METHOD FOR PRODUCING NIOBIUM AND/OR TANTALUM POWDER

PROBLEM TO BE SOLVED : To obtain a niobium and/or tantalum powder which is fine when it is in the form of primary particles, has a primary particle diameter as fine and uniform as 0.1 to 1.0 μm, has a low oxygen content, and is desirable for use in electrolytic capacitors. SOLUTION : The method for producing the niobium and/or tantalum powder comprises reducing niobium and/or tantalum oxides with an alkali metal or an alkaline earth metal in two divided stages. In the first stage reduction, a niobium and/or tantalum lower oxide powder comprising (Nb, Ta)Ox (wherein x is 0.06 to 0.35) is obtained, and the alkaline earth oxide formed from the reaction is removed. In the second stage reduction, the reaction mixture reacts with a reducing metal comprising a molten alkali metal or a molten alkaline earth metal in the presence of a molten alkali salt and/or a molten alkaline earth metal salt.