Article ID



Needle-like Powder Preparation of Ta and Nb in the Molten Salt


T. Nishiyama, R. Ishii, R. O. Suzuki, K. Takayama and K. Ono


Proc. of 2000 Powder and Powder Metallurgy World Congress, (13-18 Nov. 2000, Kyoto, Japan), Ed. by K.Kosuge and H.Nagai, (Jpn. Soc Powder and Powder Metallurgy, Tokyo, Japan) pp.513-516, (2000).


A process to produce tantalum and niobium powder continuously is proposed and its applicability is examined experimentally. The method is based on the chemical reaction with a molten magnesium and TaCl5 or NbCl5 gas. The solid TaCl5 is injected into the molten salt in which a molten magnesium is saturated as the reductant. Bubbles of gaseous TaCl5 were spread out in the salt and reacted with Mg. When TaCl5 gas reacted directly with the liquid Mg layer, the spherical Ta particles with a sub-micron size were well separated from Mg and could be recovered from the bottom of the molten salts. When TaCl5 dissolved into the salt as cation, a needle-like crystals of Ta were preferentially precipitated.