Defluorination method of acidic aqueous solution containing hydrofluoric acid

A technology of acidic aqueous solution and hydrofluoric acid, applied in chemical instruments and methods, chlorine/hydrogen chloride, halogen/halogen acid, etc., can solve the problems of bringing in metal ions, low defluorination rate, poor treatment effect, etc., to achieve High operating flexibility, avoiding chlorination process, and high defluorination efficiency

Inactive Publication Date: 2017-07-07
JUHUA GROUP TECH CENT
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

The disadvantage is that this method needs to chlorinate the intermediate product in the regeneration process to generate trialkylchlorosilane for reuse, the process is complicated, and the treatment effect on acidic aqueous solution with high fluorine content is poor
The disadvantage is that this method has the defect of long defluorination time
The disadvantage is that this method will bring in metal ions, and the treatment effect on acidic aqueous solutions with high fluorine content is poor
The disadvantage is that this method brings in nearly 1% soluble substances, and the defluorination rate is not high, and the treatment effect on acidic aqueous solutions with high fluorine content is poor

Method used

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Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0048] (1) Add 500g of 16.3% by mass hydrochloric acid (fluorine-containing 1980ppm) into a 1L polyethylene reactor, then add 40g of trimethylchlorosilane, and stir at 20°C for 60min.

[0049] (2) After the reaction is over, the layers are static and the reaction solution is divided into two layers, which are separated by a separatory funnel. The lower layer liquid is defluorinated hydrochloric acid (fluorine-containing 7.2ppm), and the upper layer is an organosilicon mixture containing trimethylfluorosilane, hexamethyldisiloxane and a small amount of trimethylsilanol.

[0050] (3) Mix the organosilicon mixture obtained in step (2) with 50 g of a 10% aqueous sodium hydroxide solution by mass, and stir at 20° C. for 60 min to hydrolyze trimethylfluorosilane to generate trimethylsilanol, The trimethylsilanol is then condensed to give hexamethyldisiloxane with a small amount of trimethylsilanol.

[0051] (4) After the regeneration reaction is finished, the layers are statically ...

Embodiment 2

[0053] (1) Add 500g of 31.8% hydrochloric acid (containing F 1640ppm) into a 1L polyethylene reactor, then add 10g of trimethylchlorosilane and 30g of hexamethyldisiloxane at 40°C The reaction was stirred for 10 min.

[0054] (2) After the reaction is over, the layers are static and the reaction solution is divided into two layers, which are separated by a separatory funnel. The lower layer liquid is defluorinated hydrochloric acid (3.2 ppm fluorine content). The upper layer is a silicone mixture containing trimethylfluorosilane, hexamethyldisiloxane and a small amount of trimethylsilanol and trimethylchlorosilane.

[0055] (3) Mix the organosilicon mixture obtained in step (2) with 50 g of a 20% aqueous sodium hydroxide solution by mass, and stir at 25° C. for 50 min to hydrolyze trimethylfluorosilane to generate trimethylsilanol, and then Condensation of trimethylsilanol yields hexamethyldisiloxane.

[0056] (4) After the regeneration reaction is finished, the layers are ...

Embodiment 3

[0058] (1) Add 500 g of 31% hydrochloric acid (containing 1840 ppm fluorine) into a 1L polyethylene reactor, then add 20 g of trimethylchlorosilane, and stir at 30° C. for 30 min.

[0059] (2) After the reaction is over, the layers are static and the reaction solution is divided into two layers, which are separated by a separatory funnel. The lower layer liquid is defluorinated hydrochloric acid (3.8 ppm of fluorine), and the upper layer is an organosilicon mixture containing trimethylfluorosilane, hexamethyldisiloxane and a small amount of trimethylsilanol.

[0060] (3) Mix the organosilicon mixture obtained in step (2) with 50 g of a 25% aqueous potassium hydroxide solution by mass, and stir at 30° C. for 40 min to hydrolyze trimethylfluorosilane to generate trimethylsilanol, The trimethylsilanol is then condensed to give hexamethyldisiloxane with a small amount of trimethylsilanol.

[0061] (4) After the regeneration reaction is finished, the layers are statically separate...

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Abstract

The invention discloses a method for defluorinating an acidic aqueous solution containing hydrofluoric acid, which comprises the following steps: (a) combining an acidic aqueous solution containing hydrofluoric acid with trialkylchlorosilane or trialkylchlorosilane and hexaalkyldisiloxane The mixture of alkane is reacted, the reaction temperature is 10-80°C, the reaction time is 5-100min, the obtained reaction solution is separated, the upper layer obtains the organic silicon mixture, and the lower layer obtains the acidic aqueous solution after defluorination; (b) the step (a ) the obtained organosilicon mixture is mixed with the alkali solution for regeneration reaction, and the obtained regeneration reaction liquid is separated, the lower layer is obtained with alkali solution containing fluoride salt, and the upper layer is hexaalkyldisiloxane. The invention has the advantages of simple process, high operating flexibility, high defluorination efficiency, and environmental protection.

Description

technical field [0001] The invention relates to a treatment method for fluorine-containing hydrochloric acid, in particular to a defluorination method for an acidic aqueous solution containing hydrofluoric acid. Background technique [0002] A large amount of acidic aqueous solution containing hydrofluoric acid, such as fluorine-containing hydrochloric acid, fluorine-containing sulfuric acid, and fluorine-containing acidic wastewater, is produced in the industrial production process. Due to the existence of hydrofluoric acid, the application value of acidic aqueous solution is greatly reduced, and it is easy to cause environmental protection problems and cause potential harm to the environment. Some enterprises even treat it as waste acid, which seriously affects economic benefits. Therefore, it is necessary to find a method for effectively removing hydrogen fluoride in acidic aqueous solution. At present, lime or carbide slag neutralization and sedimentation separation are...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C01B7/07
CPCC01B7/0706
Inventor 杨仲苗吴奕姜志田黄明星
Owner JUHUA GROUP TECH CENT
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