SiF4 and HF mixed gas separation method and system

Abstract

The invention discloses a SiF4 and HF mixed gas separation method and system, the SiF4 and HF mixed gas and hydrogen are introduced into a microwave heating device together, the mixed gas of silicon tetrafluoride, hydrogen fluoride and hydrogen is rapidly heated to 600-1200 DEG C through the microwave heating device, and silicon and hydrogen fluoride gas is generated; enabling generated silicon and hydrogen fluoride gas and unreacted silicon tetrafluoride gas and hydrogen to enter a gas-solid separation device together, separating silicon out, and introducing residual gas into a condenser together; the hydrogen fluoride gas is condensed into hydrogen fluoride condensed liquid, the hydrogen fluoride condensed liquid enters a rectifying tower to be further purified to obtain high-purity hydrogen fluoride, and hydrogen and silicon tetrafluoride gas which are not reacted completely return to the microwave heating device to be reacted; and hydrogen and silicon tetrafluoride gas are circulated in the system, so that silicon tetrafluoride is continuously reduced to generate hydrogen fluoride, and high-purity hydrogen fluoride is obtained through condensation and rectification.

Description

technical field [0001] The invention relates to the technical field of fluorine chemical industry, in particular to a method and system for separating SiF4 and HF mixed gas. Background technique [0002] Anhydrous hydrogen fluoride (hydrogen fluoride) has a boiling point of 19.5°C under normal pressure. When it is lower than 19.5°C, it is a colorless fuming liquid. It is easy to polymerize and very volatile. It emits white smoke when it is placed in the air, and it emits violently when dissolved in water. Heat into hydrofluoric acid; it is highly corrosive and can corrode glass and silicate to generate gaseous silicon tetrafluoride, but it does not corrode polyethylene, lead and platinum; hydrogen fluoride is the production of refrigerant "Freon", Raw materials for fluorine-containing resins, organic fluorides, and fluorine. Hydrogen fluoride can be used as a catalyst for organic synthesis such as alkylation, polymerization, condensation, and isomerization in chemical produ...

AI Technical Summary

Problems solved by technology

[0003] In the process of using silicon tetrafluoride and hydrogen to prepare polysilicon, a large amount of hydrogen fluoride will be produced, and this large amount of hydrogen fluoride gas is mixed with silicon tetrafluoride gas. If this mixed gas is discharged directly, it will cause air pollution and waste of resources.

In the existing technology, it is difficult to obtain high-purity hydrogen fluoride products by means of separation and purification of hydrogen fluoride, and the separated hydrogen fluoride needs to be further processed before it can be put into the above-mentioned industrial applications, and a large amount of energy will be consumed in the separation process

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