Abstract

The bioleaching of sulfide minerals involves electrochemical and chemical reactions of the mineral with the leach liquor and the extra-cellular polysaccharide layers on the microorganisms. The microorganisms derive energy by oxidizing the sulfur moiety and ferrous iron, which can be interpreted using electrochemistry and chemiosmotic theory. Kinetic models based on the proposed mechanism are used to predict the performance of continuous bioleach reactors. The implications of these models on bioleach reactor design and operation are discussed. The chemistry and electrochemistry of the ferric leaching of sulfide minerals and an electrochemical mechanism for ferrous iron oxidation based on chemiosmotic theory are presented.