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【Chinatungsten Online News Net- Tungsten News】

The influence factors of particle size and uniformity of tungsten powder are investigated based on hydrogen reduction theories, and the raw material for producing ultrafine tungsten powder is determined according to analysis of microstructures of different tungsten oxides and contrast experiment. The results show that ultrafine tungsten powder can be prepared under the conditions of forward hydrogen flow, low reduction temperature, high hydrogen flow-rate, low hydrogen moisture and thin batch layer. The special pore structure of tungsten violet oxide gives it good air permeability and enables prompt ventilation of vapors under reduction atmosphere, thus produces fine and epigranular tungsten powder, and yet charging amount and hydrogen flow-rate have little effect on particle size of tungsten powder. Meanwhile, under dry hydrogen atmosphere, tungsten violet oxide can be reduced directly to W without generating WO2, thus enables the production of epigranular ultrafine tungsten powder. The process conditions should be optimized to avoid the generation of WO2 agglomerations. Finally the optimal process condition for producing ultrafine tungsten powder is established by experimental verification, and ultrafine tungsten powder is produced. The methods for preventing oxidation and spontaneous combustion are introduced, and also how to improve production capacity.