Carbonate extraction-based refining of uranium. Separation of U(VI), Ce(IV), and Ln(III) from aqueous carbonate solutions with methyltrioctylammonium carbonate

摘要

The extraction of U(VI), Ce(IV), La(III), Nd(III), Sm(III), and Y(III) from an aqueous solution of Na2CO3 (0.25 mol/L) resulting from oxidative dissolution of U(IV) in the presence of H2O2 into a solution of methyltrioctylammonium carbonate (0.25 mol/L) in toluene. It was found that beta(U(VI)/Ln(III)) values vary from similar to 8 to 3290 as the O : W ratio changes from 2 : 1 to 10 : 1, while beta(U(VI)/Ce(IV)) varies from similar to 1.5 to 10, which allows for the extraction separation of U(VI) from Ce(IV) in a 8- to 10-stage counter-current extraction cascade and from Ln(III) in 2- to 3-stage cascade under the same conditions.