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A kind of method for reclaiming and preparing boric acid and potassium chloride from polarizing plate waste liquid

A waste liquid recovery and polarizing plate technology, which is applied to chemical instruments and methods, boron compounds, boron oxide compounds, etc., can solve the problems of high requirements for precise control of concentration ratio, high consumption of acid and alkali, etc., to reduce safety risks, The effect of avoiding secondary waste

Active Publication Date: 2020-10-09
WUXI ZHONGTIAN SOLID WASTE DISPOSAL CO LTD
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

A method for preparing boric acid in boron-containing sodium chloride potassium chloride saturated brine solution described in CN101659418 A uses the difference in solubility between borate and sodium chloride potassium chloride to separate by evaporation and concentration, but in In the process of finally obtaining boric acid products, a large amount of acid and alkali needs to be consumed, and the requirement for precise control of the concentration ratio is relatively high

Method used

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  • A kind of method for reclaiming and preparing boric acid and potassium chloride from polarizing plate waste liquid

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0029] Take 2L polarizer waste liquid, distill and concentrate under the conditions of 100°C and -0.02MPa to obtain iodine-containing crude boric acid, the mass fraction of which is as follows: 70% boric acid, 27% potassium tetraborate, 2.3% potassium iodide, and 0.01% iodine.

[0030] Take 200g iodine-containing crude boric acid, add a total of 140mL water and 1mL50g / L K 2 SO 3 The mixed solution was beaten twice, and after the beating was finished, it was separated by filtration, and it was detected that the crude boric acid did not contain KI after beating. Slowly add boric acid after beating into 600mL water at 80°C, stir to dissolve, slowly add 45mL of 30% HCl, adjust the pH of the solution to 3, stir and cool the solution to 10°C, filter and separate, collect and dry the crystals, and the purity of the obtained boric acid is 99.1 %.

[0031] Get the salt-containing boric acid filtrate obtained after acidifying 560mL, add 25g Ca(OH) 2 , start stirring, heat the solutio...

Embodiment 2

[0035] Take 2 L of polarizer waste liquid, distill and concentrate under the conditions of 100°C and -0.06MPa to obtain iodine-containing crude boric acid, the mass fraction of which is as follows: 75% boric acid, 23% potassium tetraborate, 1% potassium iodide, and 0.01% iodine.

[0036] Take 200g iodine-containing crude boric acid, add a total of 100mL water and 1mL50g / L K 2 SO 3 The mixed solution was beaten twice, and after the beating was finished, it was separated by filtration, and it was detected that the crude boric acid did not contain KI after beating. Slowly add boric acid after beating to 900mL water at 85°C, stir to dissolve, slowly add 40mL of 30% HCl, adjust the pH of the solution to 4, stir to cool the solution temperature to 10°C, filter and separate, collect and dry the obtained crystals, and the purity of the obtained product boric acid is 99.4 %.

[0037] Get the salt-containing boric acid filtrate obtained after acidifying 560mL, add 24g Ca(OH) 2 , star...

Embodiment 3

[0041] Take 2L polarizer waste liquid, distill and concentrate under the conditions of 100°C and -0.08MPa to obtain iodine-containing crude boric acid, the mass fraction of which is as follows: 65% boric acid, 32% potassium tetraborate, 2.2% potassium iodide, and 0.02% iodine. .

[0042] Take 200g iodine-containing crude boric acid, add a total of 40mL water and 2mL50g / L K 2 SO 3 The mixed solution was beaten twice, and after the beating was finished, it was separated by filtration, and it was detected that the crude boric acid did not contain KI after beating. Slowly add boric acid after beating into 1200mL water at 90°C, stir to dissolve, slowly add 50mL of 30% HCl, adjust the pH of the solution to 3, stir to cool the solution temperature to 10°C, filter and separate, collect and dry the crystals, and the purity of the obtained product boric acid is 99.6 %.

[0043] Get the salt-containing boric acid filtrate obtained after acidifying 560mL, add 23g Ca(OH) 2 , start stir...

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Abstract

The invention discloses a method for preparing boric acid and potassium chloride by recycling waste liquid of a polarizing plate. The method comprises the following steps of (1) pulping; (2) acidifying 1; (3) calcification; (4) acidifying 2; (5) concentration. According to the method, secondary waste is not generated in the process, the separation effect requirement is moderate, organic medicaments are not used, there are no precise requirements for the ratio control during evaporation and concentration, high-purity boric acid and potassium chloride can be obtained, and the waste liquid is recycled.

Description

technical field [0001] The invention relates to the technical field of wastewater treatment, in particular to a method for preparing boric acid and potassium chloride by recycling polarizer waste liquid. Background technique [0002] With the rapid development of the electronics industry, the use of LCD screens is becoming more and more common. Taking LCD TVs as an example, the export volume of LCD TVs in the first half of 2017 alone reached 40.27 million units. The polarizer is the core component of the liquid crystal panel, mainly used to transmit and block the light emitted by the backlight module. Statistics show that in 2018, the domestic polarizer market reached more than 3 billion US dollars. According to different materials, polarizers are divided into three categories: metal, iodine, and dyes. Among them, due to lower cost, iodine-based polarizers combined with iodine molecules and polyvinyl alcohol have the highest market share. In the process of preparing iodine...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): C01B35/10C01D3/04C01F11/28
CPCC01B35/1054C01D3/04C01F11/28C01P2006/80
Inventor 伍元东虞恺
Owner WUXI ZHONGTIAN SOLID WASTE DISPOSAL CO LTD