Experimental research on the purification of quartzite in Fengyang, Anhui

With the rapid development of strategic emerging industries such as semiconductors and photovoltaics, China has become the world’s largest demand market for high-purity quartz. However, domestic raw materials still heavily rely on imports, restricting the security of the development of silicon-based strategic industry in China. Therefore, the development of non-traditional high-purity quartz raw materials has become a new research focus. This study selects a quartzite ore from Fengyang, Anhui Province, as the research subject and conducts a series of purification tests. Through systematic experimentation, the optimal process flow is determined to verify the feasibility of using this quartzite ore as a substitute for natural crystal in producing high-purity quartz sand. The results indicate that the optimal magnetic induction intensity for magnetic separation is 1.7 T, and the roasting-water quenching operation significantly enhanced the acid leaching efficiency. The finalized optimal process flow is as follows: 4-stage magnetic separation–8-stage scrubbing–3-stage washing–2-stage flotation–roasting–water quenching–acid leaching. This process increases the SiO₂ content of the quartz sand product from 99.642 3% in the raw ore to 99.992 9%, while the total impurity content decreases from 3 577.11 μg/g to 71.16 μg/g. Specifically, the Al content drops from 1 747.91 μg/g to 19.75 μg/g, K from 750.98 μg/g to 5.33 μg/g, Fe from 754.04 μg/g to 1.89 μg/g, and Mn from 86.35 μg/g to 0.03 μg/g. Therefore, this study provides a purification process for a quartzite ore from Fengyang, Anhui Province. The resulting quartz sand product meets the standards for mid-grade high-purity quartz sand, offering valuable guidance for utilizing quartzite ores as raw materials for high-purity quartz sand purification, further offering abundant raw materials for the silicon-based strategic industry in China.