| 摘要 |
A process is disclosed to extract cobalt and optionally, at least one metal value selected from the group consisting of molybdenum, nickel, tungsten, and vanadium from metal-containing particles, such as spent hydroprocessing catalysts particles containing carbon residue. In this process, the spent catalyst particles are roasted in an oxygen-containing gas at a temperature of from 400 DEG C. to 600 DEG C., and then the roasted catalyst particles are contacted with an aqueous solution of ammonia, ammonium salt, and hydrogen peroxide. The aqueous solution has an initial pH of at least 9.5 and an initial hydrogen peroxide concentration of from 0.02 to 0.2 M. That aqueous solution is maintained at a pH of greater than 9.5.
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