The extraction of plutonium(VI) and plutonium(III) from sulphuric acid by TOA in toluene has been studied as a function of
the acid and tri-octyl amine concentration. A comparison of the extraction properties of plutonium with those of uranium(VI)
and uranium(IV) has been made. It was found that the extraction properties of plutonium(VI) are very similar to those of uranium(VI)
and that TOA is a relatively poor extractant for plutonium(III). Uranium(IV) shows better extraction properties than plutonium(III).
The results obtained are considered in the light of the stabilities of the complexes formed by these elements in the organic
and aqueous phase. A method of separation of both elements by solvent extraction based on changing their oxidation states