China Nonferrous Metallurgy

Scandium is an important rare earth element widely used in structural materials such as alloys and ceramics, as well as functional materials such as fuel cell electrolytes and radio frequency filters. In this paper, the preparation methods of scandium fluoride and anhydrous scandium chloride are introduced successively, and then the metal thermal reduction process of scandium halide and the treatment methods of different impurities in crude scandium distillation and purification are described in detail. Then, the further purification and impurity removal methods using zone melting, electromigration and vacuum electron beam melting technologies are discussed. Comparing with calciothermic reduction technology with scandium fluoride, the magnesiothermic reduction technology with scandium chloride to prepare metal scandium has the advantages of low temperature, environmental friendliness and low cost. In the future, the research on the preparation of metal scandium can be focused on the metal thermal reduction of anhydrous scandium chloride. The impurity elements can be removed by multiple high temperature vacuum distillation and electron beam melting, so that the purity of metal scandium can reach 4N or even 5N level. Vacuum electron beam melting, relay zone melting and other technologies have broad development prospects in the preparation of ultra-high purity metal scandium and other rare earth metals.