P-type solar cell grade polycrystalline silicon preparing process

Abstract

The invention discloses a p-type solar battery graded polycrystalline silicon preparing method, comprising the steps of: (1) selecting high- grade silica as raw material; (2) using mixture of highly pure petroleum coke and coal as reducer to reduce the silica; (3) refining by medium frequency furnace in temperature subregions; (4) electromagnetically blending at high temperature and centrifugally purifying; (5) vibrating at high temperature and medium-middle frequency to purify; (6) dephosphorizing; and (7) ingoting. And it has simple process, low power consumption, and high yield, and can largely reduce the raw material costs of the current solar batteries.

Description

Technical field [0001] The invention belongs to the technical field of metallurgy and relates to a process for preparing p-type solar cell grade polysilicon. Background technique [0002] The current production of high-purity silicon is mainly chemical and physical purification methods. In the chemical method, the production of ultra-high-purity silicon commonly used silane (SiH 4 ) Method, silane method has lower thermal decomposition temperature and relatively less power consumption, which is worthy of promotion. However, due to the strong explosiveness of silane, the cost of this method is too high to be popularized, and it is only used in a small amount in a very special process. At present, the three giants in the United States, Japan, and Germany mostly use the modified German Siemens process to produce 11N-level polysilicon on a large scale. The advantage of the chemical method is that it can deposit 11N purity U-shaped polycrystalline silicon rods at one time. The disadva...

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Problems solved by technology

In addition, p-type silicon materials are used in the international general solar cell production line almost without exception. It is much more difficult to remove phosphorus, and it will take time to promote it

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