Quartz sand is processed from quartz sandstone, quartzite, or vein quartz. Its main chemical composition is SiO2, a number of other impurities are also present in small amounts, e.g. Al2O3, Fe2O3, MgO, and CaO.
Industrial quartz sand includes ordinary quartz sand, refined quartz sand, fused quartz sand, silica fume, and high purity quartz sand.
High purity quartz sand is also named as silica sand, silica powder, and silica dioxide powder. It is an important industrial material and is widely used in glassmaking, construction, fillers, filters, semiconductor, optical fiber communication, laser, and aerospace fields. With the rapid development of these fields, the demand for high-purity quartz sand is soaring.
After being mined by open pit or dredging mining methods, quartz sand rocks need to be purified to get high purity quartz sand. The purification methods include classification, scrubbing, chemical acid leaching, flotation (fluorine flotation and non-fluorine flotation), gravity separation, magnetic separation, and microbial leaching. In practice, we usually combine these methods accordingly to improve the grade and output of quartz sand, fully utilizing quartz sand resources.
Below are six quartz sand purification processes (also called quartz sand beneficiation methods) used by quartz sand processing companies and laboratories in China.
1. Comminution, classification, and magnetic separation (Quartz sand purification process of a company in Anhui)
Raw ore: quartzite from Fengyang, Anhui, with SiO2 content of 99.01% and Fe2O3 content of 0.118%;
Quartz sand concentrate: The Fe2O3 content in the concentrate is 0.02%.
Picture 1 Quartz sand purification process of a company in Anhui
2. Comminution, classification, magnetic separation, and flotation (quartz sand purification process of a company in Fengyang, Anhui)
Raw ore: quartz sand in Anhui, its SiO2 content is 99.1%-99.3%, and the Fe2O3 content is 150-200PPM;
Quartz sand concentrate: The SiO2 content in the concentrate is 99.62%, and the Fe2O3 content is 0.0062%.
Picture 2 Quartz sand purification process of a company in Fengyang, Anhui
3. Roasting, water quenching, acid leaching, and flotation (quartz sand purification process of a company in Donghai, Jiangsu)
Raw ore: vein quartz with Fe content of 765.3 mg/kg.
Quartz sand concentrate: The Fe content of the concentrate is 0.35mg/kg.
Picture 3 Quartz sand beneficiation process of a company in Donghai, Jiangsu
4. Scrubbing, grading, grinding, magnetic separation, reverse flotation (the purification process of kaolin associated quartz sand ore in a laboratory)
Raw ore: kaolin associated quartz sandstone in the North Sea, SiO2 content 98.32%, Fe2O3 content 1044.29μg/g;
Quartz sand concentrate: the content of SiO2 is 99.89%, and the content of Fe2O3 is 74μg/g.
Picture 4 the purification process of kaolin associated quartz sandstone in a laboratory
5. Roasting, water quenching, magnetic separation, flotation, acid leaching (quartz sandstone purification process in a laboratory)
Raw ore: quartz sandstone with SiO2 content 99.02%, Fe2O3 content 178.2μg/g;
Quartz sand concentrate: the content of SiO2 is 99.99%, and the content of Fe2O3 is 5.0μg/g.
Picture 5 quartz sandstone purification process in a laboratory
6. Ultra-fine comminution, classification, flotation, microwave-assisted acid leaching (vein quartz purification process in a laboratory)
Raw ore: vein quartz rocks from Shangrao, Jiangxi, with SiO2 content of 99.58% and Fe2O3 content of 0.03%;
Quartz sand concentrate: high-purity quartz sand (electronic grade) contains 99.98% SiO2 and 0.0003% Fe2O3; high-purity quartz sand (filler grade) contains 99.63% SiO2 and 0.0018% Fe.
Picture 6 vein quartz purification process in a laboratory
