Pulsating high-gradient magnetic separation of chalcopyrite and talc

•PHGMS achieves effective separation of chalcopyrite and talc.•PHGMS produces a high-grade copper concentrate with very low talc content.•PHGMS reduces production and environmental costs for chalcopyrite-talc separation. The selective flotation of chalcopyrite from talc in practice is currently difficult and consumes a large amount of depressors, resulting in high production and environmental costs. The pulsating high-gradient magnetic separation (PHGMS) method has a strong potential for the effective separation of chalcopyrite and talc, based on their difference in magnetic susceptibility. In this work, the effects of magnetic induction, pulsating frequency and feed velocity of a pliot-scale PHGMS separator on the separation performance for pure chalcopyrite and talc minerals were investigated. The results indicate that the PHGMS achieves a selective separation of chalcopyrite from talc; and under the optimizedconditions, a chalcopyrite concentrate of 30.22% Cu grade with 75.79% chalcopyrite recovery at talc content as low as 5.77% was produced from a chalcopyrite-talc mixture assaying 10.69% Cu and 66.67% talc. It was found that the chalcopyrite recovery for the ultra-fine particles fraction below 30 µm is lower than those of coarser fractions, as a result of the increased hydrodynamic drag over the magnetic force acting upon the ultra-fine particle. Entrainment may also occur between ultra-fine talc and chalcopyrite particles, which reduces the Cu grade for such ultra-fine particles in the copper concentrate. The PHGMS method may provide an environment-friendly and low-cost technology for the separation of chalcopyrite and talc.