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AssigneeChiyoda Chemical Engineering & Construction Co., Ltd.
InventorsTakechiyo Yoshida, Masato Ushiyama, Tohru Yokoyama
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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.degree. 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.
A process for recovering vanadium accumulated on spent catalysts, the vanadium being recovered as a chloride thereof, which process comprises chlorinating a spent catalyst which has not been subjected to prior oxidation and having vanadium accumulated thereon substantially in the form of sulfides with a chlorinating agent selected from the group consisting of chlorine, hydrogen chloride, carbon tetrachloride, S.sub.2 Cl.sub.2 and mixtures thereof under a temperature of from room temperature to 600.degree. C. and a pressure above atmospheric so that substantially all of the vanadium accumulated on said spent catalyst can be chlorinated to a volatile chloride which is mainly vanadium tetrachloride.
A process for recovering vanadium accumulated on spent catalysts, the vanadium being recovered as a chloride thereof, which process comprises chlorinating a spent catalyst which has not been subjected to prior oxidation and having vanadium accumulated thereon substantially in the form of sulfides with a chlorinating agent selected from the group consisting of chlorine, hydrogen chloride, carbon tetrachloride, S.sub.2 Cl.sub.2 and mixtures thereof, under a temperature of from room temperature to 600.degree. C. and a pressure above atmospheric so that substantially all of the vanadium accumulated on said spent catalyst can be chlorinated to a volatile chloride which is mainly vanadium tetrachloride, and thereafter separating said volatile chloride from said spent catalyst and further purifying it from contaminants thereof.
Dependencies are inferred from the claim text.