What are the purification processes of high-purity quartz sand？

High-purity quartz sand is an important material used in high-tech industries such as semiconductor, solar cell, and optical fiber production. The purification of quartz sand involves several processes to remove impurities and obtain high-purity quartz sand. The following are some of the purification processes used for high-purity quartz sand:

Physical beneficiation: Physical beneficiation processes include screening, gravity separation, and magnetic separation. These processes remove impurities such as heavy minerals, iron, and titanium oxides from the quartz sand.

Acid leaching: Acid leaching is a chemical process used to remove impurities such as alkali metals, alkaline earth metals, and iron oxides from the quartz sand. Hydrofluoric acid and sulfuric acid are commonly used for this process. The acid reacts with the impurities to form soluble compounds that can be washed away.

Alkali leaching: Alkali leaching is a chemical process used to remove impurities such as alumina, alkali metals, and alkaline earth metals from the quartz sand. Sodium hydroxide or potassium hydroxide is commonly used for this process. The alkali reacts with the impurities to form soluble compounds that can be washed away.

Thermal treatment: Thermal treatment is a process used to remove organic impurities from the quartz sand. The sand is heated to high temperatures to burn off the organic matter.

Ultrasonic treatment: Ultrasonic treatment is a process used to remove impurities from the quartz sand by using high-frequency sound waves. The sound waves create cavitation bubbles that break up the impurities and dislodge them from the surface of the sand particles.

Ion exchange: Ion exchange is a process used to remove impurities from the quartz sand by exchanging ions in the sand with ions of a different type. The sand is treated with a solution containing ions that can replace the impurities in the sand. The impurities are then removed by washing the sand.

Electrostatic separation: Electrostatic separation is a process used to remove impurities from the quartz sand based on their electrical properties. The sand is charged with static electricity and passed through an electrostatic field. The impurities are attracted to the opposite charged electrode and are removed from the sand.

In conclusion, the purification of high-purity quartz sand involves several processes such as physical beneficiation, acid leaching, alkali leaching, thermal treatment, ultrasonic treatment, ion exchange, and electrostatic separation. Each process has its advantages and limitations, and the choice of process depends on the specific requirements and impurities present in the quartz sand.