Microbiological Redox Potential Control to Improve the Efficiency of Chalcopyrite Bioleaching

Autor:	Keiko Sasaki, Naoko Okibe, Tsuyoshi Hirajima, Yusei Masaki, Hajime Miki
Rok vydání:	2018
Předmět:	Chemistry Chalcopyrite Kinetics solution redox potential (Eh) chalcopyrite bioleaching 02 engineering and technology 010501 environmental sciences 01 natural sciences Microbiology Redox 020501 mining & metallurgy Bioleaching kinetics moderately thermophilic iron-oxidizers 0205 materials engineering Chemical engineering visual_art Bioleaching Earth and Planetary Sciences (miscellaneous) visual_art.visual_art_medium Environmental Chemistry 0105 earth and related environmental sciences General Environmental Science
Zdroj:	Geomicrobiology Journal. 35:648-656
ISSN:	1521-0529 0149-0451
DOI:	10.1080/01490451.2018.1443170
Popis:	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 Fe_2+ 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.
Databáze:	OpenAIRE
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