2025/04/15 更新

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写真a

グデイ パンデイ ウイスヌ スーヤンタラ
GDE PANDHE WISNU SUYANTARA
SUYANTARA GDE PANDHE WISNU
所属
工学研究院 地球資源システム工学部門 准教授
職名
准教授
連絡先
メールアドレス

研究分野

  • ものづくり技術(機械・電気電子・化学工学) / 反応工学、プロセスシステム工学

  • ものづくり技術(機械・電気電子・化学工学) / 反応工学、プロセスシステム工学

学位

  • Doctor of Engineering

研究テーマ・研究キーワード

  • 研究テーマ: Mineral processing

    研究キーワード: Mineral processing

    研究期間: 2024年

  • 研究テーマ: Mineral extraction

    研究キーワード: Mineral extraction

    研究期間: 2024年

  • 研究テーマ: Flotation

    研究キーワード: Flotation

    研究期間: 2024年

  • 研究テーマ: Copper-molybdenum separation

    研究キーワード: Copper-molybdenum separation

    研究期間: 2024年

  • 研究テーマ: Copper-arsenic separation

    研究キーワード: Copper-arsenic separation

    研究期間: 2024年

  • 研究テーマ: Bubble-surface interaction

    研究キーワード: Bubble-surface interaction

    研究期間: 2024年

  • 研究テーマ: Development of innovative Cu-As-Mo complex ore separation with seawater flotation

    研究キーワード: 浮遊選別 / 含ヒ素銅鉱物 / 含モリブデン銅精鉱 / 過酸化水素水 / ピロ亜硫酸ナトリウム / 銅ヒ素分離 / 銅モリブデン分離 / 海水利用 / 電気化学

    研究期間: 2022年4月 - 2026年3月

  • 研究テーマ: Development of separation method for secondary copper and arsenic minerals using flotation

    研究キーワード: 鉱物分離、二次硫化銅、ヒ素含有鉱物、酸化処理、選択的浮遊選鉱、表面特性

    研究期間: 2022年4月 - 2024年3月

受賞

  • 48回奨励賞

    2023年3月   一般社団法人資源・素材学会   48th Encouragement Award

  • 48回奨励賞

    2023年3月   一般社団法人資源・素材学会  

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  • Excellence Award

    2019年10月   Kyushu University Institute for Asian and Oceanian Studies  

  • Young Authors Award

    2016年9月   International Mineral Processing Congress  

論文

  • Effect of oxalic acid on the selective flotation separation of Pb-activated sphalerite from galena

    Eladl, DA; Suyantara, GPW; Miki, H; Ulmaszoda, A; Okibe, N

    ADVANCED POWDER TECHNOLOGY   36 ( 4 )   2025年4月   ISSN:0921-8831 eISSN:1568-5527

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    出版者・発行元:Advanced Powder Technology  

    The separation of sphalerite (ZnS) and galena (PbS) is challenging owing to activation of the sphalerite surface by unavoidable metal ions, such as lead ions (Pb2+) released from lead-containing minerals. In this study, oxalic acid (OA) was applied for the first time as an environmentally friendly reagent to deactivate the sphalerite surface in lead–zinc (Pb-Zn) flotation separation. Micro-flotation experiments showed that OA, at a concentration of 0.56 mM, significantly reduced sphalerite recovery. Single-mineral flotation tests demonstrated that sphalerite recovery decreased to 20 %, while galena recovery remained at 58.7 % after OA treatment. Further flotation tests on an artificial mixture of sphalerite and galena confirmed effective separation with OA treatment under mildly alkaline conditions, achieving recoveries of 83 % for galena and 17 % for sphalerite. Infrared spectroscopy and X-ray photoelectron spectroscopy analyses showed that OA removes Pb2+ ions from the surface of sphalerite by forming lead oxalate (Pb(II)-Ox) precipitates, which detach from the sphalerite surface, effectively cleaning it. This detachment prevents the adsorption of potassium amyl xanthate (PAX) by forming a dispersed lead oxalate-amyl xanthate (PbOx-AX) complex, which exposes the hydrophilic sphalerite surface and leads to its depression. In contrast, this interaction had a minimal impact on the floatability of galena.

    DOI: 10.1016/j.apt.2025.104818

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    Scopus

  • Selective depression of copper-activated pyrite by oxalic acid: Implications for enhanced chalcopyrite-pyrite separation

    Suyantara, GPW; Ulmaszoda, A; Miki, H; Eladl, DA; Sasaki, K; Okibe, N

    POWDER TECHNOLOGY   454   2025年3月   ISSN:0032-5910 eISSN:1873-328X

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    出版者・発行元:Powder Technology  

    The selective separation of pyrite (FeS2) and chalcopyrite (CuFeS2) in flotation processes poses significant challenges due to the activation of the pyrite surfaces by copper ions dissolved from associated copper sulfide minerals. This study proposes oxalic acid as an environment-friendly reagent to inhibit the copper-induced activation of pyrite. Chalcopyrite was used as a model mineral to evaluate the selectivity of oxalic acid treatment. The flotation experiments demonstrated that oxalic acid reduced the flotation recovery of copper-activated pyrite from 58 % to 16 % at pH 9 while exerting no discernible effect on chalcopyrite flotation. Further tests using artificial mixtures of chalcopyrite and pyrite confirmed the ability of oxalic acid to selectively separate chalcopyrite from copper-activated pyrite under mildly alkaline conditions, improving the separation efficiency from 30 % to 78 % with the addition of 15 kg/t (0.55 mM) oxalic acid at pH 9. The mechanism underlying this selectivity was investigated using infrared spectroscopy, X-ray photoelectron spectroscopy, and atomic force microscopy. The results revealed that oxalic acid reacts with copper ions to form copper oxalate, which effectively prevents copper deposition on the pyrite surface. This reaction inhibits pyrite activation and suppresses the adsorption of xanthate collectors. These findings highlight the potential of oxalic acid as a sustainable reagent for enhancing the selectivity and efficiency of chalcopyrite–pyrite separation in flotation processes.

    DOI: 10.1016/j.powtec.2025.120681

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  • Enhancing the biotreatment of carbonaceous matter in double refractory gold ores: The impact of various mediators on laccase performance

    Cindy; Ichinose, H; Mendoza, DM; Konadu, KT; Takimoto, R; Suyantara, GPW; Sasaki, K

    PROCESS SAFETY AND ENVIRONMENTAL PROTECTION   194   1360 - 1371   2025年2月   ISSN:0957-5820 eISSN:1744-3598

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    出版者・発行元:Process Safety and Environmental Protection  

    Despite their relatively higher Au content, double refractory gold ores (DRGOs) have not been developed for economic reasons, as Au grains are trapped by sulfides, and carbonaceous matter can adsorb Au(CN)₂⁻ during cyanidation. The enzymatic treatment of carbonaceous matter is gaining interest due to its eco-friendly benefits. The use of laccase, combined with an electron mediator, has been shown to enhance Au extraction from DRGOs. Although the effectiveness of mediators in improving lignin degradation has been reported, their significance in laccase-mediator system (LMS) treatment of DRGOs has yet to be thoroughly investigated. In this study, the mechanisms of various mediators in LMSs were investigated to improve Au extraction from DRGOs. To observe the degradation of the carbonaceous matter, thermogravimetry, Raman spectroscopy, three-dimensional fluorescence spectrometry, and CHN elemental analysis were utilized. The results demonstrated that the highest Au extraction was achieved after treatment with violuric acid monohydrate-mediated laccase, resulting in 92.9 ± 2.7 % Au extracted from DRGOs, which is equivalent to complete extraction when considering the 8.6 % Au locked in sulfides. The Langmuir model provided a better fit for the mediators' sorption than the Freundlich model, indicating that monolayer sorption is the predominant process in the mediators' adsorptions on pre-treated DRGOs. This proposed LMS represents a novel approach to enhancing our understanding of carbon science in biohydrometallurgy.

    DOI: 10.1016/j.psep.2024.12.057

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  • Utilizing oxidation treatment for arsenic mineral removalin producing a cleaner copper concentrate using flotation

    Suyantara G.P.W., Miki H., Sasaki K., Aoki Y., Ochi D., Hirajima T.

    AIP Conference Proceedings   3215 ( 1 )   2024年11月   ISSN:0094243X

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    出版者・発行元:AIP Conference Proceedings  

    The present investigation suggests an oxidation treatment utilizing hydrogen peroxide to separate chalcopyrite, a copper mineral, and enargite, an arsenic-copper mineral, with flotation. The effectiveness of the oxidation treatment in separating both minerals was evaluated through a series of flotation tests. The results of the pure mineral flotation experiment demonstrate that applying an oxidation treatment utilizing a low concentration of hydrogen peroxide has led to an enhancement in the recoveries of chalcopyrite and enargite when potassium amyl xanthate is present. The recovery of both minerals exhibited a decline as the hydrogen peroxide concentration increased. The experimental results indicate that the flotation process employing a binary combination of chalcopyrite and enargite may effectively achieve the separation of enargite and chalcopyrite through a sequential treatment including oxidation and subsequent application of potassium amyl xanthate. It was found that chalcopyrite was strongly depressed, while enargite remained floatable after the oxidation treatment. The proposed oxidation treatment exhibited a separation efficiency of 64%, in which enargite was recovered at a rate of 87% as froth, while chalcopyrite was recovered at a rate of 77% as tailing.

    DOI: 10.1063/5.0235818

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  • Arsenic removal with heat treatment - Magnetic separation from dirty copper conc

    Miki H., Hirajima T., Fukuda H., Suyantara G.P.W., Sasaki K., Ochi D., Aoki Y.

    AIP Conference Proceedings   3215 ( 1 )   2024年11月   ISSN:0094243X

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    出版者・発行元:AIP Conference Proceedings  

    Removal arsenic from dirty (arsenic containing) copper concentrate is one of the most important issues for copper processing. Currently for removal of arsenic copper concentrate roasting is applied, but this method is not good for environment. As alternative method, this research applied low temperature heat treatment (less than 400°C) followed by magnetic separation. Primary copper sulfide minerals such as chalcopyrite and bornite can make magnetic property whereas arsenic containing copper minerals such as enargite and tennantite kept non-magnetic property. Magnetic separation after these heat treatments can separate primary copper minerals as magnetic product and arsenic containing copper minerals as non-magnetic minerals. Magnetic separation has been carried out and results shows that arsenic removal from copper concentrate can be achieved with high separation efficiency.

    DOI: 10.1063/5.0237381

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  • Evaluation of micro powder electrode on sulfide mineral leaching for hydrometallurgical process

    Miki H., Hirajima T., Fukuda H., Suyantara G.P.W., Sasaki K., Daniyarov B.

    AIP Conference Proceedings   3215 ( 1 )   2024年11月   ISSN:0094243X

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    出版者・発行元:AIP Conference Proceedings  

    Electrochemical measurement is essential for hydrometallurgical process for evaluation oxidation and reduction reaction. However, electrochemical measurements for powder sample is not well developed since it is difficult to make powder sample electrode. Authors has developed new electrode system for micro gram order powder sample with relative simple method. This system can obtain high reproducibility and sensitivity compared with conventional electrode. Authors evaluates new powder electrode system for various sulfide mineral to apply various hydrometallurgical process. Powder sample indicated high resolution results which can obtain sharp peak, it can indicates oxidation process can be estimated in detail. This method can be applied not only hydrometallurgical process but also various mineral processing and water treatment system.

    DOI: 10.1063/5.0237380

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  • Investigation of chalcopyrite floatability in the presence of goethite nanoparticles

    Ulmaszoda A., Suyantara G.P.W., Rizki I.N., Sasaki K., Miki H.

    AIP Conference Proceedings   3215 ( 1 )   2024年11月   ISSN:0094243X

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    出版者・発行元:AIP Conference Proceedings  

    Chalcopyrite is one of the major sources of copper minerals which is commonly separated from other gangue minerals using a flotation process. The floatability of chalcopyrite is one of the major factors for a successful beneficiation process. It was found that chalcopyrite's floatability is greatly reduced by ferric oxyhydroxide on its surface. On the other hand, ferric oxyhydroxide, such as goethite, is abundant in nature. Therefore, this study focuses on the floatability of chalcopyrite in the presence of goethite. The goethite in the form of nanoparticles was employed in this study. Goethite nanoparticles hindered chalcopyrite flotation in column-type flotation experiments. 30 mg/L goethite nanoparticles reduced chalcopyrite flotation recovery from 93% to 15%. This flotation result indicated that goethite nanoparticles can act as nanodepressant for chalcopyrite flotation. X-ray photoelectron analysis was employed to characterize the surface. Goethite nanoparticles were adsorbed on the surface of chalcopyrite, making the exterior of it hydrophilic, thus lowering the floatability.

    DOI: 10.1063/5.0242889

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  • Preliminary evaluation of the impact of nanoparticles on enargite flotation

    Dwitama E.P., Ulmaszoda A., Sasaki K., Miki H., Suyantara G.P.W.

    AIP Conference Proceedings   3215 ( 1 )   2024年11月   ISSN:0094243X

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    出版者・発行元:AIP Conference Proceedings  

    In recent years, the development of clean energy technologies increases the consumption of valuable metals, such as copper. To meet the increasing global demand for copper metal, mining operations process low grade copper ores containing various impurities, such as arsenic minerals. However, arsenic minerals reduce copper quality, cause environmental concerns, and improve operating costs. Therefore, it is important to separate the arsenic minerals from the copper minerals. There are various studies on the separation of arsenic minerals from other copper minerals. However, there is no discussion about the study of nanoparticles in the flotation of arsenic minerals. Therefore, this study examined the impact of nanoparticles on arsenic mineral flotation. Goethite nanoparticles and enargite were employed as nanoparticles and arsenic minerals, respectively. Micro-flotation tests were performed to evaluate the flotation behavior of enargite in the presence of goethite nanoparticles. The flotation results indicated that treatment with 30 mg/L and 50 mg/L goethite nanoparticles at pH 5 drastically reduced enargite recovery from 94% to 22% and 16%. The zeta potential of enargite increased as the quantity of goethite nanoparticles increased, indicating that goethite nanoparticles adsorb on the enargite surface. This study demonstrated that goethite nanoparticles have potential as a nanodepressant for enargite flotation.

    DOI: 10.1063/5.0236697

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  • Study on the effect of iron oxide-hydroxide nanoparticles on mixed flotation of bornite and molybdenite

    Satomura K., Suyantara G.P.W., Miki H., Sasaki K.

    AIP Conference Proceedings   3215 ( 1 )   2024年11月   ISSN:0094243X

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    出版者・発行元:AIP Conference Proceedings  

    Iron oxide-hydroxide nanoparticles have high adsorption properties, and their crystalline structure has adsorption sites for water molecules. Owing to these properties, iron oxide-hydroxide nanoparticles has been reported to alter the surface hydrophobicity of chalcopyrite, depressing its floatability. However, there is no study available on the effect of iron oxide-hydroxide nanoparticles on bornite flotation. Therefore, this study examined iron oxide-hydroxide nanoparticles for their potential as a depressant of bornite. It was found that iron oxide nanoparticles acted as a depressant of bornite in flotation tests using pure mineral. Iron oxide-hydroxide nanoparticles hydrophilized the surface of bornite, suggesting the possibility of separation of bornite and other valuable associated sulfide minerals, such as molybdenite. Based on these results, the influence of iron oxide nanoparticles on the mixed flotation of bornite and molybdenite was investigated in the presence of potassium amyl xanthate and diesel oil as copper and molybdenum collectors. The separation efficiency between bornite and molybdenite was 61.5% after employing 30 mg/L of iron oxide-hydroxide as a depressant. Under this condition, molybdenite recovery was 94.9% and bornite recovery was 33.3%. This result demonstrates the potential use of iron oxide-hydroxide as a selective depressant for bornite in the selective flotation of copper-molybdenum.

    DOI: 10.1063/5.0242887

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  • The effect of various reagents on selective flotation of molybdenite and chalcocite

    Nakao R., Miki H., Dwitama E.P., Sasaki K., Ochi D., Aoki Y., Suyantara G.P.W.

    AIP Conference Proceedings   3215 ( 1 )   2024年11月   ISSN:0094243X

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    出版者・発行元:AIP Conference Proceedings  

    Copper plays an essential role in the development of renewable energy resources and the production of electric vehicles, which drive the increasing copper demand in the future. Copper is primarily extracted from copper sulfide ores which contain chalcopyrite and bornite as primary copper sulfide minerals and chalcocite as secondary copper sulfide minerals. However, these copper sulfides are associated with molybdenite. Sodium metabisulfite has been used to separate chalcopyrite and molybdenite in a selective flotation process. However, there is limited study focus on the effect of sodium metabisulfite on the separation of chalcocite and molybdenite using flotation. Therefore, this study investigates the effect of sodium metabisulfite on the floatability of chalcocite and molybdenite in the presence of various flotation collectors, i.e., xanthate, thionocarbamate, and mercaptan. The surface properties of chalcocite and molybdenite are studied by employing Fourier Transform Infrared Spectroscopy (FTIR). The flotation results show that sodium metabisulfite separated the molybdenite and chalcocite by depressing chalcocite flotation. In addition, the separation efficiency is higher if sodium metabisulfite was used for separating chalcocite and molybdenite that have been treated with thionocarbamate.

    DOI: 10.1063/5.0236779

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  • "Selective Flotation of Copper Concentrates Containing Arsenic Minerals Using Potassium Amyl Xanthate and Oxidation Treatment"

    Suyantara, GPW; Miki, H; Hirajima, T; Sasaki, K; Ochi, D; Aoki, Y

    MATERIALS TRANSACTIONS   65 ( 1 )   27 - 36   2024年1月   ISSN:13459678 eISSN:13475320

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    記述言語:英語   出版者・発行元:公益社団法人 日本金属学会  

    This study investigated the effects of potassium amyl xanthate (KAX) and oxidation treatment using hydrogen peroxide (H2O2) on the selective flotation of copper concentrates containing arsenic-bearing copper minerals. The mineralogical analysis revealed that enargite and chalcopyrite were the main arsenic-bearing copper and copper sulfide minerals, respectively, in the copper concentrate. KAX treatment at pH 9 improved the recoveries of copper sulfide and arsenic-bearing copper minerals. However, arsenic-bearing copper minerals floated more rapidly than copper sulfide minerals, indicating better separation selectivity. The separation selectivity of the KAX treatment was significantly improved at pH 10. H2O2 treatment was found to selectively improve the recovery of arsenic-bearing copper minerals. A combination treatment using 0.1M H2O2 and 60 g/t of KAX at pH 9 enhanced the separation selectivity in the selective flotation of copper sulfide and arsenic-bearing copper minerals by producing a copper concentrate with the lowest arsenic grade and highest copper grade in tailings compared to those obtained from separated KAX and H2O2 treatments.

    DOI: 10.2320/matertrans.m-m2023811

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    CiNii Research

  • Effect of oxidation treatment on the selective separation of molybdenite from chalcocite using flotation

    Berdakh, D; Miki, H; Hirajima, T; Sasaki, K; Ulmaszoda, A; Nakao, R; Ochi, D; Aoki, Y; Suyantara, GPW

    POWDER TECHNOLOGY   431   2024年1月   ISSN:0032-5910 eISSN:1873-328X

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    記述言語:その他   掲載種別:研究論文(学術雑誌)   出版者・発行元:Powder Technology  

    Molybdenite is associated with primary and secondary copper sulfide minerals. Few studies have focused on the selective flotation of molybdenite to separate it from secondary copper sulfide minerals, such as chalcocite. This study evaluated the use of oxidation treatment to separate molybdenite from chalcocite. The effects of oxidation treatment with hydrogen peroxide (H2O2) on the flotation behaviors of molybdenite and chalcocite in the presence of collectors (i.e., potassium amyl xanthate and diesel oil) were evaluated, and the impacts of H2O2 concentration, oxidation treatment duration, and pH level were assessed. Chalcocite flotation tests showed that the H2O2 treatment significantly reduced the recovery of chalcocite due to the formation of copper hydroxide and sulfate species on the chalcocite surface, which altered its surface hydrophobicity. On the other hand, the low surface oxidation of molybdenite led to high flotation recovery after the oxidation treatment. Oxidation treatment with a 10 mM H2O2 solution at a pH of 9 for 20 min resulted in a separation efficiency of 87%, with 98% molybdenite recovery and 11% chalcocite recovery. The results show that H2O2 oxidation treatment enables the selective flotation of molybdenite to separate it from chalcocite.

    DOI: 10.1016/j.powtec.2023.119078

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  • Sodium metabisulfite as a copper depressant in the selective flotation of copper-molybdenum concentrate using seawater

    Suyantara, GPW; Miki, H; Ochi, D; Aoki, Y; Ura, K; Berdakh, D; Ulmaszoda, A; Dwitama, EP; Sasaki, K; Hirajima, T

    ADVANCED POWDER TECHNOLOGY   34 ( 12 )   2023年12月   ISSN:0921-8831 eISSN:1568-5527

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    記述言語:その他   掲載種別:研究論文(学術雑誌)   出版者・発行元:Advanced Powder Technology  

    The main challenge for the selective flotation of copper and molybdenum (Cu-Mo) sulfide minerals in seawater is the formation of colloidal precipitates in strongly alkaline conditions. These precipitates hinder the selective separation of copper from molybdenum minerals in seawater by lowering the floatability of Cu-Mo sulfide minerals. The present study aimed to examine the direct utilization of seawater in the selective flotation of Cu-Mo sulfides. Additionally, the effectiveness of sodium metabisulfite (Na2S2O5) as a copper depressant for selective flotation of Cu-Mo sulfides in seawater was studied under weakly acidic, neutral, and moderately alkaline conditions. A complex Cu-Mo concentrate that largely consisted of chalcopyrite and molybdenite, as well as a tiny amount of pyrite and quartz, was used in the flotation tests. The flotation results revealed that treatment with 3.6 kg/t Na2S2O5 in seawater at pH 5.5 significantly lowered the copper recovery from 97% to 11% and caused a modest reduction in the molybdenum recovery from 98% to 94% with a Cu-Mo separation efficiency of 83%. These flotation results demonstrate that Na2S2O5 treatment in seawater selectively depresses the floatability of copper minerals. Consequently, molybdenum can be separated from copper minerals under a weakly acidic condition in seawater. In addition, this study discusses the effects of various pH conditions and dosages of Na2S2O5. The surface properties of Cu-Mo minerals were studied using X-ray photoelectron and infrared spectroscopies, and a mechanism to explain the selective flotation of Cu-Mo using Na2S2O5 treatment in seawater is proposed.

    DOI: 10.1016/j.apt.2023.104258

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  • Effect of goethite (α-FeOOH) nanoparticles on the surface properties and flotation behavior of chalcopyrite

    Suyantara, GPW; Rizki, IN; Ulmaszoda, A; Miki, H; Sasaki, K

    JOURNAL OF ENVIRONMENTAL CHEMICAL ENGINEERING   11 ( 3 )   2023年6月   ISSN:2213-2929 eISSN:2213-3437

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    記述言語:その他   掲載種別:研究論文(学術雑誌)   出版者・発行元:Journal of Environmental Chemical Engineering  

    Chalcopyrite flotation is selectively depressed by oxidation treatment. The presence of ferric oxyhydroxide on the surface of chalcopyrite after oxidation treatment is a key factor in depressing chalcopyrite flotation. However, there is no concrete evidence that ferric oxyhydroxide has a depressing effect. In addition, the effectiveness of this depressing effect could be enhanced by directly applying ferric oxyhydroxide nanoparticles. This study investigated the effect of goethite (α-FeOOH) nanoparticles on the surface properties and flotation behavior of chalcopyrite. α-FeOOH nanoparticles were produced through chemical precipitation followed by hydrothermal treatment. The crystalline structure of irregular rice grain-shaped α-FeOOH nanoparticles was confirmed by the X-ray diffraction pattern and scanning electron microscope image. Micro-flotation experiments showed that chalcopyrite recovery decreased significantly from 93 % to 13 % when 30 mg/L α-FeOOH nanoparticles was used. This flotation result demonstrated the potential of α-FeOOH nanoparticles as a nanodepressant for the flotation of chalcopyrite. These nanoparticles physically adsorbed on the chalcopyrite surface and rendered its surface hydrophilic, thereby reducing the chalcopyrite flotation recovery. The attractive electrostatic force between the positively charged α-FeOOH nanoparticles and the negatively charged chalcopyrite surface is likely responsible for the adsorption of α-FeOOH nanoparticles on chalcopyrite.

    DOI: 10.1016/j.jece.2023.110006

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  • Effect of hydrogen peroxide on selective flotation of chalcocite and enargite

    Suyantara, GPW; Berdakh, D; Miki, H; Hirajima, T; Sasaki, K; Ochi, D; Aoki, Y

    INTERNATIONAL JOURNAL OF MINING SCIENCE AND TECHNOLOGY   33 ( 6 )   703 - 716   2023年6月   ISSN:2095-2686 eISSN:2212-6066

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    記述言語:その他   掲載種別:研究論文(学術雑誌)   出版者・発行元:International Journal of Mining Science and Technology  

    Enargite is typically associated with chalcocite. Owing to the similarity in the flotation behaviors of these minerals, both minerals are reported to concentrate in the conventional flotation circuit. However, inorganic arsenic in enargite can decrease the copper concentrate quality and increase the operating cost of processing this concentrate. Separating these minerals is important for cleaner copper production to avoid these effects. In this context, this study investigated the effect of hydrogen peroxide (H2O2) treatment on the flotation behavior of chalcocite and enargite. Flotation tests of pure and mixed minerals indicated that H2O2 treatment reduced the floatability of chalcocite and enargite by forming sulfate and copper hydroxide on their surfaces. Despite the detrimental effect of the H2O2 treatment, there was a narrow window of H2O2 concentration for separating both minerals, in which enargite floated and chalcocite was depressed. This selective flotation behavior was caused by the rapid adsorption of potassium amyl xanthate (KAX) and lower surface oxidation of enargite compared with that of chalcocite.

    DOI: 10.1016/j.ijmst.2023.01.002

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  • Effect of pH and Precipitations on Copper -Molybdenum Rougher Flotation in Seawater

    Tanaka, Y; Miki, H; Suyantara, GPW; Aoki, Y; Okamoto, H; Ura, K; Hirajima, T

    MATERIALS TRANSACTIONS   64 ( 6 )   1225 - 1231   2023年5月   ISSN:13459678 eISSN:13475320

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    記述言語:その他   掲載種別:研究論文(学術雑誌)   出版者・発行元:公益社団法人 日本金属学会  

    Effect of pH and precipitations on copper-molybdenum ore rougher flotation has been investigated in seawater with flotation experiments followed by precipitation estimation with thermodynamic calculations, turbidity measurements and XRD analysis. Results of flotation experiments in seawater indicated that the effect of pH on copper and molybdenum flotation maximum recovery seems limited. On the other hand, pH drastically influences copper and molybdenum flotation kinetic constant, it decreased a lot with increasing pH, and results of pH 8.5 and 9.0 is quite similar. From thermodynamic calculation, precipitation effect on seawater less than pH 9 seems limited since CaCO3 and Mg(OH)2 does not exist on this pH region. To estimate precipitation on pH in seawater, turbidity measurements were carried out with controlled pH and results indicated even pH is less than 9, noticeable turbidity can be seen. To confirm precipitation in seawater, precipitation was collected from controlled pH seawater solution. XRD analysis of precipitation indicated that obtained precipitation at pH 8.7 is CaCO3, CaSO4 and Mg(OH)2. This result is not same as the result of thermodynamic calculation and it might be due to the activity coefficient and ionic strength effect. Although flotation kinetic is influenced with turbidity, turbidity influence on maximum recovery is limited. Effect of kinetic might be due to that precipitation exist as suspension and it prevent bubble and mineral attachments. Small effect of precipitation on maximum recovery might be due to exist of few precipitation on the surface of copper and molybdenum mineral since most of mineral in rougher flotation is gangue minerals and also most of precipitations might be on gangue minerals. These results indicated that seawater flotation have to take into account of precipitation effect more for flotation kinetic than maximum flotation recovery.

    DOI: 10.2320/matertrans.M-M2023805

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  • Arsenic removal with heat treatment - magnetic separation from dirty copper conc 査読

    Suyantara Gde・Pandhe・Wisnu, 笹木 圭子

    Proceedings of The 18th International Conference on Quality in Research   1   2023年

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  • Evaluation of micro powder electrode on sulfide mineral leaching for hydrometallurgical process 査読

    Suyantara Gde・Pandhe・Wisnu, 笹木 圭子

    Proceedings of The 18th International Conference on Quality in Research   1   2023年

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  • Evaluation of the Effect of Nanoparticles on the Flotation of Enargite 査読

    Suyantara Gde・Pandhe・Wisnu, 笹木 圭子

    Proceedings of International Symposium on Earth Science and Technology 2024   1   2023年

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  • Investigation of Chalcopyrite Floatability in the Presence of Goethite Nanoparticles 査読

    Suyantara Gde・Pandhe・Wisnu, 笹木 圭子, 三木 一

    Proceedings of The 18th International Conference on Quality in Research   1   2023年

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  • Investigation of the Effect of Goethite Nananoparticles on Chalcopyrite Floatability 査読

    Suyantara Gde・Pandhe・Wisnu

    Proceedings of International Symposium on Earth Science and Technology 2024   1   2023年

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  • Preliminary Evaluation of the Impact of Nanoparticles on Enargite Flotation 査読

    Suyantara Gde・Pandhe・Wisnu, 笹木 圭子, 三木 一

    Proceedings of The 18th International Conference on Quality in Research   1   2023年

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  • Study on the Effect of Iron Oxide-Hydroxide Nanoparticles on Mixed Flotation of Bornite and Molybdenite 査読

    Suyantara Gde・Pandhe・Wisnu, 三木 一, 笹木 圭子

    Proceedings of International Symposium on Earth Science and Technology 2024   1   2023年

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  • Study on the Effect of Iron Oxide-Hydroxide Nanoparticles on Mixed Flotation of Bornite and Molybdenite 査読

    Suyantara Gde・Pandhe・Wisnu, 三木 一, 笹木 圭子

    Proceedings of The 18th International Conference on Quality in Research   1   2023年

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  • The Effect Of Various Reagents On Selective Flotation Of Molybdenite And Chalcocite 査読

    三木 一, 笹木 圭子, Suyantara Gde・Pandhe・Wisnu

    Proceedings of The 18th International Conference on Quality in Research   1   2023年

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  • The Study of Selective Flotation on Molybdenite and Chalcocite with the Effect of Sodium Metabisulfide and Collector 査読

    Suyantara Gde・Pandhe・Wisnu, 三木 一, 笹木 圭子

    Proceedings of International Symposium on Earth Science and Technology 2024   1   2023年

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  • Utilizing Oxidation Treatment for Arsenic Mineral Removal in Producing a Cleaner Copper Concentrate using Flotation 査読

    Suyantara Gde・Pandhe・Wisnu, 三木 一, 笹木 圭子

    Proceedings of The 18th International Conference on Quality in Research   1   2023年

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  • Effect of sodium metabisulfite and slaked lime on the floatability and surface properties of chalcopyrite

    Suyantara, GPW; Semoto, Y; Miki, H; Hirajima, T; Sasaki, K; Ochi, D; Aoki, Y; Berdakh, D; Ura, K

    POWDER TECHNOLOGY   408   2022年8月   ISSN:0032-5910 eISSN:1873-328X

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    記述言語:その他   掲載種別:研究論文(学術雑誌)   出版者・発行元:Powder Technology  

    In the flotation of complex copper ores containing chalcopyrite in seawater, sodium metabisulfite (SMBS) has been widely used as a pyrite depressant. Here, calcium ions in seawater or in process water because of pH control using lime (CaO) or slaked lime (Ca(OH)2) can affect the floatability of chalcopyrite. However, the effect of SMBS on the floatability of chalcopyrite in the presence of calcium ions is unknown. Therefore, the current study investigated the flotation behavior and surface properties of chalcopyrite after treatment with SMBS in the absence and presence of Ca(OH)2. The flotation experiments demonstrated that both SMBS treatment and the addition of Ca(OH)2 exhibited a depressing effect on the natural floatability of chalcopyrite. This depressing effect of SMBS and Ca(OH)2 on the floatability of chalcopyrite was significantly decreased in the presence of potassium amyl xanthate (PAX). However, the combination of SMBS treatment and Ca(OH)2 formed calcium sulfite (CaSO3) on the surface of chalcopyrite, which significantly reduced the recovery of chalcopyrite from 97% to 66% when in the presence of PAX and at a pH of 9.

    DOI: 10.1016/j.powtec.2022.117750

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  • 九州大学・住友金属鉱山株式会社における「銅原料中からのヒ素低減技術開発」に向けた取り組み

    三木 一, 沖部 奈緒子, 小山 恵史, 笹木 圭子, 平島 剛, 中村 壮志, 青木 悠二, 田中 善之, 諏訪 貴大

    環境資源工学   68 ( 3 )   124 - 131   2022年   ISSN:13486012 eISSN:13499262

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    記述言語:日本語   出版者・発行元:一般社団法人 環境資源工学会  

    <p>Arsenic removal from copper ores/concentrates is one of the most important issue in mining industries. Under the national project led by JOGMEC, Kyushu University and Sumitomo Metal Mining Co. Ltd. has carried out systematic research on the arsenic removal from copper concentrates, including the heat treatment-magnetic separation, flotation and bioleaching. The flotation studies were carried out mainly on chalcopyrite as a main copper sulfide and enargite as an arsenic containing copper sulfide. Enargite was separated from chalcopyrite by flotation by combining potassium amyl xanthate (PAX) and hydrogen peroxide. The resultant arsenic-rich “dirty” concentrates and/or arsenic-containing copper concentrates were subjected to the magnetic separation as well as bioleaching processes. After the heat treatment, chalcopyrite exhibited magnetic property whereas enargite did not. This difference enabled the magnetic separation of the two minerals. Bioleaching was carried out with the addition of activated carbon to improve the copper dissolution as well as As immobilization.</p>

    DOI: 10.4144/rpsj.68.124

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  • Effect of Sodium Metabisulfite on Selective Flotation of Chalcopyrite and Molybdenite

    Yuki Semoto, Gde Pandhe Wisnu Suyantara, Hajime, Keiko Sasaki, Tsuyoshi Hirajima, Yoshiyuki Tanaka, Yuji Aoki, Kumika Ura

    Minerals   11 ( 12 )   2021年12月

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    記述言語:その他   掲載種別:研究論文(学術雑誌)  

    Sodium metabisulfite (MBS) was used in this study for selective flotation of chalcopyrite and molybdenite. Microflotation tests of single and mixed minerals were performed to assess the floatability of chalcopyrite and molybdenite. The results of microflotation of single minerals showed that MBS treatment significantly depressed the floatability of chalcopyrite and slightly reduced the floatability of molybdenite. The results of microflotation of mixed minerals demonstrated that the MBS treatment could be used as a selective chalcopyrite depressant in the selective flotation of chalcopyrite and molybdenite. Furthermore, the addition of diesel oil or kerosene could significantly improve the separation efficiency of selective flotation of chalcopyrite and molybdenite using MBS treatment. A mechanism based on X-ray photoelectron spectroscopy analysis results is proposed in this study to explain the selective depressing effect of MBS on the flotation of chalcopyrite and molybdenite.

    DOI: 10.3390/min11121377

  • Effect of Na<inf>2</inf>SO<inf>3</inf> on the floatability of chalcopyrite and enargite

    Gde Pandhe Wisnu Suyantara, Tsuyoshi Hirajima, Hajime Miki, Keiko Sasaki, Shigeto Kuroiwa, Yuji Aoki

    Minerals Engineering   173   2021年11月

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    記述言語:その他   掲載種別:研究論文(学術雑誌)  

    The effect of sodium sulfite (Na2SO3) on the floatability of chalcopyrite and enargite was investigated in this work. The micro flotation tests of single and mixed minerals were performed under various concentrations of Na2SO3. The micro flotation tests of single minerals showed that Na2SO3 depressed the floatability of both minerals at pH 9 in the absence of potassium amyl xanthate (PAX). Interestingly, the addition of PAX followed by the Na2SO3 treatment selectively improved the recovery of enargite. On the other hand, the recovery of chalcopyrite remained low under a similar condition. The single mineral flotation results indicate that separation of chalcopyrite and enargite might be possible using PAX and Na2SO3 treatment. Indeed, the mixed mineral flotation results were in agreement with the flotation results of single minerals. The mineral surface was analyzed by X-ray photoelectron spectroscopy (XPS) after the treatments to explain the phenomenon. The XPS results show the presence of sulfate species on both mineral surfaces after the Na2SO3 treatment. The adsorbed PAX could prevent the formation of this sulfate species on the enargite surface and rendered the surface hydrophobic. However, the adsorbed PAX could not prevent the formation of sulfate species on the chalcopyrite surface and rendered the surface hydrophilic.

    DOI: 10.1016/j.mineng.2021.107222

  • Mineralogical Prediction on the Flotation Behavior of Copper and Molybdenum Minerals from Blended Cu–Mo Ores in Seawater

    Yoshiyuki Tanaka, Hajime Miki, Gde Pandhe Wisnu Suyantara, Yuji Aoki, Tsuyoshi Hirajima

    Minerals   11 ( 8 )   2021年8月

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    記述言語:その他   掲載種別:研究論文(学術雑誌)  

    The copper ore in Chilean copper porphyry deposits is often associated with molybdenum minerals. This copper–molybdenum (Cu–Mo) sulfide ore is generally mined from various locations in the mining site; thus, the mineral composition, oxidation degree, mineral particle size, and grade vary. Therefore, in the mining operation, it is common to blend the ores mined from various spots and then process them using flotation. In this study, the floatability of five types of Cu–Mo ores and the blending of these ores in seawater was investigated. The oxidation degree of these Cu–Mo ores was evaluated, and the correlation between flotation recovery and oxidation degree is presented. Furthermore, the flotation kinetics of each Cu–Mo ore were calculated based on a mineralogical analysis using mineral liberation analysis (MLA). A mineralogical prediction model was proposed to estimate the flotation behavior of blended Cu–Mo ore as a function of the flotation behavior of each Cu–Mo ore. The flotation results show that the recovery of copper and molybdenum decreased with the increasing copper oxidization degree. In addition, the recovery of blended ore can be pre-dicted via the flotation rate equation, using the maximum recovery (Rmax) and flotation rate coeffi-cient (k) determined from the flotation rate analysis of each ore before blending. It was found that Rmax and k of the respective minerals slightly decreased with increasing the degree of copper oxida-tion. Moreover, Rmax varied greatly depending on the mineral species. The total copper and molybdenum recovery were strongly affected by the degree of copper oxidation as the mineral fraction in the ore varied greatly depending upon the degree of oxidation.

    DOI: 10.3390/min11080869

  • Bubble interactions with chalcopyrite and molybdenite surfaces in seawater

    Gde Pandhe Wisnu Suyantara, Tsuyoshi Hirajima, Hajime Miki, Keiko Sasaki

    Minerals Engineering   157   2020年10月

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    記述言語:その他   掲載種別:研究論文(学術雑誌)  

    The detrimental effect of seawater on Cu-Mo flotation has attracted much attention in recent years, which has mainly been focused on altering the detrimental effect of seawater on the floatability of molybdenum ore. The interaction between bubbles and particles during flotation is a key factor in understanding the detrimental effect of seawater. Therefore, this study aimed to investigate the effect of seawater on bubble-particle interactions with chalcopyrite and molybdenite surfaces. Moreover, the effect of emulsified kerosene, a typical molybdenite collector, on bubble-particle interactions in seawater was investigated. Artificial seawater was used as a seawater model solution in this study. Flotation tests using pure chalcopyrite and molybdenite showed that the addition of emulsified kerosene to artificial seawater at a specific pH could selectively improve the floatability of molybdenite while maintaining the low floatability of chalcopyrite. A study of the bubble-particle interactions was then performed to analyze the phenomenon. It was found that the kerosene adsorbed at the air/liquid interface of the bubble improved the bubble aspect ratio and reduced the bubble rise velocity in artificial seawater. Moreover, kerosene could accelerate the formation of three-phase contact between the bubble and both mineral surfaces at the natural pH of artificial seawater. Additionally, this study showed that seawater colloidal precipitate formed under high pH conditions might be adsorbed on the mineral surfaces and might improve the stability of the intervening liquid film on the surface, thus preventing bubble-particle attachment and decreasing mineral recovery. Under these high pH conditions, the emulsified kerosene and seawater precipitate might compete in terms of adsorption on the mineral surfaces and the flotation results would most likely depend on the kerosene and hydrophilic adsorbate coverage on the mineral surfaces.

    DOI: 10.1016/j.mineng.2020.106536

  • Effect of H2O2 and potassium amyl xanthate on separation of enargite and tennantite from chalcopyrite and bornite using flotation

    Gde Pandhe Wisnu Suyantara

    Minerals Engineering   152   2020年6月

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    記述言語:英語   掲載種別:研究論文(学術雑誌)  

    Effect of oxidation treatment using hydrogen peroxide (H2O2) on the floatability of copper sulfide minerals (i.e., chalcopyrite and bornite) and arsenic-bearing copper minerals (i.e., tennantite and enargite) is reported in this study. Pure mineral flotation shows that the floatability of each mineral significantly decreases after the oxidation treatment. Interestingly, flotation of mixed mineral of copper sulfide and arsenic-bearing copper minerals shows that enargite and tennantite exhibit a higher floatability compared to chalcopyrite and bornite after the oxidation treatment followed by the addition of potassium amyl xanthate (PAX). These flotation results indicate a possibility for selective flotation of copper sulfide and arsenic-bearing copper minerals. Indeed, bench-scale flotation tests show that the oxidation treatment using H2O2 and the addition of PAX can deliver a satisfying separation of copper sulfide and arsenic-bearing copper minerals. Difference oxidation products (i.e., CuO, Cu(OH)2, CuSO4, FeOOH, and Fe2(SO4)3) on each mineral surface are likely the cause of this different flotation behavior. Furthermore, these oxidation products may affect the adsorption amount of PAX on each mineral. Indeed, the adsorption tests show that PAX is adsorbed more on tennantite, bornite, and enargite compared to chalcopyrite owing to the formation of CuSO4 and Cu(OH)2 on the mineral surfaces under oxidizing conditions. A possible mechanism is proposed in this study to explain the selective flotation behavior of mixed minerals.

    DOI: 10.1016/j.mineng.2020.106371

  • Investigation of reagents for selective flotation on chalcopyrite and molybdenite

    H. Miki, T. Hirajima, Y. Muta, G. P.W. Suyantara, K. Sasaki

    IMPC 2018 - 29th International Mineral Processing Congress   1854 - 1861   2019年9月

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    記述言語:その他   掲載種別:研究論文(その他学術会議資料等)  

    Selective flotation of chalcopyrite and molybdenite is continuing problem since its selectivity is not perfect and current NaHS process needs closed system flotation plant because of hydrogen sulfide emission on acidic condition. Some alternative additives investigated as chalcopyrite became hydrophilic and molybdenite kept hydrophobic. XPS analysis indicated chalcopyrite became hydrophilic since iron and copper sulphate, hydroxide was covered on the surface whereas molybdenite kept hydrophobic since only molybdenite can be seen. Flotation experiments of chalcopyrite and molybdenite mixture sample indicated excellent separation that 95&#37; of molybdenite can be recovered as froth and 93&#37; of chalcopyrite can be recovered as sink. Flotation experiments with real bulk flotation concentration indicated similar separation result compared with current NaHS additive system. Possible mechanisms and detailed phenomenon were investigated based on the surface analysis and thermodynamic calculation etc. this alternative additive is easy to handle compared with NaHS since it does not emit effluent gas and commercially preferable.

  • The use of Fenton's reagent on selective flotation of chalcopyrite and molybdenite

    Gde Pandhe Wisnu Suyantara, Tsuyoshi Hirajima, Hajime Miki, Keiko Sasaki

    IMPC 2018 - 29th International Mineral Processing Congress   1862 - 1871   2019年9月

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    記述言語:その他   掲載種別:研究論文(その他学術会議資料等)  

    Hydrogen peroxide (H 2 O 2 ) is frequently used as an oxidizing agent in various applications. It has also been reported to reduce the recovery of sulfide minerals. Moreover, the previous work applied H 2 O 2 aqueous solution in selective flotation of chalcopyrite and molybdenite. However, the oxidation method suffered in pilot scale test due to too long conditioning time. Furthermore, the excessive reagent consumption increased the reagent cost, causing the method not economically feasible. Consequently, further improvement is required to reduce the conditioning time and the reagent consumption. The oxidation performance of H 2 O 2 can be improved by using ferrous iron as catalyst, producing a Fenton's reagent which is more powerful oxidizer than the H 2 O 2 itself. Therefore, the effect of Fenton's reagent on the floatability of chalcopyrite and molybdenite was investigated in this study. The flotation test results show that selective flotation of chalcopyrite and molybdenite might be possible at low concentration of H 2 O 2 aqueous solution by adding ferrous iron. Moreover, the conditioning time could be shortened by this improvement. To understand the phenomenon, surface characterization using atomic force microscopy (AFM) along with x-ray photoelectron spectroscopy (XPS) analysis were carried out. The AFM images show that the surface of chalcopyrite was readily covered with mountainous features which alters its hydrophobicity after the oxidation treatment. Meanwhile, the molybdenite surface remained clean and relatively hydrophobic. The XPS results indicate that the mountainous features are various oxidation products (i.e., FeOOH, Fe 2 (SO 4 ) 3 , CuO, Cu(OH) 2 ). Possible mechanisms of this phenomenon were proposed in this work.

  • Effect of Fenton-like oxidation reagent on hydrophobicity and floatability of chalcopyrite and molybdenite

    Gde Pandhe Wisnu Suyantara

    Colloids and Surfaces A: Physicochemical and Engineering Aspects   554   34 - 48   2018年10月

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    記述言語:英語   掲載種別:研究論文(学術雑誌)  

    A fundamental study is provided in this work to understand the effect of Fenton-like reagent made by the addition of FeSO4 in H2O2 aqueous solution on surface hydrophobicity and floatability of chalcopyrite (CuFeS2) and molybdenite (MoS2). Contact angle measurements were performed to assess the surface hydrophobicity. The contact angle results showed that Fenton-like reagent could alter the surface hydrophobicity of chalcopyrite at lower concentration of H2O2 aqueous solution compared to that of using H2O2 aqueous solution. On the other hand, molybdenite surface remained hydrophobic after the oxidation treatments using Fenton-like reagent and H2O2 aqueous solution. Surface characterizations using atomic force microscopy (AFM) and X-ray photoelectron spectroscopy (XPS) shows that the chalcopyrite surface covered with a thicker layer of oxidation products after the oxidation treatment using Fenton-like reagent, indicating a stronger surface oxidation. Flotation results were in agreement with contact angle results, showing that Fenton-like reagent could depress the floatability of chalcopyrite at lower concentration of H2O2 aqueous solution. On the other hand, molybdenite recovery remained high under various oxidation treatments owing to low surface oxidation.

    DOI: 10.1016/j.colsurfa.2018.06.029

  • Selective flotation of chalcopyrite and molybdenite using H<inf>2</inf>O<inf>2</inf>oxidation method with the addition of ferrous sulfate

    Suyantara, G.P.W., Hirajima, T., Miki, H., Sasaki, K., Yamane, M., Takida, E., Kuroiwa, S., Imaizumi, Y.

    Minerals Engineering   122   312 - 326   2018年6月

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    記述言語:その他   掲載種別:研究論文(学術雑誌)  

    Hydrogen peroxide (H2O2) has been used as an oxidizing agent in the selective flotation of chalcopyrite and molybdenite. However, this method required relatively high concentration of H2O2 to deliver flotation results (i.e., mineral grades and recoveries) comparable to those obtained by the conventional copper-molybdenum (Cu-Mo) ores flotation using sodium hydrosulfide (NaHS). Therefore, further improvements are needed to reduce the consumption of H2O2 reagent. In this study, ferrous sulfate (FeSO4) was used to enhance the oxidation performance of H2O2 through Fenton-like reactions. Flotation results showed that the consumption of H2O2 reagent could be reduced by the addition of FeSO4 without losing the flotation selectivity. The reason might be caused by increasing of oxidation performance as indicated by the increasing concentration of dissolved oxygen after the addition of FeSO4 into the H2O2 aqueous solution. Surface analysis using X-ray photoelectron spectroscopy (XPS) and atomic force microscopy (AFM) images showed that the surface of chalcopyrite was covered by more hydrophilic precipitates after the oxidation treatment using H2O2 aqueous solution with the addition of FeSO4, thus more hydrophilic surface and lower floatability. On the other hand, the surface of molybdenite was slightly oxidized and its surface remained hydrophobic as confirmed from contact angle results. Flotation tests using Cu-Mo bulk concentrate demonstrated that selective flotation might be possible using a mixture of FeSO4 and H2O2 aqueous solution. Moreover, this new method could be used as an alternative to copper depressant in Cu-Mo selective flotation, replacing the NaHS reagent.

    DOI: 10.1016/j.mineng.2018.02.005

  • Effect of Sodium Sulfite on Floatability of Chalcopyrite and Molybdenite

    Gde Pandhe Wisnu Suyantara

    Minerals   8 ( 4 )   2018年4月

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    記述言語:その他   掲載種別:研究論文(学術雑誌)  

    Sodium hydrogen sulfide (NaHS) is commonly used as a copper depressant in the selective flotation of copper and molybdenum ores. However, the process is facing health and safety issues because NaHS readily yields toxic hydrogen sulfide gas (H2S) under acidic conditions. In this study, Na2SO3 was proposed as an alternative copper depressant. The effect of Na2SO3 on the surface wettability and floatability of chalcopyrite and molybdenite—typical copper and molybdenum minerals, respectively—was intensively studied using contact angle measurements and flotation tests. Contact angle readings show that the chalcopyrite surface became hydrophilic after the Na2SO3 treatment. Meanwhile, the molybdenite surface was relatively more hydrophobic compared with that of chalcopyrite after the treatment. Flotation tests using pure minerals of chalcopyrite and molybdenite demonstrate that the floatability of chalcopyrite decreased with increasing concentration of Na2SO3. On the other hand, the floatability of molybdenite gradually increased under similar conditions, suggesting that Na2SO3 might have the potential to be used for selective flotation of chalcopyrite and molybdenite. A possible mechanism is proposed in this study to explain the phenomenon using X-ray photoelectron spectroscopy analysis.

    DOI: 10.3390/min8040172

  • Floatability of molybdenite and chalcopyrite in artificial seawater

    Suyantara, G.P.W., Hirajima, T., Miki, H., Sasaki, K.

    Minerals Engineering   115   117 - 130   2018年1月

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    記述言語:その他   掲載種別:研究論文(学術雑誌)  

    Seawater has been reported to depress the floatability of molybdenum in copper-molybdenum (Cu-Mo) flotation circuits under alkaline conditions (pH > 9.5). However, the seawater used in the process contains various minerals and flotation reagents, which make it difficult to investigate the depression mechanism. This paper presents a fundamental study into the effect of artificial seawater as a seawater model solution on the floatability of molybdenite and chalcopyrite, which are the main minerals in the Cu-Mo flotation process. Floatability tests in the absence of flotation reagents (i.e., frothers and collectors) reveal that artificial seawater adversely affects the floatability of molybdenite and chalcopyrite at pH > 9. This phenomenon can be attributed to the adsorption of hydrophilic Mg(OH)2 precipitates formed under alkaline conditions on the mineral surfaces, which increases the surface wettability of the mineral particles, as shown by contact angle measurements and atomic force microscopy (AFM) images. The effect of kerosene as a molybdenite collector has also been investigated to assess its potential in the selective flotation of molybdenite and chalcopyrite in artificial seawater.

    DOI: 10.1016/j.mineng.2017.10.004

  • Effect of hydrogen peroxide on separation of chalcopyrite and molybdenite using flotation

    Gde Pandhe Wisnu Suyantara, Tsuyoshi Hirajima, Hajime Miki, Keiko Sasaki

    14th International Symposium on East Asian Resources Recycling Technology, EARTH 2017   2017年9月

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    記述言語:その他   掲載種別:研究論文(その他学術会議資料等)  

    Various oxidation treatments (i.e., plasma, and ozone) have been applied to separate molybdenite from other sulfide metals. However, plasma and ozone treatments exhibit stronger oxidation on chalcopyrite and molybdenite, reducing the separation selectivity of both minerals in flotation tests. On the other hand, hydrogen peroxide (H2O2) is frequently used as an oxidizing agent in wastewater treatment. It has also been reported to reduce the recovery of sulfide minerals. Therefore, the effect of H2O2 on separation of chalcopyrite and molybdenite was investigated in this study. Contact angle readings and surface images using atomic force microscopy (AFM) showed that chalcopyrite surface was more sensitive to surface oxidation compared to that of molybdenite in H2O2 aqueous solution. The floatability test of single mineral confirmed the contact angle results and AFM images, indicating a possibility for selective separation of chalcopyrite and molybdenite using a H2O2 aqueous solution. In addition, iron was used to improve the oxidation performance of H2O2 and its effect on the selective flotation of chalcopyrite and molybdenite is intensively studied in this work.

  • Electrolysis oxidation of chalcopyrite and molybdenite for selective flotation

    Miki, H., Matsuoka, H., Hirajima, T., Suyantara, G.P.W., Sasaki, K.

    Materials Transactions   58 ( 5 )   761 - 767   2017年3月

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    記述言語:その他   掲載種別:研究論文(学術雑誌)  

    Electrolysis oxidation of chalcopyrite and molybdenite was investigated, via various electrochemical methods, with the aim of realizing selective flotation of these minerals. Result of potential polarization indicated that oxidation via electrolysis affected only the chalcopyrite surface, owing mainly to the difference in conductivity of these minerals. Also measurements of contact angle after electrolysis indicated that contact angle of chalcopyrite selectively decreased whereas that of molybdenite did not decrease drastically. XPS analyses after electrolysis indicated that chalcopyrite peak decreased whereas iron oxyhydroxide (goethite) and iron sulfate increased, it suggests that these oxidation products covered on the surface of chalcopyrite. On the other hand, molybdenite peak is similar after electrolysis except for molybdenum oxide/oxygen with molybdenite can be seen for oxygen peak. From these results and general knowledge that sulfide hydrophobicity and sulfate/oxyhydroxide hydrophilicity, it can be explained that with electrolysis oxidation, hydrophilic oxihydroxide and sulfate covered on the surface of hydrophobic chalcopyrite then chalcopyrite surface became hydrophilic. On the other hand, molybdenite surface keep hydrophobic since its difficulty of oxidation and it is difficult to stay molybdenum oxide on the surface due to its soluble property. These results revealed that chalcopyrite was selectively oxidized and, hence, selective flotation of chalcopyrite and molybdenite was possible. This electrolysis oxidation methods were compared with those governing other oxidation treatments.

    DOI: 10.2320/matertrans.M-M2017807

  • Selective flotation of chalcopyrite and molybdenite with H<inf>2</inf>O<inf>2</inf>oxidation

    Hirajima, T., Miki, H., Suyantara, G.P.W., Matsuoka, H., Elmahdy, A.M., Sasaki, K., Imaizumi, Y., Kuroiwa, S.

    Minerals Engineering   100   83 - 92   2017年1月

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    記述言語:その他   掲載種別:研究論文(学術雑誌)  

    The selective flotation of chalcopyrite (CuFeS2) and molybdenite (MoS2) was studied using surface oxidation treatments (i.e., ozone (O3) and hydrogen peroxide (H2O2)). The results indicated that the oxidation treatments had different effects on the wettability of chalcopyrite and molybdenite. Single mineral flotation results showed that the H2O2 treatment had higher separation selectivity for molybdenite and chalcopyrite compared with that of the ozone treatment. The contact angle measurement and X-ray photoelectron spectroscopy (XPS) analysis results showed that the chalcopyrite surface became hydrophilic owing to the surface deposition of oxidized iron and copper after the H2O2 treatment. On the other hand, the contact angle of molybdenite slightly increased following the H2O2 treatment at high concentrations. Possible mechanisms of this phenomenon were proposed in this work. Moreover, the separation selectivity of each oxidation method was discussed. Flotation tests using bulk Cu-Mo concentrate showed that H2O2 could deliver a flotation result comparable to conventional Cu-Mo flotation using NaHS.

    DOI: 10.1016/j.mineng.2016.10.007

  • Effect of Mg2+and Ca2+as divalent seawater cations on the floatability of molybdenite and chalcopyrite

    Hirajima, T., Suyantara, G.P.W., Ichikawa, O., Elmahdy, A.M., Miki, H., Sasaki, K.

    Minerals Engineering   96-97   83 - 93   2016年10月

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    記述言語:その他   掲載種別:研究論文(学術雑誌)  

    Seawater flotation has been applied to mineral processing in areas located far from fresh water resources. However, as seawater has a detrimental effect on molybdenite floatability under alkaline conditions (pH > 9.5), its application in the conventional copper and molybdenum (Cu-Mo) flotation circuit is hindered. A fundamental study of the effect of two divalent cations in seawater, Mg2+ and Ca2+, on the floatability of chalcopyrite and molybdenite is presented in this paper. Floatability tests showed that both MgCl2 and CaCl2 solutions depress the floatability of chalcopyrite and molybdenite at pH values higher than 9. Furthermore, Mg2+ exerts a stronger effect than Ca2+ owing to the adsorption of Mg(OH)2 precipitates on the mineral surfaces, as indicated by dynamic force microscopy images. The floatability of chalcopyrite was significantly depressed compared with that of molybdenite in a 10−2 M MgCl2 aqueous solution at pH 11. This phenomenon is likely due to the adsorption of hydrophilic complexes on the mineral surface, which reduces the surface hydrophobicity. A reversal of the zeta potential of chalcopyrite in MgCl2 and CaCl2 solutions at pH 11 and 8, respectively, indicated the adsorption of precipitates onto the surface. In contrast, the zeta potential of molybdenite decreased continuously under the same conditions. The floatability test of chalcopyrite and molybdenite in mixed systems showed that selective separation of both minerals should be possible with the addition of emulsified kerosene to a 10−2 M MgCl2 solution at pH 11. A mechanism is proposed to explain this phenomenon.

    DOI: 10.1016/j.mineng.2016.06.023

  • Comparison of selective flotation of chalcopyrite and molybdenite with various oxidation techniques

    Tsuyoshi Hirajima, Hidekazu Matsuoka, Hajime Miki, Gde Pandhe Wisnu Suyantara, Ahmed Mohamed Elmahdy, Keiko Sasaki

    IMPC 2016 - 28th International Mineral Processing Congress   2016年9月

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    記述言語:その他   掲載種別:研究論文(その他学術会議資料等)  

    Selective flotation of chalcopyrite and molybdenite was studied using various surface treatment methods such as electrolysis, ozone treatment, and plasma. Oxidation via electrolysis method indicated that only chalcopyrite surface is affected by electrolysis due to conductivity difference with molybdenite. Oxidation treatments and XPS analyses indicated that chalcopyrite became hydrophilic due to deposition of oxidized iron on its surface. Various oxidizing methods also showed that chalcopyrite was selectively oxidized and this can apply selective flotation of chalcopyrite and molybdenite. The possible mechanisms are proposed in this work based on surface analyses and thermodynamic calculations.

  • Effect of kerosene on bubble interaction with molybdenite and chalcopyrite in MgCl<inf>2</inf> solution

    Gde Pandhe Wisnu Suyantara, Tsuyoshi Hirajima, A. M. Elmahdy, Hajime Miki, Keiko Sasaki

    IMPC 2016 - 28th International Mineral Processing Congress   2016年9月

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    記述言語:その他   掲載種別:研究論文(その他学術会議資料等)  

    Seawater has been reported to depress molybdenite in a copper-molybdenum (Cu-Mo) flotation process at high pH due to the precipitation of Mg(OH)2. Meanwhile, to improve mineral recoveries, collectors are usually added into the flotation cells, thus adding the complexity to the mechanism of bubble-particle interactions involved in Cu-Mo flotation. Therefore, understanding the interaction mechanism in seawater flotation and in the presence of collectors is important to explain the minerals depression. The present work investigated the effect of kerosene on the bubble collision and attachment to pure chalcopyrite and molybdenite surfaces in MgCl2 solution as one of the seawater major components at pH 6 and 11. Mineral surfaces were characterized using atomic force microscopy (AFM). In addition, minerals floatability in the same system were tested in a column flotation. The study of bubble-particle interactions shows that following several collisions, bubble could displace the intervening liquid layer on the mineral surfaces, forming a three-phase contact (TPC). A TPC formed more rapidly in the presence of emulsified kerosene in a 0.01 M MgCl2 solution at pH 6 for both minerals. The reason is kerosene increased the surfaces hydrophobicity and destabilized the intervening liquid layer on the surfaces. Moreover, the average time required to form a TPC was shorter on molybdenite surface. This can be attributed to the effect of adsorbed kerosene on molybdenite surface and molybdenite surface roughness.

  • Effect of kerosene emulsion in MgCl<inf>2</inf>solution on the kinetics of bubble interactions with molybdenite and chalcopyrite

    Suyantara, G.P.W., Hirajima, T., Elmahdy, A.M., Miki, H., Sasaki, K.

    Colloids and Surfaces A: Physicochemical and Engineering Aspects   501   98 - 113   2016年7月

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    記述言語:その他   掲載種別:研究論文(学術雑誌)  

    The formation of stable bubble-particle aggregates is essential to the froth flotation process. To form such aggregates, bubbles and particles must collide, the intervening liquid film must be drained below its critical rupture thickness, and three-phase contact (TPC) formation must occur. A good understanding of the interaction mechanism between bubbles and particles during collision and attachment is important. We herein investigated the effects of emulsified kerosene in a 0.01 M MgCl2 solution (a model seawater component) on bubble interactions with pure molybdenite (MoS2) and chalcopyrite (CuFeS2) surfaces. In 0.01 M MgCl2 at pH 6 and 11, kerosene retarded the bubble surface mobility and reduced the bubble rise velocity. In the presence of kerosene at pH 6, the TPC formed more rapidly on both mineral surfaces. This was due to the increase in surface hydrophobicity caused by kerosene. In addition, TPC formation was more rapid on the molybdenite surface than on the chalcopyrite surface due to the effect of the adsorbed kerosene and the low surface homogeneity of molybdenite. Finally, floatability tests demonstrated that the separation of molybdenite and chalcopyrite should be possible by adding emulsified kerosene in a 0.01 M MgCl2 solution at pH 9.

    DOI: 10.1016/j.colsurfa.2016.04.039

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所属学協会

  • 一般社団法人資源・素材学会

    2022年 - 現在

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  • 一般社団法人資源・素材学会

学術貢献活動

  • Review, evaluation

    External Reviewer  ( Japan ) 2023年10月 - 2023年11月

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    種別:大会・シンポジウム等 

  • External Reviewer

    役割:審査・評価

    Research Projects of the National Research and Development Agency (ANID) of the Ministry of Science, Technology, Knowledge and Innovation of Chile  2023年10月 - 2023年11月

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    種別:審査・学術的助言 

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    Reviewer for Minerals Engineering  ( Japan )

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    種別:大会・シンポジウム等 

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    Reviewer for Applied Surface Science  ( Japan )

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    Reviewer for Colloids and surfaces  ( Japan )

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    Reviewer for Journal of sustainable metallurgy  ( Japan )

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    Reviewer for Journal of molecular liquids  ( Japan )

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  • Reviewer for Minerals Engineering

    役割:査読

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    種別:査読等 

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    役割:査読

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共同研究・競争的資金等の研究課題

  • 海洋性硫黄代謝微生物を用いた海水利用鉱物処理プロセスの構築

    研究課題/領域番号:23H03815  2023年 - 2025年

    日本学術振興会  科学研究費助成事業  基盤研究(C)

    小山 恵史, Suyantara Gde・Pandhe・Wisnu

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    資金種別:科研費

    海水中での鉱物-微生物反応試験を通して、海洋性硫黄代謝微生物の産業利用を目的とした工学的な基礎実験を実施する。その際、これまで鉱業分野ではマイナーな手法である局所硫黄同位体分析や遺伝子発現動態分析、シンクロトロン分析を融合させることで、今まで明らかとされなかった鉱業試験系における微生物-鉱物間の反応機構の解明に取り組む。最終的には微生物学的情報と工学的情報を統合し,海洋性硫黄代謝微生物の産業利用性判断のための指標づくりを目指す。

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    研究課題/領域番号:22H00310  2022年 - 2025年

    日本学術振興会  科学研究費助成事業  基盤研究(C)

    三木 一, 笹木 圭子, Suyantara Gde・Pandhe・Wisnu

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    資金種別:科研費

    銅資源の需要は高まっているが、銅鉱山は、複雑化・難処理化の傾向にある。また、多数の銅鉱山は乾燥地帯にあり、鉱業用水を海水の淡水化により対応している場合が多い。申請者らは、難処理銅鉱石からのCu-As、Cu-Mo分離を、酸化還元剤等の添加後、海水浮選で分離回収する方法を見出してきた。本研究では、各種鉱物の捕収剤吸着速度測定、精密な電気化学手法と各種表面分析、浮選試験等により、銅鉱物、含As銅鉱物、Mo鉱物の表面性状変化を詳細かつ定量的に調べ、これら鉱物の浮選分離メカニズムを明らかにする。回分式、連続式浮選試験による最適分離プロセス、混合鉱石の浮選産物回収率予測法を確立し、実操業への適用を目指す。

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  • Development of separation method for secondary copper and arsenic minerals using flotation

    研究課題/領域番号:22K14636  2022年 - 2023年

    日本学術振興会  科学研究費助成事業  若手研究

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    担当区分:研究代表者  資金種別:科研費

  • Development of separation method for secondary copper and arsenic minerals using flotation

    研究課題/領域番号:22K14636  2022年 - 2023年

    日本学術振興会  科学研究費助成事業  基盤研究(C)

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  • グラファイト質金鉱石のバイオハイドロメタラジーの学理

    研究課題/領域番号:19KK0135  2019年10月 - 2024年3月

    科学研究費助成事業  国際共同研究加速基金(国際共同研究強化(B))

    笹木 圭子, 三木 一, 金田 隆, GUO BINGLIN, KONADU KOJO・TWUM, Suyantara Gde・Pandhe・Wisnu

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    資金種別:科研費

    いまだに焙焼法が適用されているグラファイト質金鉱石を対象とし、マイルドなシークエンシャルバイオ処理による金回収率の向上をめざす。金回収ロスにつながる炭素の分布、金の所在とその分布、金のホスト鉱物の単体分離度、炭素のグラファイト化度などに焦点を合わせた特性化に基づき、鉄酸化菌による硫化物の分解、アルカリ洗浄、湿式粉砕、リグニンペルオキシダーゼを含む粗酵素液による芳香族炭素の分解などの工程の組み合わせを検討する。処理中間体及び最終固体残差のQEMSCAN観察を通して、Au(0)回収ロスを極限まで最小化する。QEMSCAN分析に熟練した豪州側と協働しておこなうことにより本国際共同研究を一層強化する。

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