CN-116422001-B - Waste polarizing plate recycling system and method

CN116422001BCN 116422001 BCN116422001 BCN 116422001BCN-116422001-B

Abstract

The invention provides a system and a method for recycling waste polarizing plates. The recovery system comprises a first extraction unit, a second extraction unit, a first separation unit, a second separation unit and a purification and concentration system. The first extraction unit is used for extracting the waste polarizing plate fragments containing iodine, and then the iodine-containing extract and the waste polarizing plate plastic fragments are separated by the first separation unit. The second extraction unit is used for re-extracting the waste polarizing plate plastic fragments, and then the re-extraction liquid and the waste polarizing plate plastic fragments are separated by the second separation unit. The purification and concentration system comprises a filtering unit, a membrane separation unit and a distillation and concentration unit which are connected in series. The filter unit is used for receiving the iodine-containing extract and filtering to remove jelly, so as to obtain iodine-containing filtrate. The membrane separation unit comprises at least one reverse osmosis membrane for receiving the filtrate containing iodine and separating the iodine reverse osmosis liquid and the osmosis solvent by reverse osmosis. The distillation concentration unit is used for receiving the iodine reverse osmosis liquid and distilling to obtain iodine concentrated liquid and distilled liquid. The re-extraction solvent in the second extraction unit comprises a penetrating solvent and a distillate.

Inventors

HUANG GUODONG
LIU YIJUN
PENG MEIZHI

Assignees

财团法人工业技术研究院

Dates

Publication Date: 20260508
Application Date: 20221124
Priority Date: 20221102

Claims (12)

1.A waste polarizing plate recycling system, comprising: A first extraction unit for receiving the waste polarizing plate fragments containing iodine, and extracting the waste polarizing plate fragments containing iodine by using an extraction solvent to obtain an extraction mixture; a first separation unit for receiving the extraction mixture from the first extraction unit and separating the extraction mixture to obtain an iodine-containing extract and waste polarizing plate plastic chips; the second extraction unit is used for receiving the waste polarizing plate plastic fragments from the first separation unit and re-extracting the waste polarizing plate plastic fragments to obtain a re-extracted mixture; a second separation unit for receiving and separating the re-extracted mixture from the second extraction unit, and A purification and concentration system comprising a plurality of filtering units, a membrane separation unit and a distillation and concentration unit which are connected in series, wherein The filtering unit is used for receiving the iodine-containing extract and filtering to remove jelly to obtain iodine-containing filtrate; The membrane separation unit comprises at least one reverse osmosis membrane for receiving the iodine-containing filtrate and separating iodine reverse osmosis liquid and osmosis solvent by reverse osmosis, and The distillation concentration unit is used for receiving the iodine reverse osmosis liquid and distilling to obtain iodine concentrated liquid and distilled liquid, Wherein the re-extraction solvent in the second extraction unit comprises the penetrating solvent and the distillate.
2. The recycling system of waste polarizing plate according to claim 1, wherein the first extraction unit comprises a stirring element and a heating element.
3. The waste polarizing plate recycling system according to claim 1, wherein the filtering unit comprises an ultrafiltration membrane, a nanofiltration membrane, or a series of the ultrafiltration membrane and the nanofiltration membrane.
4. The recycling system of waste polarizing plates according to claim 1, wherein the total dissolved solids rejection rate of the at least one reverse osmosis membrane is greater than 90%.
5. The recycling system of waste polarizing plates according to claim 1, wherein the extraction solvent comprises alkali and solvent, the alkali is sodium hydroxide, potassium hydroxide or alkaloid, and the solvent comprises ethanol.
6. The recycling system of waste polarizing plates according to claim 1, wherein the re-extraction solvent comprises alkali and solvent, the alkali is sodium hydroxide, potassium hydroxide or alkaloid, and the solvent comprises ethanol.
7. The recycling system of waste polarizing plate according to claim 1, wherein the re-extraction liquid separated from the re-extraction mixture is recycled to dispense the extraction solvent.
8. The recycling system of waste polarizing plate according to claim 1, further comprising a solvent preparing unit for preparing the extraction solvent.
9. A method for recycling waste polarizing plates, comprising: Mixing and stirring the waste polarizing plate fragments containing iodine with an extraction solvent to obtain an extraction mixture; Separating the extraction mixture to separate out iodine-containing extract and waste polarizing plate plastic chips; filtering the iodine-containing extract to remove gum and obtain iodine-containing filtrate; Treating the iodine-containing filtrate with a membrane separation unit comprising at least one reverse osmosis membrane to separate out an iodine reverse osmosis liquid and an osmosis solvent; distilling the iodine reverse osmosis liquid from the membrane separation unit to obtain iodine concentrated solution and distillate; Recovering the penetrating solvent and preparing the distilled liquid into re-extraction solvent or extraction solvent; re-extracting the waste polarizing plate plastic chips to obtain a re-extracted mixture, and Separating the re-extraction mixture to separate re-extraction liquid and waste polarizing plate plastic chips, wherein the re-extraction liquid is recovered for preparing the extraction solvent, Wherein the extraction solvent and the re-extraction solvent respectively comprise alkali solvents and alcohol solvents.
10. The method for recycling waste polarizing plates according to claim 9, wherein the alkali is sodium hydroxide, potassium hydroxide or alkaloid, and the alcohol solvent comprises ethanol.
11. The method of claim 9, wherein the method of filtering the iodine-containing extract comprises using an ultrafiltration membrane, a nanofiltration membrane, or a series of the ultrafiltration membrane and the nanofiltration membrane.
12. The method of claim 9, wherein the total dissolved solids rejection rate of the at least one reverse osmosis membrane is greater than 90%.

Description

Waste polarizing plate recycling system and method Technical Field The present invention relates to a waste recycling system, and more particularly, to a waste polarizing plate recycling system and method. Background The polarizing plate polarizer is one of main materials of a Liquid Crystal Display (LCD), and its structure may include a polarizing layer, upper and lower adhesive layers, upper and lower protective/release layers, and a reflective film. The polarizing layer is basically made of a PVA (polyvinyl alcohol ) film after dyeing and stretching, the layer is a main part of the polarizing plate, the polarizing performance and the light transmittance of the polarizing plate are determined, and the polarizing layer is a main part affecting the color tone and the optical durability of the polarizing plate, and other upper and lower protective/release layers and reflective film plastics can be recycled after being cleaned. The dye material of the polarizing layer is usually iodine, but iodine sublimates under slight heat, so that the waste polarizing plate emits violet smoke during incineration treatment, which causes environmental concerns, and the treatment of the waste polarizing plate by the above method has been prohibited, so that how to treat the waste polarizing plate has become an important point of research in various fields. In addition, the components of the polarizing plate are complex, so that the sorting is difficult, the whole polarizing plate is fluffy and occupies space, and the polarizing plate is not easy to recycle. Disclosure of Invention The invention aims at a recovery system of waste polarizing plates, which not only removes iodine in polarizing plates, but also can recover iodine and reuse plastics. The invention also aims at a recovery method of the waste polarizing plate, which can purify and concentrate the extracted iodide ion solution and recycle the solvent so as to reduce recovery cost. According to an embodiment of the invention, a waste polarizing plate recycling system includes a first extraction unit, a first separation unit, a second extraction unit, a second separation unit, and a purification and concentration system. The first extraction unit is used for receiving the waste polarizing plate fragments containing iodine, and extracting the waste polarizing plate fragments containing iodine by using an extraction solvent to obtain an extraction mixture. The first separation unit is used for receiving the extraction mixture from the first extraction unit and separating the extraction mixture to obtain an iodine-containing extract and waste polarizing plate plastic fragments. The second extraction unit is used for receiving the waste polarizing plate plastic fragments from the first separation unit and re-extracting the waste polarizing plate plastic fragments to obtain a re-extraction mixture. The second separation unit is used for receiving the re-extraction mixture from the second extraction unit and separating the re-extraction mixture to obtain re-extraction liquid and waste polarizing plate plastic fragments. The purification and concentration system comprises a plurality of filtering units, a membrane separation unit and a distillation and concentration unit which are connected in series. The filtering unit is used for receiving the iodine-containing extract and filtering to remove jelly, so as to obtain iodine-containing filtrate. The membrane separation unit comprises at least one reverse osmosis membrane, and is used for receiving the iodine-containing filtrate and separating iodine reverse osmosis liquid and osmosis solvent in a reverse osmosis mode. The distillation concentration unit is used for receiving the iodine reverse osmosis liquid and distilling to obtain iodine concentrated liquid and distilled liquid. The re-extraction solvent in the second extraction unit comprises the permeate solvent and the distillate. According to another embodiment of the present invention, a method for recycling waste polarizing plate includes mixing and stirring waste polarizing plate plastic chips containing iodine with an extraction solvent to obtain an extraction mixture, and separating the extraction mixture to separate iodine-containing extract and waste polarizing plate plastic chips. The iodine-containing extract is filtered to remove jelly and obtain iodine-containing filtrate, and the iodine-containing filtrate is treated by a membrane separation unit containing at least one reverse osmosis membrane to separate iodine reverse osmosis liquid and osmosis solvent. And distilling the iodine reverse osmosis liquid from the membrane separation unit to obtain iodine concentrated solution and distilled solution. Recovering the penetrating solvent and the distillate to prepare a re-extraction solvent or the extraction solvent, then re-extracting the waste polarizing plate plastic fragments, and separating the re-extraction mixture to separate re-extraction liquid and wast