Method or process for recovering Mo, V, Ni, Co and Al from spent catalysts using ultrasonic assisted leaching with EDTA

A method for the selective recovery of Mo, V, Ni, Co and Al from spent hydroprocessing catalysts, said method comprising the steps of:

• a. providing a mass of spent hydroprocessing catalysts containing up to about 10% oil, about 10 to 30 wt % coke or carbonaceous deposits, about 3 to 10 wt % Mo, about 2 to 6 wt. % Ni, and about 3 to 20% V and about 2 to 4 wt % Co and up to about 35 wt. % Al;
• b. washing the spent catalysts to remove the residual oil and drying the spent catalysts at about 110 to 120° C. in air or nitrogen;
• c. crushing and/or grinding the dried spend catalysts to a fine powder with a particle size of less than 500 microns;
• d. mixing the fine powder with an Ethylene Diamine Tetra Acetic Acid (EDTA) and subjecting the fine powder in EDTA to ultrasonic vibration for a period of about 6 hours;
• e. filtering the fine powder in EDTA and separating the dissolved metals, V, Ni, Mo, and Co with traces of Al in solutions and while undissolved alumina remains as a residue;
• f. treating the filtrate of solution with HNO3 to precipitate EDTA;
• and
• g. solvent extraction of the aqueous solution to obtain Mo, V, Ni, Co, and Al.

A method for recovery of Mo, V, Ni, Co and Al from spent hydroprocessing catalysts, said method consisting of the following steps:

• a.) providing a mass of spend hydroprocessing catalysts containing up to about 10% oil, about 10 to 30_wt % coke or carbonaceous deposits, about 3 to 10 wt % Mo, about 2 to 6_wt % Ni, about 3 to 20_wt % V, about 2-4 wt % Co and up to 35_wt % Al;
• b.) washing the spent catalysts in naphtha or toluene to remove the residual oils and drying at 110 to 120° C. in air or nitrogen;
• c.) decoking the oil free agent catalysts to remove coke, carbonaceous deposits and sulfur deposits by heating in air or in a gas containing 2-10% O2 in N2 at temperatures between 370 to 550° C. according to the following programmed temperature conditions in three steps:
• in a first step temperature was linearly raised from 40° C. to 370° C. at 330° C/hr and kept at this temperature for one hour, in a second step the temperature was then increased from 370° C. to 450° C. at 80° C/h and stayed for one hour and then a final decoking step was done by ramping from 450° C. to 550° C. in two hours at 50° C/h and then heating at 550° C. for one hour;
• d.) grinding and sieving the decoked spent catalysts to provide fine particles of less than 500 microns;
• e.) mixing the fine particles from step d. with a solution of about 10 wt % Ethylene Diamine Tetra Acetic Acid (EDTA) with a pH in the range of 9-12 and subjecting the fine particles and EDTA to ultrasonic vibration at about 60° C. to produce a solution;
• f.) filtering the solution from step e. to provide a remaining solution of Mo, V, Ni, Co, and Al and a residue of Al2O3;
• g.) treating the remaining solution from step f. with nitric acid with a pH of 0.1 to produce an aqueous solution of Mo, V, Ni, Co and Al and a residue of EDTA;
• and
• h.) solvent extraction of Mo, V, Ni, Co and Al.