Adsorption characteristics of Cu2+ species on cerussite surfaces and implications for sulfidization flotation

Abstract

Metal ions are unavoidable in pulp solution, and they frequently influence the flotation recovery of minerals, such as by activation or depression. In this work, we systematically investigated the adsorption characteristics of Cu2+ species on cerussite surfaces and the concomitant effect on sulfidization flotation by micro-flotation experiments and surface analysis. The flotation results indicated that the flotation recovery of cerussite was almost unchanged at low Cu2+ concentration in the presence of Na2S, but it decreased at high Cu2+ concentration. X-ray photoelectron spectroscopy indicated that CuCO3 species formed on cerussite surface in the presence of Cu2+, and Pb–S species and Cu–S species formed after Cu2+–Na2S treatment. Time-of-flight-secondary-ion mass spectrometry indicated that the distribution of lead species narrowed and that of copper species broadened with increasing Cu2+ concentration, which demonstrated that Cu2+ covered the mineral surfaces and inherent Pb2+ was shield. Ultraviolet–visible spectroscopy indicated that the stability of cerussite surface increased with increasing amount of added Na2S. Compared with only Na2S treatment, consumption of xanthate was almost unchanged at low Cu2+ concentration, whereas consumption of xanthate considerably increased at high Cu2+ concentration, which may be because xanthate was consumed by the residual copper ions in the pulp solution. Zeta potential measurements indicated that Cu2+ can chemisorb on cerussite surfaces and increasing the Cu2+ concentration facilitates adsorption of copper species, but it inhibits adsorption of Na2S and BX. Therefore, sulfidization flotation of cerussite is not substantially affected by low concentrations of Cu2+, but is greatly affected by high concentrations of Cu2+.