Tail gas treatment method and special device for lithium hexafluorophosphate synthesis

Abstract

The invention discloses a method and dedicated device for lithium hexafluorophosphate synthesis tail gas treatment. Tail gas is pressurized through a booster fan and then sent to a condenser, condensate is recycled to an anhydrous hydrogen fluoride reception tank, mixed gas discharged from the condenser passes through an airtight first-stage agitation reactor, a horizontal auger delivery reactor and a second-stage agitation reactor in sequence in the material stirring and guiding direction, a trace of HF in the mixed gas reacts with LiCl powder added into an agitation reaction combined device in advance, and LiCl powder in the second-stage agitation reactor returns into the first-stage agitation reactor through a material balance pipe to be forced to be stirred and circulated inside an agitation reaction system; tail gas discharged from the second-stage agitation reactor enters a water scrubber to generate hydrochloric acid after passing through a dust remover for gas trapping so that a small amount of powder can be taken away, and gas discharged from the water scrubber passes through an alkaline tower for alkaline washing and then is discharged. By the adoption of the method and dedicated device, HF in the mixed tail gas can be effectively removed, the quality of by-product hydrochloric acid is improved, and the application field is broadened.

Description

technical field [0001] The invention relates to a method and a special device for treating tail gas of lithium hexafluorophosphate synthesis. Background technique [0002] Lithium hexafluorophosphate, as the key material of lithium-ion secondary batteries, is a typical high-tech, high-risk production environment, and high-difficulty production "three high" technology product. At present, the mainstream synthesis process is anhydrous hydrogen fluoride solvent method, and the tail gas produced by it contains HCl and A mixture of HF, of which HF accounts for about 10-15%, the commonly used treatment method is to directly transport it to the tail gas scrubber for washing and absorption, and make a mixed acid containing HCl and HF (the content of HF is more than 10%) ), this treatment method cannot realize the effective separation of HCl and HF, thus limiting the scope of application of its by-product hydrochloric acid. Contents of the invention [0003] The object of the pres...

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Problems solved by technology

[0002] Lithium hexafluorophosphate, as the key material of lithium-ion secondary batteries, is a typical high-tech, high-risk production environment, and high-difficulty production "three high" technology product. At present, the mainstream synthesis process is anhydrous hydrogen fluoride solvent method, and the tail gas produced by it contains HCl and The mixture of HF, of which HF accounts for about 10-15%, the commonly used treatment method is to directly transport it to the tail gas scrubber for washing and absorption, and make a mixed acid containing HCl and HF (the content of HF is more than 10%) ), this treatment method cannot realize the effective separation of HCl and HF, thus limiting the scope of application of its by-product hydrochloric acid

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