THE POSSIBILITY FOR SEPARATION OF LANTHANUM BY SOLID-STATE COMPLEXES WITH 2-ETHYLHEXYL PHOSPHORIC-ACIDS

The elemental composition, molecule, and crystal structure of precipit ates obtained from an acetone solution of Ln(NO3)(3) (Ln = Pr + Er or La + Nd) with a mixture of bis- and mono-(2-ethylhexyl) phosphoric aci ds and their sodium salts were studied. In this study we found enrichm ent of the precipitate with the heavier lanthanide. The separation fac tor for the La-Nd couple is much greater than for the Er-Pr couple, an d decreases with increasing rare-earth yield in the precipitate. We di scuss the significant role of the stability of LnA(3) against HNO3, es pecially the formation of La complexes with mono-(2-ethylhexyl) phosph oric acid during enrichment.