Abstract:In a zinc smelter of Inner Mongolia, sulfur and silver-bearing minerals in zinc sulfide oxygen pressure leaching residue were separated by flotation using zinc electrolysis industrial backwater. Because the industrial backwater has the characteristics of high acid and high impurity ion concentration, the production index is much worse than the laboratory small flotation test ( tap water slurry ).In this paper, based on the determination of the properties of industrial backwater, the effects of high concentrations of sulfuric acid, zinc ions and iron ions on the separation and recovery of sulfur and silver-containing minerals in leaching slag were studied. According to the research results, the improvement idea of flotation technology is put forward.That is, under the condition of industrial backwater slurry adjustment, the properties of pulp are regulated to improve the dispersion of pulp, and the combined collector of ammonium dibutyl dithiophosphate and kerosene with strong adaptability is used to replace the original xanthate system.Under the optimized conditions, a sulfur concentrate with grade of 79.52 % sulfur and recovery 91.06 % sulfur recoveries. The tailings with grade of 446.4 g / t silver and 82.63 % silver recoveries. Compared with the production index, the grade and recovery rate of sulfur concentrate increased by 9.40 % and 22.10 % respectively, and the recovery rate of silver increased by 35.88 %.