Patent ID: 7658895
Filing Date: 2010-02-09
Classification: C01B,C01C,C01G,C22B,Y02P

Abstract:
1. A method of recovering metals from a spent dispersed catalyst originating from a Group VIB metal sulfide catalyst and at least a Group VB metal promoted with a Group VIII metal for hydrocarbon oil hydroprocessing, the method comprising the steps of: contacting the spent dispersed catalyst with a leaching solution containing ammonia and air to dissolve the Group VIB metal and the Group VIII metal into the leaching solution at a sufficient temperature and pressure to form a pressure leach slurry containing at least a Group VIB soluble metal complex and at least a Group VIII soluble metal complex and solid residue containing at least a Group VB metal complex and coke; separating and removing the solid residue containing the Group VB metal complex and coke from the pressure leach slurry, forming a pressure leach solution; mixing the pressure leach solution with an additive selected from the group consisting of a mineral acid, a sulfide-containing compound, and a sulfur compound under mixing conditions at a temperature in the range of 50 to 90° C. for a sufficient amount of time to precipitate at least a portion of the Group VIB metal and at least a portion of the Group VIII metal, wherein the precipitation being carried out at a first pre-selected pH to precipitate as metal complexes at least a portion of the Group VIB metal and at least a portion of the Group VIII metal.