High Purity Tungstic Acid Purification Program

Tungstic acid is an important basic chemical raw material, and it is widely used. As mordant, it is used in pigments, dyes and inks, and as a cosolvent to introduce enamel pigments to reduce firing temperature and complement color. Textile industry is used as fabric weighting agent, fabric additives, and mixture of tungstic acid, ammonium sulfate, ammonium phosphate, etc. is used for fire prevention and waterproofing of fibers, making fire-proof rayon and artificial cotton. 

Tungstic acid, as an inorganic non-metallic material, can be used in the manufacture of petroleum industry, aviation and aerospace materials. Especially with the development of aerospace, analytical science and catalysts, the demand for high purity tungstic acid is increasing.

Despite the high demand, the corresponding requirements for the purity of tungstic acid for industrial use are also very high. Unfortunately, over the years, the high purity tungstic acid products in China mainly rely on imports, but this phenomenon has improved in recent years. For example, some scholars have developed a method to purify tungstic acid, which can easily produce 5N-grade high-purity tungstic acid. The main processes are as follows:

The first step is to put the tungstic acid raw material into the inorganic acid solution. The mass ratio of the inorganic acid solution to the tungstic acid raw material is 1:1-2:1, the ultrasonic irradiation shocks for 3h-6h, the temperature is controlled at 20 ~40 ℃, and the filter cake solid is obtained.

The second step is to put the filter cake solid obtained in the first step into the inorganic acid solution. The mass ratio of the inorganic acid solution to the filter cake solid obtained in the first step is 1:1-3:1. The filter cake solid is filtered by ultrasonic irradiation for 5-10 hours and the temperature is controlled at 30-50 degrees Celsius.

Thirdly, the solid obtained in the second step is washed in deionized water for 2-3 times, filtered under vacuum, and dried in vacuum for more than 10 hours at 60-80 ℃. The purity of tungstic acid is more than 99.999%.

Using 99.95% tungstic acid as raw material, acid solvent washing combined with ultrasonic cavitation effect was used to remove impurities efficiently. The purity of the purified product was over 99.999%. The yield of high purity tungstic acid was over 90%. Moreover, the main advantage of domestic technology is that it does not involve the chemical reaction of the product itself. It has the advantages of simple process, economic and environmental protection, and high purity of the product. It provides an effective method for preparing high purity tungstic acid products.

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