Cyanide Depression Mechanism for Sphalerite Flotation Separation Based on Density Functional Theory Calculations and Coordination Chemistry

Abstract

In this paper, the adsorption of cyanide and its combination with zinc sulfate on the surface of sphalerite (110) was studied by density functional theory (DFT), and its configurational relationship was analyzed by coordination chemistry. The calculation results show that the adsorption configuration stability of CN− is stronger than that of Zn(CN)2; the chemical bond of Zn(OH)2 is less covalent. The three adsorption modes all make the surface of sphalerite lose more electrons, thereby weakening the reactivity of S and Zn atoms on the sphalerite surface. During the CN− adsorption process, both the 3d and 4p orbital peak energy levels of Zn decrease, indicating the strong inhibitory effect of CN−. Coordination chemistry also shows that CN− matches the Zn ion orbital in sphalerite and the π electron pair on the Zn ion can easily interact with the empty π orbital on CN− to form π-backbonding.