US 7,192,563 B2 · Process for recovery of high purity uranium from fertilizer grade weak phosphoric acid

Abstract

A two-cycle countercurrent extraction process for recovery of highly pure uranium from fertilizer grade weak phosphoric acid. The proposed process uses selective extraction using di-(2-ethyl hexyl) phosphoric acid (D2EHPA) and tri-n-butyl phosphate (TBP) with refined kerosene as synergistic extractant system on hydrogen peroxide treated phosphoric acid, and stripping the loaded extract with strong phosphoric acid containing metallic iron to lower redox potential. The loaded-stripped acid is diluted with water back to weak phosphoric acid state and its redox potential raised by adding hydrogen peroxide and re-extracted with same extractant system. This extract is first scrubbed with sulfuric acid and then stripped with alkali carbonate separating iron as a precipitate, treated with sodium hydroxide precipitating sodium uranate, which is re-dissolved in sulfuric acid and converted with hydrogen peroxide to highly pure yellow cake of uranium peroxide.

Claims24

Dependent claims

A process for recovery of uranium from aqueous fertilizer grade weak phosphoric acid comprising:

first extracting aqueous fertilizer grade weak phosphoric acid with a solvent blend comprising 1 M to 1.6 M di(2-ethylhexyl)phosphoric acid (D2EHPA) and 0.1 M to 0.3 M tri-n-butyl phosphate (TBP) in refined kerosene, wherein the molar ratio of D2EHPA to TBP is 10:1 to 5:1 in the refined kerosene, to provide a first extract;
reductive stripping for first extract with 11 M to 14 M phosphoric acid to provide loaded phosphoric acid;
diluting the loaded phosphoric acid with water to the concentration of the aqueous fertilizer grade weak phosphoric acid to provide a diluted loaded phosphoric acid;
oxidizing the diluted loaded phosphoric acid;
second extracting the diluted loaded phosphoric acid with 1 M to 1.6 M D2EHPA and 0.1 M to 0.3 M TBP, wherein the molar ratio of D2EHPA to TBP is 10:1 to 5:1 in refined kerosene, to provide a second extract;
scrubbing the second extract with 4.5 M–5.5 M sulfuric acid to provide a scrubbed second extract;
stripping the scrubbed second extract with a solution of alkali carbonate to provide a stripped second extract;
and
recovering uranium values from the stripped second extract.

6 more elements

A process for recovery of uranium from aqueous fertilizer grade weak phosphoric acid comprising:

pretreating the aqueous fertilizer grade weak phosphoric acid by cooling, clari-flocculating, treating with activated carbon, oxidizing, or combination thereof, to provide a pretreated phosphoric acid;
first extracting the pretreated phosphoric acid with a solvent blend comprising 1 M to 1.6 M D2EHPA and 0.1 M to 0.3 M TBP in refined kerosene, wherein the molar ratio of D2EHPA to TBP is 10:1 to 5:1 in the refined kerosene and the volume of D2EHPA to TBP is 1:1 to 1:2, to provide a first extract;
reductive stripping the first extract with 11 M to 14 M phosphoric acid to provide loaded phosphoric acid;
second extracting the loaded phosphoric acid with a solvent blend comprising 1 M to 1.6 D2EHPA and 0.1 M to 0.3 M TBP in refined kerosene, wherein the molar ratio of D2EHPA to TBP is 10:1 to 5:1 in the refined kerosene and the volume of D2EHPA to TBP is1:1 to 1:2, to provide a second extract;
scrubbing the second extract with 4.5 M–5.5 M sulfuric acid to provide a scrubbed second extract;
stripping the scrubbed second extract with a solution of alkali carbonate to provide a stripped second extract;
treating the stripped second extract with alkali to form a precipitate;
collecting the precipitate;
dissolving the precipitate in 3 M to 4 M sulfuric acid to form a sulfuric acid solution;
adjusting the pH of the sulfuric acid solution to 3.5;
treating the sulfuric acid solution with hydrogen peroxide to precipitate uranium peroxide;
and
optionally, drying and recalcining the uranium peroxide at 180° C. to 220° C. to provide uranium oxide.

10 more elements

Dependencies are inferred from the claim text.

Process for recovery of high purity uranium from fertilizer grade weak phosphoric acid

Life of this patent

Process for recovery of high purity uranium from fertilizer grade weak phosphoric acid

Life of this patent

Abstract

Claims24