Mechanochemical Reduction of Synthetic Sulphidic Copper-Bearing Minerals in an Industrial Scale

In this paper the mechanochemical reduction of binary sulphides chalcocite (Cu2S) and covellite (CuS) by elemental iron wereinvestigated. The composition and properties of nano-powders prepared by high-energy milling were analyzed by X-ray diffraction,X-ray photoelectron spectroscopy and magnetic measurements. The XRD results showed that in case of chalcocite Cu2S the reactiontakes place until 360 minutes, as no elemental iron, could be identified afterwards. In case of covellite CuS, after 480 minutes of mechanochemicalreduction, a significant amount of non-reacted elemental iron could still be observed. The investigation of magneticproperties reveals significant decrease of saturation magnetization as a result of milling. XPS results showed a significant surfaceoxidation in both systems. Unlike the conventional high-temperature reduction of chalcocite and covellite, the mechanochemicalreduction is fast and ambient temperature and atmospheric pressure are sufficient for its propagation.