Claims
- 1. A process for recovering uranium values from phosphoric acid which comprises:
- (a) contacting an aqueous phosphoric acid phase containing uranium values, from 1% to about 55% P.sub.2 O.sub.5 values by weight and impurities with a first water immiscible organic extractant phase comprising a water immiscible organic solvent containing at least one water immiscible organic sulfonic acid dissolved therein to form:
- (i) a pretreated phosphoric acid phase containing uranium values; and
- (ii) a loaded organic extractant phase containing impurities;
- (b) separating the pretreated aqueous phosphoric acid phase from the loaded organic extractant phase;
- (c) contacting pretreated aqueous phosphoric acid phase with a second water immiscible organic extractant phase comprising a water immiscible organic solvent containing at least one water immiscible organophosphorus uranium-extracting agent dissolved therein to form:
- (i) a uranium-depleted phosphoric acid phase; and
- (ii) an organic extractant phase containing uranium values;
- (d) separating the uranium-containing organic extractant phase from the uranium-depleted phosphoric acid phase; and
- (e) recovering uranium values from the uranium-containing second organic extractant phase.
- 2. The process according to claim 1 in which in step (a), the aqueous phosphoric acid phase is at a temperature of from about 20.degree. C. to about 77.degree. C. and the first organic extractant phase is at a temperature of from about 20.degree. C. to about 60.degree. C.; and wherein said phases are mixed in the volumetric ratio of the organic extractant phase to the aqueous phosphoric acid phase of from 1 to 1 to about 50 to 1.
- 3. The process according to claim 1 in which the water immiscible organic sulfonic acid is selected from the group consisting of alkylaryl, polyalkylaryl, alkanoylaryl, polyalkanoylaryl, and aromatic ring substituted sulfonic acid derivatives thereof represented by the formulae (I) and (II) ##STR3## wherein in formula I R is an alkyl group of from 5 to 25 carbon atoms or an alkanoyl group of 8 to 18 carbons [R].sub.m contains at least 8 carbon atoms when m is 1 and [R].sub.m contains at least 10 carbon atoms when m is 2 and further provided that m can be 1 or 2 when R is alkyl and m can be 1 when R is alkanoyl; wherein in formula II R is an alkyl group of 5 to 25 carbon atoms or an alkanoyl group of from 5 to 18 carbon atoms, [R].sub.n contains at least 8 carbon atoms when n is 1, [R].sub.n contains at least 10 carbon atoms when n is 2 and [R].sub.n contains at least 15 carbon atoms when n is 3, further provided that n can be 1, 2, 3 when R is alkyl and n can be 1 or 2 when R is alkanoyl; X is hydrogen, hydroxy, fluoro, chloro, bromo, iodo, methoxy, ethoxy, propoxy, carboxymethoxy, or carboxyethoxy; and Y is hydrogen, fluoro, chloro, bromo, iodo, methoxy, ethoxy, 2-propoxy, carboxymethoxy, or carboxyethoxy; provided however, that Y is in the alpha position with respect to the SO.sub.3 H group and further provided that the SO.sub.3 H group is at position 1 or 2 on the napthalene molecule.
- 4. The process according to claim 3 in which the water immiscible organic sulfonic acid is selected from the group consisting of 5-dodecanoyl-2-chlorobenzenesulfonic acid, 5-nonyl-2-ethoxy-benzenesulfonic acid, 3,5-di-t-octyl-2-(alphacarboxymethoxy)-benzenesulfonic acid and 3,5-di-t-octyl-2-hydroxybenzenesulfonic acid.
- 5. The process according to claim 1 which comprises reducing uranium values in the pretreated aqueous phosphoric acid phase to the U.sup.IV form before contacting the aqueous phase with the second organic extractant phase, and wherein the organophosphorus uranium-extracting agent comprises at least one alkylphenyl ester of orthophosphoric acid.
- 6. The process according to claim 5 in which uranium values are reduced by contacting the pretreated aqueous phosphoric acid phase with elemental iron.
- 7. The process according to claim 5 in which the organophosphorus agent comprises a mixture of octylphenylphosphoric acid and di(octylphenyl) phosphoric acid.
- 8. The process according to claim 1 in which uranium values in the pretreated aqueous phosphoric acid phase are oxidized to the U.sup.VI form before contacting the aqueous phase with the second organic extractant phase and wherein the organophosphorus uranium-extracting agent is selected from the group consisting of alkyl esters of orthophosphoric acid, alkyl esters of pyrophosphoric acid, alkyl phosphonic acids, alkyl phosphinic acids, and mixtures thereof.
- 9. The process according to claim 8 in which the organophosphorus uranium-extracting agent comprises a dialkyl ester of orthophosphoric acid.
- 10. The process according to claim 9 in which the dialkyl ester of orthophosphoric acid comprises di(2-ethylhexyl) phosphoric acid.
- 11. The process according to claim 1 wherein uranium values are recovered from the uranium containing second organic extractant phase by the steps of:
- contacting second organic extractant phase containing uranium values with a first aqueous stripping phase containing an oxidizing agent for uranium values to form:
- (i) an enriched aqueous stripping phase containing uranium values in U.sup.VI form, and
- (ii) a uranium-depleted organic phase;
- separating the enriched aqueous stripping phase from the uranium-depleted organic phase;
- contacting the enriched aqueous stripping phase with a third water immiscible organic extractant phase comprising a water immiscible organic diluent and at least one water immiscible organophosphorus uranium-extracting agent dissolved therein to form:
- (i) a uranium-depleted first aqueous stripping phase, and
- (ii) a uranium-enriched third organic extractant phase;
- separating uranium-enriched third organic extractant phase from uranium-depleted first aqueous stripping phase;
- contacting uranium-enriched third organic extractant phase with a second aqueous stripping phase containing ammonium carbonate to form:
- (i) a uranium-depleted third organic extractant phase, and
- (ii) a slurry of solid ammonium uranyl tricarbonate in second aqueous stripping phase;
- separating the slurry of solid ammonium uranyl tricarbonate from the uranium-depleted third organic extractant phase;
- separating solid ammonium uranyl tricarbonate from the slurry; and
- drying and calcining the ammonium uranyl tricarbonate to form U.sub.3 O.sub.8.
- 12. The process according to claim 1 wherein the aqueous phosphoric acid which is contacted in step (a) is obtained by conversion in dilute aqueous sulfuric acid of calcium sulfate hemihydrate containing P.sub.2 O.sub.5 values to calcium sulfate dihydrate and a solution of impure phosphoric acid, said calcium sulfate hemihydrate being obtained by adding sulfuric acid to a solution of phosphate rock in phosphric acid to precipitate said calcium sulfate hemihydrate.
- 13. A process for recovering uranium values from phosphoric acid which comprises:
- (a) contacting an aqueous phosphoric acid phase containing uranium values, from 1% to about 55% P.sub.2 O.sub.5 values by weight, and impurities with a first water immiscible organic extractant phase comprising a water immiscible organic solvent containing at least one water immiscible organic sulfonic acid and at least one water immiscible organic acid phosphate, phosphonate, or half ester thereof dissolved therein to form:
- (i) a pretreated phosphoric acid phase containing uranium values; and
- (ii) a loaded organic extractant phase containing impurities;
- (b) separating the pretreated aqueous phosphoric acid phase from the loaded organic extractant phase;
- (c) contacting pretreated aqueous phosphoric acid phase with a second water immiscible organic extractant phase comprising a water immiscible organic solvent containing at least one water immiscible organophosphorus uranium-extracting agent dissolved therein to form:
- (i) a uranium-depleted phosphoric acid phase; and
- (ii) an organic extractant phase containing uranium values;
- (d) separating uranium-containing organic extractant phase from uranium-depleted phosphoric acid phase; and
- (e) recovering uranium values from uranium-containing organic extractant phase.
- 14. The process according to claim 13 in which the water immiscible organic acid phosphate compound is selected from the group consisting of monosubstituted organic acid phosphates, disubstituted organic acid phosphates, and mixtures thereof in which the substituent group contains from about 4 to about 18 carbon atoms and is selected from the group consisting of alkyl, alkenyl, alicyclic, aryl, alkylaryl, alkenylaryl, alicyclicaryl, heterocyclic and mixtures thereof.
- 15. The process according to claim 14 wherein the water immiscible organic acid phosphate compound is selected from the group consisting of amyl acid phosphate, isooctyl acid phosphate, decyl acid phosphate, lauryl acid phosphate, stearyl acid phosphate, phenyl acid phosphate, octylphenyl acid phosphate, cyclohexyl acid phosphate, cyclohexylphenyl acid phosphate, 1-(5-hexynyl) acid phosphate, 1-(5-hexynyl) phenyl acid phosphate, 1-(6-chlorohexyl) acid phosphate, 1-(6-hydroxyhexyl)acid phosphate, and 1-(6-methoxyhexyl) acid phosphate.
- 16. The process according to claim 13 in which in step (a), the aqueous phosphoric acid phase is at a temperature of from about 20.degree. C. to about 77.degree. C. and the first organic extractant phase is at a temperature of from about 20.degree. C. to about 60.degree. C.; and wherein said phases are mixed in the volumetric ratio of the organic extractant phase to the aqueous phosphoric acid phase of from 1:1 to about 50:1.
CROSS-REFERENCE TO RELATED APPLICATION
This application is a Continuation-In-Part of U.S. patent application Ser. No. 688,265, filed May 20, 1976, now U.S. Pat. No. 4,053,564.
US Referenced Citations (6)
Continuation in Parts (1)
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688265 |
May 1976 |
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