Method for extracting uranium (VI) and actinide (IV) from organic solution through oxalic acid precipitation

A method of extracting U (VI) and An (IV) from an organic solution in which U (VI) and An (IV) are present as nitric acid U (VI) and nitric acid An (IV) at a concentration such that the concentration of nitric acid U (VI) is higher than the concentration of nitric acid An (IV) and the sum of the concentrations of nitric acid U (VI) and nitric acid An (IV) is > = 55 g/L, said organic solution comprising tributyl phosphate in an organic diluent, the present invention relates to a method for preparing an aqueous solution comprising:-contacting at least once between an organic solution and an aqueous solution comprising nitric acid in the range of 2 to 6 mol/L and oxalic acid at a concentration of > = 18 g/L, with an O/A volume ratio > = 1, selecting the concentration of oxalic acid and the O/A volume ratio in the aqueous solution such that oxalic acid is deficient with respect to stoichiometric conditions for complete precipitation of U (VI) and An (IV), thereby obtaining a precipitate comprising An (IV) in oxal