Abstract:The cadmium, contained in the chlorine-containing caustic soda slag from the process of cadmium- recycling during the zinc metallurgy, can be recycled by using hot water dissolving and liquid-solid separation process. The alkali liquor with chlorine entered into the zinc hydrometallurgy flowsheet before vitriol-sinking. When vitriol sinking, the replacement of OH- with Cl- and the hot acid leaching from the copper cadmium slag, as well as the production of CuCl from the copper slag with low-acid washing process can eliminate the harm from Cl-; and still the replacement of NH4+ with Na+ can be fully used. Thus the recovery rate of zinc and cadmium reached up to 99.90%. The trial production proved an ideal economic efficiency and environmental protection benefit.