PROCESS FOR METALS RECOVERY FROM SPENT CATALYST
First Claim
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1. A method for recovering vanadium, nickel and molybdenum from a spent, unsupported catalyst that has been used in a hydroprocessing process, said method comprising:
- a) treating said spent slurried catalyst with an aqueous solvent and an oxidizer in a leaching zone at leaching conditions;
b) passing the effluent of step (a), which comprises liquid and solid material to a filtration zone, from which solid material is recovered as a filter cake and a liquid material is generated;
c) passing the filter cake of step (b), which comprises ammonium metavanadate to a dissolution zone, to which ammonia is added under dissolution conditions;
d) passing the effluent of step (c) to a first filtration zone for removal of coke contaminants;
e) passing the effluent of step (d) to a crystallization zone, wherein the effluent is adjusted for pH and ammonium metavanadate crystallizes as a solid;
f) passing the effluent of step (e) to a second filtration zone for the removal of ammonium metavanadate solid;
g) passing the liquid material of step (b), which comprises an aqueous phase and an organic phase, to a mixer-settler zone;
h) separating the aqueous phase of step (g), which comprises molybdenum, from the organic phase, which comprises nickel;
i) subjecting the organic phase of step (h), which remains in the mixer-settler zone, to at least one cycle of extraction, scrubbing and stripping prior to the removal of nickel sulfate solution as product;
j) removing molybdenum compounds from the aqueous phase of step (h) by solvent extraction or precipitation.
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Abstract
The process of this invention is directed to the removal of metals from an unsupported spent catalyst. The catalyst is subjected to leaching reactions. Vanadium is removed as a precipitate, while a solution comprising molybdenum and nickel is subjected to further extraction steps for the removal of these metals. Molybdenum may alternately be removed through precipitation.
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20 Claims
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1. A method for recovering vanadium, nickel and molybdenum from a spent, unsupported catalyst that has been used in a hydroprocessing process, said method comprising:
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a) treating said spent slurried catalyst with an aqueous solvent and an oxidizer in a leaching zone at leaching conditions; b) passing the effluent of step (a), which comprises liquid and solid material to a filtration zone, from which solid material is recovered as a filter cake and a liquid material is generated; c) passing the filter cake of step (b), which comprises ammonium metavanadate to a dissolution zone, to which ammonia is added under dissolution conditions; d) passing the effluent of step (c) to a first filtration zone for removal of coke contaminants; e) passing the effluent of step (d) to a crystallization zone, wherein the effluent is adjusted for pH and ammonium metavanadate crystallizes as a solid; f) passing the effluent of step (e) to a second filtration zone for the removal of ammonium metavanadate solid; g) passing the liquid material of step (b), which comprises an aqueous phase and an organic phase, to a mixer-settler zone; h) separating the aqueous phase of step (g), which comprises molybdenum, from the organic phase, which comprises nickel; i) subjecting the organic phase of step (h), which remains in the mixer-settler zone, to at least one cycle of extraction, scrubbing and stripping prior to the removal of nickel sulfate solution as product; j) removing molybdenum compounds from the aqueous phase of step (h) by solvent extraction or precipitation. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20)
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Specification