COMPARATIVE EXTRACTION OF U(VI) BY NEUTRAL AND MONOACIDIC PHOSPHATES AND PHOSPHONATES
Studies were made on the extraction of U(VI) by a neutral phosphate extractant, tri(2-ethylhexyl)phosphate, and by the analogous neutrai phosphonate extractant, di(2-ethylhexyl)2-ethylhexyl phosphonate, in toluene diluent from an aqueous nitrate phase. The extraction is shown to be second-power dependent upon the concentration of extractant in the organic phase and secondpower dependent upon the concentration of nltrate ion in the aqueous phase. An inhibiting effect is noted nt nitrate concentrations in excess of 0.5F, the K falling below the theoretical curve. Under identical conditions, the phosphonate is approximntely 33 times more effective in extracting U(VI) than is the phosphate. Studies were also made on the extraction of U(VI) by a mono-acidic phosphate, di(2-ethylhexyl) phosphoric acid, and by the analogous mono-acidic phosphonate, 2-ethylhexyl hydrogen 2-ethylhexyl phosphonate, in toluene diluent from an aqueous 1.00 F (HX + NaX) phase, where X = ClO/sub 4/, Cl/sub -/, NO/sub 3/. The extraction is shown to be second-power dependent upon the concentration of extractant in the organic phase and inversely second-power dependent upon the concentration of hydrogen ion in the aqueous phase. (The extraction of U(VI) by a (GO)GPO(OH) extractant is reported for the first time.) Essentially no difference between the ClO/sub 4/ and NO/sub 3/ data was noted. The difference between the ClO/sub 4/ and Cl/sup -/ data is consistent with the assumption of a stability constant of 0.8 plus or minus 0.2 for the UO/sub 2/Cl/sup +/ complex, mu = 1.00, 22 plus or minus 1 deg C. In all of these systems, the acidic phosphonate excels the acidic phosphate by a factor of 1.9 plus or minus 0.2. The relative phosphonate/phosphate data of U(VI) are compared with those for Th(IV), lanthanides(III) and actinides(III). The possible difficulties encountered in the use of neutral phosphonates and phosphates as extractants in determining stability constant of M/sub +b/ nitrate complexes are discussed. (auth)
- Research Organization:
- Argonne National Lab., Ill.
- DOE Contract Number:
- W-31-109-ENG-38
- NSA Number:
- NSA-17-010745
- OSTI ID:
- 4732784
- Report Number(s):
- TID-15773; UAC-6191
- Resource Relation:
- Other Information: Orig. Receipt Date: 31-DEC-63
- Country of Publication:
- United States
- Language:
- English
Similar Records
ISOLATION OF NEPTUNIUM AS A MONO OCTYL PHOSPHORIC ACID COMPLEX BY LIQUID- LIQUID EXTRACTION
SYNERGISTIC EFFECTS IN THE EXTRACTION OF SELECTED METALLIC CATIONS BY MONO (2-ETHYL HEXYL) PHOSPHORIC ACID