Bevilaqua, D.Leite, ALLCGarcia, O.Tuovinen, O. H.2014-05-202014-05-202002-12-02Process Biochemistry. Oxford: Elsevier B.V., v. 38, n. 4, p. 587-592, 2002.1359-5113http://hdl.handle.net/11449/33623Chalcopyrite oxidation was evaluated with two acidophilic thiobacilli that are important in bioleaching processes. Acidithiobacillus thiooxidans in pure culture did not oxidize CuFeS2 but oxidized externally added S in the presence of CuFeS2. Acidithiobacillus ferrooxidans released Cu2+ and soluble Fe from chalcopyrite, and the time course lead to a gradual passivation of chalcopyrite whereby Cu2+ dissolution leveled off. Fe3+ acted as a chemical oxidant in CuFeS2 leaching and was reduced to Fe2+. Parallel bacterial re-oxidation of Fe2+ contributed to a high Fe3+/Fe2+ ratio and an increase in redox potential. Chemical oxidation of chalcopyrite was slow compared with A. ferrooxidans-initiated solubilization. X-ray analysis revealed new solid phases: (i) jarosite, found in solids from A. ferrooxidans cultures and in chemical controls that initially received Fe2+ or Fe3+, and (ii) S-0, found mostly in iron-amended A. ferrooxidans culture and the corresponding chemical controls. (C) 2002 Elsevier B.V. Ltd. All rights reserved.587-592engAcidithiobacilluschalcopyrite leachingiron oxidationsulphur oxidationArtigo10.1016/S0032-9592(02)00169-3WOS:000179438000015Acesso restrito