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How to make tungsten disulfide in a variety of ways?

wallpapers Industry 2021-04-01
Tungsten disulfide manufacturing conditions
Tungsten disulfide is a brown or black crystalline powder. It is mainly used as a lubricant. It has a low coefficient of friction and high compressive strength. It still has lubricity at 1316°C. Filling materials formulated with polytetrafluoroethylene and nylon can be used for self-made lubricating parts. Tungstic acid reacts with ammonia water to generate ammonium tungstate and then reacts with hydrogen sulfide to generate ammonium tetrathiotungstate, which is decomposed into the product after high-temperature roasting.
 
Three preparation methods of tungsten disulfide
1. Roasting decomposition method:
Tungstic acid reacts with ammonia water under stirring at 57-60°C for 3h, heat preservation, and natural sedimentation for more than 16h, and the generated ammonium tungstate reacts with hydrogen sulfide gas to generate ammonium tetrathiotungstate after high-temperature roasting and decompose into tungsten disulfide. The chemical formula of the reaction is as follows:
H2WO4+2NH3·H2O→(NH4)2WO4+2H2O
(NH4)2WO4+4H2S→(NH4)2WS4+4H2O
2(NH4)2WS4+3O2→2WS2+4NH3+2S+2SO2+H2O
 
2. Tungsten reacts very slowly with liquid sulfur. WS2 can be formed by passing sulfur vapor to red hot tungsten. Tungsten is mixed with stoichiometric sulphur bloom and reacted in a nitrogen atmosphere at 800°C for 24 hours to form WS2, such as reacting at 6MPa and 1800°C to form orthorhombic WS2.
 
3. Using ammonium tetrathiotungstate as the raw material, heating and decomposing the ammonium tetrathiotungstate under the condition of isolating the air, the temperature rises from room temperature to 700-1200℃ with a temperature gradient of 100-200℃/hour during heating. After being kept at this temperature for 24 to 48 hours, it is then reduced to room temperature with a temperature gradient of 30 to 110°C/hour, and the material is discharged and crushed.
 
The preparation method of ultrafine scaly crystal tungsten disulfide used for lubricants has simple process equipment, does not pollute the environment, and is safe and reliable in operation, and can produce tungsten disulfide with stable quality, high purity, and ultrafine crystal structure of hexagonal crystal system.

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Tag: WS2