Mechanisms of bioleaching. Basic understanding and possible industrial implications

GIAVENO, M. A.; URBIETA M.S.; DONATI E.R.

BioHydrometallurgical Processes

CETEM

Año: 2011; p. 1 - 1

This chapter summarizes the current understanding of bioleaching mechanisms. It includes a brief description of the model widely accepted to explain the microbial attack to the metal sulfides under aerobic conditions. This model recognizes the metal leaching as a chemical process in which the leaching reactions are carried out by iron(III) and protons using two different (thiosulfate and polysulfides) mechanisms according to the type of sulfide. Microorganisms are just responsible to regenerate those leaching agents and this role can be done through contact or non-contact ways. Attached cells are much efficient to dissolve sulfides than those in solution. The possible contribution of anaerobic growth to enhance the oxidation of sulfides is also described. As a practical consequence of these mechanisms, biomining processes are carried out by consortia characterized by iron- and sulfur-oxidizing microorganisms and heterotrophs capable of oxidizing organic compounds. The mechanisms also have some possible industrial implications which are discussed at the end of the chapter.