Method for preparing high purity quartz sand

Abstract

The invention relates to a preparation method of high-purity quartz sand. The method adopts quartz sand as basic raw material, removes ore foreign bodies on the surface of sand grains or inside the grains by carrying out roasting and water-granulating to blocky materials, removes certain soluble and flammable impurities in the quartz sand by carrying out the roasting and water-granulating again, and finally removes most of the ore foreign bodies by acid leaching to obtain the high-purity quartz sand. The quartz sand prepared by the method can be used for producing polysilicon materials.

Description

Technical field: [0001] The invention relates to a method for preparing high-purity quartz sand, in particular to a method for preparing quartz sand suitable for producing polycrystalline silicon materials by physical methods. Background technique: [0002] Quartz sand is the basic raw material for the preparation of polycrystalline silicon and monocrystalline silicon, and is widely used in high-tech fields such as semiconductor technology, solar energy, and aerospace. The purity and element content of quartz sand directly affect the quality of the prepared product. At present, the U.S. company Unimin has a relatively high level of preparation of high-purity quartz sand, and its impurity content is within 20 ppm, but its process is complicated and the cost is very expensive. The traditional quartz sand preparation process is: rough selection→crushing→roasting→water crushing→crushing→iron removal→acid soaking→flotation and other processes, and finally made into 80-100 mesh p...

AI Technical Summary

Problems solved by technology

The disadvantage of this patent is that the concentration of the acid used is relatively high, and the reaction time is long, and aqua regia, etc. with particularly strong corrosion ability are used, which has a strong corrosion effect on the equipment; in addition, if the conditions involved in the patent are to be used Ultra-low temperature is difficult to achieve; the most important thing is that the patented technology cannot remove boron and phosphorus in quartz sand. These two elements are difficult to purify metal silicon by physical methods, so it is impossible to prepare polysilicon by physical methods. and monocrystalline silicon requirements