Method for producing calcium fluoride by waste LCD panel glass etching liquid

A panel glass and etching solution technology, applied in the direction of calcium/strontium/barium fluoride, calcium/strontium/barium halide, etc., can solve the problems of waste of fluorine resources, reuse, waste of dry materials, etc., and achieve low molecular weight and high price. Low, purity-enhancing effect

Inactive Publication Date: 2014-10-01
YANGZHOU BRIGHTMAN INT
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

However, the system still has the following deficiencies: 1. The calcium fluoride produced by waste acid treatment has low purity, and is usually only treated as general waste landfill, which cannot be reused as resources, resulting in a huge waste of fluorine reso

Method used

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Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0016] The method for producing calcium fluoride from waste LCD panel glass etching solution of the present invention includes the following steps in sequence:

[0017] ⑴ A certain amount of waste LCD panel glass etching solution is used to determine the content of hydrofluoric acid, hexafluorosilicic acid and hexafluoroaluminate in the waste LCD panel glass etching solution. The weight percentage of the hydrofluoric acid in the etching solution is 16.5%, The weight percentage of the hexafluorosilicic acid in the etching solution is 20%, and the weight percentage of the hexafluoroaluminate in the etching solution is 8%.

[0018] (2) Add sodium fluoride solid to the waste LCD panel glass etching solution, the weight ratio is waste LCD panel glass etching solution: sodium fluoride=1:0.2, fully stir to make hexafluorosilicic acid and sodium fluoride completely react to produce hexafluorosilicon Sodium and hydrofluoric acid, H 2 SiF 6 +2NaF→Na 2 SiF 6 ↓+2HF; completely react hexafluor...

Embodiment 2

[0027] The method for producing calcium fluoride from waste LCD panel glass etching solution of the present invention includes the following steps in sequence:

[0028] (1) A certain amount of waste LCD panel glass etching solution is used to determine the content of hydrofluoric acid, hexafluorosilicic acid and hexafluoroaluminate in the waste LCD panel glass etching solution. The weight percentage of the hydrofluoric acid in the etching solution is 17.6%, The weight percentage of the hexafluorosilicic acid in the etching solution is 21%, and the weight percentage of the hexafluoroaluminate in the etching solution is 8.4%.

[0029] ⑵Add sodium fluoride solid to the waste LCD panel glass etching solution, the weight ratio is waste LCD panel glass etching solution: sodium fluoride=1:0.22, fully stir the hexafluorosilicic acid and sodium fluoride to completely react to produce hexafluorosilicon Sodium and hydrofluoric acid, H 2 SiF 6 +2NaF→Na 2 SiF 6 ↓+2HF; completely react hexafluo...

Embodiment 3

[0038] The method for producing calcium fluoride from waste LCD panel glass etching solution of the present invention includes the following steps in sequence:

[0039] ⑴ A certain amount of waste LCD panel glass etching solution is used to determine the content of hydrofluoric acid, hexafluorosilicic acid and hexafluoroaluminate in the waste LCD panel glass etching solution. The weight percentage of the hydrofluoric acid in the etching solution is 18.5%, The weight percentage of the hexafluorosilicic acid in the etching solution is 22%, and the weight percentage of the hexafluoroaluminate in the etching solution is 9%.

[0040] (2) Add sodium fluoride solid to the waste LCD panel glass etching solution, the weight ratio is waste LCD panel glass etching solution: sodium fluoride=1: 0.25, fully stir the hexafluorosilicic acid and sodium fluoride to completely react to produce hexafluorosilicon Sodium and hydrofluoric acid, H 2 SiF 6 +2NaF→Na 2 SiF 6 ↓+2HF; completely react hexafluo...

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PUM

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Abstract

The invention relates to a method for producing calcium fluoride by waste LCD panel glass etching liquid. The method sequentially comprises the following steps: weighting a certain amount of waste LCD panel glass etching liquid, adding a sodium fluoride solid, fully stirring to enable hexafluorosilicate and sodium fluoride in the waste liquid to completely react to generate sodium hexafluorosilicate and hydrofluoric acid and to enable hexafluoroaluminate and sodium fluoride to completely react to generate sodium hexafluoroaluminate and hydrofluoric acid; then adding ammonia water to react so as to generate silicon dioxide, sodium fluoride and ammonium bifluoride, and enabling the sodium hexafluoroaluminate and the remanent sodium hexafluorosilicate to settle rapidly; then filtering a precipitate, taking a supernatant to be added into a calcium hydroxide suspension, and stopping the addition of the supernatant until the pH is equal to 5 to enable calcium hydroxide to fully react with hydrofluoric acid so as to generate calcium fluoride; then adding the calcium hydroxide suspension into the former solution to enable the sodium fluoride and the ammonium bifluoride to respectively react with the calcium hydroxide so as to generate calcium fluoride; adding a polyacrylamide solution into the former solution, performing precipitation, filtering and cleaning, and finally drying to obtain the calcium fluoride solid. The purity of calcium fluoride is above 95%.

Description

Technical field [0001] The invention relates to a method for processing glass etching solution, in particular to a method for producing calcium fluoride from waste LCD panel glass etching solution. Background technique [0002] Generally, hydrofluoric acid is used to etch and thin the glass in the glass thinning process. The waste solid and waste liquid generated in the glass etching process are basically all recycled through a qualified third-party organization, and then processed after recycling. The sludge is disposed of in a landfill or after high temperature calcination, the supernatant is returned to the industrial sewage treatment system for reprocessing. [0003] The current common fluorine-containing wastewater treatment method is to dissolve the calcium-containing agent into a liquid, and then add it to the wastewater under mechanical stirring, so that the fluoride ion in the wastewater reacts with the calcium ion to form water-insoluble calcium fluoride suspended particl...

Claims

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Application Information

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IPC IPC(8): C01F11/22
Inventor 陈阿发
Owner YANGZHOU BRIGHTMAN INT
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