JP5385924B2 - Separation and recovery method of glass and transparent electrode material from liquid crystal panel - Google Patents

Description

  The present invention is applied to a method of recycling a product waste using a liquid crystal panel such as a liquid crystal television set or a personal computer, a defective product generated during a new manufacturing process, or a piece cut.

  In recent years, general and industrial waste in general production and consumption activities in society has increased, and global environmental problems such as illegal dumping and landfill tightness have attracted attention. The shift from an economic system to a resource recycling economic system has become an important social issue.

  In response to the situation as described above, for example, the Home Appliance Recycling Law was enforced in April 2001. According to the Home Appliance Recycling Law, as of August 2008, recycling of four home appliances such as air conditioners, televisions, refrigerators, and washing machines is obligatory. Legal reference values of 55% or more, refrigerator 50% or more, and washing machine 50% or more are set.

  Recycling of these four home appliances has progressed significantly compared to the beginning of the law enforcement, with the utmost efforts of the people concerned. In television, a recycling technique for cutting and recycling a CRT (Cathode Ray Tube) glass to remove an electron gun and a phosphor and then reusing it as the glass cullet to the original CRT glass has already been put into practical use.

By the way, in recent years, demand for thin TVs equipped with thin panels such as liquid crystal panels, plasma display panels (PDP), organic EL panels, and field emission display panels as display components has been increasing. Due to the characteristics such as being suitable for receiving images, it has been increasing rapidly in conjunction with the recent growing interest in global environmental issues and the digitization of television broadcasting. In particular, the demand for large-screen thin TVs equipped with large thin panels has increased dramatically. Along with this, an increase in the number of defective panels discharged in the manufacturing process and a rapid increase in the amount of used flat-screen TVs to be discarded in the future are expected, and there is a high demand for improving recyclability in environmental activities such as recycling activities. It has become to.

  At present, flat panel TVs (thin panels) are relatively new products and the amount of waste is small, and the products are crushed at the waste treatment facility and then incinerated. ing.

  In particular, a point to be considered in recycling the liquid crystal panel is the regeneration of materials such as glass and indium. As the base material of the liquid crystal panel, a glass substrate is mainly used. Since glass occupies most of the product weight, it is desirable to recycle from the viewpoint of improving the recycling rate, and it is more desirable to perform high-quality recycling, such as recycling it as a glass raw material of the same product again. Some base materials are processed with an indium compound such as indium tin oxide (ITO) as a transparent electrode. Indium is a rare metal and has soared due to the recent expansion of the thin panel market, and its recovery and recycling are being sought.

  From the above viewpoint, recovery and recycling of glass and indium in the liquid crystal panel are indispensable, but there are many problems.

  FIG. 7 is a diagram schematically showing a structure of a general TFT (Thin Film Transistor) liquid crystal panel. In a general TFT liquid crystal panel structure, a pixel ITO film (Indium Tin Oxide) 2 that is a transparent electrode is formed on a TFT glass substrate 1 in a matrix, and an active element 3 is formed for each pixel ITO film 2. . The pixel ITO film 2 is composed of an oxide of In and Sn. The active element 3 is connected to a scanning signal line 4 and a data signal line formed of a metal conductor film such as Al, and is formed in a lattice shape between the pixel ITO films 2 of the TFT glass substrate 1. Between the TFT glass substrate 1 and the pixel ITO film 2, there is an organic film 20 formed of a resin such as acrylic.

  Further, a color filter glass substrate 6 is disposed so as to face the TFT glass substrate 1, and a color filter 7 and an ITO film 8 are formed on the facing surface. Further, the periphery of the TFT glass substrate 1 and the color filter glass substrate 6 is filled with a sealing agent 21 such as a UV curable resin, and the liquid crystal 9 is sealed between these glass substrates. A polarizing plate 10 is provided on the outer surfaces of the color filter glass substrate 6 and the TFT glass substrate 1. In order to obtain a predetermined molecular orientation, an orientation film 23 that is an organic polymer film such as polyimide is formed.

  As a method for recovering glass and indium from liquid crystal display devices and liquid crystal panels contained in wastes such as defective waste liquid crystal panels and home appliances, personal computers and mobile phones discharged from liquid crystal panel manufacturing plants, for example, No. 170603 (Patent Document 1) devises a treatment method using supercritical water (partly including subcritical water).

  Under supercritical water conditions (partially including subcritical water) shown in Patent Document 1, the temperature and pressure are high, so the apparatus is expensive. In addition, it consumes a lot of energy, generates a large amount of greenhouse gas, and the running cost is high. Therefore, the present inventors use subcritical water (partially supercritical water) along a saturated vapor pressure curve every 20 ° C. from a temperature of 533 K (pressure 4.69 MPa) in order to reduce temperature and pressure as much as possible. The peeling performance of ITO from the TFT of the liquid crystal panel and the color filter glass was confirmed.

  Here, FIG. 8 is a graph showing the ITO peeling performance from the TFT glass when the temperature is changed, the vertical axis is the ratio of indium (%), and the horizontal axis is the temperature (K) of subcritical water. is there. FIG. 8 shows the ratio of indium remaining on the glass after the subcritical water (partially supercritical water) treatment for 5 minutes. FIG. 8 shows that 90% or more of ITO remains on the glass even in the treatment using supercritical water including subcritical water.

  FIG. 9 is a graph showing the ITO peeling performance from the color filter glass when the temperature is changed. The vertical axis represents the indium ratio (%), and the horizontal axis represents the subcritical water temperature (K). . FIG. 9 shows the ratio of indium remaining on the glass after the subcritical water (partially supercritical water) treatment for 5 minutes. FIG. 9 shows that 50% or more of ITO remains on the glass even in supercritical water including subcritical water.

  In addition, a treatment method using a critical water (partly including subcritical water) oxidation treatment method is devised in Japanese Patent Application Laid-Open No. 2003-094007 (Patent Document 2). The critical hydroxylation treatment method is a technique in which oxygen is supplied to subcritical water, a supercritical state is created in a state where there is a large amount of oxygen, and the treated product is oxidized, and is generally called a wet oxidation treatment. On the other hand, when this wet oxidation treatment is used, there is a problem that the container is oxidized due to a strong oxidizing action. As a method for solving this problem, a method of coating the container with anticorrosion has been adopted. However, the cost of the container is high, the life of the container is short, both the equipment cost and the running cost are high, and it has not been put into practical use.

JP 2001-170603 A JP 2003-094007 A

  Accordingly, an object of the present invention is to provide a method for separating and recovering at least one of glass and transparent electrode material from a liquid crystal panel at low apparatus cost, low running cost, and low energy consumption.

  The present invention is a method for recycling a liquid crystal panel using subcritical water, separating and recovering at least one selected from glass and transparent electrode (metal oxide) material from the liquid crystal panel, from the liquid crystal panel Including a step of obtaining a subcritical water state by applying heat and pressure to a mixture of a liquid crystal panel and water, the agent that improves at least one selected from the peelability of organic matter, the decomposability of organic matter, and the solubility of organic matter. Is the method.

  The transparent electrode material in the method of the present invention is preferably ITO (indium tin oxide).

  In the method of the present invention, the agent is preferably an alkali or an alcohol, more preferably a strong base, and particularly preferably sodium hydroxide. When the said chemical | medical agent is sodium hydroxide, it is preferable that the density | concentration is 0.01-1N.

  In the method of the present invention, it is preferable to perform heating and pressurization under conditions of a temperature of 493 to 647 K and a pressure of 2.3 to 22.1 MPa.

  In the method of the present invention, the treatment time in the subcritical water state is preferably 0.5 to 60 minutes.

  In the method of the present invention, it is preferable to repeatedly use an aqueous sodium hydroxide solution.

  The method of the present invention preferably further includes a step of crushing the liquid crystal panel. In this case, it is preferable to include a step of mixing the drug, the crushed panel product, and water. Moreover, it is preferable that the method of this invention includes the process of conveying the mixture of the said chemical | medical agent, a panel crushed article, and water to the container which obtains a subcritical state.

  Preferably, the liquid crystal panel recycling method of the present invention further includes a step of removing the polarizing plate of the liquid crystal panel. In this case, it is more preferable to remove the polarizing plate by wind sorting.

  According to the present invention, there is provided a liquid crystal panel recycling method capable of separating and recovering at least one selected from glass and transparent electrode material from a liquid crystal panel at low apparatus cost, low running cost, and low energy consumption. Can do.

It is a flowchart which shows a preferable example of the recycling processing method of the liquid crystal panel containing the method of this invention which isolate | separates and collect | recovers at least any one of glass and a transparent electrode material from a liquid crystal panel. It is a graph which shows the peeling performance of ITO from TFT glass when changing a sodium hydroxide density | concentration, a vertical axis | shaft is a ratio (%) of indium, and a horizontal axis is NaOH density | concentration (N). It is a graph which shows the peeling performance of ITO from TFT glass of the liquid crystal panel when the temperature condition of subcritical water is changed, the vertical axis is the ratio of indium (%), and the horizontal axis is the processing temperature (K) of subcritical water. It is. It is a graph which shows the peeling performance of ITO from the color filter (CF) glass of the liquid crystal panel when the temperature condition of subcritical water is changed, the vertical axis is the ratio of indium (%), and the horizontal axis is the treatment of subcritical water. Temperature (K). It is a graph which shows the peeling performance of ITO from liquid crystal panel TFT glass when the processing time in subcritical water is changed, the vertical axis is the ratio of indium (%), and the horizontal axis is the processing time (minute) in subcritical water. ). It is a graph showing an experimental result of confirming the amount of iron dissolved in an aqueous solution from a reaction vessel (SUS) internal surface area of 100 cm ² by performing subcritical water treatment at a 0.1N sodium hydroxide aqueous solution at a temperature of 533 K. The vertical axis is the amount of iron dissolved in the solution (mg / 100 cm ² ), and the horizontal axis is the treatment time (min) in subcritical water. It is a figure which shows typically the structure of a common TFT liquid crystal panel. It is a graph which shows the peeling performance of ITO from TFT glass when changing temperature, a vertical axis | shaft is a ratio (%) of indium, and a horizontal axis is the temperature (K) of subcritical water. It is a graph which shows the peeling performance of ITO from color filter glass when changing temperature, a vertical axis | shaft is a ratio (%) of indium, and a horizontal axis is the temperature (K) of subcritical water.

  FIG. 1 is a flowchart showing a preferred example of a method for recycling a liquid crystal panel including a method for separating and collecting at least one selected from glass and a transparent electrode (metal oxide) material from the liquid crystal panel of the present invention. . The present invention is a method for recycling a liquid crystal panel using subcritical water, separating and recovering at least one selected from glass and transparent electrode material from the liquid crystal panel, and peeling off organic substances from the liquid crystal panel The method includes a step of obtaining a subcritical water state by applying heat and pressure to a mixture of an agent that improves at least one selected from the degradability of organic matter and the solubility of organic matter, a liquid crystal panel, and water. FIG. 1 includes a step of adjusting the concentration of a drug that improves at least one selected from the peelability of an organic substance from a liquid crystal panel, the decomposability of the organic substance, and the solubility of the organic substance (drug concentration adjusting process); A process for obtaining a subcritical water state by applying heat and pressure to a mixture of a liquid crystal panel and water (subcritical water treatment process), a process for recovering glass (glass recovery process), and a process for recovering a transparent electrode material (transparent Although an example including an electrode material recovery step) and a step of recovering the treated aqueous solution (aqueous solution recovery step) is shown, the present invention is not limited to this. Hereinafter, the present invention will be described in detail with reference to the example shown in FIG.

[1] Drug concentration adjustment step In this step, first, a drug that improves at least one selected from the peelability of organic substances from a liquid crystal panel, the decomposability of organic substances, and the solubility of organic substances is mixed with water, and the drug concentration is adjusted. adjust. In addition, you may make it use the aqueous solution collect | recovered by the aqueous solution collection process mentioned later for the density | concentration adjustment of the chemical | medical agent in the said process. As such a chemical, when an acidic chemical is used, alkali or alcohol is preferably used because it is highly corrosive to metals and the like. Examples of the alkali include sodium hydroxide, calcium hydroxide, sodium bicarbonate, ammonia, an amine chemical, and examples of the alcohol include ethanol and methanol. Of these, strong bases having high organic peelability and / or decomposability are preferable, and low-cost sodium hydroxide is particularly preferable.

  When the drug is sodium hydroxide, the concentration is not particularly limited, but the effect of improving at least one selected from the peelability of organic substances from the liquid crystal panel, the decomposability of organic substances, and the solubility of organic substances. Is particularly significant, it is preferably in the range of 0.01 to 1N, and more preferably in the range of 0.05 to 0.5N. Here, FIG. 2 is a graph showing the peeling performance of ITO from the TFT glass when the sodium hydroxide concentration is changed, the vertical axis is the indium ratio (%), and the horizontal axis is the NaOH concentration (N). . Here, after performing the subcritical water treatment at a temperature of 553 K (pressure 6.42 MPa saturated water) for 5 minutes, the ratio of indium remaining on the glass, the ratio of indium dissolved in the aqueous solution, The ratio of indium recovered from suspended SS (Suspended Solids) of 0.5 μm or more is shown. From FIG. 2, the concentration of the sodium hydroxide aqueous solution after the subcritical water treatment has an effect of peeling the ITO from the TFT glass from 0.01 to 1N. It can be seen that it is minimized and optimal for ITO stripping. FIG. 2 also shows that almost no indium is dissolved in the aqueous solution, and the peeled ITO can be recovered by using a filter in the ITO recovery step (described later). Further, in the color filter of the liquid crystal panel, 100% ITO can be peeled from the glass side under the condition that the subcritical water temperature is 553K (pressure 6.42 MPa), the treatment time is 5 minutes, and the concentration of the sodium hydroxide aqueous solution is 0.1N.

  For example, when sodium hydroxide is used as the above-mentioned drug, a pH (ion concentration) sensor is installed in the tank. If the pH is less than a certain value, sodium hydroxide is adjusted. This is done by supplying from the chemical tank. The drug may be stored directly in the drug tank without being dissolved in water, or a high-concentration aqueous solution of the drug may be prepared in advance and stored in the drug tank. If the pH is above a certain value, water is supplied to keep the ion concentration of the aqueous solution constant.

[2] Liquid crystal panel crushing step The liquid crystal panel used for the treatment in the present invention is preferably crushed. That is, in the present invention, it is preferable to further include a step of crushing the liquid crystal panel (in the example shown in FIG. 1, a crushing step of the liquid crystal panel). It is more preferable to mix a chemical that improves at least one selected from the properties, a crushed liquid crystal panel product (panel crushed product), and water.

  In this process, the liquid crystal panel is crushed using, for example, a uniaxial hammer-type crusher or a biaxial crusher. The size of the crushing is not particularly limited as long as the mixture of the drug, the panel crushed product, and water can be smoothly transferred by a pressurizing means such as a pump in the subcritical water treatment process described later. However, if it is less than 0.5 mm, it takes time for crushing, so 0.5 mm or more is preferable. Further, from the viewpoint that the mixture of the drug and water can be smoothly transferred to the subcritical water treatment step, the size of the crushing is preferably 5 mm or less.

  In addition, if the liquid crystal panel has a polarizing plate, the polarizing plate is decomposed into a paste-like substance in the subcritical water treatment step, and reattachment of glass and transparent electrode material (ITO, organic matter, etc.) occurs. In order to prevent this phenomenon, the liquid crystal panel recycling method of the present invention preferably further includes a step of removing the polarizing plate of the liquid crystal panel. That is, it is preferable to remove the polarizing plate from the crushed panel after the liquid crystal panel is crushed as described above. In this case, it is desirable to remove the polarizing plate using a wind power sorter. This is because removing the polarizing plate using a wind power sorter has an advantage that it can be processed continuously as compared with the case of removing the polarizing plate by another method. It is also effective to install a device for sending air in the crusher and remove the polarizing plate while crushing. It is also effective to peel the polarizing plate from the liquid crystal panel with a jig before crushing.

  A certain amount of the crushed panel product is introduced into the above-described aqueous solution containing the medicine by a screw feeder or the like so that the crushed panel product and the aqueous solution are mixed at a certain ratio.

[3] Subcritical water treatment process The panel crushed product is mixed with the above-described aqueous solution containing the medicine, conveyed by a transporting means such as a pump, and supplied to the subcritical water treatment process. The mixture of the panel crushed product and the aqueous solution is first pressurized by a pressurizing means such as a pump. Next, the pressurized mixture is sent to a heating means and heated to be in a subcritical water state. Here, water is maintained in a liquid state up to 374 ° C. (647 K) when a pressure of 22.1 MPa is applied, and water at a temperature and pressure higher than this is called “supercritical water”. Refers to water in a state intermediate between normal water and supercritical water. A mixture of the crushed panel and the aqueous solution in a subcritical water state is introduced into the reaction vessel from the inlet.

  In the reaction vessel, the organic substance is peeled and / or decomposed from the glass of the liquid crystal panel (panel crushed product) by subcritical water treatment, and separated into glass and transparent electrode material (organic substance, ITO, etc.). The separated processed product (separated glass and transparent electrode material) is taken out from an outlet provided in the reaction vessel together with the aqueous solution. The processed product and the aqueous solution taken out are collected in the reaction product collection tank via the back pressure valve.

  The reaction pressure may be controlled by adjusting the opening of the back pressure valve. A cooling pipe may be provided immediately before the back pressure valve. When the cooling pipe is provided, the processed product can be safely recovered in a processed product recovery tank or the like.

  Subcritical water is less corrosive to metals and the like than supercritical water. Therefore, as the material for the reaction vessel, SUS316, which is much cheaper than Hastelloy, Inconel, etc., can be preferably used.

  As the heating means, known heating means can be used without particular limitation. For example, an electric heater, an induction heating device, a heat transfer oil, heating with water vapor, and the like can be given. The mixture may be preheated before being sent to the pressurizing means.

  Here, the shape of the reaction vessel is not particularly limited, but a cylindrical shape is preferable. At least one of an upper end portion, an intermediate portion, and a lower end portion of the reaction vessel is provided with an input port. The mixture of the panel crushed product and the aqueous solution is introduced into the processing container through the inlet. The inner diameter of the inlet is preferably smaller than the inner diameter of the cylindrical reaction vessel. This is to reduce the falling speed of the mixture and increase the processing time at a short distance.

  The discharge port is provided at a position different from the position where the introduction port is provided. The discharge port can take a plurality of positions downstream of the position where the input port is provided. In one example, a plurality of the discharge ports are formed on the side wall of the reaction vessel along the flow direction. By providing a plurality of discharge ports in this manner, the processed product can be taken out from the reaction vessel. Specifically, according to the processing time of the panel crushed product in subcritical water, that is, the subcritical water decomposition time of the component to be processed, the outlet of the outlet along the flow direction of the subcritical water in the reaction vessel. What is necessary is just to set a position. In addition, it is possible to take out the processed product by selecting any one of the discharge ports formed at a plurality of locations. Thus, subcritical water decomposition reaction time can be adjusted by taking out a processed material from either discharge port.

In the present invention, supercritical water may be used as necessary.
In the present invention, in the subcritical water treatment step, it is preferable to perform heating and pressurization under conditions of a temperature of 493 to 647 K and a pressure of 2.3 to 22.1 MPa. Moreover, it is preferable that the processing time in a subcritical water state is 0.5 to 60 minutes. Here, the glass of the liquid crystal panel, subcritical water temperature during peeling and / or decomposition of organic matter, the pressure for the time conditions, the case of using sodium hydroxide as the drug as an example, description To do.

  FIG. 3 is a graph showing the peeling performance of ITO from the TFT glass of the liquid crystal panel when the temperature conditions of the subcritical water are changed, the vertical axis is the indium ratio (%), and the horizontal axis is the treatment of the subcritical water. Temperature (K). Here, a 0.1N sodium hydroxide aqueous solution was used, and after the subcritical water treatment was performed for 5 minutes, the ratio of indium remaining on the glass, the ratio of indium dissolved in the aqueous solution, and floating in the aqueous solution. The ratio of indium recovered from 0.5 μm or more of SS is shown. As shown in FIG. 3, ITO is peeled from the glass at a temperature of subcritical water of 493 K (pressure 2.32 MPa saturated water) to 673 K (pressure 22 MPa), and from 533 K (pressure 4.69 MPa saturated water) to 553 K (pressure 6. In the case of 42 MPa saturated water), 90% or more of the ITO is peeled off, and the ratio of the ITO peeling from the glass is the maximum. This is considered to be because when the temperature exceeds 553 K, a part of the organic material peeled and decomposed from the glass becomes paste-like when ITO returns to the glass surface when it returns to normal temperature and pressure. From the viewpoints of prevention of reattachment and peeling performance, it is understood that 493 to 647K is desirable as the temperature condition, and 533 to 553K where the peeling performance is maximum is particularly desirable.

  FIG. 4 is a graph showing the ITO peeling performance from the color filter (CF) glass of the liquid crystal panel when the temperature condition of the subcritical water is changed, the vertical axis is the indium ratio (%), and the horizontal axis is It is the processing temperature (K) of subcritical water. Here, after performing subcritical water treatment with 0.1N sodium hydroxide aqueous solution in a treatment time of 5 minutes, the ratio of indium remaining on the glass, the ratio of indium dissolved in the aqueous solution, and floating in the aqueous solution The ratio of indium recovered from SS of 0.5 μm or more is shown. Under these conditions 493K (pressure 2.32 MPa saturated water) to 553 K (pressure 6.42 MPa saturated water), 100% of ITO is peeled from the color filter glass.

  FIG. 5 is a graph showing the removal performance of ITO from the liquid crystal panel TFT glass when the treatment time in subcritical water is changed. The vertical axis represents the indium ratio (%), and the horizontal axis represents the subcritical water. Processing time in minutes. Here, the ratio of indium remaining on the glass and the ratio of indium dissolved in the aqueous solution after performing subcritical water treatment under the conditions of 0.1N sodium hydroxide aqueous solution and temperature 533K (pressure 4.69 MPa saturated water) The ratio of indium recovered from 0.5 μm or more of SS suspended in an aqueous solution is shown. Peeling starts at 0.5 minutes and saturates at 5 minutes, and ITO peels from the TFT glass even at 60 minutes. On the other hand, when the processing time exceeds 10 minutes, ITO is dissolved in the solution, and it is difficult to recover by a filter or the like in an indium recovery process described later. Therefore, the optimal processing time is 5 to 10 minutes.

Next, in order to confirm the erosion in the reaction vessel due to the subcritical water treatment, the amount of dissolution into the aqueous solution on the inner surface of the reaction vessel when the treatment time was changed in the subcritical water was confirmed. FIG. 6 shows an experimental result in which the amount of iron dissolved in the aqueous solution from the reaction vessel (SUS) inner surface area of 100 cm ² was confirmed by performing subcritical water treatment at a 0.1N sodium hydroxide aqueous solution at a temperature of 533 K. It is a graph, the vertical axis is the amount of iron dissolved in the solution (mg / 100 cm ² ), and the horizontal axis is the treatment time (min) in subcritical water. As can be seen from FIG. 6, it can be seen that the amount of iron dissolved out decreases with time. This is thought to be due to the formation of an oxide film on the reaction vessel surface and the erosion to stop. Further, at 660 minutes, the amount of iron dissolved out is as small as 0.18 mg / 100 cm ^2, and there is no problem with erosion of the reaction vessel. Moreover, the reduction | decrease of the OH group by reduction of iron is a 10 ^<-3 > mol order in 660 minutes, and it turns out that there is no problem in reuse of sodium hydroxide.

[4] Glass Recovery Step Next, the glass is first separated and recovered from the suspended solution containing glass and transparent electrode material (ITO, organic matter, etc.) and the aqueous solution of the drug from the outlet of the reaction vessel. For separating the glass, a coarse filter such as a trommel, a vibrating sieve, or a centrifugal separator is used to separate the glass from other members and collect the glass. The mesh size at this time is preferably about 1/3 to 1/10 of the glass crushing mesh. Further, the glass may be separated and recovered using an air lift type specific gravity separator.

  Glass separated and recovered in this process is stored in a container containing water, neutralized with sulfuric acid, etc., and then washed away with salt and reused as a raw material for liquid crystal panels, or foamed glass without being washed with water. Can be suitably used for building materials.

[5] Transparent electrode material recovery process As shown in FIGS. 2 to 5, in the subcritical water treatment process, ITO hardly dissolves in the aqueous solution and floats as SS in the aqueous solution. Therefore, most ITO can be recovered by optimizing the subcritical water treatment conditions and recovering suspended matters. As a method for collecting the suspended matter, a method using a centrifuge or the like is preferable. In this case, the mesh size of the filter is preferably 0.1 μm to 30 μm, and is preferably about 0.5 μm considering the size of the suspended matter.

  The transparent electrode material (ITO, organic matter) separated and recovered in the process is separated into indium at a smelting factory and reused. Further, the aqueous solution remaining after separating and recovering the transparent electrode material is recovered, returned to the above-described drug concentration adjustment step, and reused.

[6] Aqueous solution recovery process After the transparent electrode material is separated and recovered as described above, the sodium hydroxide aqueous solution remaining after solid-liquid separation is returned to the chemical concentration adjustment process, adjusted to an optimal concentration, and circulated. Will be reused. In addition, when many organic substances are contained in the aqueous solution after multiple uses, it is possible to use the aqueous solution alone for the subcritical water treatment process without introducing the liquid crystal panel, and recycle the organic substances after decomposition. .

Form state the present invention has been described, it is to be understood that not restrictive manner in all respects as illustrative. The scope of the invention is defined by the appended claims rather than by the foregoing description, it is intended to include all modifications within the meaning and range of equivalency of the claims.

  1 TFT glass substrate, 2 pixel ITO film, 3 active element, 4 scanning signal line, 6 color filter glass substrate, 7 color filter, 8 ITO film, 9 liquid crystal, 10 polarizing plate, 20 organic film, 21 sealing agent, 23 orientation film.

Claims (8)

A method of recycling a liquid crystal panel using subcritical water, separating and recovering at least one selected from glass and transparent electrode material from the liquid crystal panel,
Removing the polarizing plate of the liquid crystal panel by wind sorting after crushing ;
A method comprising a step of obtaining a subcritical water state by applying heat and pressure to a mixture of 0.05 to 0.5 N sodium hydroxide, a liquid crystal panel after removing a polarizing plate, and water.   The method of claim 1, wherein the transparent electrode material is ITO.   The method according to claim 1, wherein the processing conditions are a temperature of 493 to 647 K and a pressure of 2.3 to 22.1 MPa.   The method of Claim 3 that the processing time in subcritical water is 0.5 to 60 minutes.   The process according to claim 1, wherein an aqueous sodium hydroxide solution is used repeatedly.   The method according to claim 1, further comprising a step of crushing the liquid crystal panel.   The method according to claim 6, further comprising the step of mixing the sodium hydroxide, the panel crushed product, and water.   The method of Claim 6 including the process of conveying the mixture of the said sodium hydroxide, a panel crushed article, and water to the container which obtains a subcritical water state.

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