High-purity quartz powder production

High-purity quartz powder has excellent optical, thermal, chemical stability and radiation resistance, so it is widely used in the fields of electronics, optical communications, military, etc. With the development of the electronics, optical communications, lasers, optics and other fields, the demand for high-purity quartz powder is increasing. Melting crystal and high-quality natural crystal have always been the main raw materials for high-purity quartz materials, and the supply of these raw materials is becoming increasingly scarce.

Because vein quartz mineralization is accompanied by many impurity minerals, and the types vary with the mineralization environment, the main impurity minerals are generally feldspar, mica, clay, hematite, etc. At present, quartz micropowder is prepared from quartz veins as raw materials. The process includes raw materials, coarse crushing, fine crushing, pickling, washing, drying, grading, and finished products. The SiO2 content in the quartz powder obtained by this process is 99.0-99.6%, while the SiO2 content in the refined high-purity quartz should reach 99.99%, and the total content of impurity elements is less than 100pm.

Xinhai provides you with a solution for preparing high-purity quartz powder using ordinary quartz veins as raw materials. The specific steps of this method are as follows.

1) Calcination

Use quartz vein as raw material, crush to 200~400 mesh, add appropriate amount of NaCl solid and mix evenly, the amount of NaCl solid added is 2~4% of the mass of quartz vein, and calcine at 800~850℃ for 2~4 hours.

2) Quenching flotation

Pour the calcined material into the flotation liquid while hot for quenching. The flotation liquid used is a mixture of 0.2~0.5g/kg dodecylamine and 0.2~0.5g/kg sodium dodecylbenzene sulfonate. Use dilute sulfuric acid to adjust the pl value to 2~3. The mass ratio of flotation liquid to quartz powder is 3~10:1. The flotation time of quartz powder in the flotation liquid is 3~10 minutes, and the temperature is maintained at 10~70℃.

3) Acid leaching

Transfer the quartz powder at the bottom of the above flotation liquid to the mixed acid solution and soak it at 10~60℃ for 6~12 hours. The mixed acid used is a mixed solution of 10~20% hydrochloric acid and 1~5% hydrofluoric acid. The mass ratio of mixed acid to quartz powder is 2 to 6:1.

4) Complexation

The above acid-leached quartz powder is transferred to the complexing solution and soaked at 10 to 60°C for 3 to 8 hours. The complexing solution used is a mixture of 0.2 to 1% citric acid and 0.2 to 1% lauric acid. The mass ratio of the complexing solution to the quartz powder is 1 to 5.

5) Washing and drying

The quartz powder soaked in the above complex solution is taken out, washed with deionized water, and dried to obtain a high-purity quartz powder product. The SiO2 content in the product is greater than 99.99%, and the total impurity content is less than 100ppm.

By treating the quartz powder, electronic and microelectronic grade high-purity quartz powder can be produced. The preparation process uses high-temperature calcination with NaCl solid, rapid cooling, flotation, acid leaching, complexation and impurity removal to make the SiO2 content reach 99.99%, the total impurity content is less than 100ppm, and the product performance is excellent, which can be used in the microelectronics and optical communication industries.