Recovery of Zinc from Chloride by Fused-salt Electrolysis.
Haver-FP; Shanks-DE; Bixby-DL; Wong-MM
NTIS: PB 252 517 :16 pages
The Bureau of Mines is developing a leach-electrolysis procedure to produce special high grade (shg) zinc from sulfide concentrate without the generation of sulfur oxide gases. Chlorine-oxygen leaching of the concentrate yields zinc chloride (zncl2) which, after purification, is electrolyzed in a fused-salt cell to obtain molten zinc metal and chlorine gas for recycle. This paper describes a laboratory-scale investigation made to develop a procedure for electrowinning zinc metal from zncl2. Zinc chloride by itself is not a suitable electrolyte because it fumes badly above its melting point and is a poor conductor of electricity. Other salts therfore must be added to prevent fuming and improve the conductivity. Optimum results were obtained with a kcl-licl-zncl2 bath at 500 deg c, using a current density of 5 amp/in2 and an electrode spacing of 0.5 Inch. Under these conditions, shg zinc was produced at a current efficiency of 94.3 pct and an energy requirement of 1.16 Kwhr/lb. Fused-salt electrowinning eliminates the need to handle and melt cathodes and increases the production of metal per unit cell volume through the use of higher current densities than are possible with aqueous electrolysis.
IH; Report of Investigation;
NTIS Accession No.
NTIS: PB 252 517