| abstract |
This invention relates to a process for selectively recovering vanadium from spent catalysts which were used in hydrodesulufurization, hydrodemetallization, etc. of heavy oils until metals in said heavy oils accumulated thereon. More particularly, it relates to a process for recovering vanadium, and if desired, vanadium along with nickel from spent catalysts in such a way that said spent catalysts are chlorinated with chlorinating agent(s) at a temperature below 600 DEG C. without being subjected to calcination so as to convert almost all the vanadium compounds to vanadium tetrachloride which is recovered in the form of a gas, including the chlorination of nickel compounds of nickel chloride which can also be recovered as such by solvent extraction. |