Process for improving the flowability and increasing the bulk density of high-surface area valve metal powders

Process for improving the flowability and increasing the bulk density of a high-surface area valve metal powder of capacitor quality suitable for being subjected to powder-metallurgical processing by compacting and sintering to produce a sintered anode, which comprises admixing with said valve metal power an additive for increasing the flow properties and bulk density of the valve metal powder, said additive consisting essentially of finely divided extraneous metal oxide in a quantity of up to 5000 ppm (relative to the quantity of metal) before the powder-metallurgical processing of the valve metal powder, said extraneous metal oxide being amorphous pyrogenic silica, aluminum oxide, talc powder, magnesium oxide or a combination thereof, or the combination of titanium dioxide and one or more of said other extraneous metal oxides.