This study investigates the process mechanisms for preparing 4N8 high-purity quartz powder from high-silicon iron ore tailings. Silicon concentrate obtained by wet high-intensity magnetic separation was used as the raw material, with impurities removed through a two-stage acid leaching process. The effects of acid concentration, temperature, time, and liquid-solid ratio on impurity removal were examined. Thermodynamic analysis shows that HF enhances the dissolution of Fe and Al impurities. In the first stage, response surface optimization determined the optimal conditions: acid concentration of 11.69 mol/L, temperature of 99.5 °C, and reaction time of 6.3 h, yielding SiO