Extraction by N,N-dialkylamides. II. Extraction of actinide cations
- CEA-DCC-DPR-SEMP-SECP, Fontenay-aux-Roses (France)
N,N-dialkylamides are potential alternative extractants to tributyl-phosphate for the actinide separation in nuclear fuel reprocessing. Extraction mechanisms of U(VI), Th(IV) and Pu(IV) from nitric acid media are investigated for the amide DOBA(((C{sub 4}H{sub 9})(C{sub 2}H{sub 5})CHCH{sub 2}){sub 2}NC(O)C{sub 3}H{sub 7}) and DO{sub i}BA(((C{sub 4}H{sub 9})(C{sub 2}H{sub 5})CHCH{sub 2}){sub 2} NC(O)CH(CH{sub 3}){sub 2}). For low aqueous acidities, amides are neutral extractants. Extraction stoichiometries of U{bar O}{sub 2}(NO{sub 3}){sub 2}(Amide){sub 2}{bar O} (Amide = DOBA or DO{sub i}BA), P{bar O}u(NO{sub 3}){sub 4}(DOBA){sub 2}{bar O} have been established. Th(IV) is supposed to form a di- and a trisolvate in the inner-coordination sphere. For concentrated solvents, bilogarithmic dependences of distribution coefficients with ligand concentration point out non-integer slopes higher than those expected from stoichiometry. Such features, very often noted for amides, do not seem to be due to new chemical second-sphere species, which has never observed experimentally, but to polyoriented interactions between free ligands and complexes and may be considered as part of non-ideality. 21 refs., 15 figs., 6 tabs.
- Sponsoring Organization:
- USDOE
- OSTI ID:
- 171542
- Journal Information:
- Solvent Extraction and Ion Exchange, Vol. 10, Issue 1; Other Information: PBD: Feb 1992
- Country of Publication:
- United States
- Language:
- English
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