In this work, both the density functional theory (DFT) calculation and X-ray photoelectron spectroscopy (XPS) were conducted to investigate the depression mechanisms of cyanide on the flotation performance of chalcopyrite. The density functional theory calculation results showed that cyanide could be adsorbed on a chalcopyrite (112) surface spontaneously, which preferably occurred on the surface Fe–Fe hollow site. Both C and N atoms of cyanide could bond with Fe atoms of the chalcopyrite (112) surface, while the interaction of Fe–C bond was more intense, where the Fe 3d orbital donated electrons to the hybrid sp orbital of a C atom forming a back-donating bond. XPS analysis indicated that the chemical interaction between cyanide and surface Fe atoms occurred, resulting in the generation of a hydrophilic iron–cyanide complex on the chalcopyrite surface, which deteriorated the flotation performance of chalcopyrite.

Density Functional Theory and XPS Studies of the Adsorption of Cyanide on Chalcopyrite Surfaces