ALPHA-BENZOINOMIXE - EXTRACTING AGENT FOR URANIUM(VI), TUNGSTEN(VI), MOLYBDENUM(VI) AND SOME TRANSITION-METALS OF THE IRON FAMILY

The effect of pH on the percent extraction of vanadium(V), iron(II), cobalt(II), nickel(II), copper(II), molybdenum(VI), tungsten(VI) and uranium(VI) by alpha-benzoinoxime in different solvents has been studied. The maximum recovery is not appreciably affected by the nature of the solvent, but occurs at different pH values for different metals. The pH corresponding to maximum extraction increases with increasing hydrolysis pK of the species in aqueous solution, and decreases with increasing stability constant of the complexes formed. Alpha-benzoinoxime allows the separation of these metal ions into three groups: V(V), Mo(VI) and W(VI) are extracted at pH = 2, U(VI) at pH = 5, Fe(II), Cu(II), Co(II) and Ni(II) at around pH = 10.