Lithium hexafluorophosphate tail gas comprehensive utilization method

A technology of lithium hexafluorophosphate and tail gas, which is applied in separation methods, chemical instruments and methods, and dispersed particle separation, etc., can solve the problems of incomplete condensation of hydrogen fluoride, waste, and low separation efficiency of fluorine and chlorine, so as to achieve efficient utilization of resources and solve fluorine resources. The effect of waste and lower production costs

Pending Publication Date: 2022-08-09
DO FLUORIDE CHEM CO LTD
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0003] At present, most of the treatment methods for the tail gas of the lithium hexafluorophosphate process adopt condensation to remove most of the hydrogen fluoride gas, and then carry out water absorption to remove hydrogen chloride and phosphorus pentafluoride that are difficult to condense under normal pressure, and dilute fluorine-containing hydrochloric acid is produced as a by-product. High, incomplete condensation of hydrogen fluoride, low separation efficiency of fluorine and chlorine, low quality of by-product fluorine-containing hydrochloric acid, difficult reuse, and phosphorus pentachloride gas in the tail gas cannot be recycled, resulting in waste of resources

Method used

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  • Lithium hexafluorophosphate tail gas comprehensive utilization method
  • Lithium hexafluorophosphate tail gas comprehensive utilization method
  • Lithium hexafluorophosphate tail gas comprehensive utilization method

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Experimental program
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Effect test

Embodiment 1

[0031] A method for comprehensive utilization of lithium hexafluorophosphate tail gas, the process is as follows:

[0032] (1) The tail gas of the lithium hexafluorophosphate process is passed into the washing tower 1. The diameter of the washing tower 1 is 0.5m, the height of the tower is 5m, and the wire mesh packing (material is C276 or Monel alloy) is used, and the height of the packing is 3m. The flow rate in the tower 1 is 1m / s, the carbon tetrachloride is used to wash the tail gas with a spray amount of 0.3L / s, and the washing temperature is controlled to 20°C. When the concentration of phosphorus pentafluoride in the washing liquid reaches 40g / L, the washing liquid is passed into the desorption tank 5, desorbed at 65 ° C for 30min, and the desorbed gaseous substances are collected and passed into the condenser 6, and the temperature of the condenser 6 is set to -10 ℃, the collected uncondensed gas is phosphorus pentafluoride, and the condensed carbon tetrachloride and ...

Embodiment 2

[0036] A method for comprehensive utilization of lithium hexafluorophosphate tail gas, the process is as follows:

[0037] (1) Pass the tail gas of the lithium hexafluorophosphate process into the washing tower 1, control the flow rate of the tail gas in the washing tower 1 to be 1.5m / s, and use carbon tetrachloride to wash the tail gas at a spray volume of 0.4L / s at 25°C , when the concentration of phosphorus pentafluoride in carbon tetrachloride reaches 50g / L, the washing liquid is passed into the desorption tank 5, desorbed at 60 ° C for 45min, the gaseous substances collected and desorbed are passed into the condenser 6, and the temperature of the condenser 6 is maintained. 0 ℃, the collected uncondensed gas is phosphorus pentafluoride, and the condensed carbon tetrachloride and the desorbed carbon tetrachloride are mixed and recycled;

[0038] (2) Pass the tail gas after the first washing in step (1) into the reaction tank 2, and use the aluminum chloride solution with a ...

Embodiment 3

[0041] A method for comprehensive utilization of lithium hexafluorophosphate tail gas, the process is as follows:

[0042] (1) Pass the tail gas of the lithium hexafluorophosphate process into the washing tower 1, control the flow rate of the tail gas in the washing tower 1 to be 2m / s, and use carbon tetrachloride to wash the tail gas at a spray volume of 0.5L / s at 30 °C, When the concentration of phosphorus pentafluoride in the carbon tetrachloride reaches 60 g / L, the washing liquid is passed into the desorption tank 5, desorbed at 50 ° C for 60 min, and the desorbed gaseous substances are collected and passed into the condenser 6, and the temperature of the condenser 6 is maintained at 20 ℃, the collected uncondensed gas is phosphorus pentafluoride, and the condensed carbon tetrachloride and the desorbed carbon tetrachloride are mixed and recycled;

[0043] (2) Pass the tail gas after the first washing in step (1) into the reaction tank 2, and use the aluminum chloride solut...

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Abstract

The invention discloses a lithium hexafluorophosphate tail gas comprehensive utilization method, which comprises: (1) phosphorus pentafluoride recovery: introducing lithium hexafluorophosphate process tail gas into a washing tower, washing with an organic solvent, carrying out heating desorption on the obtained washing liquid, carrying out condensation impurity removal on the desorbed gaseous substance to obtain a phosphorus pentafluoride gas, and recycling the phosphorus pentafluoride gas, the desorbed organic solvent and the condensed organic solvent are mixed and cyclically used for tail gas washing; the organic solvent is carbon tetrachloride or benzene; (2) fluorine recovery: introducing the tail gas washed in the step (1) into a chlorate solution to react to remove fluorine, enabling hydrogen fluoride in the tail gas to react with the chlorate in the solution to generate fluoride salt, precipitating, then filtering, washing and drying to obtain fluoride salt, supplementing the chlorate into filtrate, and then circularly using the filtrate for removing fluorine from the tail gas; and (3) hydrogen chloride recovery: carrying out multi-stage absorption on the tail gas in the step (2) by using water to obtain industrial-grade concentrated hydrochloric acid.

Description

technical field [0001] The invention relates to the field of fluorine chemical preparation, in particular to a method for comprehensive utilization of lithium hexafluorophosphate tail gas. Background technique [0002] At present, the industrial production of lithium hexafluorophosphate mainly uses the hydrofluoric acid solvent method. This method is to react phosphorus pentachloride and anhydrous hydrogen fluoride to generate phosphorus pentafluoride gas, and then pass into LiF∙HF solution formed by dissolving lithium fluoride in anhydrous hydrogen fluoride. The reaction is carried out in the middle to obtain a synthetic liquid, and then the product is obtained by cooling crystallization, separation and drying. In this process, in the process of preparing phosphorus pentafluoride by the reaction of phosphorus pentachloride and anhydrous hydrogen fluoride, due to the violent exothermic reaction, the anhydrous hydrogen fluoride is volatilized, and the gas mixture after the re...

Claims

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Application Information

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IPC IPC(8): B01D53/68B01D53/34B01D53/78
CPCB01D53/78B01D53/68B01D53/346B01D53/18B01D2257/2047B01D2257/2045B01D2257/204Y02E60/10
Inventor 杨华春李云峰刘海霞王建萍王雷李凌云闫春生周小平
Owner DO FLUORIDE CHEM CO LTD
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