VALVE METAL OXIDE POWDER AND METHOD OF PREPARING SAID POWDER Russian patent published in 2010 - IPC C01G1/02 C01G33/00 C01G35/00 

FIELD: chemistry.

SUBSTANCE: invention relates to preparing powder of valve metal oxide and can be used for preparing powder of valve metal or valve metal superoxides through reduction. The valve metal oxide is Nb₂O₅ or Ta₂O₅. The valve metal oxide powder contains spherical particles with average diametre D₅₀ = 10-80 mcm with specific BET surface area equal to at least 10 m²/g. The method of preparing valve metal oxide powder involves reacting a fluorine-containing compound of a valve metal, taken in form of H₂NbF₇ or H₂TaF₇, with an aqueous solution of ammonia with concentration of 3-15 wt % and calcination of the product. The reaction is carried out continuously at temperature of at least 45°C in a single reaction vessel. The fluorine-containing compound of valve metal is added in form of an aqueous solution with concentration of 0.3-1.2 mol/l in terms of valve metal. The ratio of bulk speed of the aqueous solution of the fluorine-containing compound of valve metal to the bulk speed of the aqueous solution of ammonia ranges from 1:0.9 to 1:2. Molar ratio of concentration of the fluorine-containing compound of valve metal, in terms of valve metal, to ammonia preferably ranges from 1:5.6 to 1:8.5.

EFFECT: obtaining valve metal oxide powder with spherical particles and high value of specific BET surface area with relatively large particles.

4 cl, 3 dwg, 7 ex