SEPARATION OF URANIUM FROM LANTHANUM IN MOLECULAR AND IONIC ORGANIC LIQUIDS

We have investigated the separation of uranium from lanthanum in two molecular organic liquids (sulfolane, TMSO2; ethylene carbonate, EC) and in one organic ionic melt: ethylammonium nitrate (EAN). A separation is achieved by chemical oxidation and precipitation of oxides in TMSO2; in this medium, the part of uranium remaining in solution may be recovered by an electrochemical reduction. In EAN, it is required to add Li2O to initiate the oxides precipitation: the separation corresponds to the difference between the solubility products Of UO3(s) and La2O3(s). Best results are obtained in EC where the insoluble phase corresponds to an U/La ratio equal to 186 instead of 1.7 in the initial conditions.