Separation of Trivalent Actinides from Lanthanides in an Acetate Buffer Solution Using Cyanex 301

The separation of trivalent actinides from the lanthanides using the active extractant in the Cyanex 301 reagent, bis(2,4,4-trimethylpentyl)dithiophosphinic acid, was studied. Specifically, the extractant was studied with an ammonium acetate/acetic acid buffered feed that would result from a transuranic separation process utilizing an ammonium acetate strip solution. Separation factors of 241 Am from 154 Eu with this extractant, as a function of total acetate concentration and pH, have been measured. Additionally, the extraction behavior of stable La, Ce, Pr, Nd, Sm and Eu was measured. Separation factors were typically very high for Am from Eu at a pH ranging from 3.8 to 5.8 and a total acetate concentration ranging from 0.2M to 1.0 M. However, separation factors across the lanthanide series varied considerably and resulted in separation of the lighter lanthanides from the heavier lanthanides at the higher pH's.