Tungsten Disulfide Prepared from Tungsten Trioxide

Generally, tungsten disulfide can be prepared from tungsten trioxide, using it as the raw material. Tungsten disulfide with different purity can be prepared by this method according to different preparation conditions.

We can prepare tungsten disulfide from tungsten trioxide under the following preparation conditions:

1. Tungsten trioxide, sulfur and potassium carbonate are mixed under the condition of air isolation. Then the mixture is heated and melted at the temperature of 900°C. In this process, it changes from the crystal phase to the liquid phase, which is caused by the increasing kinetic energy of the thermal movement between molecules. And then the melted mixture is cooled, crushed and washed step by step to obtain tungsten disulfide.

However, tungsten disulfide prepared by this method usually has low purity, containing a small amount of tungsten trisulfide or tungsten oxide.

2. Tungsten trioxide is placed in flowing hydrogen sulfide and reacted with it at 900~1200°C for 4 hours, so as to obtain tungsten disulfide. The tungsten disulfide prepared by this method is soft and smooth. The method of preparing tungsten disulfide from tungsten trioxide, sulfur and hydrogen can be expected from this time now.

3. The mixture of tungsten trioxide and sulfur is put into the reaction equipment. Pure tungsten disulfide could not be obtained if the mixture is reacted at 900~1400°C. Part of tungsten disulfide can be obtained by making tungsten trioxide, sulfur and carbon black react under the above conditions for 6-10 hours. However, there may be a problem that the product near the center of equipment is not tungsten disulfide. And then tungsten disulfide with a better quality can be obtained by adding sulfur to the above mixture and processing the new mixture under high temperature.

As for the advantages of this preparation method, he equipment needed is simple and the cost is low. Meanwhile, tungsten disulfide prepared by it has high purity of over 98%.

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