Abstract: With the rapid development of photovoltaic new energy, electronic information and other fields, the application of high-purity quartz sand is more and more extensive, the demand increases year by year, and the high-quality quartz ore that can process high-purity quartz sand are gradually reduced.Therefore, the development of beneficiation and purification technology for vein quartz with medium and low quality is very significant.Based on the routine purification method of vein quartz, alkali leaching auxiliary treatment to improve the purity of vein quartz with medium and low quality is used in this paper, which is of great significance to the development of preparation technology of high-purity quartz sand.The experiment is to remove the impurities inside the quartz, by alkali treatment to dissolve the surface of a layer of quartz, expose the internal impurity minerals, and thus easier to be removed.the purification process of roasting-water quenching-magnetic separation-flotation-alkali treatment-acid leaching is developed, and the influence of alkali treatment conditions on the quality of acid leaching concentrate is systematically studied.The results show that the best purification effect is obtained under the conditions of KOH solution, alkali treatment temperature of 40 ℃, KOH solution concentration of 0.5 mol/L and treatment time of 4 hours.The Al content in quartz concentrate is decreased from 296.79 μg/g obtained by conventional process to 245.49 μg/g.Quartz purity reached 98.91%.Scanning electron microscope analysis showed that after alkali treatment, the surface of vein quartz is partially eroded by alkali solution, so that the acid solution could better contact with impurity minerals in the process of acid treatment, so as to achieve better removal effects of impurity minerals.