Some studies on the extraction of hexavalent actinide ions from aqueous carboxylic acid media by long-chain amines

The extraction of hexavalent actinides from aqueous carboxylic acid media by tertiary amines was studied. Both U(VI) and Pu(VI) are found to be extracted well whereas Np(VI) was practically inextractable except from acetic acid medium. The absorption spectral studies revealed that the inextractability of Np(VI) is due to its reduction to Np(V). Depending on the diluent used, both tetra and triacetato complexes of U(VI) were found to be present in the organic phase. The absorption spectral studies suggested that the formation of tetraacetato species occurs in the organic phase. An amine extraction method for the separation of U(VI) from a number of metallic impurities using malonic acid medium is suggested.