CN100392477C - Liquid crystal display panel resource processing method - Google Patents

Abstract

The invention discloses a liquid crystal display panel recycling treatment method. First, the liquid crystal display panel is manually or soaked in a solvent to remove the polarizing film, and then the liquid crystal display panel is opened by cutting or soaking in acid solution to remove the sealed epoxy resin. The two glass substrates are soaked with an organic solvent to remove the liquid crystal on the glass substrates, and the glass substrates are cleaned and then immersed in an acid leaching solution to remove the metal coating on the glass substrates to obtain a clean glass substrate; The acid leaching solution of indium can be extracted and refined by the existing indium extraction process, and the finally obtained clean glass substrate can be used as a raw material. The invention realizes harmless treatment of waste liquid crystal display panels, and also recycles limited resources, realizes sustainable utilization of resources and harmonious unity of environmental benefits and economic benefits.

Description

Liquid crystal display panel resource processing method

technical field

The invention relates to a resource recovery process, in particular to a resource recovery treatment method for a liquid crystal display panel.

Background technique

As an important accessory of computers, monitors have also become the main object of recycling technology research. There are two types of displays currently in use: cathode ray tube displays (Cathode Ray Tubes, CRT for short) and liquid crystal displays (Liquid Crystal Display, LCD for short). Compared with cathode ray tube displays, liquid crystal displays have many advantages: flat display, small size, light weight, low power consumption, low driving voltage, can be directly driven by large-scale integrated circuits, can be displayed in a bright environment, the most important Because it does not contain harmful rays, it will not pollute the environment or endanger human health due to radiation. Although cathode ray tube displays still occupy a dominant position among the currently popular displays on the market, data show that with the decline in the price of liquid crystal displays and the maturity of technology, its market size is constantly expanding, and the application of liquid crystal displays It has become a trend and trend in the development of the international computer industry to desktop computers. In this situation, it is an indisputable fact that the thin liquid crystal display will replace the conventional CRT display as the standard display device for desktop computers. Not only that, liquid crystal displays are also widely used in notebook computers, digital cameras, mobile phones and other electronic audio-visual products, and have shown irreplaceable advantages. In this era of advocating health and environmental protection, people are paying more and more attention to liquid crystal displays. According to a recent data, in February 2005, the overall attention of China's LCD market increased significantly. On the one hand, it is due to the long Spring Festival holiday; on the other hand, new LCD products are emerging in an endless stream. Brands such as ViewSonic, Gigabyte and Eizo have launched new 17-inch and 19-inch LCD monitors in 2005. The innovative design of the new products has attracted the attention of many consumers. . Recently, LG has launched a 102-inch LCD TV. It can be seen that as soon as the liquid crystal display made its debut, it became the leader in the IT field.

With the rapid development of science and technology, liquid crystal displays have been widely used due to their incomparable advantages, and will gradually replace cathode ray tube displays and become standard display devices for desktop computers; at the same time, they are also used in digital cameras, mobile phones, notebooks, etc. There are irreplaceable advantages in the production of electronic products.

The extensive use of liquid crystal displays makes them one of the main sources of current and future e-waste. However, the current display recycling technology is mainly aimed at cathode ray tube displays, and the technology is relatively mature. However, there is relatively little involvement in the recycling and resource utilization of liquid crystal displays. In view of the unstoppable development momentum of liquid crystal display, it is very necessary to study the recycling of liquid crystal display.

The liquid crystal display recycling process can be roughly divided into two stages, one is the disassembly of the liquid crystal box, and the other is the recycling of various parts of the disassembled materials. Obviously, whether it is dismantling or recycling, in addition to having a full understanding of the structure of LCDs, you must also understand the main materials of LCDs. The materials used in the production of different types of liquid crystal displays are not exactly the same. However, whether it is a TN-type or a TFT-type liquid crystal display, it contains three main materials: glass, ITO film and liquid crystal. ITO film, namely transparent electrode, its main components are indium oxide and tin oxide. Metal indium is a rare metal with a low abundance in the earth's crust, but it is widely used in the electronic information industry.

The invention patent with application number 03109487.2 discloses a liquid crystal display resource treatment method. In this invention, the waste liquid crystal display panel is broken open and placed in a closed furnace for segmental heating. Catalyzed exhaust, plastic pyrolysis coking, rubbing After stripping and separating the coating layer, clean glass sheets are made. The separated coating oxides can be recycled as colorant additives. After crushing, the clean glass sheets can be made into various building materials for resource reuse. The patent does not mention the opening technology of the liquid crystal display panel, the key technology of removing the polarizing film and extracting the rare metal indium.

To sum up, there is currently a lack of a technology that can process liquid crystal displays and recycle resources to the maximum extent. Metal indium in liquid crystal display panels of liquid crystal displays has a high recycling value as a rare metal.

Contents of the invention

The purpose of the present invention is to propose a complete set of recycling technology for liquid crystal displays, so as to realize the harmless treatment of liquid crystal display panels and realize the effective recycling of resources at the same time.

The purpose of the present invention can be achieved through the following measures:

A liquid crystal display panel resource processing method, comprising the following steps:

a. Remove the polarizing film from the disassembled complete or broken liquid crystal display panel manually or by immersing in organic solvent, inorganic acid or lye;

b. The complete liquid crystal display panel obtained above with the polarizing film removed, or after cutting the sealed frame part, open the two glass substrates of the liquid crystal display panel, or soak them in inorganic acid solution to remove the sealing epoxy resin, after cleaning the panel, open the two glass substrates of the liquid crystal display panel;

c. Soak the complete glass substrate containing liquid crystal obtained in step b or the broken liquid crystal display panel obtained in step a with an organic solvent to remove the liquid crystal on the glass substrate, and clean it;

d. Soak the above-mentioned glass substrate after cleaning the liquid crystal with an acid leaching solution to remove the metal coating on the glass substrate to obtain a clean glass substrate.

For recycled waste liquid crystal displays, including scrap products produced on liquid crystal display production lines, and liquid crystal displays used in various electronic equipment, the electronic equipment containing liquid crystal displays shall be disassembled and recycled, and the liquid crystal display panels shall be put into this invented method.

The purpose of the present invention can specifically be achieved through the following steps:

A. First disassemble the electronic equipment containing the liquid crystal display, remove the printed circuit board, drive circuit, backlight, light guide plate and other components, the printed circuit board can be processed separately, and the plastic parts such as the light guide plate can be directly processed according to the plastic Reuse;

B. Remove the polarizing film of the dismantled liquid crystal display panel first, and use an organic solvent, such as one or more of acetone, chloroform, benzene, toluene, or xylene, or an inorganic acid, such as the volume ratio of water to water. 1:1 to 5 nitric acid or sulfuric acid solution, or lye, such as 1:5000 to 1:100 (mass ratio to water) sodium hydroxide or potassium hydroxide solution soaked to remove; the general soaking time is that the polarizing film falls off As the standard, the soaking time in organic solvent is generally 3-8 hours at room temperature; the soaking time in acid solution is 3-8 hours and heated to 50-90°C; the soaking time in alkali solution is 3-8 hours and heated to 50°C. ~90℃; the polarizing film can also be removed manually, and the polarizing film can be directly reused according to the plastic;

C. The liquid crystal display panel after removing the polarizing film is soaked with an acid solution, such as nitric acid or sulfuric acid solution of 1: 1 to 4 (volume ratio with water), to remove the sealed epoxy resin, and the reaction time is 2 to 8 Hours, the reaction temperature is 50 ~ 90 ℃, after cleaning the liquid crystal panel with water, open the two glass substrates of the liquid crystal display panel; you can also use diamond knife and other tools to cut the sealed frame part, then open the glass substrate, cut The frame that comes down can enter the subsequent processing steps together with the substrate glass;

D. Soak the glass substrate containing liquid crystal in an organic solvent, such as one or more of acetone, chloroform, benzene, toluene or xylene, to remove the liquid crystal on the glass, and clean the glass substrate after cleaning the liquid crystal with ethanol Remove the organic solvent, then wash with water to remove ethanol;

E. When the cleaning ability of the above-mentioned organic solvent is found to decline, the organic solvent containing liquid crystal is distilled and regenerated, and the remaining liquid crystal is incinerated after distillation;

F. Soak the glass substrate after cleaning the liquid crystal with acid leaching solution to remove metals such as ITO film on the glass substrate, and directly reuse the glass substrate from which the metal coating has been removed as glass raw material. The acid leaching solution is one or more of nitric acid, sulfuric acid or hydrochloric acid, the soaking temperature is 70-90°C, and the time is 1-6h. The preferred process is divided into the following three types: (1) The volume ratio with water is 1:1 ~4 nitric acid solution, the leaching temperature is controlled at 70~90°C, and the reaction time is 1~4h; (2) Add sulfuric acid with a concentration of 100~600g/L and add manganese dioxide in an amount of 10g/L according to the volume of sulfuric acid , heated and stirred, and the temperature was controlled at about 70-90°C. After reacting for 2-4 hours, water was added to control the final concentration of sulfuric acid to 50g/L, and the reaction was continued for 1-2 hours. (3) Mix according to the ratio of hydrochloric acid, nitric acid and water in the proportion of 5-10:1:5-10 (volume ratio), heat and stir, control the temperature at about 70-90°C, and react for 1-4 hours. According to theoretical calculations, the indium content on the glass substrate is only 0.052%, and the amount of acid used in theory is very small. In order to recycle the acid used for leaching in operation, in the above-mentioned process, the amount of acid used is generally excessive, and the leaching efficiency is limited. After falling, enter the subsequent indium extraction process;

G, with the above-mentioned acid leaching solution containing indium of leaching, carry out the extraction and the purification of indium with the technology of existing extraction indium (such as China Metallurgical Encyclopedia editor-in-chief committee " non-ferrous metal metallurgy " volume editorial committee, Metallurgical Industry Press " China Metallurgy " Edited by the editorial department of Encyclopedia. China Metallurgical Encyclopedia Nonferrous Metallurgy. Beijing: Metallurgical Industry Press, 1998.11);

H. The above steps are suitable for complete and unbroken liquid crystal display panels. If the liquid crystal display panel has been broken before recycling, step C can be omitted from steps A and B and directly enter step D for operation;

I, above-mentioned step soaking process can increase stirring operation, to improve the effect of treatment.

The treated glass substrate of the present invention can be directly used as glass raw material for reuse or as other purposes

The invention realizes harmless treatment of waste liquid crystal displays, and also recycles limited resources, such as plastics, electronic components, glass, metal indium, etc., and has certain economic benefits. The effective unification of economic benefits and environmental benefits is achieved through the processing of waste liquid crystal displays by this technology, the sustainable utilization of resources is realized, and the vigorous development of circular economy is utilized.

Detailed ways

Example 1:

A. First disassemble the electronic equipment containing the liquid crystal display panel, and remove the printed circuit board, drive circuit, backlight, light guide plate and other components. The printed circuit board can be processed separately, and the plastic parts such as the light guide plate can be directly processed according to plastic recycling;

B. Remove the polarizing film from the dismantled liquid crystal display panel, which can be soaked in acetone. The soaking time is subject to the peeling off of the polarizing film. The soaking time in organic solvent is 3 hours at room temperature;

C. Remove the sealed epoxy resin after soaking the liquid crystal display panel after removing the polarizing film with a nitric acid solution of 1:1 (volume ratio to water) under stirring. The reaction time is 4 hours, and the reaction temperature is 90° C. . After cleaning the liquid crystal panel with water, open the two glass substrates of the liquid crystal display panel.

D. Soak the glass substrate containing liquid crystal with acetone to remove the liquid crystal on the glass, wash the glass substrate with liquid crystal with ethanol to remove the organic solvent, and then wash with water to remove the ethanol;

E. When the cleaning ability of acetone is found to decline, the acetone containing liquid crystals is distilled and regenerated, and the remaining liquid crystals are incinerated;

F. Soak the glass substrate after cleaning the liquid crystal with nitric acid under stirring to remove metals such as the ITO film on the glass substrate, and directly reuse the glass substrate from which the metal coating has been removed as glass raw material. The nitric acid concentration was 1:4, the leaching temperature was controlled at 90°C, and the reaction was carried out for 1 hour. The amount of acid is generally excessive, and according to theoretical calculations, the indium content on the glass substrate is only 0.052%, and the amount of acid used is too small. The acid used for leaching in operation can be recycled, and enter the subsequent indium extraction process after the leaching efficiency drops.

G. Carry out the extraction and purification of indium with the existing indium-extracting process for the leached leaching solution containing indium;

Example 2:

Other conditions remain unchanged, in the step (B) of embodiment 1, use the nitric acid solution of 1:5 (to the volume ratio of water) instead to remove the polarizing film, heat to 80 ℃ and soak for 4 hours; In order to remove liquid crystal with xylene; in step (F), change the solution that is 5:1:5 (volume ratio) according to hydrochloric acid, nitric acid, water to remove metal coating, heat and stir, and control the temperature at about 70°C, React for 4 hours.

Example 3:

Other conditions remain unchanged, in the step (B) of embodiment 1, use the sodium hydroxide lye solution of 1:100 (to the weight ratio of water) instead to remove the polarizing film, heat to 80 ℃ and soak for 3 hours; step (F ), the metal coating was removed by a solution with a ratio of hydrochloric acid, nitric acid, and water of 7:1:9 (volume ratio), heated and stirred, and the temperature was controlled at about 80° C. for 3 hours.

Example 4:

Other conditions remain unchanged, in the step (B) of embodiment 1, use toluene instead to remove the polarizing film, and soak for 7 hours at room temperature; in step (C), use nitric acid of 1:2 (volume ratio to water) instead solution to remove epoxy resin, and soak for 2 hours at 70°C; in step (F), change to a nitric acid solution of 1:1 (volume ratio with water) to remove the metal coating, control the soaking temperature at about 70°C, and the time is 4 Hours.

Example 5:

Other conditions are constant, in the step (C) of embodiment 1, use the nitric acid solution of 1: 4 (with the volume ratio of water) instead to remove epoxy resin, soak 8 hours at 50 ℃; In step (F) , instead add sulfuric acid with a concentration of 200g/L and a solution of about 10g/L of manganese dioxide (calculated by the volume of sulfuric acid) to remove the metal coating, heat and stir, and control the temperature at about 90°C. After reacting for 4 hours, add water to control the final The sulfuric acid concentration was 50g/L, and the reaction was continued for 2h.

Embodiment 6:

Other conditions remain unchanged, in the step (B) of Example 1, use 1:5000 sodium hydroxide lye to remove the polarizing film, heat to 90 ° C and soak for 8 hours; in step (D), change to chloroform soak Remove the liquid crystal; in step (F), remove the metal coating according to a solution with a ratio of hydrochloric acid, nitric acid, and water of 10:1:10 (volume ratio), heat and stir, control the temperature at about 90° C., and react for 1 hour.

Embodiment 7:

Other conditions remain the same, the recovered liquid crystal display panel has been broken, and after directly tearing off the polarizing film manually, enter (D) in Example 1; in step (F), change it to 1:3 nitric acid solution to remove the metal coating, and control The soaking temperature is about 80°C, and the time is 3 hours.

Embodiment 8:

Other conditions remain unchanged, in the step (B) of embodiment 1, use chloroform instead to remove the polarizing film, and soak for 8 hours at normal temperature; Use a diamond knife to cut open.

Embodiment 9:

Other conditions remain unchanged, in the step (B) of Example 1, use 1:500 potassium hydroxide lye instead to remove the polarizing film, heat to 50°C and soak for 7 hours; in step (C), use 1:500 potassium hydroxide lye instead 3 (volume ratio to water) sulfuric acid solution to remove epoxy resin, soak at 60°C for 7 hours.

Example 10:

Other conditions remain unchanged, in the step (B) of Example 1, use a sulfuric acid solution of 1:1 (volume ratio to water) to remove the polarizing film, and heat to 90 ° C for 3 hours; in the step (F), Instead, add a solution of sulfuric acid with a concentration of 100g/L and manganese dioxide of about 10g/L (by volume of sulfuric acid) to remove the metal coating, heat and stir, and control the temperature at about 70°C. After reacting for 2 hours, add water to control the final sulfuric acid The concentration was 50g/L, and the reaction was continued for 2h.

Example 11:

Other conditions remain unchanged, in step (B) of embodiment 1, use chloroform to remove polarizing film instead, soak 8 hours under normal temperature; In step (F), add the sulfuric acid and manganese dioxide that concentration is 600g/L instead A solution of about 10g/L (calculated by volume of sulfuric acid) was used to remove the metal coating, heated and stirred, and the temperature was controlled at about 80°C. After reacting for 2 hours, water was added to control the final concentration of sulfuric acid to 50g/L, and the reaction was continued for 1 hour.

Claims (10)

1. liquid crystal display panel resource processing method, its feature may further comprise the steps:

A, the complete or broken display panels under will removing remove light polarizing film with the manual method or the method for soaking organic solvent, inorganic acid fluid or alkali lye;

B, the removal that obtains the complete display panels of light polarizing film, or after the frame portion cutting with its sealing-in, open two glass substrates of display panels, or it is soaked with inorganic acid fluid, remove the epoxy resin of sealing-in, after panel cleaned up, open two glass substrates of display panels;

C, the display panels of the fragmentation that obtains among the complete glass substrate that contains liquid crystal that obtains among the step b or the step a is soaked removing the liquid crystal on the glass substrate with organic solvent, and clean up;

D, the glass substrate of the intact liquid crystal of above-mentioned cleaning is soaked with acid leaching liquor, remove the metal coating on the glass substrate, obtain clean glass substrate.

2. liquid crystal display panel resource processing method according to claim 1 is characterized in that containing indium in the acid leaching liquor of the immersion in the steps d, carries out the extraction and the refining of indium with the existing technology of extracting indium.

3. liquid crystal display panel resource processing method according to claim 1 is characterized in that described organic solvent is one or more in acetone, chloroform, benzene, toluene or the dimethylbenzene.

4. liquid crystal display panel resource processing method according to claim 1 is characterized in that described alkali lye is the aqueous solution of NaOH or potassium hydroxide.

5. liquid crystal display panel resource processing method according to claim 1 is characterized in that described inorganic acid fluid is the aqueous solution of nitric acid or sulfuric acid.

6. liquid crystal display panel resource processing method according to claim 1 and 2 is characterized in that described acid leaching liquor is one or more or its aqueous solution in nitric acid, sulfuric acid or the hydrochloric acid.

7. liquid crystal display panel resource processing method according to claim 1 is characterized in that the time of soaking among the step a is 3～8h, and coming off with light polarizing film is as the criterion; Organic solvent is immersed in normal temperature to carry out, and inorganic acid fluid or dipping by lye temperature are controlled at 50～90 ℃.

8. liquid crystal display panel resource processing method according to claim 1 is characterized in that the time of soaking among the step b is 2～8h, and temperature is controlled at 50～90 ℃.

9. liquid crystal display panel resource processing method according to claim 1, after the cleansing power that it is characterized in that organic solvent among the step c descended, the organic solvent that will contain liquid crystal distilled regeneration, distills remaining liquid crystal and carries out burning disposal.

10. liquid crystal display panel resource processing method according to claim 1 is characterized in that the time of soaking in the steps d is 1～6h, and temperature is controlled at 70～90 ℃.