Hydrogen reduction is the earliest method for preparing rare metals such as tungsten and molybdenum. And the hydrogen reduction of tungsten hexachloride is the most noticeable method in the preparation of ultrafine tungsten powder at home and abroad.
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Some researchers used metal tungsten powder as a raw material to heat the reactor under the condition of passing hydrogen. The temperature of the chlorination section was heated to 800 °C for heat preservation and the reduction section was heated to 1000 °C. After the temperature rises to the required temperature, keep it warm for 1 h to effectively remove the water. Then, the outer tube continues to pass hydrogen, and the inner tube removes hydrogen and pass through argon. After the hydrogen in the inner tube is exhausted, chlorine gas can be passed into the inner tube along with ammonia gas. At this time, chlorine gas reacts with the raw material tungsten to form a gaseous mixture of tungsten hexachloride and tungsten pentachloride. And tungsten chloride mixture flows into the outer tube of the reduction section from the inner tube with argon gas, and meets the preheated hydrogen in the outer tube to have a gas phase reaction to obtain ultrafine tungsten powder.
