Abstract:The separation of galena and chalcopyrite has always been a difficult point in the field of mineral processing. The use of sulfuric acid pre-oxidation can selectively inhibit the surface floatability of the lead ore, so that the floatability of the two minerals is different, and the flotation separation is realized. In this study, the parameters of sulfuric acid pre-oxidation-flotation separation process for copper-lead mixed concentrate were systematically optimized. Firstly, the effects of key factors such as pre-oxidized sulfuric acid concentration, temperature and time on the flotation separation of copper-lead mixed concentrate were analyzed by single factor test. Secondly, the mathematical model between the influencing factors and the flotation index in the pre-oxidation process was established by using the orthogonal test analysis method. By solving the model, the optimal pre-oxidation conditions were obtained as follows : sulfuric acid concentration 5 mol / L, time 40 min, temperature 100 °C. Finally, the closed-circuit test of pre-oxidation-flotation of mixed concentrate was carried out under the above conditions, and the copper concentrate with Cu grade of 18.03 % and Cu recovery of 94.52 % was obtained. The lead concentrate has a good index of Pb grade of 47.12 % and Pb recovery of 91.29 %. The separation effect of copper and lead is remarkable, which provides a certain reference for the efficient flotation separation of copper-lead sulfide mixed concentrate.