Passivation of chalcopyrite in hydrodynamic-bioleaching

Worldwide Cu deposits mainly exist in the form of low-grade chalcopyrite (CuFeS2). Bioleaching has exhibited significant potential for Cu recovery, but the low recovery performances of chalcopyrite bioleaching has limited its commercialization. Furthermore, the mechanisms and the reaction pathways of chalcopyrite are excessively diverse and complex, therefore require a careful review to elucidate the unclear albeit significant points. A critical reason for the poor Cu recovery in chalcopyrite bioleaching to date is the occurrence of passivation layers along with oxidative leaching. The passivation layers are too thin to be directly observed and consist of various compounds including jarosite. This study also discussed several technical solutions to address the passivation issues; those include utilization of thermophilic microorganism, external electrodes, photocatalysts as well as physical removal or inhibition of jarosite.