Low-grade Quartz Beneficiation Method

Crystal, vein quartz, quartzite, quartz sandstone, quartz sand, powder quartz, and other minerals are collectively referred to as siliceous raw materials, which are widely used in traditional and high-tech glass, ceramics, cement, foundry, chemical industry, electrical engineering, electronics, semiconductor, aerospace industry. However, with the extensive use of quartz resources, high-quality crystals and vein quartz are decreasing day by day, and low-grade quartz resources are getting more and more attention. This paper introduces the beneficiation methods of three types of low-grade quartz ores, namely natural quartz sand, quartz sandstone, and powder quartz.

Natural quartz sand beneficiation method

Natural quartz sand is a kind of sandy mineral material formed by long-term weathering of granite, quartzite, quartz sandstone, and vein quartz as parent rock in nature. Its mineral composition is mainly quartz, and its associated minerals include gangue minerals such as feldspar, mica, and clay minerals, and heavy minerals such as zircon, tourmaline, ilmenite, and amphibole.

In production, natural quartz sand beneficiation generally adopts the process flow of scrubbing and desilting – classification – gravity separation – magnetic separation.

Among them, mechanical scrubbing mainly uses the collision and friction between mechanical external force and sand particles to achieve the purpose of iron removal. The scrubbing efficiency increases with increasing pulp concentration, which increases the probability of collisions between particles. When the sand scrubbing concentration is 50%-60%, the scrubbing effect is better. During the scrubbing process, if some impurities adhere to the clay minerals on the surface of the quartz sand particles, they will be stripped off to form fine particles mixed in the suspension, thereby increasing the content of fine particles in the product. Therefore, in order to ensure product quality, a classification operation is required to achieve the separation of quartz minerals and impurities.

Due to the large difference in density between heavy minerals and quartz in the original ore, they can be removed by gravity separation within a similar particle size range, and the obtained concentrate is then magnetically separated to reduce the content of iron oxide, thereby improving the grade of quartz concentrate.