ACTINIDE AND LANTHANIDE EXTRACTION FROM NITRIC-ACID SOLUTIONS BY FLOTATION

Flotation of thorium, plutonium(IV), uranium(VI) and gadolinium from aqueous nitric acid solutions (HNO3 concentration from 0.01 to 5.0M) was investigated using lauryl phosphoric acid (LPA) as a SAS-collector. It is established that the extent of removal of the metal ions increases with the amount of LPA introduced, regardless of the solution acidity. At a fixed mole LPA to metal ratio the extent of uranium(VI) and gadolinium removal is reduced with increasing acidity, while in case of plutonium(IV) and thorium this parameter remains constant. It is shown that in principle approximately 100% extraction of plutonium(IV) and thorium by flotation is possible regardless of the acidity of aqueous solutions. Ca(NO3)2 added to the system in the amount of 0.5M does not significantly affect the flotation extraction of thorium.