Abstract: This is an essay in the field of mineral processing engineering. Based on the process mineralogy, a mixed process containing roasting-water quenching-hot pressure leaching was applied to purify a white pegmatite ore from Inner Mongolia. The optimum condition was obtained via various tests. The content of SiO₂ in the final product was increased from 99.917% to 99.994%, while the total impurity content was decreased from 419.9 to 54.79 g/t, with a total removal of 86.95%. The main impurity element of Al was decreased from 250.9 g/t to 26.09 g/t, with a removal of 89.60%. Therefore, this study provides a good purification approach for high-purity quart preparation.