Bioleaching of chalcopyrite by moderately thermophilic microorganisms

► Leaching results showed the existence of an optimum pH in leaching of chalcopyrite. ► There was clear benefit in leaching chalcopyrite within the low solution potential. ► Maintenance of an appropriate concentration of total dissolved iron was necessary. ► Chalcopyrite was reduced to a series of intermediate products at the low potential. ► The reduction of chalcopyrite to talnakhite and/or bornite is the rate-limiting step.