Microbiological Redox Potential Control to Improve the Efficiency of Chalcopyrite Bioleaching

Yusei Masaki, Tsuyoshi Hirajima, Keiko Sasaki, Hajime Miki, Naoko Okibe

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31 Citations (Scopus)


The effect of controlling the redox potential (Eh) on chalcopyrite bioleaching kinetics was studied as a new aspect of redox control during chalcopyrite bioleaching, and its mechanism was investigated by employing the “normalized” solution redox potential (Enormal) and the reaction kinetics model. Different Eh ranges were established by use of different acidophiles (Sulfobacillus acidophilus YTF1; Sulfobacillus sibiricus N1; Acidimicrobium ferrooxidans ICP; Acidiplasma sp. Fv-AP). Cu dissolution was very susceptible to real-time change in Eh during the reaction. It was found that efficiency of bioleaching of chalcopyrite can be effectively evaluated on the basis of Enormal, since it is normalized for real-time fluctuations of concentrations of major metal solutes during bioleaching. For steady Cu solubilization during bioleaching at a maximum rate, it was important to maintain a redox potential range of 0 ≤ Enormal ≤ 1 (−0.35 mV optimal) at the mineral surface by employing a “weak” ion-oxidizer. This led to a copper recovery of > 75%. At higher Enormal levels (Enormal > 1 by “strong” microbial Fe2+ oxidation), Cu solubilization was slowed by diffusion through the product film at the mineral surface (< 50% Cu recovery) caused by low reactivity of the chalcopyrite and by secondary passivation of the chalcopyrite surface, mainly by jarosite.

Original languageEnglish
Pages (from-to)648-656
Number of pages9
JournalGeomicrobiology Journal
Issue number8
Publication statusPublished - Sept 14 2018

All Science Journal Classification (ASJC) codes

  • Microbiology
  • Environmental Chemistry
  • General Environmental Science
  • Earth and Planetary Sciences (miscellaneous)


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