Updated on 2025/06/23

写真a

 
TOKORO, Chiharu
 
Affiliation
Faculty of Science and Engineering, School of Creative Science and Engineering
Job title
Professor
Degree
Dr.Engineering ( 2003.03 The University of Tokyo )

Research Experience

  • 2024.09
    -
    Now

    早稲田大学   創造理工学部長・創造理工学研究科長

  • 2023.11
    -
    Now

    株式会社トッパンフォトマスク   独立社外取締役

  • 2022.07
    -
    Now

    Waseda University

  • 2021.04
    -
    Now

    JX金属株式会社   社外取締役

  • 2021.04
    -
    Now

    The University of Tokyo   The Graduate School of Engineering

  • 2016.11
    -
    Now

    東京大学生産技術研究所   特任教授

  • 2015.04
    -
    Now

    Waseda University   Faculty of Science and Engineering

  • 2022.09
    -
    2024.09

    Waseda University

  • 2022.09
    -
    2024.09

    Waseda University

  • 2020.09
    -
    2022.09

    早稲田大学   理工学術院長補佐

  • 2018.09
    -
    2022.09

    Waseda University

  • 2009.04
    -
    2015.03

    Waseda University   Faculty of Science and Engineering

  • 2007.04
    -
    2009.03

    Waseda University   Faculty of Science and Engineering

  • 2004.04
    -
    2007.03

    Waseda University   School of Science and Engineering

▼display all

Education Background

  • 1998.04
    -
    2003.03

    The University of Tokyo  

  • 1994.04
    -
    1998.03

    Waseda University   School of Science and Engineering  

Committee Memberships

  • 2015.02
    -
    2023.03

    経済産業省  中央鉱山保安協議会 委員

  • 2023.07
    -
    Now

    公益財団法人資源環境センター  理事

  • 2021.04
    -
    Now

    Scientific Reports  Editorial Board Member

  • 2020
    -
    Now

    資源・素材学会  粉体精製工学部門委員会 委員

  • 2020
    -
    Now

    環境資源工学会  編集委員長

  • 2020
    -
    Now

    環境資源工学会  常務理事

  • 2020
    -
    Now

    Minerals  Editor

  • 2019.06
    -
    Now

    公益社団法人日本工学アカデミー  正会員

  • 2019
    -
    Now

    エコデザイン推進機構  理事

  • 2015
    -
    Now

    環境資源工学会  理事

  • 2022.11
    -
    2026.10

    経済産業省  産業構造審議会 臨時委員/産業技術環境分科会廃棄物・リサイクル小委員会自動車リサイクルワーキンググループ指名

  • 2024.04
    -
    2026.04

    公益財団法人 近藤記念財団  理事

  • 2023.04
    -
    2026.03

    一般財団法人 ピースコミュニケーション財団  理事

  • 2021.06
    -
    2026.03

    国立研究開発法人科学技術振興機構  領域アドバイザー

  • 2019
    -
    2026.03

    粉体工学会  理事

  • 2022.12
    -
    2026.02

    文部科学省  科学技術・学術審議会専門委員

  • 2021.02
    -
    2026.01

    資源・素材学会  代議員

  • 2024.03
    -
    2025.06

    公益社団法人 新化学技術推進協会  GSCN 国際連携グループ 委員

  • 2023.04
    -
    2024.04

    環境省 環境再生・資源循環局、経済産業省 資源エネルギー庁  「再生可能エネルギー発電設備の廃棄・リサイクルの在り方に関する検討会」委員

  • 2023.07
    -
    2024.03

    一般社団太陽光パネルリユース・リサイクル協会  招聘客員

  • 2023.04
    -
    2024.03

    国立研究開発法人日本原子力研究開発機構  深地層の研究施設計画検討委員会委員

  • 2023.03
    -
    2024.03

    公益財団法人廃棄物・3R研究財団  二酸化炭素排出抑制対策事業費等補助金(プラスチック資源・金属資源等のバリューチェーン脱炭素化のための高度化設備導入等促進事業)審査委員会 委員

  • 2023.01
    -
    2024.03

    東京工業大学科学技術創成研究院ゼロカーボンエネルギー研究所アドバイザリー委員会  委員

  • 2022.04
    -
    2024.03

    国立研究開発法人科学技術振興機構  輝く女性研究者賞選考委員会 委員

  • 2022.04
    -
    2024.03

    一般社団法人日本粉体工業技術協会  ふるい委員会 委員

  • 2020.04
    -
    2024.03

    日本粉体工業技術協会  分級ふるい分け分科会 副コーディネータ

  • 2018
    -
    2024.03

    公益財団法人ホソカワ粉体工学振興財団  選考委員

  • 2023.03
    -
    2024.02

    国立研究開発法人産業技術総合研究所  領域アドバイザリーボード 委員(材料・化学領域)

  • 2023.02
    -
    2024.02

    経済産業省  総合資源エネルギー調査会 臨時委員/資源・燃料分科会 委員

  • 2022.06
    -
    2024.02

    公益社団法人化学工学会/一般社団法人日本能率協会  INCHEM TOKYO 2023 展示委員会委員(コアメンバー)

  • 2022.02
    -
    2024.02

    東京都  使用済太陽光発電設備リサイクル検討会 委員

  • 2020
    -
    2023.09

    日本学術会議  広報委員会「学術の動向」編集分科会 編集委員長

  • 2017.10
    -
    2023.09

    日本学術会議  第三部会員

  • 2022.10
    -
    2023.06

    公益社団法人新化学技術推進協会  GSC賞二次選考委員

  • 2021.09
    -
    2023.06

    一般社団法人循環経済協会  招聘研究員

  • 2017.04
    -
    2023.06

    化学工学会  理事

  • 2023.01
    -
    2023.03

    三菱UFJリサーチ&コンサルティング株式会社(環境省委託)  マスバランス方式に関する研究会 委員

  • 2022.11
    -
    2023.03

    人事院  令和4年度人事院総裁賞選考委員会 委員

  • 2022.11
    -
    2023.03

    国立研究開発法人日本原子力研究開発機構  深地層の研究施設計画検討委員会 委員

  • 2022.07
    -
    2023.03

    一般社団法人低炭素投資促進機構(経済産業省補助事業)  無人自動運転等のCASE 対応に向けた実証・支援事業費補助金評価委員会 委員

  • 2022.06
    -
    2023.03

    BACE(Battery Circular Ecosystem)コンソーシアム2022  アドバイザー

  • 2022.05
    -
    2023.03

    有限責任監査法人トーマツ(環境省受託事業)  令和4年度脱炭素型金属リサイクルシステムの早期社会実装化に向けた実証事業評価審査委員会 委員

  • 2022.05
    -
    2023.03

    一般社団法人資源・素材学会  資源・素材教育センター実行委員

  • 2022.04
    -
    2023.03

    一般財団法人JCCP国際石油・ガス協力機関  令和4年度企画・執行委員会(PIC) 上席調査員

  • 2022.04
    -
    2023.03

    資源・素材学会  関東支部長

  • 2022.04
    -
    2023.03

    公益社団法人日本工学アカデミー  第16回日米先端工学シンポジウム(JAFOE) 運営委員長

  • 2021.05
    -
    2023.03

    国立研究開発法人新エネルギー・産業技術総合開発機構  技術委員

  • 2019.06
    -
    2023.03

    石油天然ガス・金属鉱物資源機構  海洋鉱物資源開発検討委員会選鉱・製錬ワーキンググループ 委員

  • 2019.03
    -
    2023.03

    粉体工学会  出版委員会 委員長

  • 2017.04
    -
    2023.03

    日本粉体工業技術協会  東京粉体工業展委員会 委員

  • 2011.03
    -
    2023.03

    粉体工学会  Advanced Powder Technology Editor

  • 2022.08
    -
    2023.02

    RSC Advances  Associate Editor

  • 2022.03
    -
    2023.02

    経済産業省  令和3年度基礎素材産業の低炭素化投資促進に向けた設計・実証事業補助金に係る外部審査委員会 委員

  • 2023.01
     
     

    有限責任監査法人トーマツ(内閣府科学技術・イノベーション推進事務局委託)  「グローバル・スタートアップ・キャンパス構想関連事前調査」有識者委員会 委員

  • 2022.01
    -
    2023.01

    経済産業省  蓄電池のサステナビリティに関する研究会 委員(委員長)

  • 2022.04
    -
    2022.12

    経産省(野村総研受託事業)蓄電池先端生産技術導入・開発促進事業審査委員会  審査委員

  • 2021.12
    -
    2022.12

    経済産業省 資源エネルギー庁  総合資源エネルギー調査会 臨時委員/資源・燃料分科会 委員

  • 2022.09
     
     

    MITテクノロジーレビュー「Innovators Under 35 Japan 2022」  審査委員

  • 2020.07
    -
    2022.06

    日本学術振興会  卓越研究員候補者選考委員会 委員

  • 2020.07
    -
    2022.06

    日本学術振興会  特別研究員等審査会 委員

  • 2021.12
    -
    2022.03

    国立研究開発法人科学技術振興機構  国際科学技術共同研究推進事業(戦略的国際共同プログラム)アドバイザー

  • 2021.10
    -
    2022.03

    株式会社価値総合研究所(環境省委託)  地球温暖化対策に係る技術実証事業管理・検討及び調査等事業委託業務 委員

  • 2021.09
    -
    2022.03

    石油天然ガス・金属鉱物資源機構  グリーンレメディエーション等研究委員会 委員

  • 2021.09
    -
    2022.03

    石油天然ガス・金属鉱物資源機構  基本方針検討ワーキンググループ 委員

  • 2021.07
    -
    2022.03

    一般財団法人JCCP国際石油・ガス協力機関  令和3年度女性活躍推進のためのUAE-日本合同調査プロジェクト 企画・執行委員会検討委員会 上席調査員

  • 2021.07
    -
    2022.03

    株式会社三菱総合研究所(国立研究開発法人新エネルギー産業技術総合開発機構委託事業)  3R技術ロードマップ作成に係る検討会 委員

  • 2021.05
    -
    2022.03

    一般社団法人低炭素投資促進機構  (経済産業省補助事業)電動車普及に伴い必要となる社会システムの整備に関する実証事業評価委員会 委員

  • 2021.05
    -
    2022.03

    有限責任監査法人トーマツ(環境省委託事業)  令和3年度脱炭素型金属リサイクルシステムの早期社会実装化に向けた実証事業評価審査委員会 委員

  • 2021.04
    -
    2022.03

    粉体工学情報センター  粉体工学情報センター学術奨励賞(IP奨励賞)審査委員・研究助成選考委員

  • 2021
    -
    2022.03

    国立研究開発法人科学技術振興機構  第3回輝く女性研究者賞(ジュン アシダ賞) 選考委員

  • 2020.07
    -
    2022.03

    石油天然ガス・金属鉱物資源機構  金属資源生産技術開発研究会 委員

  • 2020
    -
    2022.03

    資源・素材学会  関東支部幹事

  • 2017.09
    -
    2022.03

    経済産業省  産業構造審議会 産業技術環境分科会廃棄物・リサイクル小委員会自動車リサイクルWG 臨時委員

  • 2022
     
     

    EcoDesign2023国際会議  国内実行委員

  • 2021.12
    -
    2022.01

    公益財団法人本多記念会  第43回本多記念研究奨励賞受賞候補者選考委員会 委員

  • 2019.10
    -
    2021.12

    経済産業省  総合資源エネルギー調査会 臨時委員/資源・燃料分科会 委員

  • 2019.05
    -
    2021.09

    石油天然ガス・金属鉱物資源機構  パッシブトリートメント導入に向けた調査研究ワーキンググループ委員会 委員

  • 2018.10
    -
    2021.09

    日本学術振興会  「リソースロジスティクスに基づくサプライチェーンリスク戦略」に関する研究開発専門委員会 委員

  • 2018.05
    -
    2021.09

    石油天然ガス・金属鉱物資源機構  休廃止鉱山における坑排水処理の高度化調査研究委員会 委員

  • 2020.03
    -
    2021.04

    国際科学技術財団  日本国際賞審査部会 委員

  • 2020.10
    -
    2021.03

    Planning and Implementing Committee

  • 2020.10
    -
    2021.03

    ㈱ブルーアースセキュリティ(経済産業省受託事業)  マンガン酸化菌利用処理技術調査研究ワーキンググループ 委員

  • 2020.10
    -
    2021.03

    ㈱ブルーアースセキュリティ(経済産業省受託事業)  令和2年度休廃止鉱山におけるグリーン・レメディエーション(元山回帰)調査研究委員会 委員長

  • 2020
    -
    2021.03

    国立研究開発法人科学技術振興機構  第2回輝く女性研究者賞(ジュン アシダ賞) 選考委員

  • 2019.11
    -
    2021.03

    日本原子力研究開発機構  鉱山跡措置技術委員会坑水処理検討部会 委員

  • 2018
    -
    2021

    化学工学会  男女共同参画委員長

  • 2011.01
    -
    2020.12

    川崎市  環境局審議会 委員

  • 2018.07
    -
    2020.07

    東京都  使用済太陽光発電設備リサイクル検討会 委員

  • 2019.11
    -
    2020.03

    環境省  低炭素製品普及に向けた3R技術・システム動向調査革新的資源循環の実現に向けた社会システム基盤に関する検討会 委員

  • 2019.09
    -
    2020.03

    石油天然ガス・金属鉱物資源機構  休廃止鉱山におけるグリーン・レメディエーション(元山回帰)調査研究委員会 委員長

  • 2019.04
    -
    2020.03

    環境省  省CO2型リサイクル等設備技術実証事業評価審査委員会 委員

  • 2018.06
    -
    2020.03

    石油天然ガス・金属鉱物資源機構  休廃止鉱山における坑排水処理の高度化調査研究委員会地下水制御技術の調査研究ワーキンググループ委員会 委員

  • 2020
     
     

    化学工学会  女性賞 選考委員

  • 2020
     
     

    公益財団法人本多記念会  第42回本多記念研究奨励賞選考委員会 委員

  • 2018.04
    -
    2020

    日本学術会議  広報委員会「学術の動向」編集分科会 副委員長

  • 2010
    -
    2020

    資源・素材学会  編集委員

  • 2010
    -
    2020

    資源・素材学会  編集幹事

  • 2017.12
    -
    2019.11

    日本学術振興会  科学研究費委員会 専門委員

  • 2017.06
    -
    2019.06

    横浜市  環境影響評価審査会 委員

  • 2018.07
    -
    2019.03

    科学技術振興機構  国際科学技術共同研究推進事業(戦略的国際共同研究プログラム) アドバイザー

  • 2017.04
    -
    2019.03

    粉体工学会  ダイバーシティ委員会 委員

  • 2017.04
    -
    2019.03

    粉体工学会  国際粉工展 東京委員

  • 2017.03
    -
    2019.03

    粉体工学会  編集員会 委員

  • 2018.09
    -
    2019.03

    経済産業省  休廃止鉱山におけるグリーン・レメディエーション(元山回帰)調査研究委員会 委員

  • 2018.04
    -
    2019.03

    環境省  低炭素製品普及に向けた3R体制構築支援事業太陽光発電設備のリユース・リサイクル・適正処分推進に係るワーキンググループ 委員

  • 2018.04
    -
    2019.03

    環境省  省CO2型リサイクル等設備技術実証事業評価検討会 委員

  • 2016.12
    -
    2019.03

    石油天然ガス・金属鉱物資源機構  大谷鉱山鉱害防止技術委員会 委員

  • 2017.02
    -
    2019.02

    粉体工学会  評議員

  • 2019
    -
     

    APCOM2019  Session organizer

  • 2019
    -
     

    DEM8  Session organizer

  • 2019
    -
     

    ISSET2019  Organizer

  • 2019
    -
     

    EcoDesign2019  Organizer

  • 2019
    -
     

    APPChE2019  Organizer

  • 2015
    -
    2019

    資源・素材学会  粉体精製工学部門委員会 委員長

  • 2017
    -
    2018.06

    日本LCA学会  年会実行委員会 委員

  • 2018
    -
    2018.03

    日本原子力研究開発機構  任期付研究員採用試験研究業績評価委員会 委員

  • 2018.02
    -
    2018.03

    環境省  リサイクルシステム統合強化による循環資源利用高度化促進業務粉砕業者における自動車リサイクルの推進・質の向上に係る検討会 委員

  • 2017.12
    -
    2018.03

    環境省  低炭素製品普及に向けた3R体制構築支援事業太陽光発電パネルのリユース・リサイクル・適正処理に係る検討分科会 委員

  • 2017.11
    -
    2018.03

    経済産業省  植物利用型坑排水浄化技術等基礎調査事業会議体 委員

  • 2017.05
    -
    2018.03

    石油天然ガス・金属鉱物資源機構  休廃止鉱山における地下水制御・管理対策調査研究委員会 委員

  • 2018
     
     

    日本学術会議  広報委員会「学術の動向」編集分科会 委員

  • 2018
    -
     

    EcoDePS2018  実行委員長

  • 2018
    -
     

    ICCCI2018  Organizer

  • 2017
    -
    2018

    資源・素材学会  理事

  • 2015.10
    -
    2017.09

    日本学術会議  連携委員

  • 2017
    -
     

    EARTH2017  Organizer

  • 2015
    -
    2017

    化学工学会  関東支部第三企画委員長、男女共同参画委員

  • 2011
    -
    2017

    経済産業省  「アジアにおけるリサイクルビジネス展開可能性調査事業」の審査委員会 委員

  • 2016
    -
     

    Copper2016  Organizer

  • 2016
    -
     

    ICCCI2016  Organizer

  • 2012
    -
    2016

    石油天然ガス・金属鉱物資源機構  調査指導鉱害防止技術委員会 委員

  • 2011
    -
    2015

    環境資源工学会  評議員

  • 2011
    -
    2013

    日本工学教育協会  国際委員会委員

  • 2011
    -
    2013

    石油天然ガス・金属鉱物資源機構  鉱害防止技術適用可能性調査検討委員会 委員

  • 2009.10
    -
    2013.01

    経済産業省  休廃止鉱山鉱害防止対策研究会 委員

  • 2010.08
    -
    2012.02

    経済産業省  自治体間(茨城市-天津市)連携による濱海新区資源循環経済構築に関する調査事業委員会 委員

  • 2012
     
     

    経済産業省  先進型坑廃水処理技術開発評価検討会 委員

  • 2010.04
    -
    2011.03

    経済産業省  レアメタル抽出技術開発に係る事業評価(有識者)委員会 委員

  • 2011
     
     

    石油天然ガス・金属鉱物資源機構  パッシブトリートメント技術委員会 委員

  • 2009.08
    -
    2010.03

    経済産業省  新資源循環推進事業審査委員会 委員

  • 2009.04
    -
    2010.03

    石油天然ガス・金属鉱物資源機構  鉱物資源分野における国際人材育成プログラム開発検討委員会 委員

  • 2008.09
    -
    2010.03

    文部科学省  資源開発人材育成プログラムに係るプログラム調整企画委員

  • 2007
     
     

    経済産業省  今後の鉱害防止の在り方に関する研究会 委員

  • 2007
     
     

    経済産業省  鉱物資源供給対策調査研究会 委員

  • 2007
     
     

    日本学術会議  総合工学委員会持続可能なグローバル資源利活用 に係る検討分科会資源基礎調査小委員会 委員

▼display all

Professional Memberships

  • 2022.03
    -
    Now

    IEEE

  •  
     
     

    化学工学会

  •  
     
     

    粉体工学会

  •  
     
     

    環境資源工学会

  •  
     
     

    資源・素材学会

  •  
     
     

    日本化学会

  •  
     
     

    循環経済協会

  •  
     
     

    日本金属学会

  •  
     
     

    The American Ceramic Society

  •  
     
     

    日本工学アカデミー

  •  
     
     

    日本粉体工業技術協会

  •  
     
     

    エコデザイン推進機構

  •  
     
     

    日本LCA学会

  •  
     
     

    廃棄物資源循環学会

▼display all

Research Areas

  • Transport phenomena and unit operations / Metals production and resources production / Earth resource engineering, Energy sciences / Environmental materials and recycle technology / Environmental load reduction and remediation

Research Interests

  • 固液プロセッシング

  • シミュレーション工学

  • エネルギーシステム

  • エネルギー輸送・貯蔵

  • リサイクル技術

  • 環境保全技術

  • 有価物回収

  • 固固分離

  • Powder Simulation

  • Powder Processing

  • Enviromental Treatment

  • Recycling

  • Solid/Liquid Separation

  • Solid/Solid Separation

▼display all

Awards

  • 資源・素材学会 2025年度春季大会 優秀発表賞

    2025.03   資源・素材学会   直接電気パルス法によるリチウムイオン電池正極材とアルミニウム箔の分離における電極接触部の抵抗の影響

    Winner: 栗原 嵩寿, 成田 麻子, 中原 萌絵, 小板 丈敏, 所 千晴

  • SATテクノロジー・ショーケース 学生奨励賞

    2025.01   つくばサイエンス・アカデミー(一般財団法人茨城県科学技術振興財団)   電気パルスを用いたCFRP積層板の資源循環

    Winner: 佐藤 啓太, 犬束 学, 小板 丈敏, 山口 晃司, 木村 正雄, 所 千晴

  • エコデザイン・プロダクツ&サービス 2024シンポジウム ベストポスター賞

    2024.11   エコデザイン学会連合   高電圧電気パルス法によるエナメル銅線のポリイミド皮膜除去に関する基礎的検討

    Winner: 桐原 拓司, 成田 麻子, 小板 丈敏, 所 千晴

  • 化学工学会 宇都宮大会 学生特別賞

    2024.11   化学工学会   電気パルスによるリチウムイオン電池正極材分離へのプライマーコート箔の適用

    Winner: 中原 萌絵,小板 丈敏,樋口 真一,成田 麻子,所 千晴

  • 化学工学会 宇都宮大会 学生奨励賞

    2024.11   化学工学会   異径媒体を投入した媒体撹拌型ミルの粉砕性能向上を目的とした離散要素法による撹拌軸形状最適化

    Winner: 宮澤 諒, 神谷 秀博, 髙谷 雄太郎, 郡司 進, 百田 憲市, 椎名 啓, 奥山 杏子, 所 千晴

  • Best poster presentation

    2024.11   The 17th International Symposium on East Asian Resources Recycling Technology (EARTH2024)   The leachabilities of boron and fluorine from incineration ash under co-existing carbonate ions

    Winner: Yusuke Furukori, Hisanori Iwai, Masaru Tomoguchi, Kenichi Yamano, Chiharu Tokoro

  • Best oral presentation

    2024.11   The 17th International Symposium on East Asian Resources Recycling Technology (EARTH2024)   Coprecipitation mechanism of Li with Al, Na and SO4 from acid leachate of spent Li-ion batteries

    Winner: Kei Toriumi, Yutaro Takaya, Shinichi Minegishi, Shigeru Aoyama, Ryoma Miyamoto, Chiharu Tokoro

  • Best oral presentation

    2024.11   The 17th International Symposium on East Asian Resources Recycling Technology (EARTH2024)   Mechanism investigation of boron removal with coprecipitated Mg-Al-layered double hydroxide

    Winner: Wang Yafan, Yusuf Olalekan Zubair, Shuo Pan, Mauricio Cordova-Udaeta, Chiharu Tokoro

  • 第68回生活と環境全国大会 環境大臣表彰 (令和6年度廃棄物・浄化槽研究開発功労者)

    2024.10   一般財団法人日本環境衛生センター  

    Winner: 所 千晴

  • 化学工学会第55回秋季大会 最優秀学生発表賞

    2024.09   化学工学会   焼却灰のCO2 鉱物化への利用に向けた炭酸イオン共存下における微 量元素の溶出機構の解明

    Winner: 古郡 友輔, 岩井 久典, 友口 勝, 山野 賢一, 所 千晴

  • 第21回「資源・素材・環境」技術と研究の交流会 優秀ポスター発表賞

    2024.08   資源・素材学会   乾式粉砕・分級プロセスによる三元系(NMC)リチウムイオン電池製造工程内廃材からの正極活物質のダイレクトリサイクルの検討

    Winner: 泉 健人, 髙谷 雄太郎, 所 千晴, 喜多 洋介, 明石 寛之

  • 第21回「資源・素材・環境」技術と研究の交流会 優秀ポスター発表賞

    2024.08   資源・素材学会   高電圧電気パルス法により回収したリチウムイオン電池の負極材の分析

    Winner: 堀内 雅喜, 成田 麻子, 小板 丈敏, 泉 健人, 所 千晴

  • 第142回学術講演会 優秀ポスター賞

    2024.06   環境資源工学会   電気パルス法によるリチウムイオン電池正極活物質層の剥離性低下の原因の把握

    Winner: 栗原 嵩寿, 成田 麻子, 小板 丈敏, 所 千晴

  • 令和5年度著作賞

    2024.05   廃棄物資源循環学会   資源循環論から考えるSDGs(エネルギーフォーラム社, 2022)

    Winner: 所 千晴

  • 優秀発表賞

    2024.03   資源・素材学会   DEMシミュレーションによる傾斜ベルトコンベアにおける湿潤粒子搬送効率の評価

    Winner: 宮澤 諒, 加茂 隆人, 高谷 雄太郎, 榎枝 成治, 西名 慶晃, 所 千晴

  • Jubilee Global Diversity Award

    2024.01   The American Ceramic Society  

    Winner: Chiharu Tokoro

  • BP(Best Poster)賞

    2023.10   粉体工学会   乾式粉砕・分級プロセスを用いたリチウムイオン電池正極活物質粒子のダイレクトリサイクルの検討

    Winner: 泉健人, 髙谷雄太郎, 所千晴

  • 第10回ZAIKEN Festa 優秀賞

    2023.10   早稲田大学 各務記念材料技術研究所   海水浮選における海洋性鉄酸化細菌による黄鉄鉱親水化機構に関する考察

    Winner: 清水佑馬, 牧田寛子, 小山恵史, 三浦響, 所千晴, 淵田茂司

  • 最優秀学生発表賞

    2023.09   化学工学会   臭素系難燃剤を含む廃プラスチックを利用した製鋼ダストの鉛除去プロセスにおける焼成時のプラスチックの挙動の観察

    Winner: 高崎 裕二, 高谷 雄太郎, 所 千晴

  • 優秀ポスター発表賞

    2023.08   資源・素材学会   海洋性鉄酸化細菌の黄鉄鉱浮遊抑制効能力と海水浮選への利用可能性

    Winner: 清水佑馬, 牧田寛子, 小山恵史, 三浦響, 所千晴, 淵田茂司

  • Best Poster Student

    2023.08   The 62nd Annual Conference of Metallurgists   Establishment of an environmental-friendly recycling flow of waste photovoltaic panel for selective recovery of copper, silver, and tin

    Winner: Kento Izumi, Yutaro Takaya, Chiharu Tokoro

  • 学生特別賞

    2023.08   化学工学会   坑廃水処理における中和マンガン殿物の除去材としての活用と地球化学的機構解明

    Winner: 古郡 友輔, 小山 恵史, 所 千晴

  • 学生奨励賞

    2023.08   化学工学会   電気パルスによる集合粉砕および剥離を用いたCFRP積層板からの炭素繊維の分離の把握

    Winner: 佐藤 啓太, 小板 丈敏, 綱澤 有輝, 山口 晃司, 所 千晴

  • Award for Best Poster Presentation

    2023.07   The 2nd workshop of the Australia-Japan Collaborative Research Network   Application of Pulsed Discharge to Laminated CFRP for the Recycling of Carbon Fiber

    Winner: Keita Sato, Taketoshi Koita, Keishi Oyama, Koji Yamaguchi, Chiharu Tokoro

  • Best Oral Presentation Award

    2022.11   EARTH2022   Evaluation of the long-term chemical stability of adsorbed Hg on pyrite surfaces under various redox 3 and pH conditions

    Winner: Shun Ishii, Keishi Oyama, Shigeshi Fuchida, Chiharu Tokoro

  • 学生奨励賞

    2022.11   化学工学会   電気パルス法を用いた廃太陽光パネルからの有価金属選択分離・回収の検討

    Winner: 今泉 友斗, 高谷 雄太郎, 小板 丈敏, 浪平 隆男, 所 千晴

  • KONA Young Researcher Award

    2022.11   ICCCI 2022   Fundamental study of separation of different resin plates bonded by solvent using wire explosion by pulsed discharge

    Winner: Yoshiki Egawa, Taketoshi Koita, Soowon Lim, Takao Namihira, Chiharu Tokoro

  • 令和4年度リサイクル技術開発本多賞(第27回)

    2022.09   一般社団法人産業環境管理協会   新規電気パルス法によるリチウムイオン電池の高精度分離技術開発

    Winner: 所千晴, 浪平隆男, 菊池康紀

  • 第5回APT Outstanding International Contribution Award

    2022.05   粉体工学会  

    Winner: 所千晴

  • 2021年度優秀論文賞

    2022.05   公益社団法人化学工学会   シリカスケール生成抑制を目的としたMg, Al, Fe共存系におけるシリカ重合へのpHおよび温度影響の速度論的評価

    Winner: 石井 駿, 田嶋 翔太, 髙谷 雄太郎, 淵田 茂司, 所 千晴

  • 粉体精製工学部門委員会学生賞

    2022.03   資源・素材学会   バーネス鉱(δ-MnO2)吸着・共沈法による高Mn, Fe負荷酸性坑廃水処理の最適条件の検討

    Winner: 田嶋 翔太, 淵田 茂司, 所 千晴

  • 2021年度早稲田大学リサーチアワード(大型研究プロジェクト推進)

    2021.12   早稲田大学   製品ライフサイクル管理とそれを支える革新的解体技術開発による統合循環生産システムの構築

    Winner: 所 千晴

  • A finalist for the Falling Walls Science Breakthroughs of the Year 2021 in Engineering and Technology

    2021.07   Falling Walls  

    Winner: Chiharu Tokoro

  • 学生奨励賞

    2021.07   化学工学会   最終処分場における有害元素溶出挙動把握のための多硫化物の空気酸化と溶出に関する基礎的研究

    Winner: 石井 駿, 王 科人, 髙谷 雄太郎, 淵田 茂司, 所 千晴

  • 優秀学生賞

    2021.07   化学工学会   銅鉱石の浮選最適化を目指した黄鉄鉱表面酸化速度に基づくカルシウム抑制剤と親水化の関係評価

    Winner: 石田 紗菜, 薛 継峰, 淵田 茂司, 忰山 卓矢, 岸本 恭暢, 青木 悠二, 所 千晴

  • 2021年度論文賞

    2021.06   環境資源工学会   シリカスケール生成抑制を目的としたシリカ重合速度におけるpHおよび温度影響評価

    Winner: 田嶋 翔太, 淵田 茂司, 加藤 達也, 所 千晴

  • 学生優秀発表賞

    2021.03   日本LCA学会   新規電気パルス法を用いた新興技術リサイクルの環境影響評価:リチウムイオン電池および太陽光パネルにおけるケーススタディ

    Winner: 諏訪 出, 兵法 彩, 竇 毅, 所 千晴, 菊池 康紀

  • 粉体精製工学部門委員会学生賞

    2021.03   資源・素材学会   DEM-CFDシミュレーションによるプラスチック相互分離を目的とした水流比重選別装置の最適設計

    Winner: 新田 彩乃, 古作 吉宏, 土井 眞, 舩橋 悟, 綱澤 有輝, 所 千晴

  • 優秀学生賞

    2021.03   化学工学会   銅鉱石の浮選最適化を目的としたカルシウム溶液中における黄鉄鉱および黄銅鉱の酸化反応モデル構築

    Winner: 石田 紗菜, 薛 継峰, 淵田 茂司, 青木 悠二, 忰山 卓矢, 岸本 恭暢, 所 千晴

  • 2020年度早稲田大学リサーチアワード(国際研究発信力)

    2021.02   早稲田大学  

    Winner: 所 千晴

  • ポスター賞

    2020.11   エコデザイン推進機構   ライフサイクルシミュレーションを用いた循環生産システムのフロー制御

    Winner: 浅井 恵斗, 福重 真一, 髙田 祥三, 所 千晴

  • ベストプレゼンテーション賞

    2020.11   粉体工学会   DEM-CFD シミュレーションによるプラスチック高精度分離を目的とした水流型比重選別機の最適装置設計

    Winner: 新田 彩乃, 古作 吉宏, 舩橋 悟, 綱澤 有輝, 所 千晴

  • ベストプレゼンテーション賞

    2020.11   粉体工学会   電気パルス法を用いたハードディスクガラスプラッタからの白金族元素含有金属層剥離の検討

    Winner: 近藤 正隆, Lim Soowon, 小板 丈敏, 浪平 隆男, 所 千晴

  • 第32回IP奨励賞

    2020.08   粉体工学情報センター  

    Winner: 所 千晴

  • 学生奨励賞

    2020.05   粉体工学会   "プラスチック比重分離高精度化を目的としたDEM-CFDによる水流型比重選別機内の粒子挙動把握"

    Winner: 新田 彩乃, 舩橋 悟, 安藤 裕二, 木原 忠志, 張田 真, 綱澤 有輝, 所 千晴

  • 学生奨励賞

    2020.05   粉体工学会   "Evaluation of adsorption performance of zerovalent iron-magnetite nano-composite for Removal of As(Ⅲ) in artificially prepared wastewater"

    Winner: Zubair Yusuf Olalekan, Shigeshi Fuchida, Chiharu Tokoro

  • 若手ポスター発表賞

    2019.09   資源・素材学会   "メカノケミカル反応による風化残留型レアアース鉱物からのイットリウム浸出促進機構解明を目的としたEXAFS解析"

    Winner: 加藤 達也、所 千晴

  • 学生特別賞

    2019.08   化学工学会   "破壊モデルを組み込んだDEMによるHPGRのロール形状の粉砕性能評価"

    Winner: 長田 悠, 綱澤 有輝, 塚田 浩二, 矢口 裕一, 蛭子 陽介, 三觜 幸平, 所 千晴

  • 学生特別賞

    2019.08   化学工学会   "低結晶性酸化マグネシウムを用いた排水中の亜セレン酸およびセレン酸除去機構の解明"

    Winner: 土屋 宏典, 淵田 茂司, 鳥羽 裕一郎, 島村 祐司, 所 千晴

  • 平成31年度文部科学大臣表彰 科学技術賞

    2019.04   "非鉄金属資源循環分野の重要性や将来性の理解増進と普及啓発".

    Winner: 所 千晴

  • 学生賞

    2019   資源・素材学会   "MLAおよびDEMを用いたHPGRの単体分離促進効果に対する考察".

    Winner: 長田 悠, 塚田 浩二, 矢口 裕一, 蛭子 陽介, 三觜 幸平, 所 千晴

  • 優秀ポスター賞

    2019   環境資源工学会   "低結晶性酸化マグネシウムを用いた廃水中のフッ素除去機構の解明および定量モデル化".

    Winner: 土屋 宏典, 淵田 茂司, 鳥羽 裕一郎, 島村 祐司, 所 千晴

  • ポスター奨励賞

    2019   プラズマ分光分析研究会   "溶液中での黄鉄鉱表面酸化に対する酸化速度論構築"

    Winner: 石田 紗菜, 土屋 宏典, 加藤 達也, 淵田 茂司, 黒岩 樹人, 青木 悠二, 所 千晴

  • 優秀学生賞

    2018   化学工学会   "鉱物の粉砕に伴うメカノケミカル反応発生機構のDEMシミュレーションによる考察".

    Winner: 皆川 真也, 久富 渉生, 加藤 達也, Granata Giuseppe, 所 千晴

  • 最優秀学生賞

    2018   化学工学会   "化学反応を考慮した地圏流体解析を用いた人形峠鉱さいたい積場内の鉄・ヒ素の自然浄化機構の再現".

    Winner: 川崎 遥平, 八木澤 真, Granata Giuseppe, 所 千晴, 小原 義之

  • 学生賞

    2018   資源・素材学会   "層状復水酸化物であるGreen Rustを用いた4価および6価セレン除去機構の比較検討".

    Winner: 小野口 愛奈, 余 哲邦, Mamun Abdullah AI, Granata Giuseppe, 所 千晴

  • ベストプレゼンテーション賞

    2018   粉体工学会   "遊星ボールミル粉砕によるレアアース浸出促進に適した鉱石中のレアアース鉱物の形態制御".

    Winner: 加藤 達也, グラナタ ジュセッペ, 所 千晴, 綱澤 有輝, 高木 哲一

  • 優秀ポスター賞

    2018   環境資源工学会   "共沈法と吸着法におけるδ-MnO2によるCd除去機構の比較".

    Winner: 鈴木 滉平, 川﨑 遥平, 加藤 達也, G. Giuseppe, G. Mariusz, 所 千晴

  • Student Poster Award

    2018   日本粉体工業技術協会   "The enhancement mechanism investigation of rare earth elements dissolution from weathered residual rare earth ores by planetary ball milling with addition of solid sodium hydroxide ".

    Winner: T. Kato, G. Granata, C. Tokoro, Y. Tsunazawa, T. Takagi

  • 学生奨励賞

    2018   化学工学会   "ナノ粒子の分散に適したビーズミル設計へのDEMシミュレーションの適用".

    Winner: 長田 悠, 皆川 真也, 関根 靖由, グラナタ ジュセッペ, 所 千晴

  • 最優秀学生発表賞

    2018   化学工学会   "δ-MnO2を用いてCd除去機構の解明及び表面錯体モデルの構築".

    Winner: 鈴木 滉平, 川﨑 遥平, 加藤 達也, Giuseppe Granata, Mariusz Grabada, 所 千晴

  • ベストポスター賞

    2018   エコデザイン推進機構   "未利用資源からの希土類元素回収に向けた高分子吸着剤の開発".

    Winner: 篠崎 智博, 尾形 剛志, 成田 弘一, 所 千晴, 田中 幹也

  • Award for Oral Presentation

    2017   環境資源工学会   "Geo-fluid analysis of the natural purification mechanism of Yotsugi mill tailings pond".

    Winner: Y. Kawasaki, M. Yagisawa, G. Granata, C. Tokoro, Y. Ohara

  • 学生賞

    2017   資源・素材学会   "高分子吸着剤の細孔制御による希土類元素の吸着特性向上".

    Winner: 篠崎智博, 尾形剛志, 柿沼遼, 成田弘一, 所千晴, 田中幹也

  • 学生奨励賞

    2017   化学工学会   "離散要素法を用いたパン型ペレタイザにおける湿式造粒過程のモデリング".

    Winner: 所 拓磨, G. Granata, 所 千晴, 綱澤 有輝

  • 優秀学生賞

    2017   化学工学会   "低結晶性酸化マグネシウムを用いた廃水中のホウ素除去機構の解明".

    Winner: 福田 宏樹, 帆保 駿吾, G. Granata, 所 千晴, 鳥羽 裕一郎, 江口 正浩

  • 学生奨励賞

    2017   化学工学会   高純度グリーンラストを用いた六価セレン除去の基礎的検討

    Winner: 小野口 愛奈, 内田 丈博, A. A. Mamun, G. Granata, 所 千晴

  • 優秀学生賞

    2017   化学工学会   鉄共存下における亜鉛の塩化揮発特性に関する検討

    Winner: 劉 暢之, 松岡 光昭, 所 千晴, 川上 智

  • BEST PRESENTATION AWARD

    2016.07   3rd AJ-BCEP Geo-Resources World Forum 2016 (Jul. 28, Bangkok, Thailand). 2016, 3.   "Application of DEM simulation for investigation of the effect of agitator shape on the grinding mechanism in agitation mill"

    Winner: T. Tokoro, S. Fukui, N. Kawabe, Y. Tsunazawa, C. Tokoro

  • 優秀学生賞

    2016   化学工学会   "高濃度H2SiF6含有廃液からのF回収を目的としたCaF2およびSiO2の析出挙動の把握".

    Winner: 森田 将夫, 所 千晴

  • e-Teaching Good Practice

    2016   早稲田大学 大学総合研究センター  

    Winner: 所 千晴

  • 優秀ポスター賞

    2016   環境資源工学会   "温度保持による銅製錬スラグ中のマグネタイト結晶促進および磁選による回収".

    Winner: 劉 暢之, 堀内 健吾, 松岡 光昭, 大蔵 隆彦, 所 千晴

  • Oral Presentation Award

    2016   環境資源工学会   "The Crystal Growth Promotion of Magnetite in Copper Smelting Slag by Temperature Retention and Recovery by Physical Separation".

    Winner: C. Liu, K. Horiuchi, M. Matsuoka, C. Tokoro

  • 粒子・流体プロセス部会 シンポジウム賞(プレゼンテーション賞)

    2016   化学工学会   "液架橋モデルを組み込んだDEMシミュレーションによる湿潤微粒子の挙動解析".

    Winner: 所 拓磨, 河辺 夏希, 福井 将, 松岡 光昭, 所 千晴, 綱澤 有輝, 酒井 幹夫

  • 平成27年度 論文賞

    2016   廃棄物資源循環学会   "Ship Breaking and the Steel Industry in Bangladesh: A Material Flow Perspective".

    Winner: M. Sujauddin, R. Koide, T. Komatsu, M. M. Hossain, C. Tokoro, S. Murakami

  • 特別賞

    2016   化学工学会   "高濃度H2SiF6廃液処理汚泥からのCaF2回収を目的としたアルカリ洗浄によるSi成分除去".

    Winner: 森田 将夫, 松岡 光昭, 所 千晴

  • 金賞

    2016   化学工学会   "Fe(Ⅲ)担持イオン交換樹脂を用いた廃水中のAs(Ⅴ)除去機構の把握".

    Winner: 内田 丈博, 森田 将夫, 松岡 光昭, 所 千晴

  • 奨励賞

    2016   化学工学会   "DEMシミュレーションを用いたボールミルにおける表面粉砕特性の予測".

    Winner: 福井 将, 綱澤 有輝, 松岡 光昭, 所 千晴

  • 優秀賞

    2016   エコデザイン推進機構   "DEMシミュレーションを用いた破砕による廃小型家電からの基板回収挙動の予測".

    Winner: 福井 将, 綱澤 有輝, 松岡 光昭, 所 千晴, 村上 進亮

  • Oral Presentation Award

    2016  

  • Oral Presentation Award

    2016  

  • Oral Presentation Award

    2016  

  • Oral Presentation Award

    2016   環境資源工学会   Powder synthesis for battery application by one-step mechanical method

    Winner: M. Matsuoka, C. Tokoro, A. Kondo, T. Kozawa, M. Naito

  • Oral Presentation Award

    2016  

  • 第40回 論文賞

    2015   資源・素材学会   "Characteristic Sorption of H3BO3/B(OH)4- on Magnesium Oxide".

    Winner: 笹木 圭子, 邱心泓, 森山 紗好, 所 千晴, 出田 圭子, 宮脇 仁

  • ベストプレゼンテーション賞

    2015   粉体工学会   "ボールミルを用いた黄銅鉱からの銅浸出の促進".

    Winner: 三谷 友梧, 所 千晴

  • 特別賞

    2015   化学工学会   "廃リチウムイオン電池からコバルト回収を目的とした最適加熱条件の検討".

    Winner: 堀内 健吾, 所 千晴, 大和田 秀二, 薄井 正治郎

  • 銅賞

    2015   化学工学会   "エトリンガイトによるホウ素除去の実用化を目的とした温度および共存元素の影響".

    Winner: 武藤 研一, 前田 素生, 帆保 駿吾, 所 千晴, 田中 善之

  • 金賞

    2015   化学工学会   "溶媒抽出法による塩酸溶液からのPt(Ⅳ)/Fe(Ⅲ)相互分離の高度化".

    Winner: 前田 素生, 成田 弘一, 所 千晴, 田中 幹也

  • Research World Excellent Paper Award

    2015   Research World International Conference   "Clarification For Hg(Ⅱ) Removal Mechanism in Ferrihydrite Co-Precipitation Process by XAFS Analysis".

    Winner: T. Kato, T. Uchida, C. Liu, C. Tokoro

  • Best Paper Award

    2015   Journal of Material Cycles and Waste Management   "Characterization of ship breaking industry in Bangladesh".

    Winner: M. Sujauddin, R. Koide, T. Komatsu, M. M. Hossain, C. Tokoro, S. Murakami

  • 特別賞

    2015   化学工学会   アルミナ製造時の廃棄物「赤泥」の硫酸中和とバイポーラ膜電気透析による改質プロセスの構築

    Winner: 岸田 真悠子, 原戸 卓雄, 所 千晴, 大和田 秀二

  • 銅賞

    2015   化学工学会   Fe(Ⅲ)担持樹脂カラムによるAs(Ⅴ)含有排水の処理

    Winner: 二見文也, 所千晴

  • 第39回論文賞

    2014   資源・素材学会   "表面沈殿モデルを用いた希薄As(Ⅴ)廃水の水酸化第二鉄共沈処理に対する定量モデル化".

    Winner: 原口 大輔, 所 千晴, 大和田 秀二, 井澤 彩

  • 学生賞特別賞

    2014   化学工学会   "物理選別による銅製錬スラグからのMo濃縮を目的としたSEM-EDSによるMo結晶化への加熱/冷却条件の影響評価".

    Winner: 須藤 俊佑, 戸井 龍太郎, 岡田 慎太郎, 所 千晴, 大藏 隆彦

  • 奨励賞

    2014   エコデザイン推進機構   "銅精錬スラグからの有用金属の回収を目的とした徐冷処理がスラグ中成分の結晶成長に及ぼす影響".

    Winner: 戸井 龍太郎, 所 千晴, 大藏 隆彦

  • ポスター賞

    2014   環境資源工学会   "濾過砂のリサイクルにおける表面粉砕の有効性の検討".

    Winner: 岡田 慎太郎, 藤橋 大輝, 綱 澤有輝, 所 千晴

  • 銅賞

    2014   化学工学会   "付着力を考慮した新規接触モデルを組み込んだDEMシミュレーションによるパン型ペレタイザ内における湿潤粒子の挙動解析".

    Winner: 藤橋 大輝, 綱澤 有輝, Gytis Basinkas, 酒井 幹夫, 所 千晴

  • 奨励賞

    2014   化学工学会   "物理選別による銅精錬スラグからの有用金属回収を目的とした除冷処理がスラグ中成分に及ぼす影響".

    Winner: 戸井 龍太郎, 所 千晴, 大藏 隆彦

  • ポスター優秀賞

    2014   日本溶媒抽出学会   "アミド含有第3級アミンによる塩化白金アニオンの抽出分離".

    Winner: 前田 素生, 成田 弘一, 所 千晴, 田中 幹也, 元川 竜平, 塩飽 秀啓, 矢坂 毅

  • 奨励賞

    2014   化学工学会   水酸化アルミニウム共沈法による希薄Si含有排水からのシリカ除去の定量モデル化

    Winner: 鈴木慎哉, 所千晴, 榊原泰佑

  • 奨励賞

    2013   資源・素材学会   "環境浄化・資源循環に寄与する分離技術のモデル化およびシミュレーションの適用".

    Winner: 所 千晴

  • Excellent Poster Presentation Award

    2013   環境資源工学会   "Mechanism of As(Ⅴ) removal in wastewater treatment using ion exchange resins supported by Fe(Ⅲ)".

    Winner: F. Futami, C. Tokoro, S. Owada, H. Kubota

  • 若手優秀ポスター賞

    2013   資源・素材学会   "DEMシミュレーションによるパン型ペレタイザにおける造粒機構の基礎的検討".

    Winner: 藤橋 大輝, 綱澤 有輝, 田原 一輝, 所 千晴, 大和田 秀二

  • Advanced Power Technology Excellence in Reviewing

    2013   Advanced Power Technology  

    Winner: C. Tokoro

  • 優秀賞

    2012   日本鉄鋼協会   "バングラデシュにおける船舶解体産業と鉄鋼産業(マテリアルフローから見た分析)".

    Winner: 小出 瑠, 所 千晴, 村上 進亮, モハマド スジャウディン

  • 論文賞

    2012   環境資源工学会   "Application of DEM Simulation to an Intensive Mixer".

    Winner: 所 千晴, 山下 達也, 久保田 英敏, 大和田 秀二

  • ポスター賞 (2位)

    2012   化学工学会   "高効率フェントン法によるCO2還元メタノール・エタノール化".

    Winner: 山岸 史弥, 原口 大輔, 所 千晴, 村田 逞詮

  • 若手優秀ポスター賞

    2012   資源・素材学会   "水酸化物による廃水中有害元素の共沈除去に対する定量モデル化".

    Winner: 原口 大輔, 井澤 彩, 所 千晴, 大和田 秀二

  • 優秀ポスター賞

    2012   資源・素材学会   過酸化水素を用いた黄銅鉱リーチングの高速化に関する基礎的研究

    Winner: 鈴木 慎哉, 須藤 俊佑, 山岸 史弥, 所 千晴, 大藏 隆彦

  • 学生賞銅賞

    2011   化学工学会   "DEMシミュレーションによる基板からの部品剥離機構の検討に関する基礎的研究".

    Winner: 綱澤 有輝, 所 千晴, 大和田 秀二, 酒井 幹夫, 村上 進亮

  • 学生賞奨励賞

    2011   化学工学会   "分光学的手法を用いた水中のフッ素の水酸化物沈殿への共沈機構解析".

    Winner: 原口 大輔, 所 千晴, 大和田 秀二

  • 若手ポスター賞

    2010   資源・素材学会   "廃携帯電話からのレアメタル濃縮における部品選別の有効性-人工鉱床(RtoS)構想の一環として-".

    Winner: 古賀 千香子, 後藤 昌也, 大和田 秀二, 所 千晴, 白鳥 寿一, 湯本 徹也

  • 若手ポスター賞

    2007   資源・素材学会   "酸性坑廃水の中和・共沈処理を目的とした赤泥のヒ素吸着特性の解明".

    Winner: 中津川 香世, 大槻 晶, 所 千晴, 大和田 秀二

▼display all

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    Newspaper, magazine

    日刊工業新聞  

    24面  

    2022.06

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    Newspaper, magazine

    鉄鋼新聞  

    4  

    2021.08

  • 粉体工学情報センター IP奨励賞に早大・所教授 日清製粉グループ本社も支援

    Newspaper, magazine

    Author: Other  

    食糧醸界新聞  

    2020.09

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Papers

  • Disassembly of Laminated CFRP using Direct Pulsed Discharge

    Keita Sato, Taketoshi Koita, Manabu Inutsuka, Koji Yamaguchi, Masao Kimura, Chiharu Tokoro

    Composites Part B: Engineering   297   112301 - 112301  2025.05  [Refereed]

    Authorship:Corresponding author

    DOI

    Scopus

  • Separation and recovery of the active material from Cu foils in lithium-ion battery anodes by electrohydraulic fragmentation using pulsed discharge

    Taketoshi Koita, Yuto Imaizumi, Asako Narita, Yutaro Takaya, Yosuke Kita, Hiroyuki Akashi, Takao Namihira, Chiharu Tokoro

    Waste Management   198   46 - 54  2025.05  [Refereed]

    Authorship:Corresponding author

     View Summary

    The increasing demand for lithium-ion batteries (LIBs) has led to a significant rise in the amount of spent LIBs, necessitating efficient recycling methods to recover valuable materials from the cathodes and anodes. Furthermore, the efficient recycling of graphite anodes (GA) from LIBs has become an important economic and environmental concern because GAs account for nearly 10% of the total production cost. This paper reports on the separation and recovery of GA material and copper (Cu) foil from LIB anode sheets made from in-process end materials that have not been immersed in electrolyte, which mimics in-process scrapped anodes, by performing electrohydraulic fragmentation (EHF) using the pulsed discharge. The previous study of life cycle assessment indicated that the separation method conducted by the discharge involves lower energy consumption and environmental impact. The objective of this study is to experimentally determine the optimal voltage and number of discharge shots for high separation rates of GA particles with low Cu contamination. The results indicate that 5–7 discharge shots at 14–20 kV are useful for separation and satisfy the required conditions for anode recycling, providing a material recovery rate of more than 95% and a Cu concentration of less than 1.0 wt%. The size of the recovered GA particles was smaller, and the size distribution was narrower as the discharge voltage of EHF increased. This study suggests that EHF is a useful and novel method for the separation from the LIB cathode, which is required in the recycling process.

    DOI

    Scopus

  • Mechanism of boron removal and stabilization by in-situ formation of layered double hydroxides: Insights from spectroscopy and density functional theory

    Yafan Wang, Yusuf Olalekan Zubair, Shuo Pan, Chiharu Tokoro

    Journal of Environmental Sciences    2025.04  [Refereed]

    DOI

  • Selective Manganese Precipitation via Neutralization and Ozone Oxidation under pH Conditions Similar to Steel Pickling Wastewater: Thermodynamic Assessment and Experimental XANES Evaluation

    Mauricio Cordova-Udaeta, Bowen Cheng, Shigeshi Fuchida, Yutaro Takaya, Jun Horiuchi, Hiroyuki Masuoka, Keishi Oyama, Chiharu Tokoro

    ACS Omega   10 ( 17 ) 18085 - 18097  2025.04  [Refereed]

    Authorship:Corresponding author

    DOI

    Scopus

  • Active Material Layer Separation From Positive Electrodes in Lithium–Ion Batteries by Joule Heating During Pulsed Discharge in Air and Water

    Moe Nakahara, Taketoshi Koita, Shinichi Higuchi, Kaito Teruya, Kazuyuki Shishino, Katsuya Teshima, Takao Namihira, Chiharu Tokoro

      53   678 - 687  2025.03  [Refereed]

    Authorship:Corresponding author

    DOI

    Scopus

  • Hydroxylation and sulfidation for nickel recovery from a spent catalyst containing the chelating agent, 2,2’-bipyridine

    Hisanori Iwai, Mauricio Cordova, Yutaro Takaya, Naoki Yokota, Yuko Takahashi, Chiharu Tokoro

    RSC advances   15   7721 - 7727  2025.03  [Refereed]

    Authorship:Corresponding author

    DOI

    Scopus

  • DEM study for investigating the mixing effect of two differently sized grinding media in an agitated media mill

    Ryo Miyazawa, Ryuto Kamo, Yutaro Takaya, Susumu Gunji, Kenichi Momota, Satoshi Shiina, Kyoko Okuyama, Hidehiro Kamiya, Chiharu Tokoro

    Advanced Powder Technology   36 ( 3 ) 104810 - 104810  2025.03  [Refereed]

    Authorship:Corresponding author

    DOI

    Scopus

  • Morphologically controlled synthesis of MgFe-LDH using MgO and succinic acid for enhanced arsenic adsorption: Kinetics, equilibrium, and mechanism studies

    Yusuf Olalekan Zubair, Shigeshi Fuchida, Keishi Oyama, Chiharu Tokoro

    Journal of Environmental Sciences   148   637 - 649  2025.02  [Refereed]

    Authorship:Corresponding author

    DOI

    Scopus

    11
    Citation
    (Scopus)
  • Selective bromination-volatilization of PbO from ZnO-PbO mixtures using bromine-containing plastic: A promising approach for recycling hazardous wastes

    Yusuf Olalekan Zubair, Yuji Takasaki, Yutaro Takaya, Chiharu Tokoro

    Journal of Material Cycles and Waste Management   27 ( 1 ) 616 - 623  2024.12  [Refereed]

    Authorship:Corresponding author

     View Summary

    Abstract

    This study explores the potential of acrylonitrile butadiene styrene (ABS) resin, a bromine-containing plastic, for selectively separating PbO from a ZnO-PbO mixture. Thermodynamic calculations suggested the susceptibility of both PbO and ZnO to bromination by HBr from ABS resin. Initial trials showed limited PbO and ZnO volatilization. Combusting ABS resin and dust mixtures converts approximately 40 wt% of PbO to PbBr2, but PbO volatilization selectivity remains below 30% due to concurrent ZnO volatilization. This low selectivity is due to the inhibiting effect of char and CO gas on PbBr2 volatilization and the enhancement of ZnO volatilization. To improve PbO volatilization selectivity, operational parameters were varied. Increasing ABS resin size, decreasing pellet size, and altering the heating method raised PbO volatilization selectivity by over three times, with more than 60 wt% PbO volatilized. Microscopic analysis confirmed PbO bromination and volatilization as lead bromide compound (e.g., PbBr2), while ZnO underwent direct volatilization through a carbothermic reaction. This study shows that optimizing operational parameters can selectively separate heavy metals using bromine-containing plastics. For practical application in steelmaking dust, it is crucial to examine the effects of coexisting Fe compounds.

    DOI

    Scopus

  • Validation of DEM simulations for a drum-type agitation mill using particle velocities measured by 3D PTV

    Takuya Tatsumoto, Yutaro Takaya, Yuki Tsunazawa, Taketoshi Koita, Keishi Oyama, Chiharu Tokoro

    Advanced Powder Technology   35 ( 12 ) 104693 - 104693  2024.12  [Refereed]

    Authorship:Corresponding author

    DOI

    Scopus

    1
    Citation
    (Scopus)
  • Efficient recovery of carbon fibers from carbon fiber-reinforced polymers using direct discharge electrical pulses

    Chiharu Tokoro, Keita Sato, Manabu Inutsuka, Taketoshi Koita

    Scientific Reports   14 ( 1 ) 29762 - 29762  2024.11  [Refereed]

    Authorship:Lead author, Corresponding author

    DOI

    Scopus

    1
    Citation
    (Scopus)
  • A comprehensive approach for the recycling of anode materials from spent lithium-ion batteries: Separation, lithium recovery, and graphite reutilization as environmental catalyst

    Yanhui Kong, Yutaro Takaya, Mauricio Córdova-Udaeta, Chiharu Tokoro

    Waste Management   188   60 - 71  2024.11  [Refereed]

    Authorship:Corresponding author

    DOI

    Scopus

    4
    Citation
    (Scopus)
  • Mechanism of pyrite depression by marine Fe(II)-oxidizing bacteria in seawater flotation

    Shigeshi Fuchida, Keishi Oyama, Jifeng Xue, Chiharu Tokoro, Yuma Shimizu, Hibiki Miura, Kokoro Kitagawa, Hiroko Makita

    Minerals Engineering   218   109029 - 109029  2024.11  [Refereed]

    DOI

    Scopus

  • Data-driven inverse mix design for sustainable alkali-activated materials

    Y. K. Kong, Kiyofumi Kurumisawa, Chiharu Tokoro, Zhanzhao Li, S. H. Chu

    Journal of Sustainable Cement-Based Materials   13 ( 12 ) 1857 - 1878  2024.10  [Refereed]

    DOI

    Scopus

  • Investigation of the influence of fluorine on metal elution from cathodic active material liberated from spent lithium-ion batteries with a focus on the underwater electrical pulse method

    Yanhui Kong, Yutaro Takaya, Mauricio Córdova-Udaeta, Chiharu Tokoro

    IOP Conference Series: Materials Science and Engineering   1318 ( 1 ) 012050 - 012050  2024.10  [Refereed]

    Authorship:Corresponding author

     View Summary

    Abstract

    As a promising candidate to separate the cathode materials and aluminum foils, the underwater electrical pulse method is an environmentally friendly method that can effectively liberate cathodic active material in a very short time. However, performing the electric pulse separation in aqueous media may cause the release of fluoridated elements, which may come from fluoridated components formed during battery cycles or due to the remaining electrolyte within the cathode particles. Thus, the purpose of this work is to study the solution obtained after pulse discharge in terms of fluoridated entities, to understand their effect on the elution of active cathodic materials. Herein, to investigate the potential source of F and its possible effects on metal extraction, leaching experiments were conducted in the presence of different fluoride concentrations with a solid/liquid ratio of 0.5g/L under circumneutral pH conditions (pH range: 5.7-7.5) using a spent nickel-cobalt-manganese lithium battery sample liberated by N-Methyl pyrrolidone. The results show that the amounts of F ions in solution increased with leaching time, with a maximum value close to 2.34 ppm F obtained after 2 h. It is worth noting that the presence of fluoride-ion can promote the elution of aluminum, as a maximum concentration of 1.85 ppm Al was observed at 2 h in the presence of 40 ppm F, whereas only about 0.32 ppm Al was detected in the case of fluoride-free solutions. Consequently, our results demonstrated that the amounts of transition metals (Ni, Mn, and Co) released towards liquid changed very little irrespective of the concentrations of dissolved fluoride, suggesting that the released F ions do not affect metals elution.

    DOI

  • DEM-CFD study with a breakage model for elucidating the grinding mechanism in cutter-type disk mill

    Ryuto Kamo, Yutaro Takaya, Kyoko Okuyama, Motonori Iwamoto, Yasuyoshi Sekine, Chiharu Tokoro

    Powder Technology   446   120156 - 120156  2024.10  [Refereed]

    Authorship:Corresponding author

    DOI

    Scopus

    1
    Citation
    (Scopus)
  • 液架橋力および粗視化モデルを組み込んだDEMによるパン型ペレタイザ内粒子挙動解析への回転速度の影響

    三崎 亜衣, 古作 吉弘, 宮澤 諒, 高谷 雄太郎, 所 千晴

    環境資源工学   71 ( 2 ) 82 - 89  2024.10  [Refereed]

    Authorship:Corresponding author

  • Insights on the Contradiction between the Affinity and Capacity of Ferrihydrite toward As(III) and As(V): Surface Reaction Revisited.

    Yuhong Huang, Xiaopeng Zhao, Xinhao Wang, Bin Gao, Keishi Oyama, Chiharu Tokoro, Dongmei Zhou, Xueyuan Gu

    Environmental Science & Technology Journal   58   15257 - 15267  2024.08  [Refereed]  [International journal]

     View Summary

    Ferrihydrite is omnipresent in nature, and its adsorption of As(III/V) decides the migration of arsenic. Although As(III) is commonly recognized as the more mobile species of inorganic arsenic, it sometimes exhibits less mobility in ferrihydrite systems, which calls for further insights. In this study, we elucidated the adsorption behavior and mechanisms of As(III/V) on ferrihydrite under different loading levels (molar ratio As/Fe = 0-0.38), solution pH (3-10), and coexisting ions [P(V) and Ca(II)] based on batch adsorption experiments, surface complexation modeling, density functional theory calculations, and X-ray photoelectron spectroscopy. Our results show that As(III) exhibits weaker adsorption affinity but a larger capacity compared with that of As(V). On ferrihydrite, As(III) and As(V) are adsorbed mainly as bidentate mononuclear complexes at type-a sites [≡Fe(OH-0.5)2] and bidentate binuclear complexes at type-b sites (2≡FeOH-0.5), respectively. As the dosage increases, As(III) further forms mononuclear monodentate complexes at both surface sites, resulting in a higher site utilization efficiency, while As(V) does not due to repulsive electrostatic interaction. The difference in surface species of As(III/V) also leads to complex responses when coexisting with high concentrations of P(V) and Ca(II). This study helps us to understand environmental behavior of As(III/V) and develop remediation strategy in As(III/V) contaminated systems.

    DOI PubMed

    Scopus

    14
    Citation
    (Scopus)
  • Separation of Palladium and Rhodium from the Spent Metal-Honeycomb Catalysts by Pulsed Discharge without Chemical Additives

    Chiharu Tokoro, Yuto Imaizumi, Taketoshi Koita, Akiko Kubota, Yutaro Takaya, Keishi Oyama, Md. Mijanur Rahman

    Materials Transactions   65 ( 8 ) 961 - 968  2024.08  [Refereed]

    Authorship:Lead author, Corresponding author

    DOI

  • リチウムイオン電池製造工程廃材のダイレクトリサイクルに向けた粉砕プロセスによる正極活物質の単体分離の検討

    泉 健人, 髙谷 雄太郎, 所 千晴

    粉体工学会誌   61 ( 8 ) 474 - 479  2024.08  [Refereed]

    Authorship:Corresponding author

    DOI

    Scopus

    1
    Citation
    (Scopus)
  • DEM study on investigation of wet particle conveying efficiency in an inclined belt conveyor system

    Yuki Tsunazawa, Yoshihiro Kosaku, Ryuto Kamo, Ryo Miyazawa, Yoshiaki Nishina, Chiharu Tokoro

    Advanced Powder Technology   35 ( 7 ) 104555 - 104555  2024.07  [Refereed]

    Authorship:Corresponding author

    DOI

    Scopus

  • Insights on the Mechanism of Manganese Oxide Precipitation from Mn 2+ Solutions Using NaClO Under Highly Acidic Conditions, via Experimental Observations and Numerical Fitting of the Kinetic ODE System

    Mauricio Córdova-Udaeta, Bowen Cheng, Shigeshi Fuchida, Yutaro Takaya, Keishi Oyama, Chiharu Tokoro

    Journal of Chemical Engineering of Japan   57 ( 1 ) 2366409 - 2366409  2024.06  [Refereed]

    Authorship:Corresponding author

    DOI

  • Effect of electric pulse treatment on silver recovery from spent solar panel sheet by acid-leaching

    Yutaro Takaya, Yuto Imaizumi, Taketoshi Koita, Cordova Udaeta Edwin Mauricio, Chiharu Tokoro

    Journal of Material Cycles and Waste Management   26 ( 4 ) 2591 - 2598  2024.04  [Refereed]

    Authorship:Corresponding author

     View Summary

    Abstract

    The number of spent photovoltaic (PV) panels is expected to increase significantly in the coming decades. Crystalline silicon photovoltaic cells contain materials, such as silver, copper, aluminum, silicon, glass, and resins. Approximately 600 g/t of silver is used as a current collector, so-called finger wires, in photovoltaic modules; therefore, silver recovery is an important issue. To establish an effective recycling process for spent photovoltaic panels, a wire explosion method using high-voltage pulsed discharge was investigated to expose and separate silver selectively. In this study, acid-leaching experiments were conducted on spent ground photovoltaic panels with and without electric pulse treatment to verify the effect of the pulse treatment on acid-leaching of silver. Electric pulse treatment improved both the maximum silver recovery rate and leaching speed. Leaching experiments were also conducted using photovoltaic samples from three different silver exposure states. It can be concluded that silver recovery was strongly controlled by the exposure state and that the electric pulse treatment could effectively promote silver exposure of spent PV panels, even in the region where the silver wires were not energized.

    DOI

    Scopus

    2
    Citation
    (Scopus)
  • Influence of elevated temperature on the species and mobility of chromium in ferrous sulfate-amended contaminated soil

    Ruolin Zhao, Xinqing Zhang, Yiwen Zhou, Jining Li, Binglin Guo, Keishi Oyama, Chiharu Tokoro

    Journal of Environmental Management   356   120457 - 120457  2024.04  [Refereed]

    Authorship:Corresponding author

     View Summary

    Ferrous sulfate (FeSO4) combined with acid pretreatment is usually employed to remediate contaminated soils containing Cr(VI). However, the long-term efficiency of this stabilization method is important for its sustainability. In this study, a gradient temperature-elevating exposure test was employed to investigate the stability of Cr in FeSO4-remediated soil when exposed to elevated temperatures (40 °C, 120 °C, and 500 °C), possibly caused by hot weather and/or wildfires. The results of chemical extraction and X-ray absorption near edge structure spectroscopy (XANES) showed that the Cr(VI) in contaminated soil was successfully transformed to Cr(III) after stabilization, resulting in the dramatic decrease of water-leachable Cr(VI). The stabilization efficiency was further improved under 40 °C treatment after 30 days. Subsequently, the 120 °C treatment (7 days) had relatively little effect on the Cr speciation and mobility in soils. However, even one day of 500 °C calcination resulted in the deterioration of stabilization efficiency, and the water-leachable Cr(VI) re-increased and became higher than the Chinese environmental standards (total Cr 15 mg/L, Cr(VI) 5 mg/L) for the classification of hazardous solid wastes. XANES results reflected that heating at 500 °C facilitate the formation of Cr2O3, which was mainly caused by thermal decomposition and dehydration of Cr(OH)3 in the soil. Besides, the transformation of Cr species resulted in the enhanced association of Cr with the most stable residual fraction (88.3%–91.6%) in soil. Based on chemical extraction results, it was suggested that the oxidation of Cr(III) to Cr(VI) contributed to the re-increased mobility of Cr(VI) in soil. However, the XANES results showed that almost no significant re-oxidization of Cr(III) to Cr(VI) happened after heating at 500 °C, which was probably caused by XANES linear combination fits (LCF) uncertainties. Moreover, the changes in soil properties, including a rise in pH to a slightly alkaline range and/or the decomposition of organic matter, possibly contributed to the enhanced mobility of Cr(VI) in soil. This study contributes to clarifying the mobility and transformation of Cr in contaminated soils and provides a support for the sustainable management of remediated soils.

    DOI PubMed

    Scopus

    2
    Citation
    (Scopus)
  • Resource recovery and regeneration strategies for spent lithium-ion batteries: Toward sustainable high-value cathode materials

    Kunhong Gu, Chiharu Tokoro, Yutaro Takaya, Jiang Zhou, Wenqing Qin, Junwei Han

    Waste Management   179   120 - 129  2024.04  [Refereed]

    DOI

    Scopus

    10
    Citation
    (Scopus)
  • Chemical stability of Hg-adsorbed pyrite under different pH and redox conditions: A fundamental study for stable management of Hg-bearing wastes

    Keishi Oyama, Shun Ishii, Shigeshi Fuchida, Chiharu Tokoro

    Journal of Environmental Chemical Engineering   12 ( 2 ) 1 - 10  2024.04  [Refereed]

    Authorship:Corresponding author

    DOI

    Scopus

    2
    Citation
    (Scopus)
  • Geochemical Evaluation of Manganese Neutralization Sludge for Mn-Containing Mine Drainage Treatment

    Yusuke Furukori, Keishi Oyama, Shigeshi Fuchida, Chiharu Tokoro

    Water, Air, & Soil Pollution   345 ( 223 ) 1 - 11  2024.03  [Refereed]

    Authorship:Corresponding author

     View Summary

    Abstract

    Conventional neutralization treatment for manganese (Mn)-bearing mine drainage provides a challenge of cost-efficiency, and new approaches should be explored for efficient removal of Mn. We focused on Mn neutralization sludge, a by-product of the Mn-bearing drainage treatment process, which was assumed to be useful as a water purification material. Mn and zinc (Zn) removal tests in simulated drainage were performed using Mn neutralization sludge, and the reaction mechanism was elucidated using geochemical modeling and X-ray absorption fine structure (XAFS) analysis. The results showed that the addition of sludge enabled to lower the Mn and Zn concentration below Japanese effluent standard (10 mg dm−3 for Mn; 2 mg dm−3 for Zn) within 1 h. Furthermore, heavy metal immobilization was achieved at neutral pH (7–8) with the sludge addition, while the conventional neutralization process without adding the sludge requires higher pH (>10) to lower Mn concentration. These removal behaviors were not explainable by considering only well-known phenomena: hydroxide precipitation, surface complexation reaction onto δ-MnO2, and autocatalytic Mn oxidation. Hence, we advanced the geochemical model for simulation, suggesting that a surface complexation reaction onto γ-MnOOH greatly contributed to the removal of Mn. Besides, Zn was calculated to be predominantly precipitated as ZnMn2O4. Solid residue analysis by XAFS measurement supported the result of above calculation, validating the reliability of the constructed geochemical model. Overall, we concluded that the advanced geochemical model would be useful in predicting the Mn and Zn behavior during mine drainage treatment with Mn neutralization sludge.

    Graphical abstract

    DOI

    Scopus

    1
    Citation
    (Scopus)
  • Biological Mn(II) oxidation under organic substrate-limited conditions and its application in mine drainage remediation

    Naoyuki Miyata, Reina Suganuma, Kimihito Sunouchi, Kunihiro Okano, Shigeshi Fuchida, Miho Watanabe, Megumu Fujibayashi, Yuya Sato, Chiharu Tokoro

    Biochemical Engineering Journal   203   109187 - 109187  2024.03  [Refereed]

    DOI

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    5
    Citation
    (Scopus)
  • Search for Optimal Conditions on Nickel Recovery from Spent Catalyst Wastewater by Sulfidation Method

    Keishi OYAMA, Shun ISHII, Hisanori IWAI, Shigeshi FUCHIDA, Naoki YOKOTA, Yuko TAKAHASHI, Chiharu TOKORO

    Resources Processing   71 ( 2 ) 75 - 81  2024  [Refereed]

    Authorship:Corresponding author

    DOI

  • Silver Recovery from Spent Photovoltaic Panel Sheets Using Electrical Wire Explosion

    Y. Imaizumi, S. Lim, T. Koita, K. Mochizuki, Y. Takaya, T. Namihira, C. Tokoro

    EcoDesign for Sustainable Products, Services and Social Systems I     365 - 380  2024.01  [Refereed]

    Authorship:Corresponding author

    DOI

    Scopus

    2
    Citation
    (Scopus)
  • Evaluating the grinding performance of cutter-type disk mills using DEM-CFD simulations with a breakage model

    Ryuto Kamo, Yuki Tsunazawa, Taketoshi Koita, Kyoko Okuyama, Motonori Iwamoto, Yasuyoshi Sekine, Chiharu Tokoro

    Advanced Powder Technology   35 ( 1 ) 104303 - 104303  2024.01  [Refereed]

    Authorship:Corresponding author

    DOI

    Scopus

    1
    Citation
    (Scopus)
  • 衝撃試験とDEMシミュレーションによる電子スクラップの単体分離機構の考察

    辰本 拓也, 綱澤 有輝, 小板 丈敏, 高谷 雄太郎, 小山 恵史, 所 千晴

    Journal of MMIJ   139 ( 11 ) 52 - 62  2023.12  [Refereed]

    Authorship:Corresponding author

    DOI

  • Comparison of size distributions of recovered particles generated from Ag wire in air by pulsed wire discharge and electric explosion of wire methods

    Taketoshi Koita, Yoshiki Egawa, Yutaro Takaya, Keishi Oyama, Soowon Lim, Takao Namihira, Chiharu Tokoro

    Advanced Powder Technology   34 ( 11 ) 1 - 14  2023.11  [Refereed]

    Authorship:Corresponding author

    DOI

    Scopus

    1
    Citation
    (Scopus)
  • Improving Flotation Separation of Mg(OH)2-Depressed Chalcopyrite and Pyrite by EDTA Modification: A Promising Method for Sustainable Cu Production

    Jifeng Xue, Keishi Oyama, Shigeshi Fuchida, Chiharu Tokoro

    Journal of Sustainable Metallurgy   9   1647 - 1659  2023.10  [Refereed]

    Authorship:Corresponding author

    DOI

    Scopus

    1
    Citation
    (Scopus)
  • A sulfidation process for recovering Ni from an acidic spent catalyst, and the chemical characterization of the sulfide precipitates

    Hisanori Iwai, Shun Ishii, Keishi Oyama, Shigeshi Fuchida, Naoki Yokota, Yuko Takahashi, Chiharu Tokoro

    Journal of the Society of Powder Technology, Japan   60 ( 10 ) 600 - 606  2023.10  [Refereed]

    Authorship:Corresponding author

    DOI

    Scopus

    1
    Citation
    (Scopus)
  • Applicability of Immersion Pretreatment to Easy Disassembly of Adhesive Joints

    Keita SATO, Keishi OYAMA, Taketoshi KOITA, Akiko KUBOTA, Chiharu TOKORO

    Resources Processing   70 ( 2 ) 65 - 72  2023.10  [Refereed]

    Authorship:Corresponding author

    DOI

  • Simple and efficient selective extraction of lithium from spent ternary lithium-ion batteries via oxidation/de-lithiation using NaClO

    Yanhui Kong, Yutaro Takaya, Mauricio Córdova-Udaeta, Chiharu Tokoro

    Separation and Purification Technology   322   124280 - 124280  2023.10  [Refereed]

    Authorship:Corresponding author

    DOI

    Scopus

    9
    Citation
    (Scopus)
  • Chemical speciation changes of an all-solid-state lithium-ion battery caused by roasting determined by sequential acid leaching

    Yutaro Takaya, Syuichi Kuwaba, Yusaku Tsujimura, Katsunori Yamaguchi, Chiharu Tokoro

    Waste Management   166   122 - 132  2023.07  [Refereed]

    Authorship:Corresponding author

    DOI

    Scopus

  • Extraction of Se(iv) and Se(vi) from aqueous HCl solution by using a diamide-containing tertiary amine

    Hirokazu Narita, Motoki Maeda, Chiharu Tokoro, Tomoya Suzuki, Mikiya Tanaka, Hideaki Shiwaku, Tsuyoshi Yaita

    RSC Advances   13 ( 25 ) 17001 - 17007  2023.06  [Refereed]

     View Summary

    A protonated diamide containing tertiary amine (EHBAA) can extract Se(iv) and Se(vi) from HCl via solvation and anion-exchange reactions, respectively.

    DOI

    Scopus

    3
    Citation
    (Scopus)
  • Applicability of Gravity Separation to Recycling Biodegradable Plastics

    Yuki Tsunazawa, Chiharu Tokoro, Yuji Ando, Tomoki Nakamura, Ryosuke Tsukimi, Nobuo Miyatake

    Journal of Chemical Engineering of Japan   56 ( 1 ) 2215269 - 2215269  2023.05  [Refereed]

    DOI

  • Prospective life cycle assessment of recycling systems for spent photovoltaic panels by combined application of physical separation technologies

    Aya Heiho, Izuru Suwa, Yi Dou, Soowon Lim, Takao Namihira, Taketoshi Koita, Kazuhiro Mochidzuki, Shinsuke Murakami, Ichiro Daigo, Chiharu Tokoro, Yasunori Kikuchi

    Resources, Conservation and Recycling   192 ( 5 ) 106922 - 106922  2023.05  [Refereed]

    DOI

    Scopus

    18
    Citation
    (Scopus)
  • Waste-Based Ceramsite for the Efficient Removal of Ciprofloxacin in Aqueous Solutions

    Juan Qin, Yeting Fang, Jian Shi, Chiharu Tokoro, Mauricio Córdova-Udaeta, Keishi Oyama, Juncheng Zhang

    International Journal of Environmental Research and Public Health   20 ( 6 ) 5042 - 5042  2023.03  [Refereed]

    Authorship:Corresponding author

     View Summary

    Ciprofloxacin (CIP), a compound with bioaccumulation toxicity and antibiotic resistance, is frequently detected in water at alarming concentrations, which is becoming an increasing concern. In this study, a low-cost ceramsite was developed from industrial solid wastes through sintering to remove CIP from wastewater. The effects of adsorbent dosage, initial pH, contact time, initial CIP concentration, and temperature were explored. More than 99% of CIP (20–60 mg/L) was removed at around pH 2–4 by the ceramsite. The kinetic data fitted well with the pseudo-second-order model, revealing that chemisorption was the main rate-determining step. The isotherm data was better described by the Freundlich model, suggesting that CIP was removed by the formation of multiple layers on the heterogeneous surface. Moreover, the removal efficiency was practically higher than 95% during five regeneration cycles, when different regeneration methods were used, including calcination, HCl, and NaOH washing, indicating that the ceramsite exhibited outstanding reusability in removing CIP. The primary mechanism of CIP removal by the ceramsite was found to be the synergism of adsorption and flocculation, both of which depended on the release of Ca2+ from the ceramsite. In addition, strong Ca-CIP complexes could be formed through surface complexation and metal cation bridging between Ca2+ and different functional groups in CIP.

    DOI

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    2
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  • A coarse grain model with parameter scaling of adhesion forces from liquid bridge forces and JKR theory in the discrete element method

    Yoshihiro Kosaku, Yuki Tsunazawa, Chiharu Tokoro

    Chemical Engineering Science   268   118428 - 118428  2023.03  [Refereed]

    Authorship:Corresponding author

    DOI

    Scopus

    19
    Citation
    (Scopus)
  • Highly Efficient Cd2+ Removal Using Tobermorite with pH Self-Adjustment Ability from Aqueous Solution

    Juan Qin, Sujuan Yuan, Mauricio Córdova-Udaeta, Keishi Oyama, Chiharu Tokoro

    Materials   16 ( 3 ) 1314 - 1314  2023.02  [Refereed]

    Authorship:Corresponding author

     View Summary

    Cadmium (Cd), as a type of heavy metal, can increase the incidence of many diseases, even in low concentrations. In this study, tobermorite was hydrothermally synthesized and then applied to adsorb Cd2+ from an aqueous solution. The physicochemical characteristics of the synthesized tobermorite were detected, and the results indicated that the well-crystallized tobermorite had a lot of mesopores and a large specific surface area of 140.92 m2/g. It acquired a pH self-adjustment ability via spontaneously releasing Ca2+ and OH- into the aqueous solution. The effects of different factors on Cd2+ removal were investigated. For Cd2+, the removal efficiency could reach 99.71% and the maximum adsorption capacity was 39.18 mg/g using tobermorite. The adsorption data was best fitted with the pseudo-second-order kinetic and Langmuir isotherm models. In addition, there was no strict limit on the solution pH in Cd2+ adsorption because the tobermorite could adjust the solution pH to an alkaline atmosphere spontaneously. The efficient removal of Cd2+ using tobermorite was a result of surface complexation and ion exchange.

    DOI

    Scopus

    7
    Citation
    (Scopus)
  • Separation of Different Resin Plates Bonded by Solvent through a Wire Explosion Induced by Pulsed Discharge

    Yoshiki Egawa, Taketoshi Koita, Soowon Lim, Takao Namihira, Chiharu Tokoro

    IEEE Transactions on Dielectrics and Electrical Insulation     Early access available - 1  2023.02  [Refereed]

    Authorship:Corresponding author

    DOI

  • Geochemical Modeling of Heavy Metal Removal from Acid Mine Drainage in an Ethanol-Supplemented Sulfate-Reducing Column Test

    Keishi Oyama, Kentaro Hayashi, Yusei Masaki, Takaya Hamai, Shigeshi Fuchida, Yutaro Takaya, Chiharu Tokoro

    Materials   16 ( 3 ) 928 - 928  2023.01  [Refereed]

    Authorship:Corresponding author

     View Summary

    A passive treatment process using sulfate-reducing bacteria (SRB) is known to be effective in removing heavy metals from acid mine drainage (AMD), though there has been little discussion of the mechanism involved to date. In this work, a sulfate-reducing column test was carried out using supplementary ethanol as an electron donor for microorganisms, and the reaction mechanism was examined using geochemical modeling and X-ray absorption fine structure (XAFS) analysis. The results showed that Cu was readily removed from the AMD on the top surface of the column (0–0.2 m), while Zn and Cd depletion was initiated in the middle of the column (0.2–0.4 m), where sulfide formation by SRB became noticeable. Calculations by a developed geochemical model suggested that ethanol decomposition by aerobic microbes contributed to the reduction of Cu, while sulfide produced by SRB was the major cause of Zn and Cd removal. XAFS analysis of column residue detected ZnS, ZnSO4 (ZnS oxidized by atmospheric exposure during the drying process), and CuCO3, thus confirming the validity of the developed geochemical model. Based on these results, the application of the constructed geochemical model to AMD treatment with SRB could be a useful approach in predicting the behavior of heavy metal removal.

    DOI

    Scopus

    1
    Citation
    (Scopus)
  • Electrical properties of adhesives designed for smart debonding by a pulsed discharge method

    Manabu Inutsuka, Masataka Kondo, Taketoshi Koita, Soowon Lim, Keisuke Ota, Tomoki Honda, Ryo Ogawa, Takao Namihira, Chiharu Tokoro

    The Journal of Adhesion   99 ( 13 ) 1996 - 2010  2023.01  [Refereed]

    Authorship:Corresponding author

    DOI

    Scopus

    7
    Citation
    (Scopus)
  • Role of Resource Circularity in Carbon Neutrality

    Shinsuke Murakami, Kotaro Shimizu, Chiharu Tokoro, Takashi Nakamura

    Sustainability   14 ( 24 ) 16408 - 16408  2022.12  [Refereed]

     View Summary

    With the help of circular strategies, products can be used longer (i.e., reuse, repair, and refurbish). Products that are difficult to use will be recycled efficiently. The present paper provides actionable guidelines for reducing environmental impact at all stages of a product’s life cycle, including the manufacture and assembly of the materials that make up the product, environmental impacts during use, and environmental impacts at final disposal, as well as specific actions and evaluation mechanisms. The circular economy is a concept that encompasses specific actions and their evaluations. To clarify the contribution of this circular economy to carbon neutrality, the present paper highlights how it is important to recognize the role of carbon as both an energy carrier and a material. CO2 is a waste product from burning and powering carbon. CO2 must be disposed of like any other waste product, but carbon itself is also an energy carrier. Thus, when promoting the carbon cycle, it is important to harmonize carbon’s function as a material with its role as an energy carrier. The further introduction of renewable energy and societal shift towards circular economy would contribute to carbon neutrality and more resource efficient use in a mutually complementary manner.

    DOI

    Scopus

    3
    Citation
    (Scopus)
  • Adsorption and Microscopic Analysis of Arsenate Uptake by Magnetic Fe Nanoparticles: a Detailed Study on Coexisting Anions Effects

    Yusuf O. Zubair, Shigeshi Fuchida, Chiharu Tokoro

    Water, Air, & Soil Pollution   233 ( 12 )  2022.12  [Refereed]

    Authorship:Corresponding author

    DOI

    Scopus

    5
    Citation
    (Scopus)
  • Investigation on Effective Neutralization Process of Acid Mine Drainage Containing High Amount of Mn and Zn by Additions of <i>δ</i>-MnO<sub>2</sub> Adsorbent and Oxidizing Agent

    Shigeshi FUCHIDA, Shota TAJIMA, Chiharu TOKORO

    Journal of MMIJ   138 ( 11 ) 160 - 169  2022.11  [Refereed]

    Authorship:Corresponding author

    DOI

  • Synthesis and selenate removal of magnesium–aluminum-layered double hydroxide particle using magnesium oxide

    Kosuke Tsuchiya, Shigeshi Fuchida, Chiharu Tokoro

    International Journal of Environmental Science and Technology   20 ( 9 ) 9481 - 9494  2022.11  [Refereed]

    Authorship:Corresponding author

    DOI

    Scopus

    2
    Citation
    (Scopus)
  • Study of the Metal Sphere Explosion Driven by Pulsed Discharge for Separating Adherends

    Masataka Kondo, Taketoshi Koita, Soowon Lim, Takao Namihira, Chiharu Tokoro

    IEEE Transactions on Plasma Science   50 ( 11 ) 4636 - 4649  2022.11  [Refereed]

    Authorship:Corresponding author

    DOI

  • Influence of Agitator Shape on Characteristics and Grinding Efficiency of Attritor Mill

    Chenzuo Ye, Yutaro Takaya, Yuki Tsunazawa, Kazuhiro Mochidzuki, Chiharu Tokoro

    International Journal of Automation Technology   16 ( 6 ) 756 - 765  2022.11  [Refereed]

    Authorship:Last author, Corresponding author

     View Summary

    Grinding is a unit of operation of a pure mechanical process. An attritor is a grinder able to be used for fine or selective grinding. However, few studies have reported on the optimum design for the attritor. The attritor’s grinding characteristics and grinding effect depend not only on the operating conditions, but also on the geometry of the agitator. Therefore, we investigated the effect of the agitator shape on the grinding efficiency from the viewpoint of experiments, kinetic analysis, and discrete element method (DEM) simulations. We conducted grinding experiments with two different agitators. One was Agitator A, a traditional design with two pairs of 90° staggered mixing arms at the middle and bottom of the mixing shaft. The other was Agitator B, with a lower mixing arm inclined by 10° along the horizontal direction. We found that the grinding rate constant of Agitator B was approximately 40% greater than that of Agitator A. Although the size distribution of the particles was relatively dispersed after grinding with Agitator B, the distribution was concentrated mainly within two ranges (<0.5 mm and 2–4 mm) with Agitator A. These results and an elemental analysis of each size fraction suggested that the dominating grinding mode in Agitator A was surface grinding, whereas in Agitator B, it was bulk grinding. In terms of the influence of the agitator shape, the DEM simulation results showed that the kinetic energy of the grinding media in Agitator B was 0.0046 J/s, i.e., larger than the 0.0035 J/s obtained for Agitator A. A collision energy analysis showed that the dominating collision was between the media and wall in the tangential direction for both models. The collision energy of the media in Agitator B was larger than that of that in Agitator A. The results from the DEM simulation can help us evaluate the experimental results and infer the reasons why the grinding rate constant in Agitator B is larger than that in Agitator A.

    DOI

    Scopus

    3
    Citation
    (Scopus)
  • Coprecipitation mechanisms of Zn by birnessite formation and its mineralogy under neutral pH conditions

    Shota Tajima, Shigeshi Fuchida, Chiharu Tokoro

    Journal of Environmental Sciences   121   136 - 147  2022.11  [Refereed]

    Authorship:Corresponding author

    DOI

    Scopus

    10
    Citation
    (Scopus)
  • Comparison of Positive Electrode Separation by Electrical Pulsed Discharge in Underwater and Air Environments

    Soowon Lim, Kaito Teruya, Fuki Mizumoto, Minori Asao, Taketoshi Koita, Takao Namihira, Chiharu Tokoro

    IEEE Transactions on Plasma Science   50 ( 10 ) 3625 - 3634  2022.10  [Refereed]

    Authorship:Corresponding author

     View Summary

    This study presents a novel method to separate positive electrode active materials (PEAMs) and aluminum (Al) foil from positive electrodes (PEs) to enable more effective recycling processes. A pulsed current was applied to a PE sample that was prepared by manual dismantlement of spent lithium-ion batteries (LiBs). Joule heating caused the temperature of the Al foil to increase to be above the melting points of adhesion included in the PEAMs. The influence of the surrounding medium of the PE sample on the delamination phenomenon was investigated. PEAMs were peeled from the Al foil in water and air environments. High-speed visible imaging was employed to discuss separation processes. Differences in the size of the separated PEAMs and the amount of residual PEAM on the surface of the Al foil occurred due to the influence of the medium filled in the voids inside the PEAM layer.

    DOI

  • Investigation of Optimum Scale-Up of Media Stirred Mill Using the Discrete Element Method

    Yoshihiro Kosaku, Yuki Tsunazawa, Kyoko Okuyama, Motonori Iwamoto, Yasuyoshi Sekine, Chiharu Tokoro

    MATERIALS TRANSACTIONS   63 ( 10 ) 1501 - 1509  2022.10  [Refereed]

    Authorship:Corresponding author

    DOI

  • Chemokine expression in human 3-dimensional cultured epidermis exposed to PM2.5 collected by cyclonic separation

    Maori Kono, Tomoaki Okuda, Nami Ishihara, Hiroyuki Hagino, Yuto Tani, Hiroshi Okochi, Chiharu Tokoro, Masayuki Takaishi, Hidefumi Ikeda, Yasuhiro Ishihara

    Toxicological Research   39 ( 1 ) 1 - 13  2022.07  [Refereed]  [International journal]

     View Summary

    Fine particulate matter (PM2.5) exposure has a risk of inducing several health problems, especially in the respiratory tract. The skin is the largest organ of the human body and is therefore the primary target of PM2.5. In this study, we examined the effects of PM2.5 on the skin using a human 3-dimensional cultured epidermis model. PM2.5 was collected by cyclonic separation in Yokohama, Japan. Global analysis of 34 proteins released from the epidermis revealed that the chemokines, chemokine C-X-C motif ligand 1 (CXCL1) and interleukin 8 (IL-8), were significantly increased in response to PM2.5 exposure. These chemokines stimulated neutrophil chemotaxis in a C-X-C motif chemokine receptor 2-dependent manner. The oxidative stress and signal transducer and activator of transcription 3 pathways may be involved in the increased expression of CXCL1 and IL-8 in the human epidermis model. Interestingly, in the HaCaT human keratinocyte cell line, PM2.5 did not affect chemokine expression but did induce IL-6 expression, suggesting a different effect of PM2.5 between the epidermis model and HaCaT cells. Overall, PM2.5 could induce the epidermis to release chemokines, followed by neutrophil activation, which might cause an unregulated inflammatory reaction in the skin.

    DOI PubMed

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    8
    Citation
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  • Quantitative Evaluation of the Effect of High-Pressure Grinding Roll on the Promotion of the Mineral Liberation of Copper Ore

    Yuki TSUNAZAWA, Yoshihiro KOSAKU, Yoshitaka SAKAIRI, Koji TSUKADA, Tamaki SAITO, Yosuke EBISU, Kohei MITSUHASHI, Youqing CHEN, Chiharu TOKORO

    Journal of MMIJ   138 ( 6 ) 95 - 102  2022.06  [Refereed]

    Authorship:Corresponding author

    DOI

  • Involvement of polycyclic aromatic hydrocarbons and endotoxin in macrophage expression of interleukin-33 induced by exposure to particulate matter

    Nami Ishihara, Tomoaki Okuda, Hiroyuki Hagino, Ami Oguro, Yuto Tani, Hiroshi Okochi, Chiharu Tokoro, Yoshiaki Fujii-Kuriyama, Kouichi Itoh, Christoph, F.A. Vogel, Yasuhiro Ishihara

    Journal of Toxicological Sciences   47 ( 5 ) 201 - 210  2022.05  [Refereed]

    DOI

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    15
    Citation
    (Scopus)
  • Kinetic Investigation of Initial Oxidative Dissolution of Pyrite in Alkaline Media (pH 9–12) and Influence of Ca and Mg: A Fundamental Study for Pyrite Depression in Froth Flotation

    Shigeshi Fuchida, Jifeng Xue, Sana Ishida, Chiharu Tokoro

    Journal of Sustainable Metallurgy   8 ( 2 ) 732 - 741  2022.04  [Refereed]

    Authorship:Last author

    DOI

    Scopus

    7
    Citation
    (Scopus)
  • Mechanochemical degradation treatment of TBBPA: A kinetic approach for predicting the degradation rate constant

    Yutaro Takaya, Yiyun Xiao, Yuki Tsunazawa, Mauricio Córdova, Chiharu Tokoro

    Advanced Powder Technology   33 ( 3 ) 103469 - 103469  2022.03  [Refereed]

    Authorship:Corresponding author

    DOI

    Scopus

    7
    Citation
    (Scopus)
  • Derivation of Flotation Kinetic Model Combining Surface Property Analysis and Kinetics

    Hidekazu MATSUOKA, Kohei MITSUHASHI, Masanobu KAWATA, Yutaro TAKAYA, Chiharu TOKORO

    Journal of MMIJ   138 ( 2 ) 12 - 18  2022.02

    Authorship:Last author, Corresponding author

    DOI

  • Utilization of underwater electrical pulses in separation process for recycling of positive electrode materials in lithium-ion batteries: Role of sample size

    Kaito Teruya, Soowon Lim, Kazuhiro Mochidzuki, Taketoshi Koita, Fuki Mizunoto, Minori Asao, Takao Namihira, Chiharu Tokoro

    International Journal of Plasma Environmental Science and Technology   16 ( 1 ) e01003  2022.02  [Refereed]

    Authorship:Corresponding author

     View Summary

    The amount of generated waste of lithium-ion batteries (LiBs) that are used in automobiles is expected to increase because of increases in EV usage. Thus, it is required to recover strategic elements, such as lithium, cobalt, nickel, and manganese in the positive electrodes (PEs) found within LiB. In recent years, a direct application of electrical pulsed power to PEs has been reported to separate the active material layer from the aluminum foil in PEs. The electrical pulsed-discharge treatment enables the separation of the active materials from the aluminum foil without changing in a significant manner the chemical composition of the materials. In this study, we investigated the influence of length of rolled PE samples on the separation of active material from the aluminum foil of PE via the electrical pulsed-discharge treatment. Calculated energy and charging voltage for specific sample sizes were applied to PE samples installed in discharging electrodes in water. After the electrical pulsed-discharge treatment, up to 98.8% cobalt and 6.7% aluminum were recovered from liberated particles of 8 mm or less. For a longer length of PE sample, the separation efficiency of cobalt for aluminum was higher, and the aluminum contamination for active material particles was lower. The internal circuit resistance should be reduced as much as possible to reduce the circuit energy consumption. In terms of energy efficiency, a longer, narrower, and thinner aluminum foil had positive effects in the separation of the positive electrode by the electrical pulsed-discharge treatment.

    DOI

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    11
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    (Scopus)
  • 開放型石灰路-アルカリ路による酸性坑廃水の処理予測とパッシブトリートメント導入に向けた示唆

    髙谷 雄太郎, 淵田 茂司, 濱井 昂弥, 堀内 健吾, 正木 悠聖, 所 千晴

    Journal of MMIJ   138 ( 2 ) 19 - 27  2022.02  [Refereed]

    Authorship:Corresponding author

  • Investigation of Cerium Reduction Efficiency by Grinding with Microwave Irradiation in Mechanochemical Processing

    Tatsuya Kato, Motonori Iwamoto, Chiharu Tokoro

    Minerals   12 ( 2 ) 189 - 189  2022.01  [Refereed]

    Authorship:Corresponding author

     View Summary

    This study evaluated the efficiency of cerium reduction by grinding with microwave irradiation in mechanochemical processing. Grinding experiments with microwave irradiation were conducted using an agitating mixer. Since the structure of the ground samples was amorphous and the cerium concentration was much lower than those of other elements, the valence change and structural change of cerium after grinding with microwave irradiation were investigated using X-ray absorption fine structure (XAFS) analysis in the cerium K-edge. The X-ray absorption near-edge structure (XANES) analysis revealed that a portion of tetravalent cerium was reduced to trivalent cerium by grinding with microwave irradiation. In addition, it was confirmed by extended X-ray absorption fine structure (EXAFS) analysis that oxygen vacancies were produced as a result of the cerium reduction reaction. To evaluate the efficiency of cerium reduction efficiency, the percentage reduction by grinding with microwave irradiation was compared to that by planetary ball milling and microwave irradiation. As a result, it was revealed that the efficiency of cerium reduction via grinding with microwave irradiation was higher than that via microwave irradiation and the same as that via planetary ball milling. Moreover, a larger amount of tetravalent cerium could be reduced to trivalent cerium by grinding with microwave irradiation than when using planetary ball milling and microwave irradiation.

    DOI

    Scopus

    3
    Citation
    (Scopus)
  • Insight on Exogenous Calcium/Magnesium in Weakening Pyrite Floatability with Prolonged Pre-Oxidation: Localized and Concomitant Secondary Minerals and Their Depression Characteristics

    Jifeng Xue, Shigeshi Fuchida, Sana Ishida, Chiharu Tokoro

    Minerals   12 ( 2 ) 115 - 115  2022.01  [Refereed]

    Authorship:Corresponding author

     View Summary

    In this study, we investigated the localized and concomitant precipitation of calcium (Ca)/magnesium (Mg)-bearing species and iron oxides/oxyhydroxides, and their depression characteristics to the pyrite floatability in flotation process at pH 9 and pH 10.5 with prolonged pre-oxidation. Contrary to the depression characteristics at pH 9, the incipient (within aeration times of 30 min) depression of pyrite floatability in Ca/Mg-bearing solutions was more obvious at pH 10.5, while the subsequent decline was only slightly when the pre-oxidation time was expanded to 120 min and 360 min. The competitive adsorption among Ca/Mg-bearing species and potassium amyl xanthate (PAX, C6H11OS2K, collector) at specific sites onto the pyrite surface was demonstrated by the regularly decreased zeta potential of the pyrite surface pretreated in Ca/Mg-bearing solutions. Further scanning electron microscopy-energy dispersive spectrometry demonstrated the concomitant secondary Ca/Mg/Fe-bearing precipitates on the pyrite surface. X-Ray photoelectron spectroscopy suggested strong reprecipitation of iron oxides/oxyhydroxides on the pyrite surface via acid–base complexation among Ca/Mg hydroxy species and iron hydroxy species. Incipient occupation efficiency of specific reaction sites by Ca/Mg-bearing species, which were mainly controlled by the metastable distribution of Ca/Mg hydroxy species and their electrostatic affinity with pyrite surface, was the crucial factor that influenced the competitive adsorption of xanthate and pyrite floatability. More obvious incipient depression at pH 10.5 rather than at pH 9 contributed to more effective Ca/Mg-bearing species and their higher affinity to pyrite surface at pH 10.5. The localized and concomitant precipitation of secondary Ca/Mg/Fe-bearing species leads to a slightly increased hydrophilic coverage upon the pyrite surface, thus a slowly decreased pyrite floatability with increasing pre-oxidation time.

    DOI

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    8
    Citation
    (Scopus)
  • Kinetic Modeling and Mechanisms of Manganese Removal from Alkaline Mine Water Using a Pilot Scale Column Reactor

    Shigeshi Fuchida, Shota Tajima, Takuro Nishimura, Chiharu Tokoro

    Minerals   12 ( 1 ) 99 - 99  2022.01

     View Summary

    Manganese (Mn) is a major element in various aqueous and soil environments that is sometimes highly concentrated in mine water and other mineral processing wastewater. In this study, we investigated Mn removal from alkaline mine water (pH > 9) with an Mn-coated silica sand packed into a pilot-scale column reactor and examined the specific reaction mechanism using X-ray absorption near-edge structure (XANES) analysis and geochemical kinetic modeling. The kinetic effect of dissolved Mn(II) removal by birnessite (δ-Mn(IV)O2) at pH 6 and 8 was evaluated at different Mn(II)/Mn(IV) molar ratios of 0.1–10. Our results confirmed the positive effect of the presence of δ-MnO2 on the short-term removal (60 min) of dissolved Mn. XANES analysis results revealed that δ-MnO2 was more abundant than Mn(III)OOH in the reactor, which may have accumulated during a long-term reaction (4 months) after the reactor was turned on. A gradual decrease in dissolved Mn(II) concentration with depth was observed in the reactor, and comparison with the kinetic modeling result confirmed that δ-MnO2 interaction was the dominant Mn removal mechanism. Our results show that δ-MnO2 contents could play a significant role in controlling Mn removability from mine water in the reactor.

    DOI

    Scopus

    15
    Citation
    (Scopus)
  • Application of CAPE Tools into Prospective Life Cycle Assessment: A Case Study in Recycling Systems Design of Lithium-Ion Battery

    Yasunori Kikuchi, Aya Heiho, Yi Dou, Izuru Suwa, Chiharu Tokoro

    Computer Aided Chemical Engineering   51   1585 - 1590  2022

    DOI

  • Elution of Sulfuric Compounds from Na-sulfide Waste for Stable Management at a Disposal Site: an Experimental Investigation

    Shun Ishii, Shigeshi Fuchida, Takaya Yutaro, Chiharu Tokoro

    Water, Air, & Soil Pollution   233 ( 1 ) 28 - 28  2022.01  [Refereed]

    DOI

    Scopus

    1
    Citation
    (Scopus)
  • Prediction of Acid Mine Drainage Quality for the Next Decades by a Tank Model and Multiple Regression Analysis

    Shigeshi FUCHIDA, Masakazu KADOKURA, Chiharu TOKORO

    Journal of MMIJ   137 ( 12 ) 116 - 122  2021.12  [Refereed]

    DOI

  • Application of electrical pulsed discharge to metal layer exfoliation from glass substrate of hard-disk platter

    Masataka Kondo, Soowon Lim, Taketoshi, Koita, Takao Namihira, Chiharu Tokoro

    Results in Engineering   12 ( 100306 ) 100306 - 100306  2021.12  [Refereed]

    Authorship:Corresponding author

    DOI

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    8
    Citation
    (Scopus)
  • Kinetic Evaluation of pH and Temperature Effects on Silica Polymerization in the Presence of Mg, Al and Fe

    Shun Ishii, Shota Tajima, Yutaro Takaya, Shigeshi Fuchida, Chiharu Tokoro

    KAGAKU KOGAKU RONBUNSHU   47 ( 6 ) 237 - 244  2021.11

    DOI

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    1
    Citation
    (Scopus)
  • Investigation on Removal Performance of Multi-Element Using Layered Double Hydroxide Produced from Magnesium Oxide and Ferrous Iron

    Kosuke Tsuchiya, Shigeshi Fuchida, Chiharu Tokoro

    KAGAKU KOGAKU RONBUNSHU   47 ( 6 ) 224 - 230  2021.11

    DOI

    Scopus

  • Mechanism of gold and palladium adsorption on thermoacidophilic red alga Galdieria sulphuraria

    Eri Adams, Kazuki Maeda, Tatsuya Kato, Chiharu Tokoro

    Algal Research   60   102549 - 102549  2021.11  [Refereed]

    Authorship:Corresponding author

    DOI

    Scopus

    13
    Citation
    (Scopus)
  • Removal Mechanisms of Arsenite by Coprecipitation with Ferrihydrite

    Yutaro Takaya, Masakazu Kadokura, Tatsuya Kato, Chiharu Tokoro

    Journal of Environmental Chemical Engineering   9 ( 5 ) 105819 - 105819  2021.10  [Refereed]

    Authorship:Last author

    DOI

    Scopus

    26
    Citation
    (Scopus)
  • Projecting future changes in element concentrations of approximately 100 untreated discharges from legacy mines in Japan by a hierarchical log-linear model

    Yuichi Iwasaki, Keiichi Fukaya, Shigeshi Fuchida, Shinji Matsumoto, Daisuke Araoka, Chiharu Tokoro, Tetsuo Yasutaka

    Science of the Total Environment   786   147500  2021.09  [Refereed]

     View Summary

    Understanding future changes in the concentrations of elements such as Cd in mine drainages, which can cause severe environmental impacts, is crucial to strategically optimize the treatment and management of such drainages. In this study, on the basis of 17-year data (2003–2019) for 99 untreated drainages from legacy mines in Japan, we developed a Bayesian hierarchical log-linear model that can capture temporal changes in the concentrations of seven elements including six metals (Cd, Pb, As, Cu, Zn, Fe, and Mn) in individual mine drainages. We also projected future changes to understand the prospective trends nationwide. The modeling results showed that, during 2003–2019, although overall decreasing trends were observed for most elements across all the drainages evaluated, decreases in the concentrations of these elements were not evident in many mine drainages (5%–28% of drainages for individual elements); in addition, any rise in the number of mine drainages with element concentrations below nationwide drainage standards over the next 100 years will likely be limited (e.g., approximately 10 drainages for Zn and Fe at median estimates). These results have significant implications for future strategies to manage mine drainages: it is probably too optimistic to assume that the element concentrations of mine drainages will always decrease, or that these drainages will satisfy drainage standards (permits) in the not so distant future.

    DOI

    Scopus

    13
    Citation
    (Scopus)
  • Investigation of Separation of Metal Layers Including Platinum Group Metals from Glass Substrates by Pulsed Power

    近藤正隆, Lim Soowon, 小板丈敏, 浪平隆男, 所千晴, 所千晴

    粉体工学会誌   58 ( 9 ) 474 - 480  2021.09

    J-GLOBAL

  • Investigating the upper limit for applying the coarse grain model in a discrete element method examining mixing processes in a rolling drum

    Yoshihiro Kosaku, Yuki Tsunazawa, Chiharu Tokoro

    Advanced Powder Technology   32 ( 11 ) 3980 - 3989  2021.09  [Refereed]

  • Recovery of silver from waste crystalline silicon photovoltaic cells by wire explosion

    Lim Soowon, Imaizumi Yuto, Mochidzuki, Kazuhiro, Koita Taketoshi, Namihira Takao, Tokoro Chiharu

    IEEE Transactions on Plasma Science   49 ( 9 ) 2857 - 2865  2021.09  [Refereed]

    Authorship:Corresponding author

    DOI

  • Separation of cathode particles and aluminum current foil in lithium-ion battery by high-voltage pulsed discharge Part II: Prospective life cycle assessment based on experimental data

    Yasunori Kikuchi, Izuru Suwa, Aya Heiho, Yi Dou, Soowon Lim, Takao Namihira, Kazuhiro Mochidzuki, Taketoshi Koita, Chiharu Tokoro

    Waste Management   132   86 - 95  2021.08  [Refereed]

    DOI

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    25
    Citation
    (Scopus)
  • Arsenate Removal by Resin-Supported Ferric Ions: Mechanism, Modeling, and Column Study

    Chiharu Tokoro, Tatsuya Kato

    Advanced Powder Technology   32 ( 6 ) 1943 - 1950  2021.06  [Refereed]

    Authorship:Lead author, Corresponding author

  • Separation of Cathode Particles and Aluminum Current Foil in Lithium-Ion Battery byHigh-voltage Pulsed Discharge Part I: Experimental Investigation

    Chiharu Tokoro, Soowon Lim, Kaito Teruya, Masataka Kondo, Kazuhiro Mochidzuki, Takao Namihira, Yasunori Kikuchi

    Waste Management   125   58 - 66  2021.04  [Refereed]

    Authorship:Lead author

    DOI

    Scopus

    51
    Citation
    (Scopus)
  • Selenite and selenate adsorption on low-crystalline magnesium oxide under alkaline conditions

    Shigeshi Fuchida, Kosuke Tsuchiya, Chiharu Tokoro

    Water, Air, & Soil Pollution   232 ( 4 ) 160  2021.04  [Refereed]

    DOI

    Scopus

    3
    Citation
    (Scopus)
  • DEM-CFDによるプラスチック高精度分離を目的とした水流型比重選別機における粒子供給速度の影響評価

    新田彩乃, 綱澤有輝, 所千晴

    粉体工学会誌   58 ( 3 ) 100 - 110  2021.03  [Refereed]

    Authorship:Last author, Corresponding author

  • Selective grinding of glass to remove resin for silicon-based photovoltaic panel recycling

    Chiharu Tokoro, Maiko Nishi, Yuki Tsunazawa

    Advanced Powder Technology   32 ( 3 ) 841 - 849  2021.03  [Refereed]

    Authorship:Lead author

  • Optimum design of agitator geometry for a dry stirred media mill by the discrete element method

    Chiharu Tokoro, Yuki Ishii, Yuki Tsunazawa, Xin Jiang, Kyoko Okuyama, Motonori Iwamoto, Yasuyoshi Sekine

    Advanced Powder Technology   32 ( 3 ) 850 - 859  2021.03  [Refereed]

    Authorship:Lead author

  • Numerical investigation of segregation behavior of multi-sized particles during pharmaceutical mini-tablet die filling

    Zhibin Xu, Shinji Yoshinaga, Yuki Tsunazawa, Chiharu Tokoro

    Journal of Drug Delivery Science and Technology   61   102301 - 102301  2021.02  [Refereed]

    Authorship:Corresponding author

    DOI

    Scopus

    9
    Citation
    (Scopus)
  • Purification of Calcium Fluoride (CaF2) Sludge by Selective Carbonation of Gypsum

    Yutaro Takaya, Shota Inoue, Tatsuya Kato, Shigeshi Fuchida, Susumu Tsujimoto, Chiharu Tokoro

    Journal of Environmental Chemical Engineering   9 ( 1 ) 104510 - 104510  2021.02  [Refereed]

    DOI

    Scopus

    16
    Citation
    (Scopus)
  • Visualization of Behavior of Microbubble Attached to Solid Wall Loaded by Underwater Shock Wave Induced by Electrical Discharge

    KOITA Taketoshi, LIM Soowon, NAMIHIRA Takao, TOKORO Chiharu

    The Proceedings of Mechanical Engineering Congress, Japan   2021   J022-06  2021

     View Summary

    This paper reports on the visualization results of the phenomena of interaction of underwater shock wave induced by the electrical pulsed discharge with microbubbles attached to the solid wall and the behavior of bubbles collapse caused by the shock wave loading. The effect of microbubble diameter on the behavior was investigated. The time histories of microbubble diameter which was constricted by the underwater shock wave loading was also researched by analyzing the visualized images. The images and analysis results quantitatively clarified that the time of microbubble collapse induced by the shock wave interaction was increased as the increased of that diameter.

    DOI

  • Control of the discharge path in adhesive for separation of the bonding structure

    Masataka Kondo, Taketoshi Koita, Soowon Lim, Takao Namihira, Chiharu Tokoro

    IEEE International Pulsed Power Conference   2021-December  2021

     View Summary

    Recently, the easy disassembly of bonding structures used in lightweight automobile bodies is needed. This is because these bonding structures are difficult to separate efficiently as there are joints using chemicals with a high adhesive strength and are commonly separated manually. In this study, we applied a pulsed discharge for the separation of bonding structures consisting of two adherends bonded by epoxy adhesive. The separation was carried out by controlling the discharge path inside the adhesive with a notch punched on the adherend and peeling the adhesive by the explosive force caused by the discharge. The discharge path in the adhesive was generated by the concentration of electric field at the tip of the notch. The effect of notch geometry on the electric field strength was studied by simulation with the AC/DC module of COMSOL Multiphysics. Simulation results indicated that the notch height affected the electric field concentration, and likewise, that the electric field strength at the notch was higher than the one at the edge of the adhered material. The discharge path of the bonding structure with the notch was visualized using the shadowgraph method. The fracture surfaces of structure without and with the notch after the pulsed discharge were also observed to confirm the discharge crater. The visualized images indicated that the discharge path occurred inside the adhesive from the tip of the notch and that the structure was separated by the expansion of gasified adhesive caused by the discharge when the notch was punched to the structure. A discharge crater was observed in the adhesive surface near the notch. In the case of the structure without a notch, the discharge luminescence appeared not in the adhesive but at the edge of the adherend because of the electric field concentration at the edge, resulting in non-separation due to surface discharge in the structure. These results indicated that the notch was responsible for controlling the discharge path inside the adhesive and caused the separation of the bonding structure.

    DOI

    Scopus

  • Application of simple notch to selective separation of adherend bonded with resin adhesive by pulsed discharge in air

    Taketoshi Koita, Masataka Kondo, Soowon Lim, Manabu Inutsuka, Takao Namihira, Satoshi Oyama, Chiharu Tokoro

    IEEE Transactions on Plasma Science   49 ( 12 ) 3860 - 3872  2021  [Refereed]

    Authorship:Last author, Corresponding author

    DOI

  • マンガンオキシ水酸化物(γ-MnOOH)に対するカドミウム表面錯体モデルの構築と酸性坑廃水中和モデルへの応用

    淵田 茂司, 田嶋 翔太, 所 千晴

    環境資源工学   67 ( 3 ) 117 - 121  2021  [Refereed]

  • シリカスケール生成抑制を目的としたMg, Al, Fe共存系におけるシリカ重合へのpHおよび温度影響の速度論的評価

    石井 駿, 田嶋 翔太, 髙谷 雄太郎, 淵田 茂司, 所 千晴

    化学工学論文集   47 ( 6 ) 1 - 8  2021  [Refereed]

    Authorship:Last author, Corresponding author

  • 酸化マグネシウムおよび第一鉄を用いた層状複水酸化物による多元素含有排水の除去性能の検討

    土屋 宏典, 淵田 茂司, 所 千晴

    化学工学論文集   47 ( 6 ) 1 - 7  2021  [Refereed]

  • Understanding the biogeochemical mechanisms of metal removal from acid mine drainage with a subsurface limestone bed at the Motokura Mine, Japan

    Shigeshi Fuchida, Kohei Suzuki, Tatsuya Kato, Masakazu Kadokura, Chiharu Tokoro

    Scientific Reports   10 ( 1 ) 20889  2020.12  [Refereed]

    Authorship:Last author

     View Summary

    Abstract

    Subsurface limestone beds (SLBs) are used as a passive treatment technique to remove toxic metals from acid mine drainage (AMD). In this study, we investigated the mechanisms and thermodynamics of metal (manganese, copper, zinc, cadmium, and lead) precipitation in the SLB installed at the Motokura Mine. Field surveys in 2017 and 2018 showed that the pH of the SLB influent (initially 5–6) increased to approximately 8 in the drain between 24 and 45 m from the inlet. This increase was caused by limestone dissolution and resulted in the precipitation of hydroxides and/or carbonates of copper, zinc, and lead, as expected from theoretical calculations. Manganese and cadmium were removed within a pH range of approximately 7–8, which was lower than the pH at which they normally precipitate as hydroxides (pH 9–10). X-ray absorption near-edge structure analysis of the sediment indicated that δ-MnO2, which has a high cation-exchange capacity, was the predominant tetravalent manganese compound in the SLB rather than trivalent compound (MnOOH). Biological analysis indicates that microorganism activity of the manganese-oxidizing bacteria in the SLB provided an opportunity for δ-MnO2 formation, after which cadmium was removed by surface complexation with MnO2 (≡ MnOH0 + Cd2+  ⇄  ≡ MnOCd+  +  H+). These findings show that biological agents contributed to the precipitation of manganese and cadmium in the SLB, and suggest that their utilization could enhance the removal performance of the SLB.

    DOI

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    17
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  • Derivation of Flotation Kinetic Model for Activated and Depressed Copper Sulfide Minerals

    Hidekazu Matsuoka, Kohei Mitsuhashi, Masanobu Kawata, Chiharu Tokoro

    Minerals   10 ( 11 ) 1027 - 1027  2020.11  [Refereed]

    Authorship:Last author, Corresponding author

     View Summary

    The wettability and floatability of oxidized chalcocite, bornite, and chalcopyrite with the conditions of sodium hydrosulfide (NaHS) dosages and pHs were studied by contact angle measurements, and single and mixture mineral flotation tests. To evaluate the results of the flotation, the flotation kinetic model for copper sulfide minerals treated by NaHS was derived. In this study, we focused on the activation and depression by NaHS, a well-known activator and depressant of copper minerals. The flotation results showed that there can be a threshold NaHS dosage to activate the mineral surfaces, as evidenced by the depression of the minerals and reduction of recoveries at higher dosages of NaHS. Chalcocite recoveries increased with an increase of NaHS dosage. Bornite recoveries tended to be depressed with a smaller amount of NaHS as pH increased. The recoveries of chalcopyrite increased as pH increased at an optimum NaHS dosage. Moreover, the flotation kinetic model that includes the surface properties and the reaction rate constant between the copper sulfide minerals and NaHS was derived. The trends of the flotation rate constants and mass fractions with NaHS dosages and pHs could quantitatively well-explain the flotation results.

    DOI

    Scopus

    9
    Citation
    (Scopus)
  • Copper/Silver Recovery from Photovoltaic Panel Sheet by Electrical Dismantling Method

    Chiharu Tokoro, Soowon Lim, Yukihiro Sawamura, Masataka Kondo, Kazuhiro Mochidzuki, Taketoshi Koita, Takao Namihira, Yasunori Kikuchi

    International Journal of Automation Technology   14 ( 6 ) 966 - 974  2020.11  [Refereed]

    Authorship:Lead author

     View Summary

    The volume of spent photovoltaic (PV) panels is expected to grow exponentially in future decades. Substantial material resources such as silver (Ag), copper (Cu), aluminum (Al), silicon (Si), and glass can potentially be recovered from silicon-based PV panels. In this paper, we targeted the recovery of Cu and Ag from a cell sheet separated to a glass panel from a spent PV panel. The technical feasibility of a novel electrical dismantling method was experimentally studied. This method employed a pulsed power technology that releases high energy in a short time. It allowed a selective separation of the Cu/Ag wires from the sheet once per discharge in water. The experimental results indicated that 95.6% of the total Cu and 17.2% of the total Ag in the sample were successfully separated from the cell sheet using a 3.5-kJ capacitor bank circuit. Moreover, 3.66% of the total Si in the sample was contaminated by the separated Cu/Ag particles from the cell sheet, mainly by shockwaves generated by plasma expansion, and some of them formed a compound with Cu and Ag by eutectic melting, resulting in low liberation. At the lower energy of 3.5 kJ, eutectic melting of Cu and Ag with Si was more suppressed than 4.6 kJ, and 94.3% of Cu and 77.5% of Ag in the separated particles were liberated, which would be acceptable for further wet gravity and/or shape separation of Cu and Ag.

    DOI

    Scopus

    30
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  • Defining Requirements on Technology Systems Assessment from Life Cycle Perspectives: Cases on Recycling of Photovoltaic and Secondary Batteries

    Yasunori Kikuchi, Aya Heiho, Yi Dou, Izuru Suwa, I-Ching Chen, Yasuhiro Fukushima, Chiharu Tokoro

    International Journal of Automation Technology   14 ( 6 ) 890 - 908  2020.11  [Refereed]

    Authorship:Last author

     View Summary

    Since the enactment of the “Feed-in Tariff” scheme in 2012, the solar power generation capacity in Japan has been steadily growing. Therefore, in the near future, the demand for the mass processing of spent photovoltaic (PV) panels is expected to increase. Secondary batteries, especially lithium-ion batteries (LiBs), have become important products for vehicles and mobile devices. The production of LiBs is also expected to significantly increase in the near future. In this study, we address the design of recycling systems for such emerging technologies. From life cycle perspectives, the requirements for the assessment of these technology systems are carefully defined through a bibliometric analysis of technology assessments, critical reviews of current research and developments in the recycling of PV panels and LiBs, and analysis of the intensities of life cycle impacts (such as greenhouse gas emissions and resource use). The necessities for life cycle assessments, material flow analyses, and other assessment methods are clarified, along with the conditions to be examined using these assessment methods.

    DOI CiNii

    Scopus

    15
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  • Insight into the Mechanism of Arsenic(III/V) Uptake on Mesoporous Zerovalent Iron–Magnetite Nanocomposites: Adsorption and Microscopic Studies

    Yusuf O. Zubair, Shigeshi Fuchida, Chiharu Tokoro

    ACS Applied Materials & Interfaces   12 ( 44 ) 49755 - 49767  2020.10  [Refereed]  [International journal]

    Authorship:Last author

     View Summary

    Mesoporous zerovalent iron-magnetite nanocomposites (ZVI-MNCs) were developed to circumvent the limitations of magnetite, such as its susceptibility to phase transition in air-water interfaces. High-resolution transmission electron microscopy images revealed the presence of Fe0 and Fe3O4 in the as-prepared adsorbent. High-resolution X-ray photoelectron spectroscopy (HR-XPS) Fe 2p deconvoluted spectra showed that electron transfer between Fe0 and Fe3O4 controlled the magnetite transformation. The isotherm equilibrium data for As(III) and As(V) are described by the Sips model, which suggests single- and multilayer formation onto a heterogeneous surface with different binding sites, whereas adsorption is controlled by a pseudo-second-order kinetic model, which indicates chemisorption. The maximum sorption capacities (qm) for As(III) and As(V) are 632.6 and 1000 μmol g-1, respectively, which are larger than the qm of similar adsorbents. The greater qm for As(V) is attributed to a higher multilayer formation and a stronger bonding force compared with As(III). The arsenic uptake capacity showed that the as-prepared adsorbent was effective over a wide pH range, and an optimal uptake capacity was recorded between pH 5.0 and 9.0 for As(III) and 3.0 and 7.0 for As(V). The adsorbent exhibited a remarkable regeneration performance for As(III) and As(V) uptake. Several microscopic analytical tools, including Fourier transform infrared spectroscopy, HR-XPS, and X-ray absorption near-edge structure together with zeta potential, confirmed that the binding mode of As(III) and As(V) on ZVI-MNCs was predominantly inner-sphere coordination. Partial redox transformation occurred for As(III) and As(V) on nearly 10 nm of the adsorbent, which indicates that a surface redox mechanism contributed partially to arsenic uptake on the near surface of the ZVI-MNCs. Extended X-ray absorption fine structure spectral analysis proposed that a corner-sharing monodentate mononuclear (1V) complex occurred for As(III) with a small portion of a corner-sharing bidentate binuclear (2C) complex, whereas As(V) formed a corner-sharing bidentate binuclear (2C) complex with octahedral Fe bonding.

    DOI PubMed

    Scopus

    49
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  • Rapid boron removal from wastewater using low-crystalline magnesium oxide

    Hiroki Fukuda, Kosuke Tsuchiya, Yuichiro Toba, Masahiro Eguchi, Chiharu Tokoro

    Journal of Environmental Chemical Engineering   8 ( 5 ) 104171 - 104171  2020.10  [Refereed]

    DOI

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    29
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  • Surface properties of copper-sulfide minerals with sodium-hydrosulfide activation

    Hidekazu Matsuoka, Kohei Mitsuhashi, Masanobu Kawata, Tatsuya Kato, Chiharu Tokoro, Kazutoshi Haga, Atsushi Shibayama

    Minerals Engineering   156   106530 - 106530  2020.09  [Refereed]

     View Summary

    The surface properties of slightly oxidized chalcocite, bornite, and chalcopyrite with sodium hydrosulfide (NaHS) treatment were investigated by solid analyses of X-ray photoelectron spectroscopy, solution analyses, and zeta potential measurements. NaHS is known as a flotation activator for copper-oxide minerals by sulfurizing their surfaces. This study focused on the surface properties before/after sulfurization by the NaHS at several NaHS dosages and alkaline pHs. Iron leaching and precipitates of copper–iron-sulfide minerals have also been investigated. The analysis results showed that NaHS sulfurized the oxidized copper species, CuO and CuSO4, to copper sulfide, but oxidized iron species, Fe2O3 and Fe(OH)3, were not sulfurized by NaHS. These oxidized iron species dissolved into solutions as complex ion, Fe(HS)20, then Fe(HS)20 was decomposed by dissolved oxygen and reprecipitated as Fe2O3. The results of chalcocite showed that Cu2S was generated on the surfaces with NaHS treatment at any pH. The bornite and chalcopyrite results indicated that Fe2O3 was produced on bornite surfaces with an increase in pH, whereas the chalcopyrite surfaces were covered as the pH decreased. A flotation test was conducted using a Chilean copper ore that contained chalcocite, bornite, and chalcopyrite, and the flotation recovery of each mineral was consistent with the surface sulfurization at several NaHS dosages and pHs.

    DOI

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    10
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  • Removal mechanisms of cadmium by δ-MnO2 in adsorption and coprecipitation processes at pH 6

    Kohei Suzuki, Tatsuya Kato, Shigeshi Fuchida, Chiharu Tokoro

    Chemical Geology   550   119744 - 119744  2020.09  [Refereed]

     View Summary

    We elucidate the removal mechanism of Cd by birnessite (delta-MnO2) in adsorption and coprecipitation processes in the context of acid mine drainage (AMD) treatments. The removal mechanism was studied through batch removal experiments at different initial Cd/Mn molar ratios (0-2) by zeta potential measurements, X-ray diffraction (XRD), small-angle X-ray scattering (SAXS), and X-ray absorption fine structure (XAFS) analysis. The sorption isotherm and zeta potential measurements suggest that surface complex formation is the dominant mechanism, and that surface precipitation and/or intercalation also occur in the coprecipitation process when the initial Cd/Mn molar ratio is high (1-2). Increasing the initial Cd/Mn molar ratio to above 0.5 decreased the particle size of delta-MnO2 and shifted its (001) XRD peak to lower angles, suggesting that the delta-MnO2 interlayer ((001) and (002) planes) was expanded and the growth of delta-MnO2 crystals was inhibited in the coprecipitation process. The results of XAFS analysis revealed the production of Mn(III) precipitates and surface complex formation with Cd at high Cd/Mn molar ratio condition ( < 1). No significant changes in the crystalline structures of delta-MnO2 over the entire range of initial Cd/Mn molar ratios were observed in the adsorption process, confirming that Cd could be adsorbed by triple-corner-sharing at neutral pH.

    DOI

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    35
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  • Experimental Investigation of Boron Removal Mechanism from Wastewater by Calcined Ettringite

    Shigeshi Fuchida, Shungo Hobo, Kosuke Tsuchiya, Yoshiyuki Tanaka, Takeshi Nakamura, Chiharu Tokoro

    Water, Air, & Soil Pollution   231 ( 7 ) 344  2020.07  [Refereed]

     View Summary

    The development of efficient and inexpensive boron removal techniques is required to treat wastewater from many industrial processes. We investigated the removal mechanism of boron from wastewater by calcinated ettringite, a concrete sludge, and compared the advantage of this method to coprecipitation with ettringite. The amount of boron remaining in solution decreased slightly from an initial concentration of 2.3 mmol/dm(3) to 1.3-1.4 mmol/dm(3) after reaction for 60 min with ettringites calcinated at 55 and 65 degrees C. The boron removal efficiency increased greatly, with only 0.30 mmol/dm(3) remaining in solution after treatment for 60 min with samples calcinated at 75 degrees C, but samples calcinated at 95 and 175 degrees C removed slightly less boron than those calcinated at 75 degrees C. This enhancement of boron removal performance is due to the amorphization of the ettringite structure by calcination. However, excess heating inhibits ion exchange between the sulfate ions in the ettringite and the borate ions in the solution. The coprecipitation method also achieved efficient boron removal at high Al/B molar ratio (0.44 mmol/dm(3) boron remaining after 60 min). However, uptake by a different amorphous precipitant became the dominant removal mechanism. Large amounts of sludge are generated by this method. Adsorption using calcinated ettringite is therefore the optimal method for the efficient and inexpensive removal of boron from wastewater.

    DOI

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    6
    Citation
    (Scopus)
  • Forecast of AMD quantity by a series tank model in three stages: Case studies in two closed Japanese mines

    Chiharu Tokoro, Kenichiro Fukaki, Masakazu Kadokura, Shigeshi Fuchida

    Minerals   10 ( 5 ) 430  2020.05  [Refereed]

     View Summary

    © 2020 by the authors. Licensee MDPI, Basel, Switzerland. There are about 100 sites of acid mine drainage (AMD) from abandoned/closed mines in Japan. For their sustainable treatment, future prediction of AMD quantity is crucial. In this study, AMD quantity was predicted for two closed mines in Japan based on a series tank model in three stages. The tank model parameters were determined from the relationship between the observed AMD quantity and the inflow of rainfall and snowmelt by using the Kalman filter and particle swarm optimization methods. The Automated Meteorological Data Acquisition System (AMeDAS) data of rainfall were corrected for elevation and by the statistical daily fluctuation model. The snowmelt was estimated from the AMeDAS data of rainfall, temperature, and sunshine duration by using mass and heat balance of snow. Fitting with one year of daily data was sufficient to obtain the AMD quantity model. Future AMD quantity was predicted by the constructed model using the forecast data of rainfall and temperature proposed by the Max Planck Institute–Earth System Model (MPI–ESM), based on the Intergovernmental Panel on Climate Change (IPCC) representative concentration pathway (RCP) 2.6 and RCP8.5 scenarios. The results showed that global warming causes an increase in the quantity and fluctuation of AMD, especially for large reservoirs and residence time of AMD. There is a concern that for mines with large AMD quantities, AMD treatment will be unstable due to future global warming.

    DOI

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    9
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  • Mechanism of arsenate coprecipitation at the solid/liquid interface of ferrihydrite: A perspective review

    Chiharu Tokoro, Masakazu Kadokura, Tatsuya Kato

    Advanced Powder Technology   31 ( 2 ) 859 - 866  2020.02  [Refereed]

  • Experimental study and surface complexation modeling of fluoride removal by magnesium hydroxide in adsorption and coprecipitation processes

    Kosuke Tsuchiya, Shigeshi Fuchida, Chiharu Tokoro

    Journal of Environmental Chemical Engineering   8 ( 6 ) 104514  2020  [Refereed]

     View Summary

    © 2020 Elsevier Ltd. High contaminated levels of fluoride (F) in groundwater and drinking water are of significant concern for human health in many countries. This study examined adsorption and coprecipitation for effective F- removal from high F-containing water using inexpensive magnesium hydroxide, Mg(OH)2. Fluoride solutions were reacted with Mg2+-or Mg(OH)2-containing solution at different F/Mg molar ratios of 0.05-2, and the F- removal performance and mechanisms were investigated in both processes. As a result, the residual amount of F- in the solution decreased with an increase in Mg2+ concentrations for both processes, and the sorption isotherms followed the Langmuir type. Mg(OH)2 was precipitated only after F- removal, which suggests that adsorption to Mg(OH)2 was the main removal mechanism in both processes. However, the saturated adsorption capacity in the coprecipitation process was two times higher than that in the adsorption process. The chemical equilibrium calculation results implied that the surface complexation of MgF° and MgOH2F° was the dominant mechanism in the adsorption process whereas multiple complexations of Mg-MgF3° and Mg-MgF4- occurred in the coprecipitation process. This complex formation improves F- removal; hence, coprecipitation with Mg(OH)2 exhibited better potential as an efficient process for the treatment of industrial wastewater that contains F-.

    DOI

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    22
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  • Kinetic modelling of chalcopyrite leaching assisted by iodine in ferric sulfate media

    Ronny Winarko, David B.Dreisinger, Akira Miura, Chiharu Tokoro, Wenying Liu

    Hydrometallurgy   197   105481  2020  [Refereed]

  • 腐葉土を充填したカラムを用いた亜鉛含有坑廃水連続処理の定量モデル化

    加藤 達也, 福島 諒, 佐藤 康市, 山縣 三郎, 所 千晴

    Journal of MMIJ   136 ( 12 ) 151 - 158  2020  [Refereed]

  • Application of nano‐scale zero‐valent iron adsorbed on magnetite nanoparticles for removal of carbon tetrachloride: Products and degradation pathway

    Xiaofan Lv, Widyawanto Prastistho, Qi Yang, Chiharu Tokoro

    Applied Organometallic Chemistry   34 ( 5 ) 5592  2020  [Refereed]

  • Effect of the roll stud diameter on the capacity of a high-pressure grinding roll using the discrete element method

    Yu Nagata, Yuki Tsunazawa, Kouji Tsukada, Yuichi Yaguchi, Yosuke Ebisu, Kohei Mitsuhashi, Chiharu Tokoro

    Minerals Engineering   154   106412  2020  [Refereed]

  • Effect of Cellulose Nanocrystals Extracted from Oil Palm Empty Fruit Bunch as Green Admixture for Mortar

    Dianah Mazlan, Santhana Krishnan, Mohd Fadhil Md Din, Chiharu Tokoro, Nur Hafizah, Abd Khalid, Izni Syahrizal Ibrahim, Hideki Takahashi, Daisuke Komori

    SCIENTIFIC REPORTS   10 ( 1 ) 6512  2020  [Refereed]

     View Summary

    This paper aims to examine the effect of cellulose nanocrystals (CNCs) derived from oil palm empty fruit bunch fiber (EFB) incorporating cement mortar on its structural performances. Cellulose nanocrystals (CNCs) were extracted from alpha -cellulose extracted from EFB using an acid hydrolysis process with a concentration of acid used was 64% w/v under the temperature of 45 degrees C for 60minutes. The Cellulose nanocrystals (CNCs) were mixed into the cement mortar ranging from 0 to 0.8% w/w and its mechanical properties were determined. The developed CNCs mortar was characterized for their compressive and flexural properties as well as microstructure. The influence of CNCs concentration, curing method, dispersion of CNCs on mortar's mechanical performance was thoroughly examined to find out the optimum condition. Overall results revealed that an addition of 0.4% cellulose nanocrystals has shown to increase the compressive and flexural strength to 46% and 20%, respectively cured under the wrapping method. The hydration of cementitious composites also improved significantly with the addition of CNCs by the formation of highly crystalline of portlandite observed under the XRD test. This present work demonstrates the importance of palm oil empty fruit bunch waste as a sustainable resource of cellulose nanocrystals admixture to achieve structural strength of cement mortar and promotes green technologies in construction.

    DOI

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    29
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  • Application of GETFLOWS Coupled with Chemical Reactions to Arsenic Removal through Ferrihydrite Coprecipitation in an Artificial Wetland of a Japanese Closed Mine

    Tatsuya Kato, Yohei Kawasaki, Masakazu Kadokura, Kohei Suzuki, Yasuhiro Tawara, Yoshiyuki Ohara, Chiharu Tokoro

    Minerals   10 ( 5 ) 475  2020  [Refereed]

  • 坑廃水処理における水酸化物への共沈機構

    所千晴, 加藤達也

    地球化学   54   5 - 14  2020  [Refereed]

  • Mechanochemical activation of chalcopyrite: Relationship between activation mechanism and leaching enhancement

    G. Granata, K. Takahashi, T. Kato, C. Tokoro

    Minerals Engineering   131   280 - 285  2019  [Refereed]

    DOI

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    30
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  • Mechanism and kinetics of enhancement of cerium dissolution from weathered residual rare earth ore by planetary ball milling

    Tatsuya Kato, Giuseppe Granata, Yuki Tsunazawa, Tetsuichi Takagi, Chiharu Tokoro

    Minerals Engineering   134   365 - 371  2019  [Refereed]

    DOI

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    20
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  • 表面錯体形成を考慮した腐葉土による亜鉛除去の定量モデル化

    加藤 達也, 福島 諒, グラナタ ジュセッペ, 佐藤 康市, 山縣 三郎, 所 千晴

    粉体工学会誌   56 ( 3 ) 136 - 141  2019  [Refereed]

    DOI

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    4
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  • 粉砕により機械的に活性化させた風化残留型希土類鉱石からの軽希土類浸出への酸の影響評価

    加藤 達也, グラナタ ジュセッペ, 所 千晴

    粉体工学会誌   56 ( 4 ) 174 - 180  2019  [Refereed]

    DOI

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    3
    Citation
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  • Iodide-assisted leaching of chalcopyrite in acidic ferric sulfate media

    G.Granata, A.Miura, W.Liu,F.Pagnanelli, C.Tokoro

    Hydrometallurgy   186   244 - 251  2019  [Refereed]

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  • Investigation of optimum design for nanoparticle dispersion in centrifugal bead mill using DEM-CFD simulation

    Yu Nagata, Masaya Minagawa, Shosei Hisatomi, Yuki Tsunazawa, Kyoko Okuyama, Motonori Iwamoto, Yasuyoshi Sekine, Chiharu Tokoro

    Advanced Powder Technology   30   1034 - 1042  2019  [Refereed]

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    19
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  • Kinetics and mechanism of selenate and selenite removal in solution by green rust-sulfate

    Aina Onoguchi, Giuseppe Granata, Daisuke Haraguchi, Hiroshi Hayashi, Chiharu Tokoro

    ROYAL SOCIETY OPEN SCIENCE   6  2019  [Refereed]

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    31
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  • Structural Change Analysis of Cerianite in Weathered Residual Rare Earth Ore by Mechanochemical Reduction Using X-Ray Absorption Fine Structure

    Tatsuya Kato, Yuki Tsunazawa, Wenying Liu, Chiharu Tokoro

    minerals   9   267 - 278  2019  [Refereed]

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    9
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  • Direct recovery of copper nanoparticles from leach pad drainage by surfactant-assisted cementation with iron powder

    Giuseppe Granataa, Uuganzaya Tsendorjb, Wenying Liuc, Chiharu Tokoro

    Colloids and Surfaces   580   267 - 278  2019  [Refereed]

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    12
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  • Preparation of copper nanoparticles for metal-metal bonding by aqueous reduction with D-glucose and PVP

    Giuseppe Granata, Aina Onoguchi, Chiharu Tokoro

    Chemical Engineering Science    2019  [Refereed]

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    38
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  • Life cycle assessment of resource recovery from waste electrical and electronic equipment: A case study of Tantalum recovery by chain-using drum-typed impact mill

    A. Heiho, Y. Kanematsu, M. Nagase, S. Murakami, C. Tokoro, Y. Kikuchi

    化学工学論文集   45 ( 6 ) 244 - 252  2019  [Refereed]

     View Summary

    The recovery of metal resources from urban mines such as waste electrical and electronic equipment (WEEE) has become an emerging issue. The establishment of technology and social systems for recycling rare metals is of especially high priority due to their worldwide shortage. This study tackles the recycling of rare metals, especially tantalum, by applying a chain-using drum-type impact mill (CDIM) for pulverization of WEEE in the intermediate treatment for physical separation of components contained in plastic routers. A life-cycle assessment (LCA) was conducted based on actual process inventories of the CDIM, segregation and concentration of electronic parts. Climate change and resource depletion were adopted as the impact category indicated by life-cycle greenhouse gas emission (LC-GHG) and characterized resource consumption in this LCA. Although the tantalum contained in WEEE is input into the copper smelting and cannot be separated from other metals in conventional recycling systems, it was demonstrated that the CDIM intermediate treatment could selectively concentrate the tantalum capacitors. The tantalum capacitors can be converted into sintered tantalum, substitutes for Ta2O5, which can reduce resource consumption potentials at the expense of additional energy consumption. Most of the LC-GHG was derived from energy, especially public electricity. Decarbonization in the power grid can reduce the LC-GHG attributable to the recycling system. Rare metals other than tantalum should also be recoverable from WEEE. Physical and chemical treatment processes for metal recovery should be developed, demonstrated, and implemented in line with the recycling systems for various products.

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    5
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  • Applying analysis of mineral surfaces to predict flotation behavior

    H. Matsuoka, R. Kawarabuki, K. Mitsuhashi, M. Kawata, C. Tokoro, K. Haga, A. Shibayama

    IMPC 2018 - 29th International Mineral Processing Congress     1481 - 1488  2019

     View Summary

    The mineral surface characteristic is important for the flotation because it affects the flotation behavior of the mineral. Conventionally, in the flotation process for Cu sulphide ores, the degree of ore floatabilities varies depending on the mineral phase such as chalcopyrite, bornite, or chalcocite. Therefore, mineral surfaces are treated with activators and depressants to control the floatability of target minerals and obtain high recovery performance. There are lots of flotation reagents which have many effects on ores depending on ore characteristics and conditioning methods. For example, sodium hydrosulphide (NaHS) as activator is known to have the effect of re-sulfurizing and activating oxidized surface of chalcocite and bornite. On the other hand, NaHS is reported to depress chalcopyrite floatability. In this study, the evaluation of mineral surfaces was conducted to predict flotation behavior. Activation of Cu minerals (chalcocite, bornite, and chalcopyrite) by NaHS was experimented. The three Cu minerals were treated in two steps. Firstly, they were oxidized in the drying oven. Secondly, they were treated with NaHS solution. After each treatment step, each mineral was measured by contact angle apparatus then analyzed by X-ray photoelectron spectroscopy (XPS). The results of surface characteristics after oxidation and NaHS treatment were utilized to accomplish the study's objective.

  • Investigation and evaluation of the detachment of printed circuit boards from waste appliances for effective recycling

    Yuki Tsunazawa, Shosei Hisatomi, Shinsuke Murakami, Chiharu Tokoro

    Waste Management   78   474 - 482  2018.08  [Refereed]

     View Summary

    To establish an effective recycling process for waste appliances, the process of recovering printed circuit boards (PCBs) containing valuable elements in comminution was investigated and evaluated. The present study performed comminution tests using three different types of waste appliances: smartphones, microwave ovens and electrical rice cookers. Comminution tests showed that a drum-type agitation mill operated at a mid-range rotation speed could achieve a relatively high recovery ratio of PCBs and inhibit excessive breakage of PCBs. Following these experiments, simulations using the discrete element method with a particle-based rigid-body model were conducted to evaluate the comminution performance of the drum-type agitation mill. Experimental and simulation results confirm that the processes of detachment of PCBs from waste appliances and subsequent breakage can be expressed by kinetic equations related to collision energy. It is concluded from these results that the kinetic equations obtained in experiments and simulations can be used to evaluate the recovery process of PCBs from waste appliances.

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    25
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  • Enhancement of copper dissolution by mechanochemical activation of copper ores: Correlation between leaching experiments and DEM simulations

    Masaya Minagawa, Shosei Hisatomi, Tatsuya Kato, Giuseppe Granata, Chiharu Tokoro

    Advanced Powder Technology   29 ( 3 ) 471 - 478  2018.03  [Refereed]

     View Summary

    In this work we investigated the influence of planetary ball milling and vertical stirred ball milling on the leaching of a copper ore containing copper sulfate and covellite. We used a mixed experimental-simulation approach to correlate the kinetic parameters of leaching to the collision energy during grinding. The effect of milling was studied by scanning electron microscopy (FE-SEM), X-ray diffraction (XRD) and X-ray absorption fine structure (XAFS). Results showed that both high-intensity grinding techniques resulted into a dramatic decrease of particle size. Furthermore, under specific grinding conditions, the planetary ball milling determined also the partial amorphization of covellite. The collision energies corresponding to specific grinding conditions in terms of rotational speed and number of grinding media were assessed by DEM simulations and were related to the specific surface area after grinding. The specific surface area of grinded samples was found to be directly proportional to the collision energy in grinding. The leaching of the ore occurred through three subsequent steps: (i) dissolution of copper sulfate, (ii) dissolution of amorphousized covellite and (iii) dissolution of residual crystalline covellite. The results of kinetic fitting highlighted an increase of the rate constants for the leaching of amorphous and crystalline covellite by intensifying the milling conditions. By correlating the collision energies from DEM simulation with the leaching rate constants, we confirmed that the rate constants for the leaching of covellite increased due to an occurred mechanochemical reaction. The mechanochemical reaction that determined the partial amorphization of covellite occurred above 0.25 J/s · g. On the other hand, the rate constants for the leaching of the residual crystalline covellite constantly and progressively increased with the collision energy, thus highlighting an improvement of leaching due to an increase of surface area.

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    32
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  • Effect of agitator shaft direction on grinding performance in media stirred mill: Investigation using DEM simulation

    Sho Fukui, Yuki Tsunazawa, Shosei Hisatomi, Giuseppe Granata, Chiharu Tokoro, Kyoko Okuyama, Motonori Iwamoto, Yasuyoshi Sekine

    Materials Transactions   59 ( 3 ) 488 - 493  2018  [Refereed]

     View Summary

    Recently, the discrete element method (DEM) has been widely applied to investigate the influence of operating and design parameters on grinding performances. However, while most studies investigated the effects of such parameters on the fineness of milling products, the relationship between them and the size dispersion of milling products has not been elucidated yet. In this study, we investigated the influence that the direction of the agitator shaft has on grinding performance in a media stirring mill. First, we proved by milling experiments that the media stirring mill with the horizontal direction of the agitator shaft can provide better grinding performances. Then, we further elucidated this experimental evidence by applying DEM simulations to a media stirring milling process in a vertical and a horizontal stirred mill. According to the simulations, in the vertical shaft configuration, the motion of the grinding media in the lower section through the vertical direction was inhibited by a too low velocity. On the other hand, the grinding media in the horizontal stirred mill moved more uniformly but with a lower collision energy. Furthermore, the grinding media in the low sections actively mixed with the grinding media in the upper sections, thereby resulting in a more uniform energy transfer and in a better grinding process. Accordingly, this study demonstrated that not only the collision energy but also the uniformity of the movement of the medium particles should be evaluated in order to investigate the grinding performance in a media stirred mill by DEM simulation.

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    17
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  • Recovery of calcium fluoride from highly contaminated fluoric/hexafluorosilicic acid wastewater

    Masao Morita, Giuseppe Granata, Chiharu Tokoro

    Materials Transactions   59 ( 2 ) 290 - 296  2018  [Refereed]

     View Summary

    We investigated the recovery of calcium fluoride (CaF2) from highly concentrated hexafluorosilicic acid wastewater by neutralization- purification. Neutralization was achieved by dosing calcium hydroxide, whereas purification was carried out by alkaline leaching with sodium hydroxide. X-ray diffraction, X-ray absorption fine structure, mineral liberation analyzer, Fourier transform infrared spectroscopy and Inductively-coupled plasma atomic emission spectroscopy were used to quantify the neutralization and leaching performance and to elucidate their mechanisms. The precipitation behavior was strongly dependent on the calcium (Ca)/silicon (Si) molar ratio. For a Ca/Si ratio of 1.12, approximately 25% of the total fluorine was precipitated selectively as CaF2. By increasing the Ca/Si ratio to 3.91, the recovery yield increased to 100% because of the precipitation of CaSiF6 and the hydrolytic decomposition of hexafluorosilicate ion (SiF6 2-) to CaF2. The hydrolytic decomposition of SiF6 2- resulted in the precipitation of silicon dioxide on the surface of the previously formed CaF2. Alkaline leaching by sodium hydroxide at 70°C resulted in an efficient removal of the silicon phase from the neutralized sludge with the formation of a CaF2 product with a grade above 90%. Leaching parameters, such as the kinetic constant and the activation energy, were determined by assuming first-order kinetics. The residual silicon phase in the final product could not be dissolved because of the formation of non-leachable SiO3 2-.

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    11
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  • Crystal formation and growth by slow cooling for recovery of magnetite particles from copper smelting slag

    Y. Tsunazawa, C. Liu, R. Toi, T. Okura, C. Tokoro

    Mineral Processing and Extractive Metallurgy   128 ( 4 ) 248 - 255  2018  [Refereed]

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  • Removal of chromate from tannery wastewater: the applicability of sulfate-green rust in real coprecipitaion processes

    A. Mamun, M. M. Khin, G. Granata, C. Tokoro

    環境資源工学   65 ( 3 ) 67 - 73  2018  [Refereed]

  • Role of pH in green rust preparation and chromate removal from water

    Abdullah Al Mamun, Aina Onoguchi, Giuseppe Granata, Chiharu Tokoro

    Applied Clay Science   165   205 - 213  2018  [Refereed]

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    22
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  • Preparation of Polymeric Adsorbents Bearing Diglycolamic Acid Ligands for Rare Earth Elements

    T. Shinozaki, T. Ogata, R. Kakinuma, H. Narita, C. Tokoro, M. Tanaka

    Industrial & Engineering Chemistry Research   57 ( 33 ) 11424 - 11430  2018  [Refereed]

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  • Comparison of the Extractabilities of Tetrachloro- and Tetrabromo-palladate(II) Ions with a Thiodiglycolamide Compound

    Hirokazu Narita, Motoki Maeda, Chiharu Tokoro, Tomoya Suzuki, Mikiya Tanaka, Ryuhei Motokawa, Hideaki Shiwaku, Tsuyoshi Yaita

    ANALYTICAL SCIENCES   33 ( 11 ) 1305 - 1309  2017.11  [Refereed]

     View Summary

    Using N,N,N',N'-tetra-2-ethylhexyl-thiodiglycolamide (TEHTDGA) in n-dodecane as the extractant, we compared the percentages of Pd(II) extracted from HCl and HBr solutions, and analyzed the structures of the Pd(II)-extractant complexes. For comparison, similar experiments were performed with di-n-hexyl sulfide (DHS), a well-known sulfide-type extractant. TEHTDGA extracted Pd(II) from both HCl and HBr solutions much faster than DHS. The Pd(II)/(TEHTDGA or DHS) stoichiometry in the organic phase was 1:2. For TEHTDGA, the extractability of Pd(II) from HBr solution was inferior to that from HCl solution, whereas the opposite was true for DHS. However, FT-IR spectroscopy and EXAFS measurements indicated that the inner-sphere structure of Pd(II) in the TEHTDGA complex was almost the same as that in the DHS system: in both cases, two of the halide ions in the tetrachloro- or tetrabromopalladate(II) ion were replaced by the sulfur atoms of two extractant molecules.

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    11
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  • In situ remediation of bauxite residue by sulfuric acid leaching and bipolar-membrane electrodialysis

    Mayuko Kishida, Takuo Harato, Chiharu Tokoro, Shuji Owada

    HYDROMETALLURGY   170   58 - 67  2017.07  [Refereed]

     View Summary

    In situ remediation of a bauxite residue by integrating a storage area with CSIRO's soda recovery process was evaluated. The process consisted of the following steps: bauxite residue is neutralized with sulfuric acid; the slurry is separated into a neutralized residue and a leachate. The, residue is sent to a storage area -and washed with rainfall. The leachate and drainage/runoff from the storage area are collected and purified; sodium sulfate in the solution is then split into sodium hydroxide and sulfuric acid using bipolar-membrane electrodialysis. Finally, the sodium hydroxide is used in a Bayer refinery and the sulfuric acid is used for neutralization of bauxite residue. This study investigated the optimum conditions and remediation of the bauxite residue. pH rebounding was observed after sulfuric acid neutralization of bauxite residue. Considering this rebound, the most suitable pH was set at 4.5. Washing remediated the residue to accomplish the goals for bauxite residue rehabilitation. Furthermore, sodium hydroxide and sulfuric acid were recovered by bipolar -membrane electrodialysis. Cost -benefit analysis for an assumed one million tons refinery showed 10% return on investment. Evaluation of the advantages of neutralized residue and technical improvements are expected to make this process feasible for remediation of bauxite residue. (C) 2016 Elsevier B.V. All rights reserved.

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  • Sorption mechanisms of chromate with coprecipitated ferrihydrite in aqueous solution

    Abdullah Al Mamun, Masao Morita, Mitsuaki Matsuoka, Chiharu Tokoro

    JOURNAL OF HAZARDOUS MATERIALS   334   142 - 149  2017.07  [Refereed]

     View Summary

    Hexavalent chromium (Cr(VI)) attracted researchers' interest for its toxicity, natural availability and removal difficulty. Nevertheless, its sorption mechanism is not clearly understood yet. In this work, we elucidated the sorption mechanism of the co-precipitation of chromates with ferrihydrite through quantitative analysis. The influence of Cr/Fe molar ratio on sorption was investigated by zeta potential measurements, X-ray diffraction (XRD) and X-ray adsorption fine-structure analysis (XAFS). Coprecipitation at pH 5 showed almost twice the sorption density of adsorption at pH 5. In co-precipitation, a shift of the XRD peak due to inner-sphere sorption of chromate was observed at Cr/Fe molar ratio 0.5. For adsorption, the same peak shift was confirmed at Cr/Fe molar ratio of 1. Zeta potential at pH 5 suggested that the sorption mechanism changed at Cr/Fe molar ratio 0.25 for coprecipitation and at Cr/Fe molar ratio of 1 for adsorption. Fitting of Cr and Fe K-edge extended X-ray adsorption fine-structure suggested that ferrihydrite immobilized Cr(VI) via outer sphere surface complexation for lower Cr/Fe ratios and via inner-sphere surface complexation for higher molar ratios. At higher molar ratios, bidentate binuclear Cr Fe bonds were well established, thus resulting in the expansion of the ferrihydrite structure. (C) 2017 Elsevier B.V. All rights reserved.

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  • Selective extraction of Pt(IV) over Fe(III) from HCl with an amide-containing tertiary amine compound

    Motoki Maeda, Hirokazu Narita, Chiharu Tokoro, Mikiya Tanaka, Ryuhei Motokawa, Hideaki Shiwaku, Tsuyoshi Yaita

    SEPARATION AND PURIFICATION TECHNOLOGY   177   176 - 181  2017.04  [Refereed]

     View Summary

    The separation properties of Pt(IV) over Fe(III) in HCl solutions using N-2-ethylhexyl-bis(N-di-2-ethylhexyl-ethylamide)amine (EHBAA) were investigated and then compared with those using the conventional extractant tri-n-octylamine (TOA). Also, the structural analyses of Pt(IV) in both of the aqueous (HCl solution) and organic (EHBAA in n-dodecane-2-ethylhexanol solution) phases were performed with EXAFS spectroscopy. The extractability of Pt(IV) was much higher with EHBAA than with TOA in the studied HCI concentration range (0.2-8 M HCl); additionally, EHBAA selectively extracted Pt(IV) over Fe(III) under the condition of [EHBAA] &lt;= 0.1 M and [HCI] &lt;= 1 M. The Pt(IV) loading capacity of 0.1 M EHBAA was about 9.2 (about 0.05 M). Most of the Pt(IV) extracted with 0.1 M EHBAA from 1 M HCI was stripped with 0.1 M NaOH; the co-extracted Fe(III) was selectively scrubbed with distilled water. The structural studies indicated that the Pt(IV) extracted with EHBAA from 1 M HCl formed an ion-pair complex, [PtCl6].(EHBAA.H)(2). (C) 2017 Elsevier B.V. All rights reserved.

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  • Ship Breaking and the Steel Industry in Bangladesh A Material Flow Perspective

    Mohammad Sujauddin, Ryu Koide, Takahiro Komatsu, Mohammad Mosharraf Hossain, Chiharu Tokoro, Shinsuke Murakami

    JOURNAL OF INDUSTRIAL ECOLOGY   21 ( 1 ) 191 - 203  2017.02  [Refereed]

     View Summary

    Bangladesh has emerged as a leading ship breaking nation. We conducted a material flow analysis of steel in Bangladesh with an emphasis on the ship breaking industry (SBI). The total aggregate domestic steel consumption in fiscal year (FY) 2010 was 2,930,000 tonnes (t) in Bangladesh; SBI met approximately 51% of the demand for raw materials and 37% of the demand for finished steel products. Rolling industries output in FY2010 was 1,451,000 t; 23% of the input for this production was from ship breaking sources. Dismantled ships also generate high-quality reusable steel scraps. SBI was found to be the sole source of scraps for small rerolling industries in Bangladesh, and their output in 2008 more than doubled as compared to 2005. Larger rolling industries fulfilled their input needs for steel scraps by using both SBI and imported materials. We found a sharp increase in input imports during the global ship breaking recession in 2003-2007 and when Bangladesh's SBI faced a temporary ban in 2010. Induction furnaces in Bangladesh in FY2010 produced a total of 787,000 t of billets; more than 40% was from ship-sourced scraps. In 2008, the country's steel consumption was 3,220,000 t, that is, 22 kilograms per person, and the intensity of steel use was 40 grams per U.S. dollar, which was much higher than that of other developing countries with a similar per capita gross domestic product (GDP). The country exhibited a high level of steel consumption relative to its GDP, which is indicative of the contribution of SBI.

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