Preparation method of 4N-grade high-purity quartz sand

The invention relates to a preparation method of 4N-grade high-purity quartz sand, which comprises the following steps: (1) calcining a quartz raw material at a high temperature, carrying out water quenching treatment, and washing and drying after water quenching to obtain an intermediate mineral; (2) performing ultrasonic acid leaching on the intermediate mineral obtained in the step (1); and (3) carrying out high-temperature leaching on the acid system subjected to ultrasonic acid leaching, and washing and drying a product subjected to high-temperature leaching, so as to obtain a 4N-grade high-purity quartz sand product. According to the method, the content of impurity elements in quartz can be obviously reduced, the quartz sand product with high purity is obtained, the energy consumption is low, the process is simple and easy to operate in the preparation process, and the technical problems that in the prior art, the high-purity quartz sand process is complex, and the energy consumption is high are solved.