LAUSR

Abstract The net effects of the alterations of surface chemistry of copper sulphide minerals on their flotation upon oxidation are documented to be either beneficial or detrimental, depending on the extent of mineral surface oxidation. However, there were limited reports in literature that established a quantitative relationship between surface oxidation and flotation, which renders the exercise of flotation optimisation for oxidised ores difficult, until our recent work on chalcopyrite and chalcocite. The degree of surface oxidation was quantified as the ratio of hydrophilic to hydrophobic oxidation species, which were characterised by X-ray Photoelectron Spectroscopy (XPS), and correlated with flotation recovery. Herein we tailored the method, which was previously developed on chalcopyrite and chalcocite, to establish a quantitative relationship between the degree of surface oxidation and flotation of bornite, one of the most valuable sources of commercial copper. The critical oxidation degree, beyond which bornite flotation becomes impossible, was determined to be 5.66. This is half that of chalcopyrite flotation and slightly higher than the upper limit of the range within which the critical degree of surface oxidation in chalcocite flotation was estimated to lie. Such knowledge betters the holistic understanding of the quantitative relationship between surface oxidation and copper sulphide flotation and will aid in providing insights on how to better handle ores of various oxidation degrees and susceptibilities. A comprehensive comparative case between bornite, chalcopyrite and chalcocite is presented in the paper.