Leaching cobalt from spent hydroprocessing catalysts with sulfur dioxide
AssigneeChevron Research Company
InventorsGale L. Hubred, Dean A. Van Leirsburg
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Abstract
A process for enhancing recovery of cobalt from spent hydroprocessing catalysts when the spent catalyst particles are first roasted at between 400.degree. C. and 600.degree. C. and then contacted with a first aqueous solution of ammonia and an ammonium salt to recover nickel, cobalt, molybdenum and vanadium. The once-leached spent hydroprocessing catalysts are contacted with a second aqueous solution of sulfur dioxide. The metal values are precipitated with hydrogen sulfide and the precipitate is roasted with unroasted spent hydroprocessing catalysts.
Claims6
A process to extract cobalt from spent hydroprocessing catalyst particles comprising:
- (a) roasting said catalyst particles in an atmosphere containing oxygen at a temperature in the range of between 400.degree. C. and 600.degree. C.;
- (b) contacting said roasted catalyst particles with a first aqueous solution of ammonia and a compound selected from the group of ammonium-containing salts consisting of ammonium carbonate and ammonium sulfate, maintained at a temperature in the range of 85.degree. C. to 95.degree. C., in the presence of an oxygen-containing gas;
- (c) separating said catalyst particles from said first aqueous solution containing cobalt values;
- (d) contacting said catalyst particles with a second aqueous solution of sulfur dioxide;
- (e) separating said catalyst particles from said second solution;
- (f) precipitating metals present in said second solution with hydrogen sulfide as metal sulfide;
- and
- (g) roasting said precipitated metal sulfides with fresh spent catalyst in step (a).
Dependencies are inferred from the claim text.