Processing method of zinc smelting byproducts

The invention relates to a processing method of zinc smelting byproducts. The method comprises the following steps: firstly, using a mixed aqueous solution of ammonia and ammonia sulfate (or salvolatile) to leach copper-cadmium slag or cadmium-rich soot after heat treatment at a room temperature; then, decoppering a leaching solution by an organic solvent extraction method; directly producing metal cadmium from a solution containing zinc and cadmium by a low current density electrolytic method instead of a technological method of adopting zinc powder replacement to obtain sponge cadmium; using a sulphuric acid solution as strip liquor to strip copper from a decoppered organic extraction agent and then electrolyzing the copper-contained strip liquor to prepare the metal copper; in addition, electrolyzing the decoppered leaching solution which only contains zinc and cadmium to extract the cadmium; eliminating the mutual interference of copper ions and cadmium ions in the electrolytic process of the cadmium; and returning the electrolyzed leaching solution to the zinc production process. The method simplifies the processing technological process, shortens the product period, can respectively obtain a purer copper product and a purer cadmium product and decreases the zinc smelting byproducts and the processing cost.