Method for recycling fluorine-containing sulfuric acid

A technology of sulfuric acid and hydrofluoric acid, applied in the direction of sulfur trioxide/sulfuric acid, hydrogen fluoride, fluorine/hydrogen fluoride, etc., can solve the problems of waste of fluorine resources, high reaction temperature, low concentration of sulfuric acid, etc., and achieve low equipment corrosion, mild conditions, The effect of simple method

Pending Publication Date: 2021-04-13
JIUJIANG TINCI ADVANCED MATERIALS CO LTD
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AI Technical Summary

Problems solved by technology

This method has the following disadvantages: (1) a large amount of fluorine-containing sewage produced needs further treatment before it can be discharged outside the environment
(2) Calcium sulfate and calcium fluoride contained in solid waste also need further solid waste treatment, which increases the cost a lot
(3) Causes waste of fluorine resources and has not been fully utilized
This method can separate hydrofluoric acid, but its shortcomings mainly include the following two points: first, fluorine-containing sulfuric acid itself is extremely corrosive, and in addition, the reaction temperature is high, which requires extremely high corrosion resistance of equipment; second, Continuous steaming leads to too low concentration of sulfuric acid produced

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  • Method for recycling fluorine-containing sulfuric acid
  • Method for recycling fluorine-containing sulfuric acid

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Experimental program
Comparison scheme
Effect test

Embodiment 1

[0042] Under normal pressure, add 15% deionized water into the reaction kettle equipped with fluorine-containing sulfuric acid, then pass in pure nitrogen and heat to 110°C, treat for 6.5h, during this process, pass the tail gas generated into In the deionized water tank, the temperature of the deionized water tank was kept at 10°C.

[0043] After the reaction was completed, leave fluorine-free sulfuric acid in the final reactor, and the concentration of sulfuric acid is 96%; the content of hydrofluoric acid is below 10ppm; Below 20ppm.

[0044] like figure 1 It is the ion chromatogram before fluorine-containing sulfuric acid is processed by the inventive method, figure 2It is an ion chromatogram of fluorine-containing sulfuric acid treated by the method of the present invention. As can be seen from the comparison of the two figures, after the fluorine-containing sulfuric acid is processed by the method of the present invention, figure 2 F peak and FSO have not been dete...

Embodiment 2

[0046] Under normal pressure, feed pure nitrogen into the reaction kettle equipped with fluorine-containing sulfuric acid and heat it to 110°C for 12 minutes. Keep at 10°C. Then take a sample from the reactor, after 100-fold dilution, measure the FSO 3 - content, and then calculate the FSO in the fluorine-containing sulfuric acid in the reactor 3 - content, calculate the theoretical water amount M required for the complete hydrolysis of fluorosulfonic acid in all the fluorine-containing sulfuric acid in the reactor, add 1.05M water into the reactor, stir, then feed nitrogen and heat to 110°C, treat for 5h, During this process, the generated tail gas was passed into the deionized water tank, and the temperature of the deionized water tank was kept at 10°C.

[0047] After the reaction is completed, leave fluorine-free sulfuric acid in the final reactor, and the sulfuric acid concentration is 97%; the hydrofluoric acid content is below 10ppm; the hydrofluoric acid with a hydr...

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Abstract

The invention relates to a method for recycling fluorine-containing sulfuric acid. The method comprises the steps of under normal pressure, adding a certain amount of deionized water into a reaction kettle filled with fluorine-containing sulfuric acid, with the addition amount of the deionized water being 90 to 120% of the theoretical water amount required for hydrolyzing fluorosulfonic acid in fluorine-containing sulfuric acid; introducing inert gas which does not react with sulfuric acid, hydrofluoric acid and water, heating, collecting tail gas, and absorbing with deionized water to obtain hydrofluoric acid; and fluorine-free sulfuric acid being left in the reaction kettle. After treatment, fluorine-free sulfuric acid is finally left in the reaction kettle, and the concentration of the sulfuric acid is 80 to 98%; the content of hydrofluoric acid is below 10ppm; after the tail gas is absorbed by the deionized water, hydrofluoric acid with the concentration of 30 to 48% is obtained, and the content of sulfuric acid is 20 ppm or below. Therefore, after the fluorine-containing sulfuric acid is treated by adopting the method disclosed by the invention, high-concentration and high-purity sulfuric acid and hydrofluoric acid which are directly commercialized or produced and applied can be obtained.

Description

technical field [0001] The invention relates to the recovery and utilization of by-product sulfuric acid, in particular to a method for the recovery and utilization of fluorine-containing sulfuric acid. Background technique [0002] In the fluorine chemical industry, a large amount of fluorine-containing sulfuric acid will be produced during the industrial production of hydrogen fluoride gas and phosphorus pentafluoride gas purification process. The concentration of sulfuric acid is generally between 60% and 80%. Because this part of sulfuric acid contains fluorosulfonic acid and has a high concentration, it is extremely corrosive to various metals. Recycling and storage are problems faced by various enterprises. [0003] The existing method for treating fluorine-containing sulfuric acid mainly uses lime for neutralization, and the calcium fluoride and calcium sulfate solutions produced after neutralization are filtered to collect the solids for solid waste treatment. This ...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C01B7/19C01B17/90
CPCC01B7/191C01B17/90
Inventor 秦小康刘杜邓建军
Owner JIUJIANG TINCI ADVANCED MATERIALS CO LTD
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