摘要
High-purity RE oxides are usually ob-tained by dissolving mixed RE oxides inhydrochloric acid,and the obtained chlo-ride solution is then extracted and se-parated after the non-rare earth impuri-ties,especially the high content Pb<sup>+2</sup>,have been removed.This process is oneof the keys to the improvement of theproduct quality.Some smelters use butylxanthate as a purifying agent,but largequantities of poisonous gases are evol-
