Nicholas A Gomez

US Patent:

51084970, Apr 28, 1992

Filed:

Sep 5, 1990

Appl. No.:

7/578013

Inventors:

Nicholas B. Gomez - Golden CO
John P. Hager - Golden CO
Charles E. T. White - New Hartford NY
Laurence G. Stevens - Clinton NY

Assignee:

Indium Corporation of America - New Hartford NY

International Classification:

C22B 1300

US Classification:

75432

Abstract:

Indium-containing feedstocks, such as flue dusts from a refining or smelting process, are treated to increase the concentration of indium and at the same time to reduce the concentrations of lead, copper, and arsenic. The flue dusts are treated in a sodium-doped lead bath at temperatures of 675. degree. to 800. degree. C. Soda ash in the amount of 15 to 35 weight percent is blended with the feed stock and added to the sodium-doped lead bullion. The sodium reacts with the dusts to form a liquid dross, which is removed, cooled, and crushed. The powdered dross is water leached to remove the sodium salts. The indium remains in the filler cake and can be processed by conventional methods for the recovery of indium. About 95% of the indium reports to the filter cake, while lead retention in the filter cake is only about 5-15% of the initial lead content in the dust. A majority of the zinc also reports to the filter cake.