Mechanism of silver-catalyzed bioleaching of enargite concentrate

Keishi Oyama, Tsuyoshi Hirajima, Keiko Sasaki, Hajime Miki, Naoko Okibe

研究成果: Chapter in Book/Report/Conference proceedingConference contribution

1 被引用数 (Scopus)

抄録

Silver-catalyzed bioleaching of enargite concentrate with three bacteria (Acidimicrobium ferrooxidans ICP, Sulfobacillus sibiricus N1, Acidithiobacillus caldus KU) and one archaeon (Ferroplasma acidiphilum Y) was conducted in order to elucidate the catalytic mechanism of silver sulfide in enargite bioleaching. Whereas Cu recovery remained relatively low (43%) and Fe dissolved completely without silver sulfide, Cu recovery was greatly enhanced (96%) and Fe dissolution was suppressed (29%) in the presence of 0.04% silver sulfide. In the latter case, 52% of the solubilized As was re-immobilized, in contrast to only 14% As re-immobilization in the former. The silver-catalyzed bioleaching (at 0.04% silver sulfide) proceeded at low redox potentials within the optimal range, which likely promoted enargite dissolution via formation of intermediate Cu2 S. XAFS analysis revealed that As was mainly immobilized as As(V), which was in agreement with the EPMA results detecting ferric arsenate passivation on some enargite grains. Furthermore, formation of trisilver arsenic sulfide (Ag3 AsS4) was detected by XRD and EPMA, covering the surface of enargite particles. An intermediate layer, consisting of (Cu,Ag)3 AsS4, was also observed between the enargite grain and trisilver arsenic sulfide layer, implying that Cu in enargite may be gradually substituted by solubilized Ag. Kinetic study suggested that these secondary minerals do not rate-limit the enargite dissolution. The overall mechanism of silver-catalyzed bioleaching of enargite concentrate will be proposed.

本文言語英語
ホスト出版物のタイトル22nd International Biohydrometallurgy Symposium
編集者Sabrina Hedrich, Axel Schippers, Kathrin Rubberdt, Franz Glombitza, Wolfgang Sand, Wolfgang Sand, Mario Vera Veliz, Sabine Willscher
出版社Trans Tech Publications Ltd
ページ273-276
ページ数4
ISBN(印刷版)9783035711806
DOI
出版ステータス出版済み - 2017
イベント22nd International Biohydrometallurgy Symposium, 2017 - Freiberg, ドイツ
継続期間: 9 24 20179 27 2017

出版物シリーズ

名前Solid State Phenomena
262 SSP
ISSN(印刷版)1012-0394
ISSN(電子版)1662-9779

その他

その他22nd International Biohydrometallurgy Symposium, 2017
Countryドイツ
CityFreiberg
Period9/24/179/27/17

All Science Journal Classification (ASJC) codes

  • Atomic and Molecular Physics, and Optics
  • Materials Science(all)
  • Condensed Matter Physics

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