Method for preparing 4N7-grade high-purity quartz sand from muscovite type granite quartz

The invention provides a method for preparing 4N7-grade high-purity quartz sand from muscovite granite quartz, which comprises the following steps of: sorting quartz raw ore to obtain quartz concentrate, and heating, acid-leaching, washing and drying the quartz concentrate to obtain primary quartz sand; the primary quartz sand is calcined, subjected to normal-temperature water quenching and dried, and intermediate minerals are obtained; the intermediate minerals are added into oxidation or reduction system acid, ultrasonic normal-temperature acid leaching is conducted firstly, then heating acid leaching is conducted, and leaching liquid and leaching residues are obtained; and the leaching residues are subjected to ultrasonic washing and drying, and the 4N7-grade high-purity quartz sand is obtained. By means of the method, the content of impurity elements in muscovite type granite quartz can be remarkably reduced, a high-purity quartz sand product with SiO2 larger than or equal to 99.997% is obtained, the prep