輝; 堀邦紘; 越智大司; 岡田英明; 広吉直樹; 伊藤真由美, 資源・素材学会北海道支部春季講演会講演要旨集, 2007, 45, 46, 2007
Japanese

深海底鉱物資源の有効利用に関する研究~コバルトリッチクラストと基盤岩のJIG選別~
恒川昌美; 伊藤真由美; 山口英志; 關村健吾; 柏谷公希; 広吉直樹, 資源・素材学会北海道支部春季講演会講演要旨集, 2007, 43, 44, 2007
Japanese

Effects of Carrier-Microencapsulation on Surface Chemical Properties of Pyrite
SATUR Jacqueline; HIROYOSHI Naoki; ITO Mayumi; TSUNEKAWA Masami, 春季大会講演集. I, 資源編, 18, 2, 65, 66, 27 Mar. 2006
English

ジグ選別における水の圧力損失と選別性の関係
堀 邦紘; 恒川 昌美; 上田 将経; 越智 大司; 広吉 直樹; 伊藤 真由美; 伊藤 正澄, 春季大会講演集. I, 資源編, 18, 2, 43, 44, 27 Mar. 2006
Japanese

気泡を利用したジグ選別の改良
恒川 昌美; 上田 将経; 堀 邦紘; 越智 大司; 岡田 英明; 広吉 直樹; 伊藤 真由美; 伊藤 正澄, 春季大会講演集. I, 資源編, 18, 2, 45, 46, 27 Mar. 2006
Japanese

プラスチックのジグ選別における分離プロセスに関する一考察
恒川 昌美; 越智 大司; 堀 邦紘; 上田 将経; 岡田 英明; 広吉 直樹; 伊藤 真由美; 伊藤 正澄, 春季大会講演集. I, 資源編, 18, 2, 47, 48, 27 Mar. 2006
Japanese

リーチングとセメンテーションによる都市ゴミ溶融飛灰からのPb除去・回収
広吉 直樹; 三谷 慎一; 伊藤 真由美; 恒川 昌美, 春季大会講演集. I, 資源編, 18, 2, 135, 136, 27 Mar. 2006
Japanese

鉛汚染土壌からの鉛分リーチングおよび鉛濃縮に関する基礎的研究 第2報
伊藤 真由美; 久保 泰政; 帆苅 直弘; 広吉 直樹; 恒川 昌美, 春季大会講演集. I, 資源編, 18, 2, 179, 180, 27 Mar. 2006
Japanese

Removal of Arsenic Ions in Sulfuric Acid Solutions by Sulfide Minerals
TOMIOKA Yuichi; HIROYOSHI Naoki; TSUNEKAWA Masami, Journal of MMIJ, 122, 6/7, 345, 352, 2006
Removal of arsenite and arsenate in sulfuric acid solutions were investigated with PbS, ZnS, FeS and CuS at 298K. Both arsenic species were removed by PbS, ZnS and FeS. Especially, PbS was most effective to remove arsenic species from the solutions. The removal of the arsenic species by PbS depends on the sulfuric acid concentration and is minimum at sulfuric acid concentrations around 0.01 kmol m^-3. Thermodynamic analysis of the experimental results and XRD and SEM-EDX analysis of the solid residue suggest that the removal of the arsenic species by PbS is due to both arsenic adsorption on PbS surface and precipitation of As₂S_3(am) by the reaction of the arsenic species and H₂S generated by PbS., The Mining and Materials Processing Institute of Japan, Japanese

微量の水分を含む非水溶液中での微粒子の分散・凝集
恒川昌美; 佐々木勇太; 中村孔亮; 伊藤真由美; 広吉直樹, 資源・素材学会北海道支部春季講演会講演要旨集, 2006, 57, 58, 2006
Japanese

プラスチックのハイブリッドジグ選別のための表面物性評価
恒川昌美; 岡田英明; 堀邦紘; 上田将経; 越智大司; 広吉直樹; 伊藤真由美; 伊藤正澄, 資源・素材学会北海道支部春季講演会講演要旨集, 2006, 55, 56, 2006
Japanese

ハイブリッド自動車用ニッケル水素電池からの湿式磁選法を用いた有価金属の回収
恒川昌美; 角谷直宏; 伊藤真由美; 広吉直樹, 資源・素材学会北海道支部春季講演会講演要旨集, 2006, 51, 52, 2006
Japanese

鉛汚染土壌の新しい修復法に関する基礎的研究
伊藤真由美; 帆苅直弘; 久保泰政; 恒川昌美; 広吉直樹, 資源・素材学会北海道支部春季講演会講演要旨集, 2006, 11, 12, 2006
Japanese

廃コンクリートの湿式選別リサイクルプロセスの開発~再生骨材の性状に及ぼす原コンクリートの影響~
恒川昌美; 桑澤毅成; 伊藤真由美; 広吉直樹; 名和豊春; 西田法文; 田村幸保; 伊藤正澄, 資源・素材学会北海道支部春季講演会講演要旨集, 2006, 53, 54, 2006
Japanese

コバルトリッチクラストの選鉱に関する基礎的研究
恒川昌美; 山口英志; 伊藤真由美; 広吉直樹; 柴崎洋志; 吉田友之, 資源・素材, 2006, C/D, 167, 168, 2006
Japanese

Application of jig separator to recycle plastics used in electrical appliances
Masami Tsunekawa; Kunihiro Hori; Tsuyoshi Hirajima; Naoki Hiroyoshi; Masazumi Ito, REWAS'04 - Global Symposium on Recycling, Waste Treatment and Clean Technology, 1651, 1660, 01 Dec. 2005

The removal of manganese ions using a sulfate-reducing bacteria bioreactor
Kyoungkeun Yoo; Naoki Hiroyoshi; Masami Tsunekawa, Proceedings - European Metallurgical Conference, EMC 2005, 4, 1751, 1765, 01 Dec. 2005

Bioleaching of Sarcheshmeh molybdenite concentrate for extraction of rhenium
MAA Zamani; N Hiroyoshi; M Tsunekawa; R Vaghar; M Oliazadeh, HYDROMETALLURGY, 80, 1-2, 23, 31, Nov. 2005
English

鉛汚染土壌からのクエン酸による鉛分リーチングおよび担体を用いた鉛濃縮・除去に関する基礎的研究
伊藤真由美; 久保泰政; 広吉直樹; 恒川昌美, 地球環境シンポジウム講演論文集, 13th, 311, 315, 14 Jul. 2005
It is important to establish washing methods for contaminated soils by toxic metals such as lead in rifle shooting areas. In the lead-contaminated soils weathered after a long period, metal lead is extracted as ion, and is penetrated into the ground, depositing on the surface of soil particles or immersing into the pores of the particles mainly as a lead carbonate. Therefore it is difficult to remove lead from the weathered contaminated soils by conventional soil washing techniques such as sizing or gravity separation. In this study, a new method is proposed for removing lead from the contaminated soil. Lead components in the soil are extracted into the solution by sodium citrate as a chelating agent, and the extracted lead is precipitated on the surface of iron powder by redox reaction. Then the iron powder is recovered by physical separation techniques such as magnetic separation. Thermodynamic calculation showed that removal efficiency of lead was higher when leaching iron powder, sodium citrate, and lead carbonate simultaneously than when leaching first lead carbonate by sodium citrate and then adding iron powder to the lead citrate solution. This calculation result was supported by ICP and XRD results. The XRD pattern for the iron powder recovered by magnetic separation indicated that lead is present as solid form on the powder. The recovered powder would be used as a lead source in smelting process., Japan Society of Civil Engineers, Japanese

Jig separation of plastics from scrapped copy machines
M Tsunekawa; B Naoi; S Ogawa; K Hori; N Hiroyoshi; M Ito; T Hirajima, INTERNATIONAL JOURNAL OF MINERAL PROCESSING, 76, 1-2, 67, 74, Apr. 2005
English

Acidithiobacillus thiooxidans による硫ヒ鉄鉱の溶解抑制
富岡 祐一; 広吉 直樹; 恒川 昌美, 春季大会講演集. I, 資源編, 17, 2, 1, 2, 28 Mar. 2005
Japanese

都市ごみ溶融飛灰からの金属回収のための湿式プロセス
広吉 直樹; 岸本 直輝; 恒川 昌美; 野々山 裕貴; 三谷 慎一; 三嶋 弘次, 春季大会講演集. I, 資源編, 17, 2, 185, 186, 28 Mar. 2005
Japanese

都市ごみ溶融飛灰浸出液からの硫化法による金属回収
広吉 直樹; 野々山 裕貴; 岸本 直輝; 三谷 慎一; 恒川 昌美; 三嶋 弘次, 春季大会講演集. I, 資源編, 17, 2, 183, 184, 28 Mar. 2005
Japanese

都市ごみ溶融飛灰の安定化に関する研究
広吉 直樹; 三谷 慎一; 岸本 直輝; 野々山 裕貴; 恒川 昌美; 三嶋 弘次, 春季大会講演集. I, 資源編, 17, 2, 181, 182, 28 Mar. 2005
Japanese

CARRIER-MICROENCAPSULATION FOR PREVENTING PYRITE OXIDATION (2^ Report) : Selective Adsorption of Ti-catechol complex on Pyrite over Silica
HIROYOSHI Naoki; SATUR Jacqueline; TSUNEKAWA Masami; OKAMOTO Hideyuki, 春季大会講演集. I, 資源編, 17, 2, 151, 152, 28 Mar. 2005
English

黄銅鉱浸出の最適電位に関する研究
広吉 直樹; 北川 宏子; 恒川 昌美; 恩田 真吾, 春季大会講演集. I, 資源編, 17, 2, 111, 112, 28 Mar. 2005
Japanese

キャリア浮選を用いた白色結晶質石灰石の高品位化
恒川 昌美; 本間 佑吾; 柳 庚槿; 広吉 直樹; 伊藤 真由美, 春季大会講演集. I, 資源編, 17, 2, 53, 54, 28 Mar. 2005
Japanese

低比重細粒破砕物のジグ選別における粒子流動性と最適分離条件
恒川 昌美; 堀 邦紘; 上田 将経; 越智 大司; 広吉 直樹; 伊藤 真由美; 伊藤 正澄, 春季大会講演集. I, 資源編, 17, 2, 55, 56, 28 Mar. 2005
Japanese

プラスチックのジグ選別における粒子物性の影響
恒川 昌美; 上田 将経; 堀 邦紘; 越智 大司; 広吉 直樹; 伊藤 真由美; 伊藤 正澄, 春季大会講演集. I, 資源編, 17, 2, 57, 58, 28 Mar. 2005
Japanese

物理選別による廃2次電池中の有価物回収(第2報)
恒川 昌美; 古谷 尚稔; 広吉 直樹; 伊藤 真由美; 北村 修; 市川 良二; 菊田 和幸, 春季大会講演集. I, 資源編, 17, 2, 63, 64, 28 Mar. 2005
Japanese

再生粗骨材を用いたコンクリートの強度に及ぼす湿式選別条件の影響
恒川 昌美; 上杉 浩平; 伊藤 真由美; 伊藤 正澄; 名和 豊春; 西田 法文; 広吉 直樹; 平島 剛, 春季大会講演集. I, 資源編, 17, 2, 173, 174, 28 Mar. 2005
Japanese

63. Soil Improvement Tests on Sealability Using Biogrout
Kawasaki Satoru; Murao Akira; Hiroyoshi Naoki; Tsunekawa Masami; Kaneko Katsuhiko, 研究発表会講演論文集, 17, 221, 222, 2005
日本応用地質学会, Japanese

Effect of Jarosite on the Removal of Arsenic ions in Sulfuric Acid Solution
TOMIOKA Yuichi; HIROYOSHI Naoki; KUBO Yasumasa; TSUNEKAWA Masami, Shigen-to-Sozai, 121, 12, 597, 602, 2005
Jarosite (KFe₃(SO₄)₂(OH)₆) is a secondary mineral in acidic polluted environments such as mine tailing dump, but few investigations have evaluated arsenic removal by jarosite.
This study investigated the role of jarosite in arsenic removal using flask shaking experiments in diluted sulfuric acid solutions (pH1-3). Jarosite was synthesized and the chemical composition of the jarosite was K_0.54(H₃O)_0.46Fe_2.38(SO₄)₂(OH)₆. The shaking experiments found that As(V) was removed by the jarosite but As(III) was not removed. The mechanisms of As(V) removal were adsorption on the jarosite and co-precipitation with Fe(III) extracted from jarosite. The removal of As(V) from the liquid phase were increased with increasing pH, indicating that the adsorption of As(V) and SO₄^2- is competitive or that ionic As species (H₂AsO₄^-) is selectively adsorbed. The results suggest that jarosite is a sink for As(V) in acidic polluted environments., The Mining and Materials Processing Institute of Japan, Japanese

Effects of Solution Composition on Arsenic Extraction from Arsenopyrite-Study on Arsenopyrite Dissolution in Acidic Environments (1st report)-:-Study on Arsenopyrite Dissolution in Acidic Environments (1st report) -
TOMIOKA Yuichi; HIROYOSHI Naoki; TSUNEKAWA Masami, Journal of MMIJ, 121, 8, 392, 398, 2005
Weathering of arsenopyrite is a main cause of arsenic ions in acid mine drainage, and establishing the mechanism of arsenopyrite dissolution is important to design and develop methods for suppressing the dissolution. However, the factors affecting the oxidation state of arsenic formed by arsenopyrite dissolution are not established.
This study investigated the effect of Fe(II) and Fe(III) concentrations as well as the presence of dissolved oxygen on the oxidation states of arsenic ions formed from arsenopyrite in sulfuric acid solutions by a shaking-flask method. Dissolved oxygen or Fe(III) was required as oxidant for dissolving arsenopyrite. When only Fe(III) was present as the oxidant, arsenic extracted from arsenopyrite was As(III). In the presence of dissolved oxygen, both As(III) and As(V) were formed and the concentrations of these ions were varied depending on the solution composition: As(V) was dominant when Fe(II) or Fe(III) were not added, and As(III) was dominant with high concentrations of Fe(III) and Fe(II). It was also found that under aerobic conditions arsenopyrite acts as a catalyst for the oxidation of As(III) to As(V), and that Fe(II) and Fe(III) inhibit the As(III) oxidation. Based on the results, the mechanism for arsenopyrite dissolution and the oxidation state of extracted arsenic are discussed., The Mining and Materials Processing Institute of Japan, Japanese

Normalized Redox Potential Used to Assess Chalcopyrite Column Leaching
OKAMOTO Hideyuki; NAKAYAMA Ryoichi; KUROIWA Shigeto; HIROYOSHI Naoki; TSUNEKAWA Masami, Journal of MMIJ, 121, 6, 246, 254, 2005
Column leaching experiments for two chalcopyrite concentrates agglomerated on supporting particles were performed with sulfuric acid solutions under various conditions. The results of the column leaching were compared to results of shaking flask leaching experiments reported previously.
Factors such as solution composition, coexisting minerals like pyrite, and presence of iron-oxidizing bacteria affected chalcopyrite dissolution, causing a significant variation in the copper extraction fraction vs. time plots. However, copper extraction rate from unit surface area of chalcopyrite could be determined simply from the normalized redox potential proposed previously, a function of the ferric, ferrous and cupric ion concentrations. The copper extraction rate vs. normalized potential plot for the column leaching data fitted well with the plot obtained by shaking flask experiments, and the copper extraction rate has a maximum at normalized potentials of 0.4 to 0.5. These results suggest that the normalized potential could be used to assess and optimize chalcopyrite leaching with different methods and under various conditions., The Mining and Materials Processing Institute of Japan, Japanese

低品位黒曜石の資源化
山口英志; 恒川昌美; 広吉直樹; 伊藤真由美, 資源・素材, 2005, 50, 2005
Japanese

Leaching Cementation Separation~重金属汚染土壌の新しい修復法~
伊藤真由美; 久保泰政; 広吉直樹; 恒川昌美, 資源・素材, 2005, 66, 2005
Japanese

ジグ選別におけるプラスチック粒子の分離挙動
恒川昌美; 越智大司; 堀邦紘; 上田将経; 広吉直樹; 伊藤真由美; 伊藤正澄, 資源・素材, 2005, 55, 2005
Japanese

プラスチックのジグ選別における表面物性の影響
恒川昌美; 上田将経; 堀邦紘; 越智大司; 広吉直樹; 伊藤真由美; 伊藤正澄, 資源・素材, 2005, 56, 2005
Japanese

プラスチックのジグ選別―最適分離条件と粒子の流動
堀邦紘; 恒川昌美; 上田将経; 越智大司; 広吉直樹; 伊藤真由美; 伊藤正澄, 資源・素材, 2005, 57, 2005
Japanese

ジグ選別における粒子の分離挙動と選別性の簡易評価
恒川昌美; 越智大司; 堀邦紘; 上田将経; 広吉直樹; 伊藤真由美; 伊藤正澄, 資源・素材学会北海道支部春季講演会講演要旨集, 2005, 61, 62, 2005
Japanese

Recent Topics on Environmental Contamination Caused by Minerals Containing Arsenic and its Remediation -Arsenic Dissolution and Stabilization in Mine Tailing Dumps-
Yuichi Tomioka; Naoki Hiroyoshi; Masami Tsunekawa, Resources Processing, 52, 3, 145, 150, 2005
English

The Role of Mineral Processing Technology in a Society Based on Recycling
Masami Tsunekawa; Kyoungkeun Yoo; Naoki Hiroyoshi; Mayumi Ito, Resources Processing, 52, 1, 32, 38, 2005
English

Synergistic effect of cupric and ferrous ions on active-passive behavior in anodic dissolution of chalcopyrite in sulfuric acid solutions
N Hiroyoshi; S Kuroiwa; H Miki; M Tsunekawa; T Hirajima, HYDROMETALLURGY, 74, 1-2, 103, 116, Aug. 2004
English

石灰石中の微量不純物除去に関する研究
恒川 昌美; 本間 佑吾; 広吉 直樹; 平島 剛, 春季大会講演集. I, 資源編, 16, 2, 119, 120, 29 Mar. 2004
Japanese

CARRIER-MICROENCAPSULATION FOR PREVENTING PYRITE OXIDATION (1^ Report) : Suppressive Effect of TiO_2 and Catechol on Pyrite Oxidation
HIROYOSHI Naoki; SATUR Jacqueline; TSUNEKAWA Masami; OKAMOTO Hideyuki, 春季大会講演集. I, 資源編, 16, 2, 151, 152, 29 Mar. 2004
English

硫酸還元菌による Metastable γ-MnS の合成
柳 庚槿; 笹木 圭子; 広吉 直樹; 恒川 昌美, 春季大会講演集. I, 資源編, 16, 2, 153, 154, 29 Mar. 2004
Japanese

酸性環境における硫ヒ鉄鉱の溶解メカニズムに関する研究
富岡 祐一; 広吉 直樹; 恒川 昌美; 笹木 圭子, 春季大会講演集. I, 資源編, 16, 2, 65, 66, 29 Mar. 2004
Japanese

硫酸酸性条件下での黄銅鉱アノード溶解に及ぼす液組成の影響
広吉 直樹; 恒川 昌美, 春季大会講演集. I, 資源編, 16, 2, 81, 82, 29 Mar. 2004
Japanese

ジグによる低比重細粒物質相互の比重選別
恒川 昌美; 堀 邦紘; 広吉 直樹; 丸山 正浩; 伊藤 正澄, 春季大会講演集. I, 資源編, 16, 2, 19, 20, 29 Mar. 2004
Japanese

物理選別による廃2次電池中の有価物回収
恒川 昌美; 古谷 尚稔; 広吉 直樹; 北村 修; 小島 和浩; 菊田 和幸, 春季大会講演集. I, 資源編, 16, 2, 21, 22, 29 Mar. 2004
Japanese

アンモニア/塩化物リーチングによる都市ごみ溶融飛灰からの金属回収
広吉直樹, 資源 素材学会平成16年度春季大会講演集, 2004, 2, 31, 32, 2004

Redox Potential Dependence and Optimum Potential of Chalcopyrite Leaching in Sulfuric Acid Solutions
OKAMOTO Hideyuki; NAKAYAMA Ryoichi; HIROYOSHI Naoki; TSUNEKAWA Masami, Journal of MMIJ, 120, 10/11, 592, 599, 2004
Leaching rate of chalcopyrite in sulfuric acid solutions depends on a solution redox potential, determined by a concentration ratio of ferric to ferrous ions, and it become maximum at a certain potential (an optimum potential) depending on leaching conditions. In this study, factors affecting the optimum potential were investigated.
Shaking flask leaching experiments for two chalcopyrite concentrates were performed at 303 K under various pH values, pulp densities, and concentrations of ferrous and ferric ions with or without iron-oxidizing bacteria. The experimental results were analyzed based on a reaction model for the redox potential dependence of chalcopyrite leaching, which assumes the formation of an intermediate Cu2S from chalcopyrite. Plotting the leaching rate to a normalized potential in the model showed that the rate is controlled by the normalized potential and is independent of solution compositions, pulp densities, and iron-oxidizing bacteria when ferric ions do not precipitate. A maximum rate was achieved at a certain value of the normalized potential. Converting the normalized potential to the solution redox potential gives the optimum potential for chalcopyrite leaching as a function of cupric and ferrous ion concentrations. The optimum potential increases with increasing the cupric ion concentration and decreases with the ferrous ion concentration. Cupric ions affect stronger than ferrous ions on the optimum potential., The Mining and Materials Processing Institute of Japan, Japanese

Fundamental study on the removal of Mn2+ in acid mine drainage using sulfate reducing bacteria
Kyoungkeun Yoo; Keiko Sasaki; Naoki Hiroyoshi; Masami Tsunekawa, Materials Transactions, 45, 7, 2422, 2428, 2004
Japan Institute of Metals (JIM), English

The effect of Mn2+ concentration on Mn removal by a sulfate reducing bacteria bioreactor
Kyoungkeun Yoo; Keiko Sasaki; Naoki Hiroyoshi; Masami Tsunekawa; Tsuyoshi Hirajima, Materials Transactions, 45, 7, 2429, 2434, 2004
Japan Institute of Metals (JIM), English

Freshmen Seminar at University based on Children s Experience
TSUNEKAWA Masami; HIRAJIMA Tsuyoshi; HIROYOSHI Naoki, 工学・工業教育研究講演会講演論文集, 15, 453, 454, 04 Sep. 2003
Japanese Society for Engineering Education, Japanese

Cu(II)とFe(II)を含む硫酸溶液中における黄銅鉱アノード溶解反応の速度論的検討
広吉 直樹; 黒岩 樹人; 恒川 昌美; 平島 剛, 春季大会講演集. I, 資源編, 15, 2, 114, 115, 27 Mar. 2003
Japanese

A. ferrooxidans による硫ヒ鉄鉱の溶解に及ぼす諸要因の影響
富岡 祐一; 広吉 直樹; 恒川 昌美; 平島 剛; 笹木 圭子, 春季大会講演集. I, 資源編, 15, 2, 171, 172, 27 Mar. 2003
Japanese

ジグによる低比重細粒物質相互の比重選別
恒川 昌美; 堀 邦紘; 小川 真吾; 平島 剛; 広吉 直樹; 柳生 秀樹; 丸山 正浩; 伊藤 正澄, 春季大会講演集. I, 資源編, 15, 2, 98, 99, 27 Mar. 2003
Japanese

アドバンスト・ミネラルプロセッシング技術の開発に関する調査研究
平島剛; 広吉直樹; 恒川昌美; 大木達也; 伊藤真由美; 大和田秀二; 長岡亨, 日本鉱業振興会助成研究成果報告書, 2002, 65, 70, 08 Nov. 2002
Japanese

廃蛍光管からの希土類元素の再資源化とその有効利用に関する研究(第3報)
平島 剛; 濱田 暢哉; 平井 宏尚; 恒川 昌美; 広吉 直樹; 笹木 圭子; 高橋 徹; 長野 伸泰, 春季大会講演集. I, 資源編, 14, 2, 191, 192, 28 Mar. 2002
Japanese

OA機器リサイクルプラントにおけるプラスチック選別試験
恒川 昌美; 小川 真吾; 直井 万隆; 平島 剛; 広吉 直樹; 尾谷 賢; 宮本 政博; 伊藤 正澄, 春季大会講演集. I, 資源編, 14, 2, 206, 207, 28 Mar. 2002
Japanese

黄銅鉱浸出に対する活性炭の触媒作用の機構
三木 一; 広吉 直樹; 平島 剛; 恒川 昌美, 春季大会講演集. I, 資源編, 14, 2, 69, 70, 28 Mar. 2002
Japanese

黄銅鉱浸出における鉄沈殿共存の効果
広吉 直樹; 黒岩 樹人; 平島 剛; 恒川 昌美, 春季大会講演集. I, 資源編, 14, 2, 65, 66, 28 Mar. 2002
Japanese

Ammonical thiosulphate leaching : A friendly route for processing of refractory gold ore
RATH Rajendra Kumar; HIROYOSHI Naoki; TSUNEKAWA Masami; HIRAJIMA Tsuyoshi, 春季大会講演集. I, 資源編, 14, 2, 67, 68, 28 Mar. 2002
English

硫酸溶液中における黄銅鉱アノード溶解反応のCu(II)-Fe(II)共存による活性化
広吉 直樹; 三木 一; 平島 剛; 恒川 昌美, 春季大会講演集. I, 資源編, 14, 2, 89, 90, 28 Mar. 2002
Japanese

A new reaction model for the catalytic effect of silver ions on chalcopyrite leaching in sulfuric acid solutions
N Hiroyoshi; M Arai; H Miki; M Tsunekawa; T Hirajima, HYDROMETALLURGY, 63, 3, 257, 267, Mar. 2002
English

銅鉱リーチングに関する最近の研究動向とカザフスタンにおける選鉱廃さい資源化技術の開発
広吉 直樹; 恒川 昌美; 平島 剛; 宮川 博; 星野 浩二; 神田 慶太; 土屋 春明, 資源・素材, 2001, 29, 32, 24 Sep. 2001
Japanese

ジグ選別を用いた廃OA機器リサイクルプラントの開発
直井 万隆; 恒川 昌美; 平島 剛; 広吉 直樹; 田窪 徹雄; 尾谷 賢; 宮本 政博; 伊藤 正澄, 資源・素材, 2001, 18, 18, 24 Sep. 2001
Japanese

都市ゴミ焼却飛灰のリーチング処理
広吉 直樹; 後藤 昌範; 恒川 昌美; 平島 剛, 資源・素材, 2001, 32, 32, 24 Sep. 2001
Japanese

物理選別による廃蛍光管からの希土類蛍光体回収
平井 宏尚; 平島 剛; 恒川 昌美; 広吉 直樹; 中山 和久; 笹木 圭子; 高橋 徹; 長野 伸泰, 資源・素材, 2001, 27, 27, 24 Sep. 2001
Japanese

Enhancement of chalcopyrite leaching by ferrous ions in acidic ferric sulfate solutions
N Hiroyoshi; H Miki; T Hirajima; M Tsunekawa, HYDROMETALLURGY, 60, 3, 185, 197, May 2001
English

硫酸溶液中での黄銅鉱のサイクリックボルタモグラムに及ぼす各種金属イオンの影響 : 黄銅鉱浸出の電位依存性に関する研究(第2報)
三木 一; 広吉 直樹; 平島 剛; 恒川 昌美, 一般発表(研究・業績発表)講演要旨集, 2001, 2, 189, 190, 01 Mar. 2001
Japanese

黄銅鉱浸出の臨界電位に及ぼす各種金属イオンの影響 : 黄銅鉱浸出の電位依存性に関する研究(第1報)
広吉 直樹; 黒岩 樹人; 三木 一; 平島 剛; 恒川 昌美, 一般発表(研究・業績発表)講演要旨集, 2001, 2, 187, 188, 01 Mar. 2001
Japanese

アンモニアリーチングによる都市ゴミ焼却灰中重金属の除去・回収
広吉 直樹; 後藤 昌範; 恒川 昌美; 平島 剛, 一般発表(研究・業績発表)講演要旨集, 2001, 2, 26, 27, 01 Mar. 2001
Japanese

廃蛍光管からの希土類元素の再資源化とその有効利用に関する研究(第2報) : 湿式及び乾式選別による希土類蛍光体の回収
平島 剛; 平井 宏尚; 中山 和久; 恒川 昌美; 広吉 直樹; 笹木 圭子; 高橋 徹; 長野 伸泰, 一般発表(研究・業績発表)講演要旨集, 2001, 2, 10, 11, 01 Mar. 2001
Japanese

コピー機に用いられている各種プラスチックのジグによる選別
恒川 昌美; 直井 万隆; 田窪 徹雄; 平島 剛; 広吉 直樹; 尾谷 賢; 宮本 政博; 伊藤 正澄, 一般発表(研究・業績発表)講演要旨集, 2001, 2, 4, 5, 01 Mar. 2001
Japanese

Basic Study on Separation Characteristics of Permanent Magnetic Roll Separator
TSUNEKAWA Masami; HORIE Syu; HIROYOSHI Naoki; HIRAJIMA Tsuyoshi, Journal of MMIJ, 117, 4, 277, 281, 2001
Magnetic separation experiments were carried out using a rare earth magnet type of magnetic roll separator and hematite, chalcopyrite and pyrite as feed material. The effects of feed sizes, their magnetic susceptibility and belt speed on the performance of the magnetic separator were investigated.
The difference in magnetic susceptibility of the three minerals was a little, however the order of their values was hematite>chalcopyrite>pyrite. Irrespective of feed size and belt speed, hematite was recovered as magnetic product, and pyrite as non-magnetic product. Chalcopyrite was collected as non-magnetic product at high belt speed or with coarse feed size, but with decreasing belt speed and feed size its collecting region was shifted to magnetic product zone. Under a suitable condition chalcopyrite concentrate with 96.4% recovery and 85.0% grade was obtained from the mixture of three minerals.
Based on the experimental results mentioned above, a mathematic model of particle movement in magnetic separation zone was derived, considering magnetic force, gravitation, centrifugal force, and frictional force and drag force. The movements under various conditions were calculated using the model, and the calculation results were in close agreement with the experimental results., The Mining and Materials Processing Institute of Japan, Japanese

Batch Leaching Behavior of Chalcopyrite in Acidic Ferric Sulfate Solutions : Relationship between solution redox potential and copper extraction
MIKI Hajime; HIROYOSHI Naoki; HIRAJIMA Tsuyoshi; TSUNEKAWA Masami, Journal of MMIJ, 117, 3, 215, 220, 2001
Batch leaching behavior of ground chalcopyrite (median particle diameter 6 μ mm) was investigated anaerobically by a shaking flask method. The experiments used 0.1 mol dm^-3 sulfuric acid solutions containing 0.25 mol dm^-3 ferric ions and known concentrations of ferrous and cupric ions at 303 K. The initial pulp density of the chalcopyrite was 10 kg m^-3.
When 1.00 mol dm^-3 of ferrous ions were added, copper extraction proceeded in three steps: (1) an induction period, (2) a leaching period, and (3) a stationary period. This extraction behavior can be interpreted by the following reaction model: in the induction period, copper is extracted slowly by the direct oxidation of chalcopyrite with ferric ions and the redox potential of the solution decreases due to the consumption of oxidant ferric ions. When the solution potential becomes lower than a critical potential, a leaching period, intermediate Cu₂S that is oxidized faster than chalcopyrite is formed by the reduction of chalcopyrite and copper extraction rate becomes high. When the solution potential decreases further, a stationary period, Cu₂S oxidation and copper extraction stop.
Based on this reaction model, the effects of the initial pulp density and the initial concentrations of ferric, ferrous, and cupric ions on the leaching behavior were simulated numerically. As a result, it was predicted that the induction period could be eliminated by adding more than a critical amount of cupric ions with ferrous ions and that the stationary period can be eliminated by solution potential regulation during the leaching.
The simulation agreed with the experimental results. When 1.00 mol dm^-3 ferrous ions and 0.05 mol dm^-3 cupric ions were added together, 56 % copper extraction was obtained after 9 days without an induction period, then extraction stopped. Further when the solution potential was regulated by the addition of ferric ions, 80 % of copper was extracted in two weeks. On the other hand, without the ferrous and cupric addition and the potential regulation, copper extraction was only 11 % even after 27 days., The Mining and Materials Processing Institute of Japan, Japanese

Basic Study on Separation Characteristics of Permanent Magnetic Roll Separator
TSUNEKAWA Masami; HORIE Syu; HIROYOSHI Naoki; HIRAJIMA Tsuyoshi, J. Mining and Material Processing Inst. Japan, 117, 4, 277, 281, 2001
Magnetic separation experiments were carried out using a rare earth magnet type of magnetic roll separator and hematite, chalcopyrite and pyrite as feed material. The effects of feed sizes, their magnetic susceptibility and belt speed on the performance of the magnetic separator were investigated.
The difference in magnetic susceptibility of the three minerals was a little, however the order of their values was hematite>chalcopyrite>pyrite. Irrespective of feed size and belt speed, hematite was recovered as magnetic product, and pyrite as non-magnetic product. Chalcopyrite was collected as non-magnetic product at high belt speed or with coarse feed size, but with decreasing belt speed and feed size its collecting region was shifted to magnetic product zone. Under a suitable condition chalcopyrite concentrate with 96.4% recovery and 85.0% grade was obtained from the mixture of three minerals.
Based on the experimental results mentioned above, a mathematic model of particle movement in magnetic separation zone was derived, considering magnetic force, gravitation, centrifugal force, and frictional force and drag force. The movements under various conditions were calculated using the model, and the calculation results were in close agreement with the experimental results., The Mining and Materials Processing Institute of Japan, Japanese

Batch leaching Behavior of Chalcopyrite in Acidic Ferric Sulfate Solutions- Relationship between solution redox potential and copper extraction-
MIKI Hajime; HIROYOSHI Naoki; HIRAJIMA Tsuyoshi; TSUNEKAWA Masami, J. Mining an Material Processing Inst. Japan, 117, 3, 215, 220, 2001
Batch leaching behavior of ground chalcopyrite (median particle diameter 6 μ mm) was investigated anaerobically by a shaking flask method. The experiments used 0.1 mol dm^-3 sulfuric acid solutions containing 0.25 mol dm^-3 ferric ions and known concentrations of ferrous and cupric ions at 303 K. The initial pulp density of the chalcopyrite was 10 kg m^-3.
When 1.00 mol dm^-3 of ferrous ions were added, copper extraction proceeded in three steps: (1) an induction period, (2) a leaching period, and (3) a stationary period. This extraction behavior can be interpreted by the following reaction model: in the induction period, copper is extracted slowly by the direct oxidation of chalcopyrite with ferric ions and the redox potential of the solution decreases due to the consumption of oxidant ferric ions. When the solution potential becomes lower than a critical potential, a leaching period, intermediate Cu₂S that is oxidized faster than chalcopyrite is formed by the reduction of chalcopyrite and copper extraction rate becomes high. When the solution potential decreases further, a stationary period, Cu₂S oxidation and copper extraction stop.
Based on this reaction model, the effects of the initial pulp density and the initial concentrations of ferric, ferrous, and cupric ions on the leaching behavior were simulated numerically. As a result, it was predicted that the induction period could be eliminated by adding more than a critical amount of cupric ions with ferrous ions and that the stationary period can be eliminated by solution potential regulation during the leaching.
The simulation agreed with the experimental results. When 1.00 mol dm^-3 ferrous ions and 0.05 mol dm^-3 cupric ions were added together, 56 % copper extraction was obtained after 9 days without an induction period, then extraction stopped. Further when the solution potential was regulated by the addition of ferric ions, 80 % of copper was extracted in two weeks. On the other hand, without the ferrous and cupric addition and the potential regulation, copper extraction was only 11 % even after 27 days., The Mining and Materials Processing Institute of Japan, Japanese

浮選による廃蛍光体からの希土類蛍光体の回収
平島 剛; 中山 和久; 恒川 昌美; 広吉 直樹; 笹木 圭子; 高橋 徹; 長野 伸泰, 廃棄物学会研究発表会講演論文集 = Proceedings of the Annual Conference of the Japan Society of Waste Management Experts, 11, 1, 495, 497, 10 Oct. 2000
廃棄物学会, Japanese

OA機器に使用されている各種プラスチックのジグによる選別
恒川 昌美; 直井 万隆; 田窪 徹雄; 平島 剛; 広吉 直樹; 尾谷 賢; 宮本 政博; 伊藤 正澄, 廃棄物学会研究発表会講演論文集 = Proceedings of the Annual Conference of the Japan Society of Waste Management Experts, 11, 1, 430, 432, 10 Oct. 2000
廃棄物学会, Japanese

種々の物理選別における都市ゴミ焼却灰中の有価物の挙動
恒川 昌美; 田窪 徹雄; 平島 剛; 広吉 直樹; 堀江 周, 一般発表(研究・業績発表)講演要旨集, 2000, 2, 158, 159, 01 Mar. 2000
Japanese

廃蛍光管からの希土類元素の再資源化とその有効利用に関する研究 -希土類蛍光体の回収-
平島 剛; 中山 和久; 恒川 昌美; 広吉 直樹; 笹木 圭子; 高橋 徹; 長野 伸泰, 一般発表(研究・業績発表)講演要旨集, 2000, 2, 169, 170, 01 Mar. 2000
Japanese

FE (II) による黄銅鉱浸出促進に関する研究 (第4報) -Cu (II) 添加と電位調節の効果-
三木 一; 広吉 直樹; 平島 剛; 恒川 昌美, 一般発表(研究・業績発表)講演要旨集, 2000, 2, 127, 128, 01 Mar. 2000
Japanese

硫酸溶液中における黄銅鉱浸出の溶液電位依存性とAg (I) の触媒作用
広吉 直樹; 荒井 政俊; 三木 一; 平島 剛; 恒川 昌美, 一般発表(研究・業績発表)講演要旨集, 2000, 2, 129, 130, 01 Mar. 2000
Japanese

Sar Chesmeh 斑岩銅鉱山における金資源とその回収
SALARI RAD M. M.; 恒川 昌美; 岩瀬 広幸; 中山 和久; 平島 剛; 広吉 直樹; 米田 哲朗, 一般発表(研究・業績発表)講演要旨集, 2000, 2, 133, 134, 01 Mar. 2000
Japanese

Model for ferrous-promoted chalcopyrite leaching
Naoki Hiroyoshi; Hajime Miki; Tsuyoshi Hirajima; Masami Tsunekawa, Hydrometallurgy, 57, 1, 31, 38, 2000
Elsevier Science Publishers B.V., English

Inhibitory effect of iron-oxidizing bacteria on ferrous-promoted chalcopyrite leaching
N Hiroyoshi; M Hirota; T Hirajima; M Tsunekawa, BIOTECHNOLOGY AND BIOENGINEERING, 64, 4, 478, 483, Aug. 1999
English

高硫黄石炭ずり浸出水の水質制御に関する基礎的研究
伊藤真由美; 山田龍一; 恒川昌美; 平島剛; 広吉直樹, 資源・素材学会春季大会講演集, 2, 17, 29 Mar. 1999
Japanese

石炭の脱硫浮選に関する基礎的研究 (第3報)
伊藤真由美; 湯川健太郎; 恒川昌美; 平島剛; 広吉直樹, 資源・素材学会春季大会講演集, 2, 18, 29 Mar. 1999
Japanese

硫酸酸性溶液中での黄銅鉱浸出に及ぼす鉄(II)イオンの影響
広吉 直樹; 前田 英人; 恒川 昌美; 平島 剛, 一般発表(研究・業績発表)講演要旨集, 1997, 1, 204, 204, 25 Mar. 1999
Japanese

バクテリアリーチングにおける鉄酸化細菌の役割に関する疑問-黄銅鉱の浸出実験結果に基づく考察-
広吉 直樹; 恒川 昌美; 平島 剛; 廣田 雅彦, 一般発表(研究・業績発表)講演要旨集, 1997, 1, 25, 25, 25 Mar. 1999
Japanese

石炭浮選における脱灰性評価法
恒川 昌美; 今 行忠; 平島 剛; 広吉 直樹; 伊藤 真由美, 一般発表(研究・業績発表)講演要旨集, 1997, 1, 186, 186, 25 Mar. 1999
Japanese

石炭の脱流浮選に関する基礎的研究
伊藤 真由美; 恒川 昌美; 平島 剛; 広吉 直樹, 一般発表(研究・業績発表)講演要旨集, 1997, 1, 187, 187, 25 Mar. 1999
Japanese

Fe(II)による黄銅鉱浸出促進に関する研究(第2報)-Fe(II)-Cu(II)混合溶液で前処理した黄銅鉱電極のアノード分極特性-
広吉 直樹; 荒井 政俊; 三木 一; 平島 剛; 恒川 昌美, 一般発表(研究・業績発表)講演要旨集, 1999, 2, 113, 113, 01 Mar. 1999
Japanese

Fe(II)による黄銅鉱進出促進に関する研究(第1報)-Fe(III)による黄銅鉱酸化に及ぼすFe(II)の影響とCu(II)の重要性-
広吉 直樹; 三木 一; 平島 剛; 恒川 昌美, 一般発表(研究・業績発表)講演要旨集, 1999, 2, 111, 112, 01 Mar. 1999
Japanese

Fe(II)による黄銅鉱浸出促進に関する研究(第3報)-進出促進を説明する反応モデルとその熱力学的成立条件-
広吉 直樹; 三木 一; 平島 剛; 恒川 昌美, 一般発表(研究・業績発表)講演要旨集, 1999, 2, 114, 115, 01 Mar. 1999
Japanese

Sar-Cheshmeh鉱石中の金の存在状態と選別プロセスにおけるその挙動
ラド サラリ; 岩瀬 広幸; 恒川 昌美; 平島 剛; 広吉 直樹; 米田 哲朗, 一般発表(研究・業績発表)講演要旨集, 1999, 2, 21, 22, 01 Mar. 1999
Japanese

高硫黄石炭ずり浸出水の水質制御に関する基礎的研究
伊藤 真由美; 山田 龍一; 恒川 昌美; 平島 剛; 広吉 直樹, 一般発表(研究・業績発表)講演要旨集, 1999, 2, 17, 17, 01 Mar. 1999
Japanese

石炭の脱硫浮選に関する基礎的研究(第3報)
伊藤 真由美; 湯川 健太郎; 恒川 昌美; 平島 剛; 広吉 直樹, 一般発表(研究・業績発表)講演要旨集, 1999, 2, 18, 18, 01 Mar. 1999
Japanese

Basic Study on Separation of Pyrite from Coal by Flotation Using Ferric Solution
ITO Mayumi; TSUNEKAWA Masami; HIRAJIMA Tsuyoshi; HIROYOSHI Naoki; YUKAWA Kentaro, Shigen-to-Sozai, 115, 10, 737, 742, 1999
Flotation behavior of coal and pyrite was investigated by bubble pick-up tests and Hallimond tube flotation. Flotation recovery of coal and pyrite was high in the acidic region and decreased with increasing pH. In solutions containing iron species the recovery of pyrite decreased drastically at pHs where iron hydroxide was precipitated, but coal flotation was not influenced. Zeta potentials of pyrite and iron hydroxide precipitates were measured under various conditions and the formed precipitates were characterized by XRD, FTIR, and settling velocity measurements. The precipitates formed at the pH where depression of pyrite flotation occurred were very fine sized amorphous ferric hydroxides, which preferentially adhered on pyrite surfaces and rendered pyrite hydrophilic. Selective flotation of artificial high sulfur coal (mixture of coal and pyrite) was performed in the following three solutions containing ferric iron adjusted to pH 2.5 : a) prepared with ferric sulfate, b) prepared by oxidizing ferrous sulfate with iron-oxidizing bacteria (Thiobacillus ferrooxidans), and c) prepared by centrifuging the solution of b). In all solutions coal was selectively recovered as a froth product with high combustible recovery and high separation efficiency., The Mining and Materials Processing Institute of Japan, Japanese

Effects of Several Inhibitors to Thiobacillus ferrooxidans on Ferrous Promoted Chalcopyrite Leaching
HIROYOSHI Naoki; MIKI Hajime; HIRAJIMA Tsuyoshi; TSUNEKAWA Masami, Journal of MMIJ, 115, 3, 172, 176, 1999
Ferrous ions enhance copper extraction from chalcopyrite in sulfuric acid solutions in air at ambient temperatures, because they promote chalcopyrite oxidation with dissolved oxygen. However iron-oxidizing bacteria such as Thiobacillus ferrooxidans rapidly consume ferrous ions, suppressing copper extraction. In this paper, three compounds were used to inhibit ferrous oxidation by T. ferrooxidans and their effects on ferrous promoted chalcopyrite leaching were investigated in the presence and absence of the bacteria. Sodium lauryl sulfate and tannic acid suppressed not only the bacterial ferrous oxidation but also the chalcopyrite oxidation with dissolved oxygen, resulting in a suppression of copper extraction. High concentrations of sulfuric acid (> 0.05 mol dm-3) suppressed the bacterial ferrous oxidation and promoted chalcopyrite oxidation with dissolved oxygen, causing enhanced copper extraction., The Mining and Materials Processing Institute of Japan, English

Basic Study on Sepatation of Pyrite from Coal by Flotation Using Ferric Solution
ITO Mayumi; TSUNEKAWA Masami; HIRAJIMA Tsuyoshi; HIROYOSHI Naoki; YUKAWA Kentaro, Shigen-to-Sozai, 115, 10, 737, 742, 1999
Flotation behavior of coal and pyrite was investigated by bubble pick-up tests and Hallimond tube flotation. Flotation recovery of coal and pyrite was high in the acidic region and decreased with increasing pH. In solutions containing iron species the recovery of pyrite decreased drastically at pHs where iron hydroxide was precipitated, but coal flotation was not influenced. Zeta potentials of pyrite and iron hydroxide precipitates were measured under various conditions and the formed precipitates were characterized by XRD, FTIR, and settling velocity measurements. The precipitates formed at the pH where depression of pyrite flotation occurred were very fine sized amorphous ferric hydroxides, which preferentially adhered on pyrite surfaces and rendered pyrite hydrophilic. Selective flotation of artificial high sulfur coal (mixture of coal and pyrite) was performed in the following three solutions containing ferric iron adjusted to pH 2.5 : a) prepared with ferric sulfate, b) prepared by oxidizing ferrous sulfate with iron-oxidizing bacteria (Thiobacillus ferrooxidans), and c) prepared by centrifuging the solution of b). In all solutions coal was selectively recovered as a froth product with high combustible recovery and high separation efficiency., The Mining and Materials Processing Institute of Japan, Japanese

Ferrous promoted chalcopyrite leaching
N Hiroyoshi; H Miki; T Hirajima; M Tsunekawa, HYDROMETALLURGY OF COPPER, 4, 231, 243, 1999
English

Effects of Several Inhibitors to Thiobacillus ferrooxidans on Ferrous Promoted Chalcopyrite Leaching
Naoki HIROYOSHI; Hajime MIKI; Tsuyoshi HIRAJIMA; Masami TSUNEKAWA, J. Mining and Material Processing Inst. Japan, 115, 3, 172, 176, 1999
Ferrous ions enhance copper extraction from chalcopyrite in sulfuric acid solutions in air at ambient temperatures, because they promote chalcopyrite oxidation with dissolved oxygen. However iron-oxidizing bacteria such as Thiobacillus ferrooxidans rapidly consume ferrous ions, suppressing copper extraction. In this paper, three compounds were used to inhibit ferrous oxidation by T. ferrooxidans and their effects on ferrous promoted chalcopyrite leaching were investigated in the presence and absence of the bacteria. Sodium lauryl sulfate and tannic acid suppressed not only the bacterial ferrous oxidation but also the chalcopyrite oxidation with dissolved oxygen, resulting in a suppression of copper extraction. High concentrations of sulfuric acid (> 0.05 mol dm-3) suppressed the bacterial ferrous oxidation and promoted chalcopyrite oxidation with dissolved oxygen, causing enhanced copper extraction., The Mining and Materials Processing Institute of Japan, English

黄銅鉱浸出における鉄(III),鉄(II)イオンおよび鉄酸化細菌の役割 -鉄(II)イオンによる黄銅鉱酸素酸化浸出の促進と関連して-
広吉 直樹; 恒川 昌美; 平島 剛, 資源・素材, 1998, 3, 173, 176, Nov. 1998
Japanese

レアアースロール磁選機の分離挙動に関する基礎的研究
恒川 昌美; 堀江 周; 平島 剛; 広吉 直樹, 一般発表(研究・業績発表)講演要旨集, 1998, 2, 95, 95, 01 Mar. 1998
Japanese

鉄(II)イオンを促進剤とする黄銅鉱酸素酸化浸出における鉄酸化細菌の生育抑制とその効果
広吉 直樹; 恒川 昌美; 平島 剛, 一般発表(研究・業績発表)講演要旨集, 1998, 2, 9, 9, 01 Mar. 1998
Japanese

鉄(II)イオンを促進剤とする黄銅鉱酸素酸化浸出の過程における鉄(III)イオンの生成
広吉 直樹; 三木 一; 前田 英人; 恒川 昌美; 平島 剛, 一般発表(研究・業績発表)講演要旨集, 1998, 2, 10, 10, 01 Mar. 1998
Japanese

石炭の脱硫浮選に関する基礎的研究 (第2報)
伊藤真由美; 恒川昌美; 平島剛; 広吉直樹, 資源・素材学会春季大会講演集, 21, Mar. 1998
Japanese

微粉炭浮選における脱灰性の評価と鉱物質単体分離度の推定
恒川昌美; 今行忠; 伊藤真由美; 平島剛; 広吉直樹, 資源・素材学会春季大会講演集, 22, Mar. 1998
Japanese

石炭の脱硫浮選に関する基礎的研究(第2報)
伊藤 真由美; 恒川 昌美; 平島 剛; 広吉 直樹, 一般発表(研究・業績発表)講演要旨集, 1998, 2, 21, 21, 01 Mar. 1998
Japanese

微粉炭浮選における脱灰性の評価と鉱物質単体分離度の推定
恒川 昌美; 今 行忠; 伊藤 真由美; 平島 剛; 広吉 直樹, 一般発表(研究・業績発表)講演要旨集, 1998, 2, 22, 22, 01 Mar. 1998
Japanese

Desulfurization flotation of imaginary high sulfur coal using the ferruginous solution.
ITO MAYUMI; YUKAWA KENTARO; TSUNEKAWA MASAMI; HIRASHIMA TSUYOSHI; HIROYOSHI NAOKI, 資源・素材学会北海道支部春季講演会講演要旨集, 1998, 15, 16, 1998
Japanese

Basic research on property control of the leach from high sulfur coal.
ITO MAYUMI; YAMADA RYUICHI; TSUNEKAWA MASAMI; HIRASHIMA TSUYOSHI; HIROYOSHI NAOKI, 資源・素材学会北海道支部春季講演会講演要旨集, 1998, 17, 18, 1998
Japanese

Leaching of Low Grade Copper Ore.
HIROYOSHI Naoki; TSUNEKAWA Masami; HIRAJIMA Tsuyoshi, Resources Processing, 45, 4, 263, 268, 1998
The Resources Processing Society of Japan, Japanese

Ferrous Promoted Chalcopyrite Leaching -Ferric formation and its effects on the leaching-
HIROYOSHI Naoki; MAEDA Hideto; MIKI Hajime; HIRAJIMA Tsuyoshi; TSUNEKAWA Masami, Journal of MMIJ, 114, 11, 795, 800, 1998
This paper shows that ferrous ions are more useful for leaching chalcopyrite than oxidant ferric ions in sulfuric acid solutions in air at ambient temperatures. Leaching experiments and dissolved oxygen consumption measurements were carried out with a very pure chalcopyrite and 0.001 ∼ 1 mol dm-3 sulfuric acid containing 0 ∼ 0.1 mol dm-3 ferrous or ferric ions at 303 K. Chalcopyrite oxidation with dissolved oxygen was promoted by ferrous ions and was suppressed by ferric ions. As a result, the amount of extracted copper was higher with ferrous ions than with ferric ions in air. During the ferrous promoted chalcopyrite leaching, extracted copper ions catalyzed oxidation of ferrous ions to ferric ions which suppressed copper extraction. This result indicates that higher leaching rates can be achieved by reducing the ferric ions formed during the leaching., The Mining and Materials Processing Institute of Japan, English

微粒石炭浮選における脱灰性の評価と単体分離度の推定(共著)
恒川昌美; 今行忠; 伊藤真由美; 平島剛; 広吉直樹, 資源と素材, 114, 6, 421, 425, 1998

A New Method to Characterize the Flotation Performance of Fine Coal
Proc. 13th Int. Coal Preparation Congress, 1, 397, 406, 1998

Leaching of Low Grade Copper Ore
HIROYOSHI Naoki; TSUNEKAWA Masami; HIRAJIMA Tsuyoshi, RESOURCES PROCESSING, 45, 4, 263, 268, 1998
The Resources Processing Society of Japan, Japanese

Ferrous Promoted Chalcopyrite Leaching-Ferric formation and its effects on the leaching-
Naoki HIROYOSHI; Hideto MAEDA; Hajime MIKI; Tsuyoshi HIRAJIMA; Masami TSUNEKAWA, J. Mining and Material Processing Inst. Japan, 114, 11, 795, 800, 1998
This paper shows that ferrous ions are more useful for leaching chalcopyrite than oxidant ferric ions in sulfuric acid solutions in air at ambient temperatures. Leaching experiments and dissolved oxygen consumption measurements were carried out with a very pure chalcopyrite and 0.001 ∼ 1 mol dm-3 sulfuric acid containing 0 ∼ 0.1 mol dm-3 ferrous or ferric ions at 303 K. Chalcopyrite oxidation with dissolved oxygen was promoted by ferrous ions and was suppressed by ferric ions. As a result, the amount of extracted copper was higher with ferrous ions than with ferric ions in air. During the ferrous promoted chalcopyrite leaching, extracted copper ions catalyzed oxidation of ferrous ions to ferric ions which suppressed copper extraction. This result indicates that higher leaching rates can be achieved by reducing the ferric ions formed during the leaching., The Mining and Materials Processing Institute of Japan, English

A Method to Characterize Flotation Performance of Fine Coal and Estimate its Liberation
TSUNAKAWA M., J. Mining and Material Processing Inst Japan, 114, 6, 421, 425, 1998

Biotechnology for Waste Treatment and Recycling
HIROYOSHI Naoki, Proceedings of the Institute of Electrostatics Japan, 21, 4, 166, 169, 31 Jul. 1997
静電気学会, Japanese

Enhancement in Bacterial Leaching of Chalcopyrite by Surfactant Addition
Proceedings of the 20th International Mineral Processing Congress, 4, 546, 547, 1997

A case of ferrous sulfate addition enhancing chalcopyrite leaching
Naoki Hiroyoshi; Masahiko Hirota; Tsuyoshi Hirajima; Masami Tsunekawa, Hydrometallurgy, 47, 1, 37, 45, 1997
Elsevier, English

Mineral Bioprocessingへの挑戦〜北大・鉱物処理工学研究室における最近の研究〜
伊藤 真由美; 恒川 昌美; 平島 剛; 広吉 直樹; 笹木 圭子, 資源・素材, 1996, 1, 67, 67, 21 Oct. 1996
Japanese

黄銅鉱のバクテリアリ-チングに及ぼす菌体量の影響
広吉 直樹; 廣田 雅彦; 恒川 昌美; 平島 剛, 一般発表(研究・業績発表)講演要旨集, 1996, 1, 227, 227, 29 Mar. 1996
Japanese

界面活性剤添加による黄銅鉱のバクテリアリ-チングの浸出性改善-数種の界面活性剤の効果の比較-
広吉 直樹; 西田 信一; 恒川 昌美; 平島 剛, 一般発表(研究・業績発表)講演要旨集, 1996, 1, 228, 228, 29 Mar. 1996
Japanese

強酸性領域における黄鉄鉱の浮選挙動
伊藤 真由美; 広吉 直樹; 恒川 昌美; 平島 剛, 一般発表(研究・業績発表)講演要旨集, 1996, 1, 153, 153, 29 Mar. 1996
Japanese

Feed grain size and limitative ash content in coal flotation.
TSUNEKAWA MASAMI; KON YUKITADA; HIRAJIMA TSUYOSHI; ITO MAYUMI; HIROYOSHI NAOKI, 資源・素材学会北海道支部春季講演会講演要旨集, 1996, 5, 6, 1996
Japanese

Simple and Rapid Cell Growth Estimation Method for Thiobacillus ferrooxidans and the Growth Rate in the Presence of Polyoxyethylenes
HIROYOSHI Naoki; ITO Mayumi; TSUNEKAWA Masami; HIRAJIMA Tsuyoshi, Journal of the Mining and Materials Processing Institute of Japan, 112, 3, 171, 175, 1996
資源・素材学会, Japanese

Simple and Rapid Call Growth Estimation Method for Thlobacillus Ferrooxidans and the Growth Rate in the Presence of Polyoxyethylene
Naoki HIROYOSHI; Mayumi ITO; Masami TSUNEKAWA; Tsuyoshi HIRAJIMA, J.Mining and Materials Processing Inst.Japan, 112, 3, 171, 175, 1996

ポリオキシエチレンソルビタンモノラウレートによる黄銅鉱のバクテリアリーチングの浸出性改善
広吉 直樹; 中村 剛; 恒川 昌美; 平島 剛, 一般発表(研究・業績発表)講演要旨集, 1995, 1, 42, 42, 28 Mar. 1995
Japanese

鉄酸化細菌の増殖挙動の簡便測定法とその応用 : ポリオキシエチレン化合物存在下での増殖挙動の把握
広吉 直樹; 伊藤 真由美; 恒川 昌美; 平島 剛, 一般発表(研究・業績発表)講演要旨集, 1995, 1, 33, 33, 28 Mar. 1995
Japanese

Effects of Phosphatidylethanolamine on Bacterial Leaching of Chalcopyrite by Thiobacillus ferrooxidans
HIROYOSHI Naoki; TSUNEKAWA Masami; HIRAJIMA Tsuyoshi; SAWADA Mitsuru, Journal of the Mining and Materials Processing Institute of Japan, 111, 1, 43, 47, 1995
資源・素材学会, Japanese

Enhancement in Bacterial Lerching of Chalcopyrite by Polyoxyethylene Sorbitan Monolaurate Addition
Naoki HIROYOSHI; Takeshi NAKAMURA; Masami TSUNEKAWA; Tsuyoshi HIRAJIMA; Mayumi ITO, J.Mining and Material Processing Iust.Japan, 111, 13, 943, 948, 1995
資源・素材学会, English

Effects of Phosphatidylethanolamine on Bacterial Leaching of chalcopyrite by Thiobacillus ferroocidans
Naoki HIROYOSHI; Masami TSUNEKAWA; Tsuyoshi HIRAJIMA; Mitsuru SAWADA, J. Mining and Materials Processing Inst. Japan, 111, 1, 43, 47, 1995

鉄酸化細菌の簡便な増殖測定法
広吉直樹; 伊藤真由美; 恒川昌美; 平島剛, 資源・素材学会北海道支部春季講演会講演要旨集, 1994, 3, 4, 1994
Japanese

硫化鉱のバクテリアリーチングの基礎実験法
資源と素材, 109, 7, 558, 561, 1993

Experimental Methods for Bacterial Leaching of Sulfide Minerals
J. Mining and Materials Process. Inst. Japan, 109, 7, 558, 561, 1993

Thiobacillus ferrooxidans による黄銅鉱精鉱の微生物学的浸出に及ぼすりん脂質の影響-Phosphatidylglycerol の影響-
広吉 直樹; 恒川 昌美; 平島 剛; 高森 隆勝, 資源と素材, 108, 2, 129, 133, 1992

Effects of Phospholipid Bacterial Leaching of Chalcopyrite Concentrate by Thiobacillus ferrooxidans-Effect of Phosphatidylglcerol-
Naoki HIROYOSHI; Masami TSUNEKAWA; Tsuyoshi HIRAJIMA; Takakatsu TAKAMORI, J. Mining and Materials Processing. Inst. Japan, 108, 2, 129, 133, 1992

亜鉛精鉱の微生物学的浸出とインジウムの浸出挙動
北海道応用地学合同研究会論文集, 2,14-18, 1991

Dissolution Behavior of Zinc, Indium and Iron in Bacterial Leaching Process of Sphalerite Concentrate Containing Indium
Hokkaido Geotechnics, 2,14-18, 1991

Comparison of the suppressive effect of ferric- and ferrous-catechol complexes on pyrite oxidation
X. Li; N. Hiroyoshi; K. Naruwa; M. Ito; C.B. Tabelin, Proceedings of International Symposium on Earth Science and Technology, 605, 607
English, Summary international conference

微生物資源工学(共著)
コロナ社, 1996

Microbiology and Its Applications to Resources Engineering
CORONA PUBLISHING CO. , LTD., 1996

大学院共通授業科目（一般科目）：自然科学・応用科学, 2024年, 修士課程, 大学院共通科目

金属製錬工学, 2024年, 修士課程, 工学院

金属製錬工学特論, 2024年, 修士課程, 工学院

金属製錬工学特論, 2024年, 博士後期課程, 工学院

資源化学Ⅰ, 2024年, 学士課程, 工学部

資源化学Ⅱ, 2024年, 学士課程, 工学部

資源循環システム実験Ⅰ, 2024年, 学士課程, 工学部

応用数学Ⅰ, 2024年, 学士課程, 工学部

資源循環システム実験Ⅲ, 2024年, 学士課程, 工学部

資源循環システムⅠ, 2024年, 学士課程, 工学部

資源循環工学, 2024年, 学士課程, 工学部

資源循環システム実験Ⅱ, 2024年, 学士課程, 工学部

教科教育法（工業Ⅱ）, 2024年, 学士課程, 教育学部

科学・技術の世界, 2024年, 学士課程, 全学教育

資源工学概論, 2024年, 学士課程, 工学部

地下水工学, 2024年, 学士課程, 工学部

Selective and intelligent aggregation system using biological functions
Grants-in-Aid for Scientific Research
01 Apr. 2024 - 31 Mar. 2027
中島 一紀; 廣吉 直樹; 五十嵐 健輔; 高野 力
Japan Society for the Promotion of Science, Grant-in-Aid for Scientific Research (B), Hokkaido University, 24K03104

Development of gold extraction method for green mining and its application to refractory ore processing
Grants-in-Aid for Scientific Research
01 Apr. 2023 - 31 Mar. 2026
廣吉 直樹; 伊藤 真由美; PARK ILHWAN
硫ヒ鉄鉱などの硫化鉱物の結晶中に金が閉じ込められた形で存在する難処理金鉱石から，毒性の高いシアンに替わる安全な溶媒を用いて金を抽出する技術を開発することを目指して，チオ硫酸アンモニア溶液を用いたヒ素含有難処理鉱から金の浸出・回収法について検討した.
金粉末と硫ヒ鉄鉱の混合物を用いたモデル実験を行い, チオ硫酸アンモニウム溶液中での金の抽出に及ぼす硫ヒ鉄鉱の影響を調べた. このモデル実験では硫化鉱物の結晶中に金が含まれているわけではないが, それでも硫ヒ鉄鉱が共存すると金の抽出率が著しく低下した.SEM-EDX や XPS による表面分析の結果, 浸出の過程で金の表面には硫化銅, 酸化鉄および元素硫黄などの薄膜が生成することが確かめられたが, この薄膜は硫ヒ素鉄鉱の共存の有無に関わらず生成しており, 金の浸出を抑制する不動態膜とは考えられない．溶液分析の結果によれば, 硫ヒ鉄鉱が共存する場合には存在しない時よりも急速に 金の浸出に不可欠なチオ硫酸イオンが分解することが確かめられたことから, 硫ヒ鉄鉱の共存によるチオ硫酸イオンの分解が金浸出抑制の主原因であるものと考えられる.
浸出貴液からの金の回収法として，アルミニウムを電子供与体，活性炭を電子伝達媒体粒子とするセメンテーション法について検討した．溶液分析や電子顕微鏡観察などの結果，金はアルミニウムの表面に付着した活性炭上に還元析出して回収されることが確認された．活性炭を用いた場合，溶液中に浸出触媒として含まれる銅も金とともに非選択的に還元析出してしまったが，活性炭の代わりに半導体性の酸化鉄 (マグネタイトあるいはヘマタイト) を用いて実験したところ，金のみが選択的に還元析出することを見出した．
Japan Society for the Promotion of Science, Grant-in-Aid for Scientific Research (C), Hokkaido University, 23K04642

New development on carrier micro-encapsulation for prevending acid mine drainage formation
Grants-in-Aid for Scientific Research
01 Apr. 2017 - 31 Mar. 2020
Hiroyoshi Naoki
Carrier micro-encapsulation (CME) was studied as a new method to suppress oxidative dissolution of pyrite, causing the formation of acid mine drainage. A novel technique of CME using Fe or Al ions, which are easy to be obtained at mine site, was proposed and its suppressive effects on pyrite dissolution was confirmed based on electrochemical studies and surface analysis. When Ti and Fe-catecholate complexes coexisted, a high acid resistant protective coating was formed on pyrite surface, and it suppressed cathodic reduction of oxygen on the mineral surface and pyrite oxidation.
Japan Society for the Promotion of Science, Grant-in-Aid for Scientific Research (B), Hokkaido University, 17H03503

Understanding of host minerals for radioactive cesium fixation and proposal for reasonable volume reduction of the contaminated soils
Grants-in-Aid for Scientific Research
01 Apr. 2015 - 31 Mar. 2018
Sato Tsutomu
Detail observations for the contaminated soils particles collected from different areas in Fukushima prefecture,percentage of the contaminated particles was limited to be only 0.3%.The contaminated particles were categorized to agglomerated weathered biotite, complex of organic matter and weathered biotite and weathered biotite.From the observation,the weathered biotite would be dominant host of radioactive cesium in Fukushima prefecture and supported by adsorption experiments.From our observation,spherical glass particles (so called "Cs ball") were not detected. Therefore, we can conclude that the host of radioactive cesium is the weathered biotite in Fukushima prefecture.Our laboratory experiments showed that the weathered biotite can be collected by magnet.After ball milling crushing and ultra sonic dispersion for agglomerated weathered biotite and complex of organic matter and weathered biotite, the contaminated particles would be efficiently collected by magnetic cobbing machine.
Japan Society for the Promotion of Science, Grant-in-Aid for Scientific Research (B), Hokkaido University, 15H04222

Development of environment-friendly preservation material with self-healing function
Grants-in-Aid for Scientific Research
01 Apr. 2012 - 31 Mar. 2015
KAWASAKI SATORU; HIROYOSHI Naoki; HATA Toshiro
Self-healing and environment-friendly novel preservation materials for remains, relics, stone cultural heritages and others were developed by using the function of microorganisms living in nature. The preservation materials were primarily composed of calcium carbonate or calcium phosphate compounds which were typical cement substances in nature. In addition, mechanical properties of soils using the preservation materials and the population of microorganisms were investigated during the testing periods, and the validity of the newly developed preservation materials were evaluated. As a result, a possibility that they were effective as self-healing and environment-friendly preservation materials was obtained approximately.
Japan Society for the Promotion of Science, Grant-in-Aid for Scientific Research (B), Hokkaido University, 24300299

Selective recovery of precious metals from solution using magnetite
Grants-in-Aid for Scientific Research
01 Apr. 2011 - 31 Mar. 2014
HIROYOSHI Naoki; ITO Mayumi; FUKUSHIMA Masami
A new method to recover precious metals like gold and platinum group metals selectively from the solutions containing common metal ions. Reduction potential of the precious metal ions are high and they are reduced and precipitated on magnetite surface, but reduction potential of common metals like copper and zinc are lower than that of magnetite and they are not reduced on magnetite surface. Magnetic separation can be used to recover precious metal loaded magnetite from the suspension of precious metal ores and scraps. It was confirmed that slag magnetite (a magnetic portion of crushed copper converter slag) can be used to recover precious metals.
Japan Society for the Promotion of Science, Grant-in-Aid for Scientific Research (B), Hokkaido University, 23360398

Self-sealability of fractures in rock and its application to fracture and strength control
Grants-in-Aid for Scientific Research
01 Apr. 2010 - 31 Mar. 2014
KANEKO Katsuhiko; KAWASAKI Satoru; NARA Yoshitaka; ITO Mayumi; MUKUNOKI Toshifumi; HIROYOSHI Naoki; SAKAGUCHI Kiyotoshi; HARADA Syusaku
A series of experimental studies on the sealability of fracture has been performed and its application to geotechnical engineering has been discussed. Firstly, analyzing the influence of environments on the sub-critical crack growth in rock, the mechanism of crack growth has been clarified. Secondarily, the self-sealing process of fracture in the rocklike material in water was investigated and the mechanism of self-sealing was clarified. Thirdly, the process of fracture propagation was analyzed numerically and a design method to control fracture propagation, i.e., crack orientation and so on. From these results, a method to estimate the long-term strength of rock has been proposed. Furthermore it is pointed out that the strength of rock can be controlled by controlling the environmental condition.
Japan Society for the Promotion of Science, Grant-in-Aid for Scientific Research (A), Hokkaido University, 22246114

Advanced jig separation technology for resource recycling and wettability control of plastics
Grants-in-Aid for Scientific Research
2011 - 2013
ITO Mayumi; HIROYOSHI Naoki
Industrial systems and daily life in Japan are shifting to a society based on recycling to reduce energy and resource consumption and efficient separation technology of valuable component from used products is important. The authors have developed the RETAC jig (a modified TACUB jig) and the RETAC jig can separate relatively low density particles such as plastics. To further improve the separation ability, a hybrid jig (a RETAC jig with an air bubbler under the particle bed), which can separate plastics having similar specific gravities by the differences in the wettabilities of the particles was developed. Surface modification of plastics with similar wettability enabling separation in the hybrid jig and precise control of the wettability of plastic surfaces are investigated. Effect of bubble size on apparent density of particles was also investigated and recovery system of floating and suspending particles was developed.
Japan Society for the Promotion of Science, Grant-in-Aid for Scientific Research (C), Hokkaido University, 23560990

Proposal of environment-friendly preservation material using microbial function
Grants-in-Aid for Scientific Research
2009 - 2011
KAWASAKI Satoru; HIROYOSHI Naoki; HATA Toshiro
An environment-friendly novel preservation material for remains, relics, stone cultural heritages, etc. was produced by using the function of microorganisms living in nature. The preservation material was primarily composed of silica which was one of the typical cement substances. In addition, mechanical properties of soils using the preservation material made and the numbers of microorganisms were investigated during the testing periods, and the validity of the newly developed preservation material was evaluated. As a result, a possibility that it was effective as an environment-friendly preservation material was obtained approximately.
Japan Society for the Promotion of Science, Grant-in-Aid for Scientific Research (B), Hokkaido University, 21300326

Application of carrier-microencapsulation for coal flotation to remove pyrite and to suppress acid mine drainage formation at tailing dam
Grants-in-Aid for Scientific Research
2008 - 2010
HIROYOSHI Naoki; TSUNEKAWA Masami; ITO Mayumi; IGARASHI Toshifumi; FUKUSHIMA Masami
Pyrite associated with coal generates SOx causing acid rain during coal combustion. In coal preparation, pyrite is rejected as a gangue mineral using the physical separation technique such as froth flotation and wasted into tailing pond. In the froth flotation, pyrite is frequently entrapped in froth together with valuable mineral due to its hydrophobic nature. Formation of acid mine drainage due to the air-oxidation of pyrite in tailing pond is also a serious problem. In the present study, carrier-microencapsulation (CME) is proposed to suppress both the floatability and oxidation of pyrite in coal preparation.
Japan Society for the Promotion of Science, Grant-in-Aid for Scientific Research (B), Hokkaido University, 20360401

分けるのは訳ないリサイクル用ハイパー比重選別機の開発
科学研究費助成事業
2009 - 2009
恒川 昌美; 廣吉 直樹; 伊藤 真由美
研究代表者および分担者らの研究室で開発した網下気室型湿式比重選別機(TACUB JIG)をベースにして,より選別効率の高い比重選別機の開発に取り組み,以下に述べる3タイプの新しい比重選別機を開発した。
1)TACUB JIGのフィード部および産物回収部に改良を加え,さらに制御法を工夫して,廃棄物の資源化・リサイクルに適した比重選別機(RETAC JIG)を開発し,種々のプラスチックを素材別に選別することを可能にした。
2)このRETAC JIGをベースにして,比重差が無くても濡れ性に差があれば比重選別できるHybrid JIGを開発した。この選別機では,気泡を導入して,より疎水性の粒子表面に微細気泡を選択的に付着させることで,その見かけ比重を小さくして,物質間に見かけ比重差を生じさせて,比重分離する。このJIGにより,比重の同じプラスチックの相互選別が可能になった。
3)水より軽い物質相互を分離するため,RETAC JIGの選別槽上部に天網を設置し,この天網の下にフィードして上下に脈動を与えることで,天網下部に比重別に産物を成層させて選別できるREVERSE JIGを開発した。
4)上述の新たに開発した3タイプの比重選別機をあわせてAdvanced JIGと総称し,本Advanced JIGを組み合わせることで廃家電リサイクルプラントから排出されるプラスチックを素材別に選別して,マテリアルリサイクルできることを実証した。
5)いずれのJIGでも,純度99%以上の産物を回収することができた。
日本学術振興会, 挑戦的萌芽研究, 北海道大学, 21656232

Development and evaluation of a novel preservation materialcementing due to microbial metabolism
Grants-in-Aid for Scientific Research
2006 - 2008
KAWASAKI Satoru; HIROYOSHI Naoki
土や岩の代表的なセメント物質の1つである炭酸カルシウムを主成分とし, 自然の土の中に生息する微生物の代謝活動を利用した環境に優しく新しい遺構, 遺物, 石造文化財などの保存材料(強化材料, 接着剤, 補填材料など)を作製した。また, 作製した保存材料を使用した土の力学・水理学特性およびその使用前後における微生物の菌数と帰属分類群について調査し, 新たに作製した保存材料の有効性について評価を実施した。その結果, 保存材料として有効であるとの見通しが大略得られた。
Japan Society for the Promotion of Science, Grant-in-Aid for Scientific Research (B), Hokkaido University, 18300304

有機・無機複合廃棄物のハイパー解砕・資源化技術の開発
科学研究費助成事業
2005 - 2007
恒川 昌美; 廣吉 直樹; 伊藤 真由美; 米田 哲朗; 吉田 豊; 柳 庚槿
循環型社会を構築していくうえで鍵を握るのは,都市域における廃棄物の資源化・リサイクル技術および環境保全技術の開発である。我々は,廃自動車や廃家電・OA機器類の資源化技術を開発してきている。この開発過程で,現状の処理プロセスでは解砕・破砕が主として減容化を目的に行われているため,その後の有価物選別・回収の段階で低い選別精度,回収率にとどまること,解砕・破砕時に発生するシュレッダーダストの軽比重物(例えばウレタンなど)に絡み込んでいる有価物が十分に回収できないことを見出した。そこで種々の有機・無機複合廃棄物を効率的に資源化・リサイクルする立場から,解砕・破砕,選別を合理的に行うための要素技術の開発研究に取り組んだ。
最終年度にあたる19年度は,下記のような検討を行い,有用な知見を得た。
1)二つの使用済み自動車のシュレーダーダストを対象に,破砕後に種々の風力分級をして,産物について化学分析,灰分測定,組成解析などを行った。その結果,サーマルリサイクルに適した,ウレタンなどの可燃分からなる産物を回収できるプロセスの条件を明らかにした。
2)ウレタン類に鉄・銅・アルミニウムなどの金属類,繊維などが絡まっている場合は,ある種の界面活性剤溶液に浸漬することで,有価金属類を分離回収できることを見出した。
3)17〜19年度の成果を踏まえ,各種有機・無機複合廃棄物に対する適切な破砕・解砕法と有価物回収法についてまとめた。
日本学術振興会, 萌芽研究, 北海道大学, 17656293

Advanced Heap-leaching for Chalcopyrite
Grants-in-Aid for Scientific Research
2005 - 2007
HIROYOSHI Naoki; TSUNEKAWA Masami; YONEDA Tetsuro; ITO Mayumi
Heap-leaching has become important in copper production: over 20% of copper in the world is now produced at open pit mines of porphyry copper deposits through this method. In this method, copper in low-grade oxide and secondary sulfide ores is extracted into sulfuric acid solutions, and the extracted copper is recovered by solvent-extraction and electro-winning methods. However, the leaching rate of chalcopyrite (CuFeS_2), a major copper mineral in the deepest parts of the deposits, is very slow, and the development of advanced heap-leaching methods for this mineral is an object for copper hydrometallurgy in the future.
One factor affecting the leaching rate of chalcopyrite is the redox potential determined by the concentration ratio of Fe^<3+> to Fe^<2+> in the solution: the leaching rate increases when increasing the redox potential to reach a maximum at an optimum redox potential, and then decreases at higher redox potentials. This study investigated the effect of redox potential control on chalcopyrite leaching rates.
Shaking flask leaching experiments and electrochemical experiments were carried out to clarify factors affecting the redox potential dependence of chalcopyrite leaching, and the results indicates that the optimum redox potential is a function of the cupric and ferrous ion concentrations. Based on the experimental results and theoretical considerations of the leaching mechanism, a computer simulation model was developed and the optimum leaching conditions for chalcopyrite were determined. The simulated results agree with the results of column leaching experiments using a chalcopyrite powder sample supported on inert silica host rocks: About 80% of copper was extracted from the chalcopyrite in 100 days when the chemical composition and redox potential of solution were controlled. This extraction rate is comparable to the rate in the conventional heap-leaching operation for secondary copper sulfides, indicating that the redox potential control established here is effective for chalcopyrite leaching.
Japan Society for the Promotion of Science, Grant-in-Aid for Scientific Research (B), Hokkaido University, 17360427

Development of Urban Mines as Urban Resource Recovery Centers to Utilize Solid Waste and Create a Holonic Path for a Sustainable Society
Grants-in-Aid for Scientific Research
2004 - 2007
TSUNEKAWA Masami; HIROYOSHI Naoki; ITO Mayumi; YONEDA Tetsuro; NAWA Toyoharu; HIRAJIMA Tsuyoshi
Industrial systems and daily life in Japan are shifting to become recycling-based to reduce energy and resource consumption. To establish a society based on recycling, urban resource recovery centers (urban mines) are important as places to reduce waste volumes, reusing and recycling valuable materials with application of mineral processing technology. The authors have studied advanced mineral processing technology for urban mines, and have developed new processes as described below. Based on these results, the creation of a holonic path in a sustainable society is discussed and proposed.
1) A process for recycling of plastics and metals from scrapped copy machines was developed and a processing Pilot plant was constructed around the RETAC jig developed in our laboratory.
2) A process for recovering fine and high quality glass from waste fluorescent lamps was developed using RETAC jig.
3) A hybrid jig using the differences in specific gravity and surface affinity for water was developed for separating plastics with the same specific gravities.
4) A metal recovery process for incinerated municipal solid waste was developed using leaching and cementation-in-pulp methods.
5) A process for recovering electrode materials from waste nickel metal hydride batteries was developed using selective crushing at low temperature and with 3 stages magnetic separation.
6) A microencapsulation method to remediate soils contaminated with heavy metals was developed.
7) A process to recover heavy metals and to remediate soils contaminated with heavy metals was developed using a hybrid method combined with leaching, cementation and magnetic separation.
8) Sustainable societal systems linked with urban mines are discussed and proposed.
Japan Society for the Promotion of Science, Grant-in-Aid for Scientific Research (A), Hokkaido University, 16206090

キャリアマイクロエンカプセレーション 〜鉱山汚濁水発生防止のための新しい方法〜
科学研究費助成事業
2005 - 2006
廣吉 直樹; 恒川 昌美; 伊藤 真由美
本研究では,鉱山酸性汚濁水の発生を防止する新しい方法としてキャリアマイクロエンカプセレーション(Carrier Micro Encapsulation, CME)を提案する.本法では,地殻中に存在するTiO_2などの鉱物中のTiを有機キャリアで水に可溶化して,汚染源となる黄鉄鉱FeS_2などの表面に吸着させた後,キャリアを分解して化学的に安定なTiO_2薄膜で汚染源を被覆し,水や空気から遮蔽する.
昨年度の結果に基づき,Tiとの錯体形成能力や酸化分解性に優れたカテコール(1,2-dihydroxybenzene, C_6H_4(OH)_2)をキャリアとして選択し,黄鉄鉱粉末(粒子径53〜75μm)の溶解に対するCMEの効果を振盪フラスコ法によるモデル実験で調べた.実験は天然Ti鉱物の代替物として試薬アナターゼ(TiO_2)5kg/Lを用いて,黄鉄鉱-溶液比0.6kg/L,温度25℃,大気下で行った。CMEを施した実験(カテコールとTiO_2を添加した実験)では,黄鉄鉱表面にTiO_2あるいはTi(OH)_2の被膜が形成され、対照実験(カテコールとTiO_2の双方あるいは一方を添加しなかった実験)に比べて黄鉄鉱の溶解量(硫酸とFeの溶出量)が少なくなり,pHの低下が緩和された.黄鉄鉱溶解に対するCMEの抑制作用は,カテコール添加濃度0.01kmol m^<-3>以上,pH4〜7の範囲で発現した.また,別の実験では,Ti-カテコール錯体は代表的な造岩鉱物である石英SiO_2には吸着せず,黄鉄鉱に選択的に吸着することが確認され,黄鉄鉱の周辺に石英などが共存してもCMEの効果は低下しないものと推定された.これらの結果は,CMEが鉱山の廃さい堆積場や掘削跡地に存在する黄鉄鉱の溶解を抑制し,酸性汚濁水の発生防止に役立つことを示唆している.
日本学術振興会, 萌芽研究, 北海道大学, 17656287

微生物代謝による固化する新しいグラウトの開発に関する基礎的研究
科学研究費助成事業
2005 - 2006
川崎 了; 広吉 直樹
本研究の目的は,微生物代謝を利用した安価で環境に優しい新たなグラウト(以下,バイオグラウトと呼ぶ)を開発し,バイオグラウトの注入前後における地盤(土および岩)の水理学・力学特性について評価を行うことである。最終年度である平成18年度はセメント物質としてシリカを対象とし,(1)イースト菌およびエタノールを用いたシリカコロイドのゲル化試験,(2)シリカコロイドを主成分とするバイオグラウトにより改良した砂質地盤の透水試験,(3)メタ珪酸ナトリウム水溶液のゲル化試験を実施した。
得られた主な知見をまとめると,以下に示すとおりである。
(1)シリカコロイドにイースト菌とグルコースを添加すると,シリカコロイドはゲル化する。
(2)シリカコロイドに高濃度のエタノールを添加すると,シリカコロイドはゲル化する。
(3)イースト菌によるシリカコロイドのゲル化には,グルコースの微生物代謝産物(二酸化炭素およびエタノール)と菌体細胞の双方が関与している。
(4)シリカコロイドを主成分とするバイオグラウトを用いた豊浦砂の改良試験および改良の前後における豊浦砂の透水試験を実施した結果,改良後の透水係数が改良前よりも約1桁低下した。
(5)メタ珪酸ナトリウム水溶液を用いたゲル/ゾル/ゲル法によるゲル化試験を実施した。具体的には,塩酸による中和で生じたメタ珪酸ナトリウム水溶液のゲルを機械的に撹拝することでゾルにし,その直後にグルコースを添加することで再ゲル化を抑制し,さらにイースト菌を添加することにより微生物代謝によるゲルを生じさせることができた。
(6)メタ珪酸ナトリウム水溶液を用いた直接ゲル法によるゲル化試験を実施した。具体的には,高いpH領域においても,イースト菌およびグルコースを添加したメタ珪酸ナトリウム水溶液がゲル化することが確認された。
以上,2年間の研究により,バイオグラウトの技術開発に関して見通しが得られた。
日本学術振興会, 萌芽研究, 北海道大学, 17651035

Quality Improvement of Pyrolysis Char Derived From Various Kind of Solid Waste for Recycling
Grants-in-Aid for Scientific Research
2005 - 2006
MATSUTO Toshihiko; TOJO Yasumasa; TSUNEKAWS Masami; HIROYOSHI Naoki; ITO Mayumi; KAKUTA Yoshitada
In this study, sixteen kinds of char obtained from various sources including industrial waste were used for experiments. In order to use char as fuel, chlorine level should be reduced to avoid corrosion. Chlorine in char derived from MSW was characterized in terms of solubility. CO2 bubbling could reduce chorine to acceptable level for cement kiln use. Pulverization was proven to be ineffective in the dissolution of non water-soluble chlorine.
Ash content is another fraction which should be lowered for fuel use of char. Ash rich fraction (r<125 um) was subjected to float-sink separation, froth flotation, and oil agglomeration methods. As a result, a lower combustible recovery rate was resulted to get a good quality of char with high heating values. For MSW-derived char, the targeted quality level (20000 kJ/kg heating value and 30% ash content) was attained using froth floatation or oil agglomeration. Results of the EDX/SEM analysis indicated that char particles were not segregated to single substances even after being milled for 1 h.
Even in the case that char quality is not good enough for fuel use, carbonization was considered as a thermal pretreatment method before landfilling. Soluble organic carbon levels were fairly decreased by carbonization both in batch and column leaching tests. The release amount of heavy metals from carbonization residue decreased but its extent could be varied with the aerobic/or anaerobic condition, and which relys on the physical adsorption onto the surface or pore structure of carbonization residue.
Japan Society for the Promotion of Science, Grant-in-Aid for Scientific Research (B), Hokkaido University, 17360435

Production of Eco-Friendly Slurry Fuel from Biomass and Low Rank Coal Mixture by Hydrothermal Treatment
Grants-in-Aid for Scientific Research
2003 - 2005
HIRAJIMA Tsuyoshi; TSUNEKAWA Masami; HIROYOSHI Naoki; SASAKI Keiko; ITOI Ryuichi; NONAKA Moriyasu
During circulative hydrothermal treatments of biomass and low rank coal, it is clarified that the blend of these materials reveals a discrepancy in TOCs between the theoretical and experimental values due certainly to the adsorbent effect of the coal. Therefore, coalffication and partial adsorption of extractives are expected by mixing up the biomass with the coal during hydrothermal treatment. TOC variation is predicable from an on-line monitoring of the absorbance intensity during the treatment. Effects of treatment temperature and mixing ratio on the fuel characterization of the solid phase of the treated material were studied by the batch and continuous treatments. The treatment at higher temperature affects more on degree of the upgrading for both the materials and the upgrading reaction of the mixture was independent and in parallel with each other. The fuel ratio decreased as the mixing ratio increased, however, the chemical compositions of C,H,N and 0,and the gross calorific value were almost identical on a dry ash-free basis, independent of the mixing ratio. The continuous test produced the solid phases having a gross calorific value similar to that for the batch test. In addition, it is worth mentioning that a five-hour run of the continuous treatment was conducted successfully. The characterization of the liquid phase clarified that reducing phenols such as 2,6-dimethoxyphenol, guaiacol and etc. as well as acetic acid and methanol were contained in the liquid phase. The liquid phase reduced Cr (VI) effectively to Cr (III) and the addition of slaked lime or quicklime to the reduced system removed almost all amount of Cr (III) as a precipitate. The amount of sludge decreased 1/2 - 1/3 as compared with the use of iron (I) sulfate as a reducer.
Japan Society for the Promotion of Science, Grant-in-Aid for Scientific Research (B), KYUSHU UNIVERSITY, 15360470

次世代銅生産技術としての鉱石中銅・金・銀の同時リーチング
科学研究費助成事業
2002 - 2003
廣吉 直樹
従来の銅鉱石のリーチングでは,鉱石に含まれる金・銀は溶出されず,その回収法が確立していない。本研究では,チオ硫酸イオンとアンモニウムを含む浸出液を用いて銅(II)アンミン錯体を酸化剤として鉱石中の銅・金・銀を同時に酸化浸出する方法(チオ硫酸アンモニウム浸出)を検討した。
鉱石試料として5種類の黄銅鉱浮選精鉱を,浸出液として所定濃度のアンモニア,硫酸アンモニア,チオ硫酸ナトリウムを含む水溶液を用いてフラスコ振盪浸出実験を行ない,銅,金,銀の溶出に及ぼす時間(0〜144h),温度(25〜70℃),pH(5〜13),試薬濃度(チオ硫酸濃度;0〜1M,アンモニア濃;0〜4M,硫酸アンモニウム濃度0〜2M)の影響を調べた。銅の溶出量は時間の経過に伴い多くなるが,金と銀の溶出は24h程度で停止した。銅,金,銀いずれの溶出に関しても最適温度は40℃,最適pHは12〜13であった。高濃度のチオ硫酸ナトリウムは金と銀の溶出を促進するが,銅の溶出を妨げた。全アンモニア濃度(硫酸アンモニウムとして添加したアンモニウムイオンと分子態アンモニアの総和)の増加は金,銀,銅いずれの溶出も促進した。
銅浮選精鉱のチオ硫酸アンモニウム浸出の貴液からの金属の回収法として直接電解法を試みた。カソード電極に電圧を印加するとチオ硫酸イオンが還元されて硫化物イオンが発生し,浸出液中の銅,銀が硫化物としてほぼ完全に沈殿した。金も銅,銀と共に沈殿したが一部は溶液中に液中に残留した。
日本学術振興会, 若手研究(B), 北海道大学, 14750731

Redox Controlled Chalcopyrite Leaching as a New Method for Copper Production
Grants-in-Aid for Scientific Research
2001 - 2003
TSUNEKAWA Masami; HIROYOSHI Naoki; HIRAJIMA Tsuyoshi
Heap leaching of low-grade copper ore, combined with solvent-extraction/electro-winning, has become important in copper production, because of its low capital and operation costs, operational simplicity However, the process has not been fully successful, due to the extremely slow leaching kinetics of a common copper source, chalcopyrite (CuFeS_2). Chalcopyrite leaching is a redox process and the control of the redox potential determined by the concentration ration of oxidant ferric ion to reductant ferrous ion has been proposed to improve the leaching rate. In this study, the redox potential dependence of chalcopyrite leaching in sulfuric acid solutions and the factors affecting the potential dependence of the leaching were investigated to establish the redox controlled chalcopyrite leaching. Leaching and anodic-polarization experiments showed that coexistence of cupric and ferrous ions activate anodic dissolution of chalcopyrite, causing faster copper extraction at the potentials below a certain value (critical potential). The analysis of the AC impedance spectra for chalcopyrite electrode indicated that a high-resistance passive layer grows on the chalcopyrite surface without cupric and/or ferrous ions, and that coexistence of these ions causes a formation of another product layer and inhibits the passive layer growth at low potentials. These results are explained by a reaction model assuming the formation of intermediate Cu_2S due to chalcopyrite reduction and the subsequent oxidation of the Cu_2S. The critical potential corresponds to the redox potential of the Cu_2S formation and the predicted values matched with the experimental results, and the optimum redox potential for chalcopyrite dissolution is a function of cupric and ferrous ion concentrations. Effects of catalysts like silver ions and activated carbon on chalcopyrite leaching were also explained based on the above model.
Japan Society for the Promotion of Science, Grant-in-Aid for Scientific Research (B), HOKKAIDO UNIVERSITY, 13450412

Development of Advanced Mineral Processing, Material Recycling and Waste Water Treatment Technology for establishment of Urban Mines
Grants-in-Aid for Scientific Research
2001 - 2003
TUNEKAWA Masami; HIRAJIMA Tsuyoshi; HIROYOSHI Naoki; YONEDA Tetsuo; YOSHIDA Yutaka; SASAKI Keiko
Industrial systems and daily life in Japan are shifting to a recycling-based society to reduce energy and resource consumption. To establish a society based on recycling urban resource recovery centers (mines) are important as places to reduce waste volumes, reusing and recycling valuable materials with application of mineral processing technology. The authors have studied applications of mineral processing in urban mines, and developed new methods and processes as described below.
1)A process for recycling of plastics and metals from scrapped copy machines was developed and the processing pilot plant was constructed using the TACUB jig developed in our laboratory.
2)A metal recovery process from melting plants of incinerated municipal-solid waste was developed using a leaching-sulfudization method.
3)A process recovering electrode materials from waste nickel metal hybrid batteries in a hybrid vehicle was developed using selective crushing at low temperature and 3 stages magnetic separation.
4)A process recovering fine and coarse aggregate and cement hydrate powder from waste concrete was developed using TACUB jig and multi-gravity separator.
5)An advanced process to treat wastewater containing manganese was developed using sulfur reducing bacteria.
6)A microencapsulation method to remediate soils contaminated by heavy metals was developed.
Japan Society for the Promotion of Science, Grant-in-Aid for Scientific Research (A), Hokkaido University, 13355038

Improvement of Energy Use Efficiency and Reduction of Environmental Load by Upgrading of Unused Low Rank Coal
Grants-in-Aid for Scientific Research
2000 - 2002
HIRAJIMA Tsuyoshi; SASAKI Keiko; HIROYOSHI Naoki; TSUNEKAWA Masami; FUKUSHIMA Masami
Hot water drying (HWD) treatment was carried out at different temperatures such as 270, 300 and 330℃. With increasing temperature water content and carboxyl content of the both coals were decreased and their floatability became higher. Combustible matter recovery of the HWD treated coals by flotation was 20-30% higher than that of the raw coals and the ash content of the froth product was lower for the treated coals than the raw coals. Products containing 4.1-4.3% ash were also recovered by oil agglomeration of the fine HWD treated Beluga coals. Chemical coal cleaning method of the HMD treated coals with aqueous caustic process leads to a drastic decrease in ash content with a high recovery of combustible matter than that of raw coal. The ultra clean coal with 0.5% ash and 86% recovery of combustible matter was produced by a combination of three treatments such as the HWD, flotation and chemical cleaning.
Liquid products produced in a HWD process were characterized by GC/MS, HPLC, GPC, TOC measurement and cyclic voltammetry. The ability of the liquid products to reduce Cr(VI) was investigated by analyzing solutions containing the liquids and Cr(VI), and by fluorescence spectrometry. With increasing treatment temperature TOC concentration of the liquid products became larger. The liquid product at 270℃ contained acetic acid, acetic acid-methyl ester and oligomer of mass weight 1600-3400. The liquid product at 300℃ and 330℃ contained catechol and phenol, and the latter product included more catechol groups. The reduction behavior of both liquids obtained above 300℃ was similar to that of catechol in cyclic voltammetry.
All liquid products reduced the Cr(VI) to Cr(III), and their reduction ability became stronger with decreasing pH. For a solution containing high Cr(VI) concentration the liquid obtained at 330℃ successfully reduced Cr(VI) below the allowed level at pH 2. It was found by fluorescence spectroscopy that Cr(VI) was reduced to catechol groups in the liquid products.
Japan Society for the Promotion of Science, Grant-in-Aid for Scientific Research (B), HOKKAIDO UNIVERSITY, 12450409

アンモニアリーチングによる焼却灰中重金属の除去・回収
科学研究費助成事業
2000 - 2001
広吉 直樹
都市ごみ焼却灰は、1000〜10000ppm程度の重金属(Cu,Pb,Zn,Cdなど)を含んでおり、埋立地周辺の土壌・地下水汚染を引き起こす潜在的可能性を持つことから、重金属の除去・回収技術を確立することが望まれている。本研究では、焼却灰中重金属の除去・回収法としてアンモニアリーチング法を適用することを提案し、その実用化の可能性を検討した。昨年度は、浸出工程について検討し、硫酸アンモニウム溶液を浸出液に用いると、飛灰中のCu,ZnおよびCdがアンミン錯体として溶液中に溶出し、Pbが硫酸鉛として残渣中に安定化されることを明らかにした。本年度は、この結果を受けて、浸出液からのCu,ZnおよびCdの回収法と繰り返し使用に伴う浸出液の劣化について検討した。
模擬浸出液として所定濃度のCu(II),Zn(II)およびCd(II)を含むアンモニア-硫酸アンモニウム混合液を用い、硫化ナトリウムを沈殿剤とする重金属の回収実験を行った。いずれの金属も硫化ナトリウム添加により沈殿した。X線回折分析とX線蛍光分析の結果、沈殿物が金属硫化物であることが確認された。重金属の回収率は硫化ナトリウム添加量の増加につれて増大し、等量の硫化ナトリウムを添加すると98%以上となった。
飛灰の浸出ろ液に所定量の硫化ナトリウムを添加して重金属を沈殿回収し、このろ液を浸出液に用いて再び飛灰の浸出実験を行った。重金属の沈殿回収工程の際に等量以上の硫化ナトリウムを添加した場合、液中に過剰分の硫化物イオンが残留するため、2度目の浸出の際には飛灰からの重金属の浸出率が低下した。また、浸出液の硫酸アンモニウム濃度が低いと、液の繰り返しに伴ってpHが上昇し、浸出率の低下を招いた。したがって、浸出液の繰り返し利用に際しては、金属回収工程での過度の硫化ナトリウムの添加を避け、pHを調整する必要がある。
日本学術振興会, 奨励研究(A), 北海道大学, 12750824

都市代謝システム構築のためのハイブリッド資源回収プロセス
科学研究費助成事業
1999 - 2001
恒川 昌美; 米田 哲朗; 広吉 直樹; 平島 剛
人類が将来にわたり持続可能な発展を遂げていくためには,限りある資源を有効に活用し,環境と調和した生活や生産活動を営むことができる資源循環型社会を築くことが不可欠となる。都市における資源循環型システム,即ち都市代謝システムを構築するうえで,量的に多い焼却灰を含めた資源回収プロセスを確立する必要がある。本研究の目的は,廃OA機器および焼却灰を主な対象として適切な資源回収プロセスを検討し,将来の都市代謝システム構築に向けた基礎的知見を得ることにある。
本年度は,昨年度までの研究成果に基づき,廃コピー機リサイクルプラントの基本設計について検討した。また,都市ゴミ焼却飛灰中の重金属を各種リーチング法で除去・回収することを試みた。得られた主な知見は,以下のようである。
1)廃コピー機中の有価物を回収し,リサイクルするための適正なプロセスとして,次のようなものが提案される。
a)初めにプリント基板を手選別して製錬プロセスに送り,そこで有価物を回収する。
b)残りの部分は,圧縮,切断,衝撃作用を適切に組み合わせた解体・破砕プロセスで処理し,金属とプラスチックを剥離する。
c)上記の剥離した金属から,磁選機を用いて鉄を,水力分級機を用いて非鉄を回収する。
d)プラスチックについては,ジグ選別により成分別に分離,回収する。
2)都市ゴミ焼却飛灰については,次のようなことを明らかにした。
a)硫酸アンモニウム溶液で処理すると,銅,亜鉛,カドミウムは選択的に溶出し,鉛は残渣中に安定な形で残る。
b)チオ硫酸アンモニウム溶液で処理すると,銅,亜鉛,カドミウムとともに鉛も溶出する。
c)これらの溶出金属は,沈殿として回収できる。
日本学術振興会, 萌芽的研究, 北海道大学, 11875221

Refining and Utilization of Rare Earth Elements from Phosphors in Waste Fluorescent Lamp
Grants-in-Aid for Scientific Research
1999 - 2001
HIRAJIMA Tsuyoshi; SASAKI Keiko; HIROYOSHI Naoki; TSUNEKAWA Masami; NAGANO Nobuhiro; TAKAHASHI Touru
The separation and acidic leaching behaviors of phosphor sludge have been examined to establish the recycling system of rare earth components contained in fluorescent lamp waste. At first, separation characteristic of rare earth components and calcium phosphate in phosphor sludge was investigated by heavy media separation, hydro separation, pneumatic separation, gravity separation and flotation. Newly developed heavy media separation method showed highest separation efficiency, recovery and grade of rare earth phosphors and the pneumatic separation was the second result. After pneumatic separation of phosphor sludge, rare earth components were leached in various acidic solutions and sodium hydroxide solution. For recovery of soluble component in leaching solution, rare earth component was recovered by treatment processes such as hydroxide and oxalate precipitations. Yttrium and europium from phosphor sludge contained in fluorescent lamp waste were recovered effectively by three processes of pneumatic separation, sulfuric acid leaching and oxalate precipitation methods. Their recovery was finallv about 65%, and its purity was 98.2%. It was also found that separation and recovery of rare earth elements from the leaching solution by multistage countercurrent extraction were possible.
Synthesis method and sintering conditions have been examined to establish the synthesizing Y_20_3 : Eu^<3+> from phosphor sludge in processing waste fluorescent lamp. Y_20_3 : Eu^<3+> were synthesized by 1.5 mol/l sulfuric acid leaching, subsequent treatment processes such as hydroxide and oxalate precipitations, freeze-dry, and sintering in optimum condltions ; sintering temperature is 1200℃, sintering time is 40 hours, with addition of 1% barium borate as the flux. Y_20_3 : Eu^<3+> powder synthesized from phosphor sludge, was obtained well crystal structure of above 0.2 μm crystal size, and with 50% particle size in the range of 5-6 μm. It was found that Y_20_3 : Eu^<3+> powder synthesized from phosphor sludge by this work could be used substantially as a red rare earth phosphor.
Japan Society for the Promotion of Science, Grant-in-Aid for University and Society Collaboration, HOKKAIDO UNIVERSITY, 11793009

Gold Occurrence in Sulfide Ore Deposit and Process Mineralogy
Grants-in-Aid for Scientific Research
1999 - 2001
YONEDA Tetsuro; HIROYOSHI Naoki; HIRAJIMA Tsuyoshi; TSUNEKAWA Masami
The Sar Cheshmeh porphyry copper ores were studied as a case study for the sulfide ore deposits. Processed ore samples in addition to collected ore samples from outcrop and drilling core were examined in this study.
The mineralogy of the samples suggests that the mineral assemblages in ores of SarCheshmeh depositare alike to those in the typical porphyry copper deposit. The average gold contents of the samples rontaining >0.25 % and >0.4 % Cu in the hypogene were determined as 58.2 and 64.4 ppb Au and in the supergene ores were 70.7 and 71.5 ppb Au, respectively. Based on the metal ratios the Sar Cheshmeh porphyry copper ore can be evaluated as "Mo-rich, relatively Au-poor type".
The gold distribution in the mill products of the porphyry copper beneficiation plant demonstrates that only about 44 % of the gold is routinely recovered as the byproduct in the copper concentrate, and the remaining is lost to the tailings. The recovery of gold in the flotation circuit was controlled mainly by its degree of association with copper minerals and the recovery of pyrite. Gold was present in the ore and mill products in different modes of occurrence including "visible" ,"invisible" and encapsulated forms Though there was some gold in solid solution and/or colloidal size within the sulfide minerals, "visible" gold was the principal form of the gold.
Based on these results, attempts were made to scavenge gold from the plant tailings by bulk sulfide flotation. Then bio-leaching of the bulk flotation concentrate with Thiobacillus ferrooxidans was conducted, followed by cyanidation. Using this process, about 61 % and 70% of gold recovery were obtained from the concentrates bio-leached for 1 and 2 weeks, respectively. The recovery was found to be higher than that by another leaching methods with cyanidation.
Japan Society for the Promotion of Science, Grant-in-Aid for Scientific Research (B), HOKKAIDO UNIVERSITY, 11450391

Slow Crack Growth in Rock Mass
Grants-in-Aid for Scientific Research
1998 - 1999
NAKASHIMA Iwao; HIRASHIMA Tuyoshi; KANEKO Katsuhiko; TUNEKAWA Masami; HIROYOSHI Naoki; YONEDA Tetsuro
In this research project, a series of experimental and analytical studies on the mineralogical and the chemical properties of weathered rock, micro-crack distribution and permeability of rock, and crack propagation in rock, have been performed to clarify the mechanism of the slow crack growth in rock mass.
(1) A method to quantify the weathering of rock by using XFD and ATEM analyses was proposed and the mineralogical property of weathering rock was made clear.
(2) A method to evaluate the three dimensional orientation distribution of micro-cracks in rock was developed. It is pointed out that the anisotropy of rock permeability can be estimated by analyzing crack orientation distribution.
(3) A computer program to simulate the crack propagation in rock has been developed. Comparing the crack propagation processes in static and dynamic loading, a relation between the dynamic strength and the static one of rock is made clear.
(4) A mechanism of the giant rock fall occurred at the entrance of Toyohama tunnel has been analyzed. Analyzing the mineralogical property of smectite in the rock, it is pointed out that the long time strength of the rock may be reduced by the existence of smectite. From these result a theoretical model for slow crack propagation in rock mass was proposed.
Japan Society for the Promotion of Science, Grant-in-Aid for Scientific Research (A), HOKKAIDO UNIVERSITY, 10305075

Inhibition of Acid-Mine-Drainage Formation in Mine Environments and Remediation of Acid Contaminated Sites
Grants-in-Aid for Scientific Research
1997 - 1999
TSUNEKAWA Masami; HIROYOSHI Naoki; HIRAJIMA Tsuyoshi
Weathering of pyrite and chalcopyrite plays an important role in formation of acid mine drainage and releases toxic trace elements, such as Ni, Co, Zn and As from the minerals. In mine environments, and especially in aerobic environments, the pyrite and chalcopyrite weathering is accelerated by iron- and sulfur-oxidizing bacteria. This research was conducted on the weathering mechanism, inhibitor to the bacteria and remediation of acid contaminated sites.
In acid solutions the preferential dissolution of iron took place resulting in the formation of a surface layer enriched with sulfur. Natural organic acid, such as tannic acids, wood vinegar, fulvic acids, and humic acids, suppressed microbially mediated dissolution of pyrite. It was caused by adsorption of natural organic acids on pyrite, inhibition of cell growth, as well as reduction and complexation of Fe(III) ions.
Ferrous ions enhanced copper extraction in sulfuric acid solutions in air at ambient temperatures because they promoted chalcopyrite oxidation with dissolved oxygen. However iron-oxidizing bacteria consumed ferrous ions, suppressing copper extraction. Sodium lauryl sulfate and tannic acid suppressed not only the bacterial ferrous oxidation but also the chalcopyrite oxidation with dissolved oxygen, resulting in a suppression of copper extraction.
Dissolution of iron from high sulfur coal refuse by iron-oxidizing bacteria was depressed in the presence of sodium lauryl sulfate, which inhibited cell growth. However, the refuse contained some soluble iron species that could release into drainage. For decreasing iron concentration of drainage addition of lime was effective.
Japan Society for the Promotion of Science, Grant-in-Aid for Scientific Research (B), HOKKAIDO UNIVERSITY, 09450380

Application of Agglomeration in Liquid to Recycling and Waste Treatment Processes
Grants-in-Aid for Scientific Research
1995 - 1997
HIRAJIM Tsuyoshi; HIROYOSHI Naoki; TSUNEKAWA Masami
Fine particles suspended in a liquid are agglomerated by addition of a second immiscible liquid (bridging liquid) which preferentially wets the particles under appropriate agitation conditions. Distinct noises are emitted when agglomerates impinge on the walls of the agglomeration vessel in the process of agglomeration in an organic liquid. In addition, the turbidity of the suspension changes from opaque to transparent during the progress of agglomeration. The technical feasibility of on-line monitoring of the agglomerate's diameter and recovery was demonstrated by measuring relative energy and laser attenuation.
The effects of various operating variables on the oil agglomeration of electrostatic precipitator soot (EP soot), such as oil dosage, impeller speed, temperature of suspension, and time of agglomeration on yield and ash content of the products were studied in a laboratory batch agglomeration cell. The yield increases and the ashcontent of the agglomerates decreases with increasing oil dosage, impeller speed and time of agglomeration. From the results, it was concluded that a high energy consumption is required to recover low ash content agglomerates with high yields. Wet sieve analysis indicated that the ash content of EP soot increases with decreases in particle size. This was simulated using the equation derived from a model of petroleum coke combustion. X-ray diffraction patterns of the feed revealed that most peaks are consistent with metal compounds such as FeV_2O_4, Fe_2SiO_4, NiFe_2O_4, MgFeAlO_4, NiSO_4・2H_2o, and CaV_2O_6. Wet magnetic separation was conducted on the -400 mesh sample containing 53.8% ash. Semiquantitative study of the XRD results showed that in the magnetic fraction FeV_2O_4, Fe_2SiO_4, NiFe_2O_4, and MgFeAlO_4 contents increase and in the non-magnetic fraction CaSO_4・1/2H_2O content increase.
In this report, the authors also reviewed recent progress in fundamental studies of agglomeration and its application ; especially, the main factors affecting the agglomeration, on-line monitoring systems and topics in industrial fields were described. Agglomeration in liquid is a promising method for mineral and material processing, fuel beneficiation, recycling and waste treatment.
Japan Society for the Promotion of Science, Grant-in-Aid for Scientific Research (B), HOKKAIDO UNIVERSITY, 07455404

バクテリアリーチングの半導体光電気化学的研究
科学研究費助成事業
1996 - 1996
廣吉 直樹
バクテリアリーチングの過程では、硫化鉱物表面の組成と半導体的性質が変化し、浸出速度にその影響が現れてくることが予想される。本研究の目的は、半導体光電気化学的手法により、バクテリアリーチングの過程における硫化鉱表面の半導体的性質の変化と浸出挙動の関係を明らかにすることである。本年度は、鉄酸化細菌を接種した硫酸鉄(II)溶液中に黄銅鉱電極を浸漬して電極電位の経時変化および光応答について調べ、つぎのような知見を得た。
1)黄銅鉱電極電位は、主として溶液の酸化還元電位により決定され、鉄酸化細菌の作用で鉄(II)イオンが鉄(III)イオンへ酸化されて溶液電位が上昇するのに伴い高くなる。しかし、溶液電位が約0.68Vvs.SHE以上になるとほとんど上昇しなくなった。
2)浸漬直後の黄銅鉱電極に光を照射すると、電極電位は負方向へ変化し、照射終了後、正方向へと変化した。このことは、鉱物内の電子のバンドのエネルギー準位が鉱物/溶液界面から鉱物内部に向かって低下していることを意味する。浸漬数時間後、黄銅鉱電極電位は、光照射と同時に瞬間的に正方向へ立ち上がった後、ゆるやかに下降し、照射終了後、正方向へ変化するようになった。光照射開始直後の立ち上がりは、溶液電位の上昇に伴い大きくなるが、溶液電位が約0.66Vvs.SHE以上になるとほとんど認められなくなった。以上のことから、黄銅鉱表面には内部とは異なる半導体層が形成され、溶液の酸化還元電位が0.66-0.68Vvs.SHE付近を境にその状態が変化するのではないかと推察される。
日本学術振興会, 奨励研究(A), 北海道大学, 08751080

Surface Modification of Coal With Carbon Dioxide and Its Application to Advanced Coal Cleaning
Grants-in-Aid for Scientific Research
1994 - 1996
TSUNEKAWA Masami; HIROYOSHI Naoki; HIRAJIMA Tsuyoshi
Four coals from different localities (Datong, Wandoan, Illinois and Shenmu) were used in this study. Immersion time measurements were carried out to assess wettability of coal surface using 100-200 mesh coals. Flotation tests were conducted by introducing air, nitrogen and carbon dioxide gases, respectively. After sparging the gases into coal slurries, the slurries were chemically analyzed. For flotation and chemical analysis fine coals (mean particle size : about 30mum) were used. Some of the coals were treated with 0.6kgf/cm^2 of carbon dioxide gas prior to the experiments. The collectors used were kerosene for Datong and Shenmu coal, and heavy oil A for the other coals.
The hydrophobicity of four coals treated with carbon dioxide became slightly higher than that of untreated coal. When sparging carbon dioxide gas, the highest amounts of calcium and magnesium were dissolved from Datong and Wandoan coals and the amounts of bassanite and calcite in the coals were simultaneously decreased. By flotation with carbon dioxide, the maximum yield was obtained for the coals treated with carbon dioxide than the untreated coals. In the case of Shenmu coal containing calcite and dolomite, separation efficiency of combustibles from mineral matters became higher with decreasing pH.
Fine grinding of four coals were investigated. The ground product with a mean size of 2mum was obtained at a suitable operating conditions for all coals. The wear loss of the grinding media and vessel depended strongly on the amount of the hard minerals disseminated in coal, such as quartz, pyrite and iron oxide.
Japan Society for the Promotion of Science, Grant-in-Aid for Scientific Research (B), HOKKAIDO UNIVERSITY, 06453157

微生物を利用する石炭浮選パルプの酸化還元電位の制御とその脱硫浮選への応用
科学研究費助成事業
1995 - 1995
広吉 直樹
本研究は、鉄イオンを含んだ鉱廃水の酸化還元電位を鉄酸化細菌により調節し、この液を浮選用水として用いて石炭中に含まれる黄鉄鉱を分離するプロセスを開発することを目的としている。本年度は、鉄(II)イオンと鉄(III)イオンをそれぞれ所定の濃度で含む模擬浮選液中での黄鉄鉱(柵原鉱山産)の濡れ性について、種々の方法(バブルピックアップ法、ハリモンドチューブ法、マイクロフローテーションセル法)で検討し、以下のような知見を得た。
1.鉄イオン無添加の場合、黄鉄鉱はpH6以上の中・アルカリ性領域では親水性で気泡とあまり付着しないが、pH6以下の酸性領域では疎水性となり気泡とよく付着した。
2.鉄イオンの添加濃度が高くなるに従い、黄鉄鉱が気泡と付着し始めるpHはより酸性側へと移行した。また、溶液の酸化還元電位が高くなるに従い、すなわち、全溶存鉄イオンにしめる鉄(III)イオンの比率が高い場合ほど、黄鉄鉱が気泡と付着し始めるpHは低下した。このpHは、水酸化鉄(III)の沈殿が生成し始めるpHとよく一致し、黄鉄鉱は水酸化鉄(III)の付着により親水化されるものと考えられる。
3.水酸化鉄(III)が存在しない強酸性領域では、溶液の酸化還元電位が高くなるにつれ黄鉄鉱の疎水性は増した。これは、鉄(III)イオンにより黄鉄鉱が酸化され、元素硫黄が表面に生成してくるためと考えられる。
日本学術振興会, 奨励研究(A), 北海道大学, 07751025

Experimental Studies on Metal Extraction Improvement in Bacterial leaching
Grants-in-Aid for Scientific Research
1993 - 1995
TSUNEKAWA Masami; YOSHIDA Yutaka; HIROYOSHI Naoki; HIRAJIMA Tsuyoshi
Bacterial leaching has the advantages of low energy consumption and operation costs over abiological conventional processes, and is now used commercially to recover copper from low-grade sulfide ore which would otherwise be waste. However, the leaching rate is generally slow and metal extraction is incomplete. To achieve higher leaching rates and metal recovery, it is important to establish the factors influencing leaching behavior. The authors have investigated the effects of extracellular phospholipids and polyoxyethylene sorbitan monolaurate on bacterial leaching of chalcopyrite by Thiobacillus ferrooxidans.
Phosphatidylglycerol and phosphatidylethanolamine are main phospholipids detected in the cultures of iron-oxidizing bacteria. The former depressed chemical leaching of chalcopyrite with ferric sulfate and ferrous oxidation by T.ferrooxidans. The final copper extraction in bacterial leaching decreased with increasing phosphatidylglycerol addition.
On the other hand, phosphatidylethanolamine accelerated slightly the chemical leaching and had no effect on the ferrous oxidation. The copper extraction in bacterial leaching was not affected by phosphatidylethanolamine.
Polyoxyethylene sorbitan monolaurate is a nonionic surfactant. Without the surfactant, most cells of T.ferrooxidans adhered to chalcopyrite surfact and soluble iron was dominantly present in ferrous form. The surfactant depressed the cell adhesion to the mineral surface and number of cells in the liquid phase increased with increasing addition. When adding 20 to 50 g/m^3 of the surfactant, the cells in the liquid phase rapidly oxidized ferrous ions to ferric ions and chalcopyrite was chemically oxidzed by the ferric ions, as a result the amount of extracted copper increased markedly. However, the excessive addition depressed the bacterial ferrous oxidation and the chemical leaching of chalcopyrite with ferric ions, consequently copper extraction was decreased.
Moreover, the authors have developed a simple and rapid cell growth estimation method for T.ferrooxidans.
Japan Society for the Promotion of Science, Grant-in-Aid for Developmental Scientific Research (B), HOKKAIDO UNIVERSITY, 05555274

カラム浮選機のファジィ制御に関する研究
科学研究費助成事業
1994 - 1994
平島 剛; 広吉 直樹; 恒川 昌美
本研究は、申請者らが開発したカラム浮選機用のファジィ制御プログラムを改良し、カラム浮選機の完全自動運転を可能にすることを目的に行った。得られた結果を要約すると次のようである。1.実験室用カラム浮選機を用い、空気流量の増加は、気泡径、気泡充満率を増大させ、液面レベルを上昇させることなどを確認した。2.豊羽鉱山選鉱場亜鉛精選系カラム浮選機(直径2.7m、高さ13.5m)で空気流量をステップ状に変化させた場合のフロス層厚さおよびフロス層内の亜鉛品位の変動について測定を行った。液面レベルは空気流量増加後、振幅約20cmで振動した後ほぼ一定の液面レベル(フロス層厚さ160cm)となった。亜鉛精鉱品位は、空気流量の増加により低下した。その変化は速く、5分後にはほぼ定状状態となった。これらの結果より、空気流量の変化に対する精鉱品位の応答は敏速であり、精鉱品位制御において、空気流量は有効な操作量であることが分かった。3.申請者らが先に開発したファジィ制御プログラムの問題点について現場担当者と検討を行った。比較的処理しやすい鉱石の場合には、空気流量を変化させて精鉱品位を制御する基本制御規則には問題がないことが分かった。しかし、処理しにくい鉱石の場合、原鉱および尾鉱中の亜鉛品位、液面レベルなどの情報をさらに加え、精鉱品位または液面レベルを空気流量変化により制御する必要があること、原鉱の性状によってはフロス層を安定に維持するため最高空気流量および最低空気流量を自動的に変化させる必要があることなどが明らかになった。それらについての経験則等を基に制御規則を追加しカラム浮選機の制御を行った結果、処理困難な鉱石の場合にも自動運転が可能であることが分かった。完全自動運転のためには、各種情報の整理、長期間の運転による新たな経験則の構築などが必要であるが、本研究で改良されたプログラムにより完全自動運転へ一歩前進することができた。
日本学術振興会, 一般研究(C), 北海道大学, 06651088

都市ゴミ焼却灰からの有価物回収
Competitive research funding

バクテリアリーチングに関する研究
Competitive research funding

Recovery of valuable materials from municipal waste incineration ash
Competitive research funding

Study on Bacterial Leaching
Competitive research funding