Increased current efficiency of zinc electrowinning in the presence of metal impurities by addition of organic inhibitors

The influence of antimony, germanium and nickel ions, and of the organic additives hydroxyethylated-butyne-2-diol-1,4 (EAA) and triethyl-benzylammonium chloride (TEBA), on the process of zinc electrowinning from sulphuric acid electrolytes is studied. It is established that metal impurities decrease the current efficiency of zinc (CEZ) and, at higher concentrations, cause total redissolution of the deposited metal. The organic additives stop the process of zinc redissolution, increase current efficiency and improve the quality of the deposited metal. The results obtained were confirmed by pilot plant and industrial trials.