Abstract:The production situation of extracting arsenic and iron from sulfuric acid leaching solution by double-solvent extraction composed of P507+N235 in a zinc smelter was introduced, and the problems existing in returning high-acid arsenic and iron solution obtained by stripping to zinc smelting system were analyzed. Membrane separation process was used to treat stripping solution. The technological conditions and investment and operation costs of nanofiltration membrane and diffusion dialysis membrane were compared and analyzed. The results show that both nanofiltration membrane and diffusion dialysis membrane can effectively separate impurity elements in the solution. In the membrane process, the retention rate of Fe, As, Zn, H2SO4 and oil in retained concentrate is 91.2%, 88.55%, 87.5%, 47.44% and 50%, respectively, and acid recovery rate is 52.56%; in diffusion dialysis membrane process, the retention rate of Fe, As, Zn, H2SO4 and oil in dialysis residue is 92%, 87.94%, 90%, 5.13% and 75%, respectively, and the acid recovery rate is 94.87%. Both the retained concentrate and the dialysis residue are treated by lime neutralization method to remove arsenic and iron in the solution, and the filtration solution is returned to the system to realize resource recycling. Compared with nanofiltration membrane method, diffusion dialysis membrane method has low investment, simple operation and maintenance, low production cost, and is more suitable for industrial production.