Vapor Phase Extraction and Mutual Separation of Rare Earths Using Chemical Vapor Transport Mediated by Vapor Complexes

摘要

A dry process for rare earth separation was investigated using a chemical vapor transport reaction mediated by metal halide vapor complexes. After the chlorination of raw materials containing rare earths at elevated temperatures, rare earth chlorides (RCl_3) were converted to the vapor complexes, KRCl_4(g) or RAl_nCl_(3+3n)(g), and were transported along temperature gradients. Chlorides of heavier rare earths including yttrium are generally more readily transported and concentrated in the deposit at the lower temperature fractions (973-1173 K), and lighter ones at higher temperature fractions (> 1173 K).