Purifying system of high purity polysilicon and purifying method

Abstract

The invention discloses a purifying system of high purity polysilicon and a method for preparing the high purity polysilicon by using the system. The system comprises a silicon material melting device arranged in a closed cavity, an electromigration device and an orientation solidification device, wherein the silicon material melting device and the electromigration device are connected through a first overflow pipe, and the electromigration device and the orientation solidification device are connected through a second overflow pipe. The method is characterized in that a horizontal direct current electric field which is vertical to the flowing direction of silicon liquid is forced on melted silicon liquid, cation impurities and anion impurities in the silicon liquid respectively migrate towards the direction of a cathode and the direction of an anode under the function of an electric field and gather in electrode regions at both sides, high impurity concentration silicon liquid and high purity silicon liquid are separated by a division baffle, the high purity silicon liquid is treated by orientation solidification ingot casting, and finally, a high purity polysilicon ingot is obtained. The invention can realize large scale continuous purifying production of high purity silicon and has the advantages of favorable purifying effect, simple equipment, little investment and low production cost.

Description

technical field [0001] The invention relates to a purification system for preparing high-purity polysilicon and a method for preparing high-purity polysilicon by using the system. Background technique [0002] With the rapid development of the photovoltaic industry, the demand for polysilicon raw materials for the production of crystalline silicon solar cells is increasing. At present, high-purity polysilicon is mainly produced by the improved Siemens method. Although the polysilicon obtained by this method has high purity, the energy consumption in the production process is too large, making the price high, which cannot meet the low-cost development requirements of solar cells, and hinders photovoltaic power generation. popularity. In recent years, some new technologies and methods for preparing solar-grade polysilicon have been developed rapidly, including not only traditional purification processes such as out-of-furnace refining, vacuum refining, hydrometallurgy, and di...

AI Technical Summary

Problems solved by technology

Although this method can achieve the purpose of purification to a certain extent, it is complicated to operate under high temperature conditions and can only be carried out on a small test device. It is difficult to use in actual production, let alone realize continuous industrial production, and the production efficiency is too low.

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