Extraction and Mutual Separation of Rare Earths from Used Polishes by Chemical Vapor Transport

A dry recovery process tor rare earths from used polishes has been investigated by using a chemical vapor transport method via the formation of vapor complexes RAl(n)Cl(3+3n) (R = rare earth). The used polishes were chlorinated with N^ + Cl^ gas mixture at 1273 K, and the resulting rare earth chlorides were transported chemically with the vapor complexes along the temperature gradient. Most rare earth chlorides, AlCl(3), and FeCl(3), were transported during 82 hours of heating. The rare earth chlorides were mainly condensed over the temperature range of 1220 to 730 K. On the other hand, AlCl(3) and FeCl(3) were deposited at temperatures below 400 K.. The highest LaCl(3) and CeCl(3)., purity of about 80 pct was obtained in the process.