Effet de la température sur l’efficacité de la séparation chromatographique de certaines paires de terres rares

Abstract

The ratios of the stability constants of the EDTA and HEDTA complexes of the rare earths have been established for several pairs of these elements. At 25°, the pair Eu-Gd cannot be satisfactorily separated on ion exchangers by means of EDTA as eluant; the separation is easy at 75°.
At room temperature, the stability of the HEDTA complex of yttrium is almost the same as that of neodymium but differs markedly from that of samarium; at 70°, the situation is just inverted. Eluation at 50° may provide the best conditions for obtaining pure yttrium using HEDTA as an eluant.