Interactions of xanthate with pyrite and galena surfaces in the presence and absence of oxygen

In this study, first-principles calculations were performed to investigate the interactions of hydrogen xanthate (HOCS2−) with pyrite (1 0 0) and galena (1 0 0) surfaces. The calculation results suggest that strong chemisorption of HOCS2− occurs at Fe sites on the pyrite (1 0 0) surface, whereas its interaction at Pb sites on the galena (1 0 0) surface is weak. The interaction of xanthate with oxidized pyrite surface is weakened while the interaction of xanthate with oxidized galena surface is enhanced. The hydration of xanthate and mineral surfaces is discussed. Dixanthogen could be formed on the pyrite surface but not on the galena surface.