The role of solution potential on the reductive leaching of Co(III) from oxide ore in the presence of mesophilic bacteria and added pyrite

摘要

The dissolution of Co(III) from a heterogenite-type ore has been studied in the presence of mesophilic bacteria and pyrite addition from outside. The latter has been supplied in order to play role of a ferric iron reducing agent. The redox potential of the system has been varied and microscopic observations of the leached ores performed showing the role played by the microorganisms in the system at various potential levels. Apart from ferrous iron and pyrite concentration, Co(III) leaching efficiency and kinetics are largely influenced by the redox potential of the system. Bacteria/pyrite interactions play a role in the leaching kinetics of Co(III), but also contribute to maintaining ferrous/ferric iron cycling in the system. The industrial implication is that Colli is brought into solution by ferrous iron having concentration well below the stoichiometric requirement which could be beneficial for the metallurgical economics.