Improving the Preparation Method of Tungsten Oxide Reduction Fluidity

At present, the main equipments for producing tungsten powder are propulsion reduction furnace and rotary reduction furnace. The feeding way of a propelled reduction furnace is to place tungsten oxide in a boat, feed and discharge through the the push rod. The feeding mode of the rotary reduction furnace is to put tungsten oxide into the inlet of the reduction furnace and use its own gravity to flow itself into the furnace tube, which has a high requirement for the fluidity of tungsten oxide.

In order to improve the fluidity of tungsten oxide, improve the automation of tungsten powder production and reduce the production cost of tungsten powder, the researchers have improved a set of tungsten oxide reduction method to achieve the target effectively.

(1) With ammonium tungsten compound as raw material, calcined in a vacuum closed calciner, the furnace temperature is controlled by gradient type. The calcining process has 2-6 temperature control belts, the temperature of the feed end is 700 -800°C, the temperature of the discharge end is 500 C -700°C, the difference between the front temperature zone and the post temperature zone is 0-300°C.

(2) The degree of vacuum (0.1-1.5) * 104Pa in the furnace of the calciner is non oxidizing atmosphere in the hearth of the calciner.

(3) Feeding rate of raw material is 50-250kg/h.

(4)  Calcine for 20-50min in the calciner with the closed negative pressure.

(5) The furnace charge is cooled by cooling water jacket after calcining furnace, and then the furnace is oxidized. After that, the tungsten oxide whose fluidity is less than 30s/50g is obtained.

The tungsten oxide produced has high fluidity, which effectively solves the problem of uneven feeding of automatic feeding equipment and uneven weighing of automatic weighing equipment. The automation level of tungsten powder production is increased, the labor intensity of workers is reduced, and the production cost of tungsten powder is reduced. 

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