LEACHING COBALT, MOLYBDENUM, NICKEL, AND VANADIUM FROM SPENT HYDROPROCESSING CATALYSTS

摘要

ABSTRACT OF THE DISCLOSUREA process is disclosed to extract metal valuesselected from the group consisting of cobalt, molybdenum,nickel, tungsten, and vanadium from metal-containingparticles, such as spent hydroprocessing catalyst parti-cles containing carbon residue. In this process, thespent catalyst particles are roasted in an oxygen-containing gas at a temperature of from 400°C to 600°C,and then the roasted catalyst particles are contacted withan aqueous solution of ammonia, ammonium salt, andhydrogen peroxide. That aqueous solution has an initialpH of at least 9.5 and an initial hydrogen peroxideconcentration of from 0.02 to 0.2 M. That aqueoussolution is maintained at a pH of greater than 9.5.