Preparation of Silica Powder from Low-Grade Quartz by Mechanical Activation Acid Leaching and Its Mechanism

Quartz is crucial in semiconductors and electronic packaging. Due to the depletion of high-grade quartz, there's a need to use low-grade quartz to produce high-purity products. Traditional methods use environmentally harmful hydrofluoric acid (HF). This study presents a mechanical activation fluorine-free acid leaching method (F-free MA-AL) to produce high-purity silica powder from low-grade quartz, achieving an impurity content of 154.18 ppm and a removal rate of 97.76%. Optimal conditions are 600 rpm for 90 min, increasing the quartz’s specific surface area by 6.04 times. XRD refinement and XPS tests revealed that mechanical activation modifies quartz’s crystal structure, enhances impurity activity, and facilitates acid leaching. This method avoids HF use while maintaining purification effectiveness. Kinetic studies on Al and Fe removal indicate that mechanical activation reduces activation energy by 45.27% and 17.5%, respectively. This method realizes the comprehensive utilization of low-grade quartz ore and provides a theoretical basis for the industrialization of low-grade quartz application under the premise of fluoride-free environment.

1. Investigated quartz's mechanical activation behavior.

2. Analyzed quartz's microstructure changes using XRD refinement.

3. Proposed a fluorine-free acid leaching method for impurity removal in quartz.

4. Found mechanical activation lowers activation energy in impurity removal reactions.

5. Made it possible to prepare high-purity silica powder from low-grade quartz.