Method for recovering tail gas generated by polycrystalline silicon production

Abstract

The invention provides a method used for recycling exhaust gases from the production of polysilicon. The exhaust gases mainly include hydrogen, hydrogen chloride, dichlordihydrosilicate and silicon tetrachloride. The method mainly includes the following steps: exhaust gases are compressed and cooled to separate hydrogen, hydrogen chloride and dichlordihydrosilicate from liquid trichlorosilane andsilicon tetrachloride with the liquid-gas separation method; gaseous hydrogen, hydrogen chloride dichlordihydrosilicate are mixed with liquid absorbent to separate hydrogen and hydrogen chloride fromdichlordihydrosilicate; hydrogen chloride and dichlordihydrosilicate are separated from liquid absorbent through heating and / or compression; hydrogen chloride and dichlordihydrosilicate are separatedthrough heating and / or compression; trichlorosilane and silicon tetrachloride are separated through heating and / or compression and are separated through heating and / or compression. The method of the invention is used for dry processing and recycling of exhaust gases, and can be used in production of polysilicon; raw materials can be fully utilized, pollutants are reduced, environmental pollution is avoided, and the cost is reduced.

Description

technical field [0001] The invention relates to a method for recovering and treating tail gas produced by industrial production of polysilicon, more specifically, to a method for dry recovery of tail gas produced by producing polysilicon. Background technique [0002] Polycrystalline silicon is the raw material for preparing monocrystalline silicon, which is ultimately used in the production of integrated circuits and electronic devices. It is one of the basic raw materials with the largest consumption and the highest purity requirements in the information industry. It is also a product and industry that the country encourages the development of. [0003] The world's advanced polysilicon production technology has always been monopolized by companies from the United States, Japan, and Germany. Each company has its own technical secrets and technical characteristics. After continuous research and development, it has formed its own production process. Set out, strictly control ...

AI Technical Summary

Problems solved by technology

However, during the water washing process, impurity gases such as oxygen and carbon dioxide in the water will pollute the hydrogen, so a large amount of recovered hydrogen needs to be purified again

In addition, the hydrolysis of chlorosilane during the washing process produces sewage, which requires further treatment, resulting in environmental pollution and large material consumption.

At the same time, the generated hydrogen has not been fully utilized, which not only wastes energy, increases costs, but also causes environmental pollution.

Images