Method for producing solar energy stage polycrystalline silicon by using high-pure quartz sand as raw material

Abstract

The invention provides a method for producing solar energy level polysilicon by taking quartz sands with high purity as materials. In the method, silica materials, in which the SiO2 content is more than 99 percent, are chosen to undergo water quenching, crushing, sieving, acid cleaning, magnetic separation and high voltage ionizing treatments, which makes the purity of silica particles reach more than 99.99 percent, and the quartz sands with high purity are obtained; carbonaceous reducing agents and graphite electrodes in a mine hot stove are chloridized at a high temperature in a chlorination furnace, making the purity of carbonaceous reducing agents reach more than 99.99 percent; in the mine hot stove, the carbonaceous reducing agents are used to reduce the quartz sands with high purity so as to produce silicon, and while producing, silicon liquids are periodically discharged from the mine hot stove; the obtained silicon liquids are injected in a holding furnace, and the products directly undergo the high-frequency plasma air refining for impurity removal under the non oxidizing atmosphere, and at the same time oxidizing gases are added in the melting silicon; the silicon liquids are injected in a directional solidification furnace for the directional solidification, and the silicon is further purified, so that the solar energy level polysilicon is obtained. The method of the invention has the advantages of low investment, short building period, low manufacturing cost, simple process and no pollution; moreover, the method is also suitable for industrialization.

Description

technical field [0001] The invention relates to a method for producing solar-grade polysilicon, in particular to a method for producing solar-grade polysilicon by using high-purity quartz sand as a raw material. Background technique [0002] With the advent of the energy crisis, the green energy and photovoltaic industries have developed rapidly, and polysilicon materials for solar cells have become the cornerstone of the new energy industry. There is a serious gap in the independent supply of polysilicon in my country, and more than 95% depend on imports. In recent years, the soaring price of polysilicon market has endangered the normal operation of my country's polysilicon downstream industry and has become a bottleneck restricting the development of my country's photovoltaic industry. Therefore, it is of great significance to research and develop the process technology of low-cost solar-grade polysilicon. [0003] The world's advanced polysilicon production technology ha...

AI Technical Summary

Problems solved by technology

[0007] These methods generally have the problems of low growth rate, low primary conversion efficiency, low output, high reduction temperature, high energy consumption, large one-time investment, long construction period, low input-output rate, and high production cost.

And by-products cannot form an industrial chain, causing serious environmental crisis