Recovery of Waste Residue from Tungsten Disulfide

The waste residue of tungsten disulfide usually contains a large amount of versatile tungsten oxide. So we must attach importance to the recovery of waste residue from tungsten disulfide to avoid resource wasting.

Tungsten disulfide is often prepared from ammonium tetrathiotungstate in industry. In the preparation process, the raw material is firstly dissolved with HCl hydrochloric acid to form tungstic acid. Then tungstic acid is mixed with ammonia water to form ammonium tungstate. Next, ammonium tungstate is added to hydrogen sulfide to form tetrathiotungstate. Finally, tungsten disulfide is prepared by the reduction reaction of tetrathiotungstate by hydrogen in high temperature reflector. According to the data of a factory, the annual output of ammonia solution residue was 8.58 t, and about 0.79 t of tungsten oxide contained in it. Concentrated filter residue was 14.28t, and approximately 9.28 t of tungsten oxide contained in it.

Tungsten oxide is yellow powder. Being insoluble in water, soluble in alkali and slightly soluble in acid, it is the most stable tungsten oxide. Its melting point is 1473°C, the boiling point is higher than 1750°C, and the relative density is 7.16°C. Due to its outstanding physical and chemical properties, tungsten oxide is widely used in industrial production and people's daily life, with extremely high use value:

1. Tungsten oxide has gas sensitivity and is used for the detection of nitrogen dioxide, ammonia and other harmful gases.

2. Tungsten oxide is an intermediate product, which is widely used in the production of metal tungsten products and tungsten alloy products, such as tungsten-copper, tungsten-nickel, tungsten-rhenium, etc.

3. Tungsten oxide is used to produce chemical products such as paints, coatings and catalysts for the petroleum industry. Because of its rich yellow element, it is used as a pigment in ceramics and paints.

4. Tungsten oxide is used to produce electrochromic windows. The windows allow users to adjust and provide them living convenience.

5. Tungsten oxide, a tungstate product, is often used in industrial X-ray screen phosphors, fireproof fabrics, and the preparation of ammonium tungstate.

Obviously, it would be a pity to discard the residue containing tungsten oxide. To recycle the residue, we use them to make tungsten salts and then return the tungsten salts to production. This process not only increased the recovery rate of tungsten, but also greatly increased the economic efficiency.

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