Recovery of vanadium from petroleum coke slurry containing solubilized base metals

摘要

A method for recovering vanadium from a spent slurry catalyst for hydrocarbon oil hydroprocessing is disclosed. In one embodiment after de-oiling, the spent catalyst is treated with ammonia and air, forming a leach slurry. The leach slurry is subsequently treated with a flocculant. After solid-liquid separation to recover the solid residue containing coke and ammonium metavanadate, the solid residue is washed with an ammonium sulfate solution and leached with hot water. After solid-liquid separation to recover a solution containing ammonium metavanadate, the ammonium metavanadate is crystallized and purified from the leach solution.

主权项

1. A method for recovering vanadium from a spent slurry catalyst that has been used in hydroprocessing, the method comprising:
(a) leaching the spent slurry catalyst with an ammonia-containing leach solution at a temperature and pressure sufficient to form an ammonia-leached slurry comprising at least a Group VIB soluble metal complex and at least a Group VIII soluble metal complex and a first solid residue; (b) contacting the ammonia-leached slurry with a flocculant to form a treated ammonia-leached slurry; (c) separating from the treated ammonia-leached slurry a second solid residue comprising coke, ammonium metavanadate and entrained Group VIB and VIII soluble metal complexes; (d) contacting the second solid residue with an ammonium sulfate solution to remove the entrained Group VIB and VIII soluble metal complexes from the second solid residue to form a treated second solid residue; (e) leaching the treated second solid residue with water at a temperature and a pressure sufficient to form an aqueous-leached slurry comprising soluble ammonium metavanadate and a third solid residue comprising coke, the third solid residue having reduced vanadium content compared to the treated second solid residue; (f) separating and removing the third solid residue from the aqueous-leached slurry to recover a filtrate comprising ammonium metavanadate; (g) crystallizing at least a portion of the ammonium metavanadate from the filtrate to form a crystallized ammonium metavanadate; (h) washing the crystallized metavanadate of step (g) with an aqueous ammonium metavanadate solution to form a washed crystallized ammonium metavanadate; and (i) drying the washed crystallized ammonium metavanadate to form a dried crystallized ammonium metavanadate.