Tungsten Oxide with Low Specific Surface Area Preparation

The super coarse tungsten powder is the main raw material for the production of coarse grain cemented carbide, and its downstream products are widely used in mining tools, stamping dies, oil drilling and hard surface materials and so on.

Tungsten trioxide, as raw material for producing tungsten powder and tungsten carbide powder, plays an important role in granularity control of tungsten powder. Tungsten oxide with high specific surface area is used to produce ultrafine tungsten powder and tungsten oxide with low specific surface area is used to prepare ultra coarse tungsten powder. Controlling the specific surface area of tungsten powder is helpful for producing ultrafine or ultra coarse tungsten powder. This paper mainly introduces a technology for preparing tungsten powder with low specific surface area.

(1) With ammonium tungsten compound as raw material, the calcined furnace is calcined in a vacuum closed calciner, and the furnace temperature is controlled by gradient type. The calcining process has 2-6 temperature control belts, which are 300°C, 300°C, 650°C, 650°C, 700°C, 750°C, and the temperature difference between the post temperature zone and the front temperature zone is 0℃-500℃.

(2) Furnace vacuum degree (0.1-1.5) * 104Pa, proceed aerobic calcination.

(3) Calcined raw material ammonium tungsten compound, Fisher particle size Fsss:30-60μm, raw material feeding speed 50-250kg/h.

(4) The calcining time is 20-50min.

(5) The furnace charge is cooled by cooling water jacket after calcining furnace and then discharged. Then the tungsten trioxide with a surface area less than 1m2/g is obtained after sifting.

The low specific surface area of tungsten oxide is helpful for the production of ultra coarse tungsten powder. Ultra coarse tungsten powder is the main raw material for the production of coarse crystalline cemented carbide. Its downstream products are widely used in mining tools, stamping dies, oil drilling and hard surface materials and other fields. 

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