CN-121990727-A - Method and equipment for recovering waste lye from polarizer pretreatment
Abstract
The invention provides a method and equipment for recycling waste lye for pretreatment of a polaroid, wherein the method comprises the steps of removing suspended particles from the waste lye for pretreatment of polaroid manufacture through multistage filtration, decomposing total organic carbon in the waste lye for pretreatment of polaroid manufacture through UV light to generate intermediate liquid containing sodium carbonate, adding calcium oxide into the intermediate liquid to generate calcium hydroxide, reacting with sodium carbonate in the intermediate liquid to generate calcium carbonate sediment and sodium hydroxide, separating the calcium carbonate sediment through centrifugal separation to obtain clear liquid containing sodium hydroxide, and finally filtering the clear liquid through a precise filtering device to obtain regenerated lye meeting the recycling standard. The invention gives up the traditional sulfuric acid neutralization method, adopts the combination processes of UV photolysis, chemical carbonate removal, precise filtration and the like to treat the waste alkali liquid, and enables the waste alkali liquid to be reused.
Inventors
- ZOU HAO
- ZHANG JIANJUN
- RUAN ZHIYI
- LI XIANGQUAN
- XUE PEIPEI
- HUANG JUNHUI
Assignees
- 深圳市三利谱光电科技股份有限公司
Dates
- Publication Date
- 20260508
- Application Date
- 20260331
Claims (10)
- 1. The method for recovering the polarizer pretreated waste lye is characterized by comprising the following steps: carrying out multistage filtration on the pretreated waste alkali liquor produced by the polaroid to remove suspended particles; decomposing the total organic carbon in the polarizer manufacturing pretreatment waste alkali liquor by UV light to generate an intermediate liquor containing sodium carbonate; calcium oxide is added into the intermediate liquid to generate calcium hydroxide, and the calcium hydroxide reacts with sodium carbonate in the intermediate liquid to generate calcium carbonate sediment and sodium hydroxide; separating the calcium carbonate precipitate by adopting centrifugal separation to obtain clear liquid containing sodium hydroxide; and finally filtering the clear liquid by a precise filtering device to obtain regenerated alkali liquor meeting the recovery standard.
- 2. The method for recycling a polarizer pretreatment waste lye according to claim 1, wherein the manufacturing the pretreatment waste lye by decomposing the polarizer by UV light comprises: And adding hydrogen peroxide into the filtered polarizer manufacturing pretreatment waste alkali liquor, and carrying out mineralization decomposition on total organic carbon in the polarizer manufacturing pretreatment waste alkali liquor by utilizing the synergistic irradiation of dual-wavelength ultraviolet light, wherein the dual-wavelength ultraviolet light comprises a vacuum ultraviolet band and a deep ultraviolet band.
- 3. The method for recycling a polarizer pretreatment waste lye according to claim 2, wherein the manufacturing of the pretreatment waste lye by decomposing the polarizer by UV light further comprises: And monitoring the total organic carbon concentration in the polarizer manufacturing pretreatment waste alkali liquid after the advanced oxidation reaction in real time through an online TOC analyzer, and automatically adjusting the addition amount of the hydrogen peroxide and the irradiation power of the dual-wavelength ultraviolet light through a PID feedback control algorithm.
- 4. The method for recycling the polarizer pretreated waste lye according to claim 1, wherein the multi-stage filtration comprises a primary bag type filtration, a secondary precise filtration and a tertiary ultrafiltration, the secondary precise filtration has a micron filtration grade, the tertiary ultrafiltration adopts a hollow fiber ultrafiltration membrane made of polyvinylidene fluoride for filtration, and an automatic backwashing function based on transmembrane pressure difference monitoring is integrated.
- 5. The method for recycling waste lye from pretreatment of polarizer according to claim 1, wherein the precise filtration device is a renewable filtration device, and the renewable filtration device adopts an alkali-resistant ceramic membrane filtration or a metal sintered filter core filtration and is equipped with an automatic backwashing function.
- 6. A polarizer pretreatment waste lye recycling apparatus, comprising: a pretreatment device comprising a multistage filtration assembly; the UV photolysis device comprises an ultraviolet light reactor connected with the multistage filtering component; The chemical carbon removal device comprises a reaction kettle connected with a discharge port of the ultraviolet light reactor and a calcium oxide feeding component communicated with the reaction kettle; The solid-liquid separation device comprises a centrifugal machine connected with a discharge port of the reaction kettle; and the precise filtering device is connected with the clear liquid outlet of the centrifugal machine.
- 7. The polarizer pretreatment waste lye recycling apparatus according to claim 6, wherein the UV photolysis device further comprises a hydrogen peroxide adding assembly, the UV photolysis device comprises a dual-wavelength ultraviolet irradiation assembly, the UV photolysis device is used for adding hydrogen peroxide into the polarizer manufacturing pretreatment waste lye through the hydrogen peroxide adding assembly, and mineralizing and decomposing total organic carbon in the polarizer manufacturing pretreatment waste lye through advanced oxidation reaction by utilizing the dual-wavelength ultraviolet irradiation assembly to cooperatively irradiate.
- 8. The polarizer pretreatment waste lye recycling apparatus according to claim 7, wherein the UV photolysis device further comprises an online TOC analyzer for monitoring the total organic carbon concentration in the polarizer manufacturing pretreatment waste lye after the advanced oxidation reaction in real time, and automatically adjusting the addition amount of the hydrogen peroxide addition assembly and the irradiation power of the dual-wavelength ultraviolet irradiation assembly through a PID feedback control algorithm, wherein the ultraviolet light emitted by the dual-wavelength ultraviolet irradiation assembly comprises a vacuum ultraviolet band and a deep ultraviolet band.
- 9. The polarizer pretreatment waste lye recovery device according to claim 6, wherein the multistage filtration assembly comprises a first stage bag type filtration assembly, a second stage precise filtration assembly and a third stage ultrafiltration assembly, wherein the third stage ultrafiltration assembly adopts a hollow fiber ultrafiltration membrane made of polyvinylidene fluoride for filtration, and an automatic backwash pipeline based on transmembrane pressure difference monitoring is integrated.
- 10. The polarizer pretreatment waste lye recycling apparatus according to claim 6, wherein the fine filtration device is a renewable filtration device which adopts an alkali-resistant ceramic membrane filtration or a metal sintered filter core filtration and is equipped with an automatic backwash line.
Description
Method and equipment for recovering waste lye from polarizer pretreatment Technical Field The invention relates to the technical field of polarizer production, in particular to a method and equipment for recovering waste lye from polarizer pretreatment. Background In the polarizer manufacturing engineering, 30m3 of waste lye for pretreatment can be produced in each production line per month, and the existing waste lye for polarizer pretreatment contains organic small molecules such as cellulose Triacetate (TAC) which are difficult to degrade, so that the existing industry generally uses sulfuric acid for neutralization treatment and then discharges the waste lye, the treatment cost is high, sulfate ions and the organic small molecules in the treated water are difficult to completely remove, the COD (chemical oxygen demand), the conductivity and the like of the wastewater are difficult to meet the recycling standard, and the waste lye can only be used as wastewater discharge, and the prior art still needs to develop a polarizer waste lye treatment scheme capable of purifying reusable lye from the waste lye in polarizer manufacturing and realizing zero discharge of wastewater. Accordingly, the prior art is still in need of improvement and development. Disclosure of Invention The invention provides a method and equipment for recovering waste lye for polarizer pretreatment, and aims to solve the technical problems in the prior art in the background art. The invention comprises the following steps: The first aspect of the invention provides a polarizer pretreatment waste lye recovery method, which comprises the following steps: carrying out multistage filtration on the pretreated waste alkali liquor produced by the polaroid to remove suspended particles; decomposing the total organic carbon in the polarizer manufacturing pretreatment waste alkali liquor by UV light to generate an intermediate liquor containing sodium carbonate; calcium oxide is added into the intermediate liquid to generate calcium hydroxide, and the calcium hydroxide reacts with sodium carbonate in the intermediate liquid to generate calcium carbonate sediment and sodium hydroxide; separating the calcium carbonate precipitate by adopting centrifugal separation to obtain clear liquid containing sodium hydroxide; and finally filtering the clear liquid by a precise filtering device to obtain regenerated alkali liquor meeting the recovery standard. In an alternative embodiment of the first aspect of the present invention, the preparing the pretreatment waste lye by UV photodecomposition of the polarizer comprises: And adding hydrogen peroxide into the filtered polarizer manufacturing pretreatment waste alkali liquor, and carrying out mineralization decomposition on total organic carbon in the polarizer manufacturing pretreatment waste alkali liquor by utilizing the synergistic irradiation of dual-wavelength ultraviolet light, wherein the dual-wavelength ultraviolet light comprises a vacuum ultraviolet band and a deep ultraviolet band. In an alternative embodiment of the first aspect of the present invention, the preparing the pretreatment waste lye by UV photodecomposition of the polarizer further comprises: And monitoring the total organic carbon concentration in the polarizer manufacturing pretreatment waste alkali liquid after the advanced oxidation reaction in real time through an online TOC analyzer, and automatically adjusting the addition amount of the hydrogen peroxide and the irradiation power of the dual-wavelength ultraviolet light through a PID feedback control algorithm. In an alternative embodiment of the first aspect of the present invention, the multi-stage filtration includes a first-stage bag filtration, a second-stage precision filtration, and a third-stage ultrafiltration, wherein the second-stage precision filtration has a filtration grade of micron, and the third-stage ultrafiltration uses a hollow fiber ultrafiltration membrane made of polyvinylidene fluoride for filtration, and is integrated with an automatic backwash function based on transmembrane pressure difference monitoring. In an alternative embodiment of the first aspect of the present invention, the precision filtration device is a renewable filtration device, and the renewable filtration device adopts alkali-resistant ceramic membrane filtration or metal sintered filter core filtration and is equipped with an automatic backwashing function. In a second aspect, the present invention provides a polarizer pretreatment waste lye recycling apparatus, comprising: a pretreatment device comprising a multistage filtration assembly; the UV photolysis device comprises an ultraviolet light reactor connected with the multistage filtering component; The chemical carbon removal device comprises a reaction kettle connected with a discharge port of the ultraviolet light reactor and a calcium oxide feeding component communicated with the reaction kettle; The solid-liquid separation