METHOD OF PRODUCING NIOBIUM POWDER Russian patent published in 2013 - IPC B22F9/22 C22B34/24 

FIELD: process engineering.

SUBSTANCE: invention relates to nonferrous metallurgy and may be used for metallothermic production of nanocrystalline niobium powders, mainly, for electrolytic capacitors. Niobium oxide compound, magnesium or calcium niobate, is reduced by vapors of magnesium or calcium. Reduction by magnesium vapors is carried at 600-950°C and by calcium vapors at 950-1050°C for 2-9 hours. Said reduction is performed in either vacuum at residual pressure of 1.3-13.3 Pa or atmosphere of argon or helium at 1-50 kPa. Reduction products are processed by solution of mineral acid to remove formed magnesium or calcium oxides. Obtained powder is flushed with deionised water to neutral state and dried.

EFFECT: niobium powder specific surface increased to 73 m²/g that corresponds to niobium particle size of 9,6 nm, content of magnesium and calcium impurities makes (8-31)·10^-4 and (7-15)·10^-4 wt %, respectively, oxygen content does not exceed 0,27 wt % per m².

4 cl, 10 ex, 1 tbl