Method adopting trichlorosilane and dichlorosilane mixed raw materials to produce polycrystalline silicon

Abstract

The invention discloses a method adopting trichlorosilane and dichlorosilane mixed raw materials to produce polycrystalline silicon. After trichlorosilane produced by hydrogenation of silicon tetrachloride or purchased outside is rectified and purified, the rectified and purified trichlorosilane is mixed with recycled trichlorosilane and dichlorosilane mixed materials, the volume percent of dichlorosilane in the mixed raw materials is controlled to be between 3% and 15%, preferably between 5% and 10%, then impurity removal by adsorption and vaporization operation are performed, vaporized chlorosilane mixed gas and high-purity hydrogen are mixed according to mole ratio of 1:2 to 1:10, preferably 1:4 to 1:6, and finally the vaporized chlorosilane mixed gas and the high-purity hydrogen enter into a reduction furnace to produce the polycrystalline silicon. After reactions, tail gas undergoes low-temperature condensation recycle, chlorosilane obtained by recycle is sent to a rectification process to perform separation of silicon tetrachloride and impurities, and the trichlorosilane and dichlorosilane mixed raw materials are obtained. The method makes full use of byproduct dichlorosilane in the polycrystalline silicon production process to improve sedimentation velocity of silicon and reduce power consumption and material consumption, simultaneously can reduce treatment cost and loss of silicon, and improves trichlorosilane utilization rate.

Description

[0001] technical field [0002] The invention relates to polysilicon, in particular to a method for producing polysilicon. [0003] Background technique [0004] With the development of the world economy, the demand for energy is constantly increasing, and the traditional fossil energy is almost exhausted. Finding a low-carbon, clean and renewable new energy has become the main topic of the current world economic development. Solar photovoltaic energy has many advantages such as renewable, clean, and low-carbon. In the future development of world energy, photovoltaic solar energy will become the first choice for energy sources in all countries in the world. Therefore, countries all over the world are currently vigorously developing the solar photovoltaic industry to reduce Dependence on traditional fossil fuels. Solar grade polysilicon is the most basic material for solar photovoltaic power generation. [0005] At present, most polysilicon production enterprises at home a...

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Problems solved by technology

[0008] The invention provides a method for producing polysilicon by using a mixed raw material of dichlorodihydrosilane and trichlorosilane, which can effectively solve the problem that the by-product dichlorodihydrogensilane is difficult to handle in the polysilicon production process

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