New areas of advanced science and technology, for example, semiconductors, microelectronics, optoelectronics, superconducting materials, vacuum technology, nuclear metallurgy, space industry, require materials, metals and their special alloys and compounds with high chemical purity and defined physical and structural parameters and specific applied properties. The “Metallurgy of pure metals” is a subject of university courses dealing with methods of refining and preparation of high purity substances. A special attention is paid not only to the high degree of chemical purity attainable by chemical or physico-chemical or hydrometallurgical methods, such as sorption, extraction, crystallization from aqueous solutions, electrolysis, and also by pyro-metallurgical methods such as crystallization from melts, evaporation, condensation and transport reactions, electro-transport, diffusion separation of substances, removal of gases from melts and vacuum refining of metals.