Extraction of Uranium(VI) and Plutonium(IV) with Tetra-Alkylcarbamides |
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Authors: | Clémence Berger Dominique Guillaumont Elisabeth Zekri Laurence Berthon |
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Affiliation: | 1. CEA, Nuclear Energy Division, Research Department on Mining and Fuel Recycling Processes, SPDS, LCPE, Bagnols-sur-Cèze, France;2. CEA, Nuclear Energy Division, Physico-Chemistry Department, SECR, LRMO, Gif-sur-Yvette, France |
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Abstract: | ABSTRACTThe use of tetra-alkylcarbamides as novel extractants for the separation of uranium(VI) and plutonium(IV) by solvent extraction from spent nuclear fuels is investigated in this study. Batch extraction experiments show that tetra-alkylcarbamides strongly extract U(VI) with high distribution ratios. Plutonium(IV) can be co-extracted with U(VI) at high nitric acid concentration, while high U(VI)/Pu(IV) selectivities can be reached at lower acidity. Loading capacity experiments with high uranium concentrations show that alkyl chains longer than butyl are necessary to avoid third phase formation. Nevertheless, the viscosity of uranium-loaded solvents gets too high with alkyl chains longer than pentyl. Overall, this study shows that with TPU extractant (with four pentyl chains), an efficient co-extraction of uranium and plutonium can be reached (DU,Pu > 1) for a concentration of nitric acid higher than 4 mol?L?1, while the partition between uranium(VI) and plutonium(IV) could be operated even at 2 mol?L?1 nitric acid without redox chemistry. |
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Keywords: | Carbamide uranium(VI) plutonium(IV) solvent extraction loading capacity |
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