H.c. Starck Gmbh

H. C. Starck, Gmbh & Co Kg

Frank Behrens

Josua Löffelholz

Siegfried Schmieder

The invention relates to the production of valve metal powders, in particular, tantalum powders by reduction of a corresponding valve metal compound, for example, KTaF, with an alkali metal in the presence of a diluent salt, whereby the reduction is carried out in the presence of a particle diminution agent, preferably, NaSO, which is added to the reaction mixture continuously or in aliquots.

Production of valve metal powders

The process comprises the reduction of niobium and/or tantalum oxides by means of alkaline earth metals and/or rare earth metals, wherein the first reduction stage is carried out as far as an average composition corresponding to (Nb, Ta)O.sub.x where x=0.5 to 1.5 and before the second stage the reduction product from the first stage is freed from alkaline earth oxides and/or rare earth metal oxides which are formed (and optionally from excess alkaline earth metal and/or rare earth metal) by washing with mineral acids.

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Goslar, Germany

Frank Behrens