The researchers proposed a method for preparing high purity tungsten hexachloride, which requires the following steps: raw material pretreatment, tungsten hexachloride preparation, tungsten hexachloride refining, condensation reception and tail gas treatment.
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A Preparation Method of High Purity Tungsten Hexachloride
Step One: Raw material pretreatment. Screening or sintering to obtain large particle size tungsten powder (> 75um), chlorine gas is preheated while purifying, the temperature rises to 600-1000 °C, screening large particle size activated carbon (> 75um) through high temperature chlorine atmosphere for dehydration and deoxidation treatment. The molar ratio of tungsten powder, chlorine gas and activated carbon is 100: (300-600): (1-20).
Step Two: Tungsten hexachloride preparation. Large particle size tungsten powder and 80% -95% purified high temperature chlorine gas react at the bottom of the chlorination furnace. The chlorination temperature is 600-1000 °C. The generated tungsten hexachloride and tungsten chloride impurities flow out through the gas outlet in the form of steam.
Step three: Tungsten hexachloride refining. The treated activated carbon is filled in the refining furnace, the steam generated by the chlorination furnace and 5% -20% of purified high-temperature chlorine gas are refined in the refining furnace, the refining temperature is 600-1000 °C, and the tungsten oxychloride and low-cost tungsten chloride are reduced in the steam to tungsten hexachloride to obtain refined steam.
Step Four: Condensation reception. The refined steam enters the receiver, and the cooling water is controlled at a temperature of 30-250 °C to obtain high purity tungsten hexachloride powder, and the tail gas is discharged.
Step Five: Tail gas treatment. The tail gas is absorbed by the sodium hydroxide solution in the tail gas absorption tank.
