Synergistic extraction of uranium(VI) by lower fatty acids in the presence of amines and its separation from some lanthanides

The synergistic extraction of UO₂(II) in a chloroform solution of propionic, butyric and valeric acids (HA) in the presence of some aliphatic and aromatic amines (B) has been investigated. The effect of various variables, like the concentration of hydrogen and metal ion, carboxylic acid and amine on extraction has been studied. The composition of the synergistic adducts has been determined on the basis of slope analysis and the species is proposed to be UO₂A₂B₂ 2HA. The extraction constants (K_ex) have been calculated and the relative effectiveness of the amines as synergists is compared. Extraction data have been used to separate UO₂(II) from lanthanides, like Ce(III), Nd(III), Gd(III), Eu(III) and Yb(III).