Controlling magnetic agglomeration in superconducting high gradient magnetic separation processing of iron ore tailings for high-grade silica recovery

• Hematite exhibits the highest magnetic moment among IOT minerals, making it the primary driver of magnetic agglomeration. • The dispersant SDSH hydrolyzes to form HPO4 2− and RSO3 − groups that chemically adsorb onto non-quartz metal ions, increasing electrostatic repulsion. • RSO3 − groups physically adsorb onto quartz surfaces, inducing steric repulsion and enhanced hydrophilicity to inhibit agglomeration. • Under optimal conditions, SiO2 grade increased from 76.32% to 97.42% with a recovery rate of 54.81%, meeting glass-grade quartz sand requirements.