ELECTROCHEMICAL RECOVERY OF ZINC FROM NH4CI LEACHING SOLUTION OF ZnO

摘要

Ammonium chloride leaching and electrowinning were used for dissolution of ZnO and recovery of zinc metal as a part of recycling research program of electric arc furnace dust. The effects of process variables were evaluated by factorial design experiments. The leaching was greatly affected by concentration of NH4CI. Zn(NH_3)_2Cl_2 was precipitated when solution temperature was lowered after leaching. Adding ammonia in the leaching solution prevent the precipitation at low temperature below 50°C. The current efficiency of electrowinning was steeply increased in proportion to current density at low current densities. In the process region over the current efficiency of 80%, ammonia content in electrolyte had a great effect on current efficiency.