A Novel CaCl2 Chlorination Roasting Process for High-Efficiency Purification of Quartz Sand

To address the challenges of high impurity content and low whiteness in quartz sand, this study proposes a combined process of solid-state chlorination roasting followed by acid leaching. By using calcium chloride (CaCl2), a safe and low-cost solid chlorinating agent, mixed with quartz sand for chlorination rofasting, the process effectively removes key impurity elements such as aluminum (Al) and iron (Fe), thereby enhancing the whiteness of the quartz sand. The quartz sand used in the experiment had an aluminum content of 4519 ppm and an iron content of 496.3 ppm. Under optimized conditions—a mass ratio of quartz sand to CaCl2 of 1:0.1, a roasting time of 2 h, and a roasting temperature of 1100 °C—the contents of aluminum and iron impurities were reduced to 422.62 ppm and 124.43 ppm, respectively, although the calcium content increased significantly. Subsequent acid leaching further reduced the residual impurities and the introduced calcium elements. The results demonstrate that the combined process achieved removal rates of 91.1% for aluminum, 90.7% for iron, and 50.2% for calcium, while increasing the whiteness to 85.2 Wb. This approach exhibits significant advantages compared to standalone acid leaching or chlorination roasting. This approach exhibits significant advantages compared to standalone acid leaching or chlorination roasting, thus offering a viable technical route for the production of high-quality panel-grade quartz sand.