METHOD OF HIGH-PURITY NIOBIUM PRODUCTION Russian patent published in 2000 - IPC

FIELD: metallurgy of refractory rare metals, particularly, niobium metallurgy; applicable in production of high-purity niobium and articles from niobium for SHF engineering and microelectronics. SUBSTANCE: method includes electrolytic refining of crude niobium in salt melt containing potassium fluoroniobate and equimolar mixture of potassium and sodium chlorides, and subsequent electron-beam melting of cathode deposit in vacuum. Added to electrolyte is sodium fluoride in amount of 5-15 wt.%. Electron-beam melting of cathode deposit is carried out in oil-free vacuum at pressure of residual gases of 5.10^-5-5.10^-7 mm Hg, with inleakage in melting chamber of not in excess of 5.10^-2 l.mcm/s and melting rate 0.7-2 mm/min. In manufacture of articles, obtained ingot of niobium is subjected to plastic metal working at temperature of 300-800 C and to heat and chemical treatment. The method allows to produce high-purity niobium and articles from it with total content of impurities 0.002-0.007 mas.%. EFFECT: higher yield of niobium with reduced losses. 3 cl, 5 tbl, 1 ex