Preparation of Rare-Earth and Yitrium Metals by Electrodeposition and Vacuum Distillation of Alloys

摘要

Gadolinium, dysprosium, and yttrium are difficult to electrowin as high-purity liquid metals because of their high melting points. The rare-earth metal was electrodeposited on a solid manganese, chromium, or iron cathode to form a low-melting alloy. The alloy was then vacuum distilled to separate the rare-earth metal from the ferrous metal. A typical samarium metal product, obtained as the distillate from vacuum distillation of a samarium-iron alloy, contained 150 ppm oxygen, 80 ppm carbon, and 50 ppm iron as impurities. Gadolinium metal, obtained as a residue from the distillation of a gadolinium-chromium alloy, contained 300 ppm oxygen, 200 ppm carbon, and 100 ppm chromium. (Author)