Method for manufacturing polycrystalline silicon by reducing silicon chloride with active metal

Abstract

The invention discloses a method for manufacturing polycrystalline silicon by reducing silicon chloride with an active metal. The invention aims to overcome the defects of the prior art and provides a method for manufacturing the polycrystalline silicon by reducing the silicon chloride with the active metal, wherein the method has less energy consumption, simple process and low cost. The method comprises the following steps of: reducing the silicon chloride with the active metal, separating and washing reactants to obtain silicon powder, distilling and purifying the obtained silicon powder in vacuum, and separating silicon from the active metal and other impurities in the silicon through vacuum distillation to enable the purity of the silicon to reach the silicon purity requirement of a solar battery or an electronic industry. The method is used for manufacturing a polycrystalline silicon raw material for the solar battery or the electronic industry.

Description

technical field [0001] The invention relates to a method for purifying silicon, in particular to a method for producing polysilicon by using active metals to reduce silicon chloride. technical background [0002] Now as solar cells are more and more widely used, the demand for silicon, the material used to make solar cells, is increasing. However, because industrial silicon products contain more impurities, they cannot be directly used to make solar cells at present. At present, the purification of silicon mainly adopts the Siemens purification method. This method is to first turn silicon into trichlorosilane, and then reduce it with hydrogen at high temperature after refining. This process is very polluting and energy-intensive. Although there are also some other technical purification methods, such as the patent application number 200610166374.6 published by the Chinese Patent Office on 2007.07. All have great limitations, and the problem of high production costs, conver...

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Problems solved by technology

However, because industrial silicon products contain more impurities, they cannot be directly used to make solar cells at present.

At present, the purification of silicon mainly adopts the Siemens purification method. This method is to first turn silicon into trichlorosilane, and then reduce it with hydrogen at high temperature after refining. This process pollutes a lot and consumes a lot of energy.

Although there are also some other technical purification methods, such as the patent application number 200610166374.6 published by the Chinese Patent Office on 2007.07. All have great limitations, and the problem of high production costs, conversion into silane for purification, chemical methods pollute the environment, high energy consumption, complex process

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