Single and multicomponent equilibrium data for the extraction of SmCl3, NdCl3, and CeCl3 in acidic chloride solutions with DI-(2-Ethylhexyl) phosphoric acid

Abstract

The extraction equilibria of the lanthanide chloride systems MC13-HC1-H2O-1 M D2EHPA (in mineral spirits), where M designates Sm, Nd, and trivalent Ce cations, was studied over an extensive range of concentrations. The metal aqueous concentration was varied from 0.05 to 2.0 M and the aqueous acidity ranged from 0.3 to 1.0 M. The equilibrium curves, with the aqueous acidity as a parameter, exhibit a behavior typical of other lower lanthanides. Further, trivalent cerium behaves the same as other trivalent rare earths. A study of the binary extraction systems Sm-Nd, Sm-Ce, and Nd-Ce indicate that the separation factor remained nearly constant for all conditions studied. The arithmetic averages were βsm.Nd ∼ 8.4, βNd.Ce ∼ 2.0, and βsm.Ce∼ 18.9. In the ternary system Sm-Nd-Ce, the separation factor of each combination pair of elements remained essentially constant for all conditions studied. Furthermore, the separation factor of each pair of elements in the ternary system remained the same as in the case where each pair of elements is extracted together.