Open AccessSurface sulphur as promoting agent of pyrite leaching by Thiobacillus ferrooxidans
Author(s) -
Mustin C.,
Donato Ph.,
Berthelin J.,
Marion Ph.
Publication year - 1993
Publication title -
fems microbiology reviews
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 5.91
H-Index - 212
eISSN - 1574-6976
pISSN - 0168-6445
DOI - 10.1111/j.1574-6976.1993.tb00269.x
Subject(s) - pyrite , sulfur , bioleaching , leaching (pedology) , thiobacillus , ferrous , sulfate , chemistry , ferric , inorganic chemistry , metallurgy , materials science , mineralogy , copper , geology , soil water , soil science
Methanol extraction conducted with a HPLC‐Iike device and spectroscopic analysis were used to remove and characterize the sulphur layer (Ss) present on freshly ground pyrite surface after dry grinding. Accurate measurements of ferric and sulphate contents in the leachate showed a significant delay in the lag phase and in the first step of oxidation by Thiobacillus ferrooxidans for the so‐cleaned pyrite (without sulphur layer) in comparison to the initial pyrite (with sulphur layer). Voltammetric studies (current‐potential curves) showed a modification of the anodic behaviour of the initial pyrite, corresponding to a higher chemical oxidability of the uncleaned pyrite. During the bacterial oxidation, the difference in redox potential between a special pyrite electrode and a platinum standard electrode both placed in the bioleaching reactor was shown to be related to the occurrence of a sulphur layer. This difference, which is more important in the case of the initial pyrite (with sulphur layer), corresponded to an increase in oxidation kinetics of the pyrite by Thiobacillus ferrooxidans .