In nature, crystal, ganguite, quartzite, silica sandstone, silica sand, powder silica and other minerals are collectively referred to as siliceous raw materials, and its main component is SiO2, which is widely used in glass, ceramics, cement, casting, chemical industry, electrical, electronics, semiconductor, aerospace and other traditional and high-tech industries. However, with the extensive use of slica resources, high-quality crystal and gangue are decreasing day by day, and low-grade silica resources are getting more and more attention. Next, this article will take you to understand the purification process of low grade silica sand such as natural silica sand, quartz sandstone and powder silica.
Natural silica sand purification process
Natural silica sand is a kind of sandy mineral material formed by the long-term weathering of granite, quartzite, silica sandstone and gangue silica as parent rock in nature. The mineral composition is mainly silica, and the associated minerals include gangue minerals such as feldspar, mica and clay minerals, as well as heavy minerals such as zircon, tourmaline, ilmenite and hornblende.
The purification process of natural silica sand generally adopts the process flow of scrubbing desliming – classification – gravity separation – magnetic separation.
Scrubbing and desliming: It is to use the collision and friction between the mechanical external force of the mechanical scrubbing machine and the sand particles to achieve the purpose of removing iron. The scrubbing efficiency increases with the increase of slurry concentration, and increasing slurry concentration can increase the probability of collision between particles. The cleaning concentration of placer is better at 50%-60%.
Separation: During the scrubbing process, some impurities such as clay minerals attached to the surface of quartz sand particles will be stripped, forming fine particles mixed in the suspension, increasing the fine particle content in the product. Because these substances are very fine, it is difficult to achieve complete separation from silica under the disturbance of the water medium. In order to ensure the quality of the product, the separation of the desired minerals and impurities needs to be achieved through classification.
Gravity separation: Due to the large difference in density between the heavy minerals and silica in the raw ore, it can be removed by the heavy contestant section in the similar particle size range.
Magnetic separation: The concentrate obtained after re-separation can reduce the content of iron oxide and improve the grade of concentrate through magnetic separation.