Abstract:The surfaces of galena and pyrite, the adsorption of oxygen, and the reactions of ethyl xanthate on the sulfides were studied using quantum chemical calculations. In addition, the surface electron structures of the minerals were discussed. According to the results, the mechanisms of ionic exchange reaction and dixanthogen adsorption for the xanthate flotation of galena and pyrite were explained. The important role of oxygen in collector and collectorless flotation processes was also investigated.

Key words: sulphide minerals,  oxidation,  flotation,  galena,  pyrite,  quantum chemistry