Effect of grinding media on the flotation of sulfide minerals

As a necessary preparation before flotation, grinding shows great significance for flotation. Grinding, as a kind of complex physical, chemical and physicochemical process, would affect the subsequent sulfide processing considerably. Therefore, it has great importance on theory and practice to study the relationship between grinding environment and sulfide flotation. Aiming at typical sulfide minerals such as galena, sphalerite, chalcopyrite and pyrite, the changes of the surface properties and the pulp chemistry of those sulfide minerals ground in various environment are detected by X-ray diffraction (XRD), scanning electron microscope (SEM), X-ray photoelectron spectroscopy (XPS), transmission electron microscope (TEM), and other modern physical and chemical analysis techniques. The effects of different grinding environment and reagent addition on the floatability of sulfide mineral was investigated by a great deal of flotation tests. The main reasons of causing evident difference in flotation behaviour of sulfide minerals ground with iron or ceramic media include the following: 1. the deposition and adsorption of hydroxy iron complex on the surface of sulfide minerals would enhance the surface hydrophilicity and reduce the flotability of sulfide minerals; 2. strong reducing environment caused by ground with iron media would block the moderate surface oxidisation of sulfide minerals, which is necessary for flotation, while oxidising environment caused by ground with ceramic media would be beneficial to the moderate surface oxidisation of sulfide minerals; and 3. when ceramic is used as grinding media, the oxidising environment with higher potential would promote the oxidisation of xanthate to dixanthogen, but when iron media is used, the situation would be reversed. The research results indicates that sulfides ground with ceramic media have better floatability than being ground with iron media.