Effects of Au doping on the adsorption of xanthate on pyrite surface in presence of H2O: A DFT study

Despite density functional theory (DFT) has been widely applied in the study of Au-doped pyrite, effects of Au doping on the structural properties and floatability of pyrite still remain uncertain. Most of the previous studies were carried out in vacuum disregarding the existence of water molecules, which were inconsistent with the real flotation system. This work aims to study the adsorption behavior of ethyl xanthate on the surface of perfect pyrite and Au-doped pyrite in presence of water molecules through DFT calculations. It was found that the doped Au expanded the lattice of pyrite (100) surface, with enhanced conductivity and chemical reactivity. After Au-doping, the population and covalence level of Fe-S bond of pyrite was reduced, making Fe atoms prone to interact with water molecules and xanthate. The binding energy and density of states (DOS) analysis indicated that Au-doping enhanced the binding ability of xanthate with pyrite surface more significantly than water molecules. Therefore, Au-doping promoted the adsorption of xanthate on pyrite surface in presence of water molecules. This study is of guiding significance for investigating the flotation behavior of Au-doped pyrite and flotation reagents design.