Patent ID: 8282897

Claim:
A method for recovering boehmite and/or γ-alumnia from alumina-supported spent catalyst containing from 1-10 wt. % molybdenum, 1-6 wt. % nickel, 1-20 wt. % vanadium, and 1-30 wt. % carbonaceous deposits containing carbon, sulfur and oil residue, said method comprising the steps of: b.) removing oil residue from said spent catalysts; c.) drying the spent catalysts after removal of said oil residue; d.) grinding the dried spent catalysts after removal of the oil residue to produce a particle size of less than 500 microns; e.) removing carbonaceous deposits by decoking said dried spent catalysts from step d at a temperature of 370-500° C. to produce a residue; f.) roasting the residue from step e.) with soda ash in the range of 650° C. to 850° C.; g.) removing extracted vanadium and molybdenum contaminants leaving a NiO/Al 2 O 3 residue; h.) digestion of the NiO/Al 2 O 3 residue in NaOH; i.) separating nickel oxide as a solid residue wherein sodium aluminate is precipitated by CO 2 as a partially crystallized boehmite; and j.) hydrothermal treatment of the partially crystallized boehmite to obtain well crystallized boehmite.