The higher the content of SiO2 in quartz sand, the higher the purity and the higher the value. How to remove impurities and improve the purity of quartz sand is an important direction of quartz sand research. Mica is a common associated mineral of quartz sand. The separation method of quartz sand and mica determines the purity of quartz sand to a certain extent. Now high-purity quartz sand has been used in new energy, optical fiber, laser, information technology, aerospace, microelectronics and other high-tech fields, and is an important resource.
Magnetic separation is an effective method to remove magnetic impurities from quartz sand. The application of magnetic separation technology can remove weak magnetic minerals such as biotite to a greater extent. For biotite with weak magnetism, a strong magnetic separator can be used when the magnetic field strength is 8 × It can be selected when it is above 105A/m (ampere/meter).
Flotation is a common method to separate quartz sand and mica. It can be separated by flotation with cationic collector at pH 3-4.
Mica dissociates a large number of anions O2 - and F - with very low zero electric point. After exposure to the layered structure, it can be recovered with cationic collectors in a wide pH range (pH=2-13). The range of pH value of feldspar in the cationic collection system (pH=4-11) is smaller than that of mica, so mica can be preferentially floated out under strong acidic conditions to remove mica impurities.
Mica minerals in quartz sand are removed by three-stage flotation process. The primary flotation is to use the corresponding reagent system to float the iron containing slime from the pulp under the neutral or weak acid environment; The secondary flotation refers to the flotation of mica like minerals and the intergrowth of mica and quartz from the pulp under neutral or weak acid environment by adopting corresponding reagent system; Tertiary flotation refers to the flotation of feldspar minerals and the intergrowth of feldspar and quartz from the pulp under neutral or weak acid environment with corresponding reagent system.
Mica impurities in quartz sand can be removed by the above methods, among which flotation is an important method for separating quartz sand from mica. In addition to removing mica impurities, impurities such as aluminum and iron must be removed to improve the purity of quartz sand. Only by increasing the SiO2 content can high-purity quartz sand be obtained.
