Upgrading Quartz-Rich Tailings as Secondary Silica Resources: Process Mineralogy, Beneficiation, Purification, and Product Qualification

Quartz-rich tailings are potential secondary silica resources, but bulk SiO2 content alone does not establish their upgrading potential. Previous comminution, separation, dewatering, and storage modify particle size distributions, mineral liberation, mineral associations, and surface conditions, affecting subsequent beneficiation and purification. This review examines studies published up to September 2026 on quartz-rich tailings and related mineral processing residues, prioritizing actual tailings studies that report feed characteristics, processing conditions, product quality, or recovery. The reviewed results indicate that flowsheet selection depends primarily on how the impurities occur and whether they can be liberated, exposed, or selectively removed. Surface coatings, slimes, and liberated impurity minerals can generally be removed by conventional beneficiation, whereas intergrowths may require controlled liberation followed by appropriate separation. Deep purification is justified only when the residual impurities can be effectively exposed or removed by the selected treatment. Final SiO2 grade is reported more consistently than mass yield, SiO2 recovery, saleable size yield, and impurity deportment, limiting comparisons of overall flowsheet performance. Moreover, high chemical purity alone does not establish suitability for a specific application. The treatment endpoint should therefore be the consistent production of quartz meeting its intended specification at acceptable recovery and within the required product size range, rather than the maximum purity obtained from a small fraction of the tailings.