1. Introduction of quartz sand
Quartz sand is quartz particles processed by crushing and screening quartz stone. Its main mineral component is silicon dioxide (SiO2). Quartz sand has stable chemical properties, and it is insoluble in acid (but slightly soluble in KOH solution). The melting point of quartz sand is up to 1750℃, so it has high refractory property.
2. Purification of quartz sand
Quartz sand often contains impurity elements such as iron, aluminum, and calcium, these impurities can significantly affect the utilization and quality of quartz sand. For example, in glass production, impurity of iron can reduce the light transmittance of glass and affect product quality. Therefore, in practical applications, quartz sand usually needs to be purified. The purpose is to remove impurities and improve the purity of quartz sand to meet the requirements of high-end fields for quartz.
Main steps
The main steps of purification includes: crushing, grinding, grading and desliming, scrubbing, magnetic separation, flotation and acid leaching.
① Crushing
Crushing of quartz sand is the beginning of purification process. Usually, a jaw crusher or a cone crusher is used to crush mined quartz ore to a certain particle size. And then the crushed ore is screened. The qualified particles are left, and unqualified particles are returned to the crusher for further crushing.
② Grinding
Grind quartz particles into powders. The commonly used equipment includes ball mill and rod mill. During grinding, the grinding time and the ratio of grinding media need to be strictly controlled, to ensure grinding effect and quality stability of quartz.
③ Grading and desliming
Due to weathering and sedimentation of quartz sand, a large amount of clay minerals and iron accumulate on the surface of quartz to form cement or bonding minerals. Through equipment, such as hydrocyclone and spiral classifier, can remove most of the muddy materials and improve the content of SiO2.
④ scrubbing
The mechanical force and abrasive force between particles can remove the thin iron film and the bonding and muddy impurities on the surface of quartz sand. There are two main scrubbing methods: rod friction scrubbing and mechanical scrubbing. The main factors affecting the scrubbing effect include the structural characteristics and configuration of the scrubbing machine, scrubbing time and concentration.
⑤ magnetic separation
Iron impurities in quartz sand can be removed by adjusting magnetic strength and magnetic time. Commonly used magnetic separation equipment includes permanent magnetic drum separator, wet magnetic separator and strong magnetic roller, etc.
⑥ Flotation
By adjusting the ratio and dosage of anionic and cationic mixed collectors, non-magnetic associated impurities such as feldspar and mica can be removed. Flotation is divided into two types: fluorine-containing and fluorine-free. Currently, fluorine-free flotation is more commonly used method.
⑦ Acid leaching
Quartz is insoluble in acid while impurity minerals in quartz can be dissolved by acid, so impurities that are difficult to remove by magnetic separation and flotation can be removed by acid leaching.
3. Application
Through the above methods, high purity quartz sand can be obtained to meet the needs of different application. High purity quartz sand has a wide range of applications, such as in industries of semiconductors, optical fiber communications, aerospace, solar energy and glass etc.
Qingdao Epic Powder Machinery Co., Ltd is a manufacturer specializing in the production of powder machinery. Ball mill produced by our company is suitable for grinding quartz sand.
Our main products include:
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If you are interested in ball mill or other products from Qingdao Epic, contact our staff directly, we are always at your service.
