Simple Method for Producing Tungsten Trioxide

Tungsten trioxide is mainly used for calcination and reduction to produce tungsten powder and tungsten carbide powder, which are then used to produce high-melting-point alloys and hard alloys. With the progress of industry, the demand for ultrafine tungsten oxide and its downstream tungsten powder products is increasing, market demand for ultrafine tungsten oxide and its downstream tungsten products is increasing. 

Or from the price point of view, the price of nanometer ultrafine tungsten powder is 1-2 times higher than that of ordinary tungsten powder, and the profit rate is even higher. This is also the power for enterprises to develop ultra-fine tungsten powder.

As a precursor of tungsten powder, tungsten powder and tungsten trioxide granularity with inheritance, so if there is any method does not require large area update equipment can produce ultra-fine tungsten trioxide? This article will briefly introduce a scheme with the following processes:

(1)Seed preparation: using organic acid or inorganic acid to adjust the sodium tungstate solution with mass concentration of 45% to make the solution pH to 4 to 8 and hydrothermal reaction for 12 hours, the obtained precipitates were filtered, concentrated and crystallized to obtain seeds.

(2)Material ratio: adding crystal seed to sodium tungstate solution with mass concentration of 10% ~ 55%, the ratio of the quality of sodium tungstate in the crystal and solution is 1:4.5;

(3)Hydrothermal reaction: in the autoclave, the mixture of crystal seed and sodium tungstate in step reactor (2) is heated at 200~220 degrees, and then cooled to room temperature after 12 hours of hydrothermal reaction, and then the slurry of reaction product is obtained.

(4)Filtration and separation: filter and wash the reaction products, and the filter cake and mother liquor are obtained.

(5)Low-temperature roasting: The filter cake was calcined at a low temperature of 350°C to obtain an ultrafine tungsten trioxide product;

(6) Mother liquor concentration: The mother liquor and the filter cake washing liquid are combined and concentrated to obtain a mother liquor having a sodium tungstate concentration of 3% to 20%, it is also used in the preparation of tungsten trioxide for the preparation of 10% to 55% sodium tungstate solution.

Ultra-fine tungsten powder with a particle size of 0.2-0.7 um can be produced by the above method. Compared with the production process of traditional ultra-fine tungsten trioxide, this solution has a short process flow, low energy consumption, high purity, and stable quality.

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