Hydrogen fluoride recycling method of electrolytic fluoride processing exhaust gas

Abstract

The invention discloses a hydrogen fluoride recycling method of electrolytic fluoride processing exhaust gas. The method is characterized by comprising a buffering and voltage stabilizing process, a deeply condensing process and an alkali liquor absorbing process. The method comprises the following concrete steps of after cathode exhaust gas produced by electrolytic fluoride processing enters into a processing system, the gas pressure is maintained in the range of -50-50Pa; HF (Hydrogen Fluoride) gas is cooled to be -80+ / -1 DEG C from the normal temperature through the deeply condensing process to obtain HF condensate, so that the volume fraction of HF in the exhaust gas is reduced to be the limitation of 2 percent from 6 percent; then the cathode exhaust gas with the HF being recycled is fed into an absorption tower, and the concentration of the HF in the cathode exhaust gas subjected to alkali liquor absorbing is less than 9mg / m<3>; finally, the HF is ignited by an incinerator so as to be discharged at high attitude. Compared with the prior art, the hydrogen fluoride recycling method of the electrolytic fluoride processing exhaust gas has the advantages that the HF recycling efficiency achieves 67 percent, the HF purification efficiency achieves 99.9 percent, the effective utilization of resources is improved, the environment pollution is reduced, and the processing cost is low, and is a hydrogen fluoride recycling process with high industrial value.

Description

technical field [0001] The invention relates to the technical field of waste gas recovery and treatment, in particular to a hydrogen fluoride recovery and treatment method for electrolytic fluorine cathode tail gas. Background technique [0002] In the fluorine chemical industry and nuclear chemical industry, the industrial preparation of fluorine monomer is mainly by electrolysis. The electrolyte is a molten mixture prepared by potassium bifluoride and anhydrous HF. Direct current is passed through the electrolytic cell for electrochemical reaction, and the anode produces F. 2 , the cathode produces H 2 . The boiling point of HF is 19.2°C, and the electrolysis temperature of the electrolytic cell is much higher than the boiling point of HF, causing HF to volatilize, so the cathode of the electrolytic cell generates H 2 While entraining a certain amount of HF, forming a 2 and HF cathode tail gas (wherein hydrogen accounts for 94% by volume and hydrogen fluoride accounts...

AI Technical Summary

Problems solved by technology

[0004] The problem existing in the existing technology is: HF in the cathode tail gas is not recycled, but directly purified and discharged up to the standard, which is a great waste of production resources. Only H 2 Two substances with HF, especially hydrogen fluoride can be recycled as raw materials for electrolytic fluorine production after separation and recovery

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