Adsorption characteristics of CN- species on the chalcopyrite surface and its response to flotation

Among cyanide tailings, chalcopyrite is one of the main minerals. However, little study is available regarding the flotation behavior and mechanism of cyanide chalcopyrite, especially the influence of cyanide leaching time on the physical and chemical properties of chalcopyrite surface. In this work, the cyanide adsorption mechanism of the chalcopyrite surface over time and its response to flotation was probed for the first using contact angle, zeta potential, microflotation, X - ray photoelectron spectroscopy (XPS) and time-of-flight secondary ion mass spectrometry (ToF-SIMS). The results of contact angle showed that the surface hydrophobicity of the chalcopyrite surface decreased with increasing cyanidation time, thus preventing the adsorption of xanthate, which was confirmed by zeta potential and microflotation. XPS analysis indicated that with the gradual progress of cyanidation, hydrophilic CN-, CNO-, SO42- and CuCN- were formed on the surface of chalcopyrite. ToF-SIMS investigated the distribution of anion species on the surface of chalcopyrite, showing that with the increasing cyanidation time, more cyanide species formed on the surface of mineral layer, and gradually diffuse from the mineral surface to the bulk phase, finally forming a film with depth of about 20 nm. Thus, the chalcopyrite hydrophobicity was depressed.