Resource Utilization of Iron Ore Tailings to Recover SiO₂ Sand Through S-HGMS: Parametric Optimization and Mechanism Analysis

Iron ore tailings (IOTs) are an important solid waste in the mining industry, which can pollute the environment and endanger human health. However, the disposal and high value-added utilization of iron tailings have always been a challenge. Notably, superconducting high-gradient magnetic separation (S-HGMS) technology is a promising technology in mineral processing with the advantages of low carbon, green, high efficiency, and easy operation. This study used S-HGMS technology to separate and purify SiO₂ concentrate from IOTs. Under the optimal conditions of magnetic flow ratio of 0.038 T s/m for the first magnetic separation, 0.085 T s/m for the second, pulp flow rate of 0.5 L/min, and pulp concentration of 50 g/L, increasing the SiO₂ content from initial 61.38% to 95.23%, SiO₂ recovery reached 38.51%. After the S-HGMS process, weak and non-magnetic particles realized effective separation, which created the conditions for the subsequent processing of SiO₂ concentrate into high-purity silica. S-HGMS technology was used to extract SiO₂ particles from IOTs, improving the utilization value of the tailings. This study provides an efficient and eco-friendly research direction for the industrial application of IOTs.