Bioleaching of the mixed oxide-sulfide copper ore by artificial indigenous and exogenous microbial community

Bioleaching has been widely applied to recover sulfide minerals, however, little is known about the bioleaching behavior and mechanism of mixed oxide-sulfide copper ore with high-oxidative ratio. The leaching efficiency of artificial indigenous and exogenous microbial communities on a mixed oxide-sulfide copper ore with and without energy substrate was investigated. The results indicated that extra energy substrate was needed when bioleaching was applied to this kind of ore. The variation of leaching parameters caused by indigenous community was inferior to that caused by exogenous ones due to its lower activity. The leaching efficiency of sulfide part induced by indigenous strains was superior to that induced by exogenous ones, due to the stronger colonization ability of indigenous strains. It verified that both microbial activity and colonization ability were important properties affecting leaching efficiency. Sulfur oxidizers, which can oxidize sulfur or polysulfide formed on mineral surface and decrease leachate pH, played a more important role than ferrous oxidizers in bioleaching of high-oxidative oxide-sulfide ore. (C) 2016 Elsevier B.V. All rights reserved.