Review of upscale quartz sand purification process: From raw material properties to efficient technologies

Quartz sand is a high-end raw material with excellent physical and chemical properties derived from quartz stone. China heavily relies on imports for quartz, with the proportion of high-purity quartz being low in the market. Therefore, it is strategically important to strengthen independent technological research and development to efficiently utilise China's quartz sand resources. This work summarises and explains the physical and chemical properties of quartz, including its chemical components, phase composition, element existing state and embedded particle size. It also summarised various physical purification methods, such as colour separation, scrubbing–grading desliming, gravity concentration, magnetic separation and flotation. The work focused on the two major chemical purification methods, hydrometallurgy and pyrometallurgy, and clarified the challenges and dilemmas in quartz purification, such as high energy consumption, incomplete impurity removal and environmental pollution. On this basis, a green and efficient purification process for quartz sand, combining nonfluorinated acid leaching and microwave roasting, was proposed.