Method for preparing polysilicon

Abstract

The invention relates to a method for producing polysilicon. Industrial silicon reacts with chlorine hydride to generate trichlorosilane which reacts with hydrogen gas to generate the polysilicon after being purified; tail gases which main include the hydrogen gas, chlorine hydride, dichlorosilane, trichlorosilane and silicon tetrachloride are collected; the tail gases are pressurized and cooled, and gas-liquid separation is conducted to separate the hydrogen gas, the chlorine hydride and the dichlorosilane from the liquid trichlorosilane and the silicon tetrachloride; the gaseous hydrogen gas, the chlorine hydride and the dichlorosilane are led to pass through a liquid absorbent to separate the hydrogen gas from the chlorine hydride and the dichlorosilane; the chlorine hydride and the dichlorosilane are desorbed out from the liquid absorbent through heating and / or pressurizing; the chlorine hydride is separated from the dichlorosilane through controlling the pressure and / or temperature; in addition, the gas-liquid separation is conducted to separate the trichlorosilane from the silicon tetrachloride through the temperature and the pressure. The method recovers and utilizes the tail gases, makes the best of the raw material, reduces pollutants, solves the pollution problem, lowers the cost, and increases the output and the efficiency.

Description

technical field [0001] The invention relates to a method for industrially producing polysilicon, more specifically, to a method for producing polysilicon capable of dry recovery and utilization of tail gas. 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 technology transfer and monopoli...

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.

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