Selective separation of galena and sphalerite from pyrite-rich lead-zinc ores: A case study of the Kooshk mine, Central Iran

In this research, the selective flotation of galena and sphalerite minerals was evaluated from a pyrite-rich lead-zinc sample. An optimum mixture of selective collectors against pyrite and also organic/inorganic pyrite depressants was obtained in the flotation of galena and sphalerite by an experimental mixture design. The effect of different collectors and pH values were investigated in the obtained optimum flotation condition. The results indicated that the mixture of Aero 404 Promoter collector with Potassium Ethyl xanthate (PEX) has the highest Pb recovery and separation efficiency. The mixture of auxiliary collectors of Aero 3477, Aerophine 3418 and Florrea 2255 with Potassium Amyl Xanthate (PAX) improved Zn recovery in comparison with the test in which PAX was added alone in the Zn rougher flotation stage. The highest Zn separation efficiency was achieved by Aerophine 3418 when it was mixed with PAX for which the lowest pyrite particles were floated. Zn separation efficiency was markedly improved from 47.47% to 65.31% from pH 9 to 12. It can be concluded that increasing pH with lime, up to 12, successfully depressed pyrite without any significant negative effect on Zn recovery.