RARE-EARTH SEPARATION USING A CHEMICAL-VAPOR TRANSPORT PROCESS MEDIATED BY VAPOR COMPLEXES OF THE LNCL3-ALCL3 SYSTEM

Mutual separations of rare earth chlorides in the Pr-Er, Pr-Sm and Pr-Nd binary systems and the Pr-Gd-Er ternary system were performed using chemical vapour transportation of vapour complexes LnAlnCl3+3n (Ln, rare earths). Heavier rare earth chlorides were more readily transported and concentrated in the deposits in lower temperature zones while lighter ones were selectively deposited in higher temperature zones. Good separation characteristics (efficiency and purity) were observed for the resulting LnCl3 deposits by optimization of temperature gradients for the selective deposition of LnCl3 and by repeating the transport reaction. The separation factors, expressed as atomic ratios for the resulting chlorides, Pr:Er and Pr:Sm, were equal to 10.8 and 2.3 respectively.