How to Prepare Tungstic Acid with Calcium Tungstate?

Calcium tungstate is a very important chemical raw material, which is mainly used to produce ammonium paratungstate, tungsten trioxide, ferrotungsten, alloy steel, hard alloy, tungsten material, tungsten wire and tungsten alloy. It can be concluded that calcium tungstate is a kind of substance with wide application, and the preparation of tungstate from calcium tungstate is also a very interesting process.

Calcium tungstate is a kind of white powder, which can be slightly dissolved in water and ammonium chloride, and can also be decomposed in hot hydrochloric acid. Therefore, the method of producing tungstic acid with it is extended, which decomposes in hot hydrochloric acid, and then goes through a series of steps to achieve the purpose.

Calcium tungstate can be decomposed into tungstate and calcium chloride by hydrochloric acid. The solubility of tungstate in hydrochloric acid is very small, but calcium chloride is completely dissolved in hydrochloric acid. Tungstate can be obtained by separating tungstate and calcium chloride. In the reaction process, a certain acidity and temperature should be controlled. Too low acidity is easy to cause incomplete decomposition of calcium tungstate, so that the generated tungstic acid contains high impurities; too low temperature is easy to generate white colloidal tungstic acid, which makes it difficult to filter and wash tungstic acid, and the white colloidal tungstic acid has large volume, fine particles, and easy to absorb impurities in the solution.

After decomposition, the Yellow tungstic acid is filtered by vacuum filtration and washed for many times to remove the adsorbed impurities. Calcium tungstate can be decomposed into tungstate and calcium chloride by hydrochloric acid. The solubility of tungstate in hydrochloric acid is very small, but calcium chloride is completely dissolved in hydrochloric acid. Tungstate can be obtained by separating tungstate and calcium chloride. In the process of reaction, a certain acidity and temperature should be controlled. If the acidity is too low, the decomposition of calcium tungstate will be incomplete, and the tungstic acid produced will contain high impurities.

When the temperature is too low, it is easy to generate white colloidal tungstic acid, which makes it difficult to filter and wash tungstic acid, and the volume of white colloidal tungstic acid is large, the particles are fine, and it is easy to absorb impurities in the solution; after decomposition, the Yellow tungstic acid generated is filtered by vacuum filtration and washed for many times to remove the adsorbed impurities.

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