Commissariat a L'energie Atomique

Bernard Mauborgne

Pascal Baron

Xavier Heres

Michael Lecomte

Claude Ginisty

Michel Marteau

The invention concerns a cyclic method for separating at least one chemical element Efrom at least one chemical element Efrom an aqueous solution containing said elements, which employs a mixture of two extractants operating in non-overlapping chemical fields. Each cycle of said method comprises: a) co-extracting elements Eand Eby means of an organic phase containing a first extractant suited to causing the migration of said elements into said organic phase; b) adding to the organic phase a second extractant suited to selectively retaining the element(s) Ein said organic phase during step c): c) selectively stripping the element(s) Efrom the organic phase; d) selectively stripping the element(s) Efrom the organic phase; e) separating the first and second extractants present in said organic phase at the end of step d).

Cyclic method for separating chemical elements present in an aqueous solution

Process for the recovery of uranium (VI) present in a phosphoric acid solution by contacting the latter with an organic solvent able to extract uranium, the organic solvent comprising a system of extractants constituted by a neutral phosphine oxide and an acid organophosphorus compound. The process comprises a re-extraction stage for the uranium extracted in the organic solvent, said re-extraction stage being performed in a re-extraction apparatus comprising at least two stages in which the uranium-containing organic solvent is circulated in the said stages by introducing it into the first stage, an aqueous ammonium carbonate solution is circulated in countercurrent with respect to the organic solvent in the said stages by introducing it into the final stage in a quantity such that it represents 50 to 80% of the stoichiometric quantity necessary for neutralizing the acid organophosphorus compound and for transforming the uranium present in the organic solvent into uranyl ammonium tricarbonate, ammonia being added in the form of a gas or an aqueous solution to the ammonium carbonate solution circulating in the first stage in order to keep the pH of the final stage as a value between 8 and 9.5 and preferably between 8 and 8.5.

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Equeurdreville Hanneville, France

Bernard Mauborgne