Method for removing hydrogen halide in polysilicon production tail gas

Abstract

The invention discloses a method for removing hydrogen halide from polycrystalline silicon production tail gas. The hydrohalosilanes in the production tail gas react with hydrogen halide to convert them into the corresponding hydrohalosilanes. The composite nitrogen-containing polymer resin catalyst used in the invention has the ability to capture hydrogen-containing halosilane molecules and activate metals, so that the metals have high activity and selectivity in the above reaction system. The hydrogen halide content in the reaction product discharged from the reaction system can be reduced to less than 5ppm, which can simplify the tail gas treatment process of polysilicon production, reduce the consumption of raw and auxiliary materials, make the treatment process environmentally friendly, and reduce the investment and operation costs of equipment and devices.

Description

technical field [0001] The invention relates to the technical field of preparation of high-purity polysilicon, in particular to a hydrogen halide removal process in tail gas of polysilicon production. Background technique [0002] As the basic raw material of electronics industry and solar photovoltaic industry, high-purity polysilicon is known as "the cornerstone of the microelectronics building". With the economic recovery of the solar industry, the global demand for polysilicon is growing rapidly. The manufacture of high-purity polysilicon mainly adopts the modified Siemens method and the fluidized bed method, among which the modified Siemens method is the most widely used. The improved Siemens method uses trichlorosilane as the raw material, adopts a high-temperature reduction process, and in a high-purity hydrogen atmosphere, trichlorosilane is reduced and deposited on the silicon core to form polysilicon. The reduction reaction tail gas will contain a large amount of ...

AI Technical Summary

Problems solved by technology

But its disadvantage is that the halogen-containing catalyst can be dissolved in methyl chlorosilane and leave the reaction system with the flow of methyl chlorosilane, resulting in a short service life of the catalyst

The U.S. patent of US5401872 adopts chlorination catalyst to reclaim chlorine in the hydrogen chloride-containing gas stream to obtain more chlorinated silanes, and the catalyst used is selected from one or more of palladium, platinum, rhodium, ruthenium, nickel, osmium, iridium, However, the catalyst is relatively expensive, which is not conducive to industrial scale-up production.