SEPARATION OF LEAD, CADMIUM, AND GERMANIUM SULFIDES FROM ZINC SULFIDE CONCENTRATES

摘要

Lead sulfide, cadmium, and germanium, presumably also as sulfides, were successfully removed from Tri-State zinc concentrates by volatilization. Although 0.5 to 3 percent of the zinc also was volatilized, the volatile product was greatly enriched in lead, cadmium, and germanium. The experiments were performed over a temperature range of 700° to 1,050°C. Volatilizations were made in a partial vacuum, in an inert atmosphere, and in a reducing atmosphere. n Highest extractions were attained in experiments utilizing the partial vacuum and the reducing atmosphere. Temperatures of 1,000° C and over were necessary to obtain substantial removal of the volatiles under atmospheric pressure. By placing the vacuum tube in a hot furnace with the charge initially under a pressure of 50 microns, roughly equivalent results could be obtained at temperatures of 100° C less. Proper preparation of the finely ground concentrate was a beneficial adjunct to the heat treatment. An increase of' 100°C in the treatment temperature was more effective than increasing the time of treatment from 1 hour to 2 hours.