Niobium and tantalum

Some aspects of the chemistry and the technology of niobium and tantalum are considered. They were shown to be close in chemical and physical properties by considering their compounds with oxygen, halogens, nitrogen, hydrogen, sulfur. Data are presented on the corrosion resistance of Nb and Ta in various media. Discussed are the major applications of niobium and tantalum in the atomic energetics, chemical machine-building, as basic components of heat-resistant alloys. Considered are the principal methods for enrichment of tantalum-niobium ores, reprocessing of concentrates to niobium and tantalum compounds and reprocessing of ferroniobium. Reviwed are methods for extraction separation of niobium and tantalum, such methods being based on differences in volatility of halogens and on exchange reactions. Industrial techiques for obtaining metallic niobium and tantalum are described