The dissolution and passivation mechanism of chalcopyrite in bioleaching: An overview

Chalcopyrite (CuFeS2) is the most abundant copper-containing resource in the earth and is also widely distributed in solid wastes and secondary resources. Biohydrometallurgy (bioleaching) is considered as a promising minerals processing and extractive metallurgy technology because of its environmental and economic advantages over the conventional beneficiation-pyrometallurgy process, and the bioleaching of chalcopyrite is always a challenge because chalcopyrite can be easily passivated in bioleaching. Hence, it is important to understand the dissolution process and passivation mechanism of chalcopyrite in bioleaching. In this paper, the dissolution process and passivation mechanism of chalcopyrite bioleaching have been summarized and discussed according to previous publications. The reported possible passivating species are mainly S-containing species consisting of polysulfide (S-n(2-)), elemental sulfur (S-0) and insoluble sulfate (SO42-). The effects of physico-chemical properties of chalcopyrite and multiple factors on the dissolution and passivation mechanism of chalcopyrite bioleaching have been summarized. We particularly discussed the role of redox potential in chalcopyrite bioleaching and its controlling techniques.