Patent ID: 6406512
Filing Date: 2002-06-18
Classification: C22B,C25C

Abstract:
A method for producing high-purity niobium by refining crude niobium in an electrolyte consisting of a melt of salts including a complex niobium and potassium fluoride and an equimolar mixture of alkali metal chlorides, said electrolyte further containing sodium fluoride in the amount of from 5 to 15% by weight to obtain a cathode deposit, and subjecting the obtained cathode deposit to electron-beam melting in a vacuum free of oil vapors at a residual gas pressure in the range of from 5*10âˆ’5 to 5*10âˆ’7 mm Hg, a melting rate from 0.7 to 2 mm/min and a leakage into the melting chamber from 0.05 to 0.005 lÂ·&mgr;m/s to produce an ingot of niobium.