A REVIEW OF THE EXTRACTIVE METALLURGY OF NIOBIUM

BS>The preparation of niobium was attempted by a number of chemical and electrochemical routes. Chemical reduction of oxides and halides such as Nb/sub 2/O/sub 5/, K/sub 2/NbOF/sub 5/, K/sub 2/NbF/sub 7/, and NbCl/sub 5/ was conducted with varying degrees of success. Aqueous electrochemical reduction has not yet yielded a metallic deposit. The electrolysis of molten baths containing K/sub 2/NbOF/sub 5/ or K/sub 2/NbF/sub 7/ produced niobium metal. The more promising methods of preparation for Nb metal at the present time include the reaction of Nb/sub 2/O/sub 5/ with C, the H/sub 2/ and active metal reduction of NbC1/sub 5/, and electrolysis of K/sub 2/NbF/sub 7/- NaC1 melts. (auth