JP2010022966A - Treatment method and treatment apparatus for liquid crystal panel - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a treatment method capable of performing simple and efficient re-utilization of a waste liquid crystal panel and performing inexpensive and useful re-utilization of indium oxide. <P>SOLUTION: A waste liquid crystal panel crushed product is stored in a material feeder 5, is fed to a burner 2 of a heating furnace 1, and is fed into the flame of the burner 2. Dilution air is introduced into the heating furnace 1 to adjust the temperature of the inside to 850-1,400°C. The organic substance is burned/decomposed in the heating furnace 1 and indium oxide is sublimated. The gas containing a solid content from the heating furnace 1 is fed to a cyclone 12 while retaining it to 850-1,400°C and a glass cullet is captured here. The dilution air is mixed with the gas from the cyclone 12, and the temperature is made 850°C or lower to condense the indium oxide and solidify it. It is captured and recovered by a bag filter 14. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

The present invention relates to a technique for recovering glass and indium oxide from a liquid crystal panel.
Specifically, liquid crystals, polarizing films, etc. contained in raw powders by supplying pulverized material obtained by pulverizing waste liquid crystal televisions or waste liquid crystal panels as factory waste generated from the production process of liquid crystal televisions to a burner and heating in a flame Inorganic tin in the indium tin oxide (ITO) thin film that forms a transparent electrode attached to the color filter substrate and the array substrate is sublimated to recover the glass powder remaining as a solid, and indium oxide It is related with the technology which collects and collects.

The amount generated is expected to increase after 2012, and an effective recycling method of waste liquid crystal panels as factory waste generated from the liquid crystal television production process is desired.
A liquid crystal panel is composed of a polarizing plate, a color filter substrate, a spacer, a liquid crystal, a sealing material, an array substrate, and the like. More specifically, a polarizing plate is a film material such as PVA, TAC, and PET, and a color filter substrate is an alkali-free glass and transparent. ITO (5-10% SnO ₂ -In ₂ O ₃ ), which is an electrode, pigments, etc., the array substrate is non-alkali glass, ITO (5-10% SnO ₂ -In ₂ O ₃ ), which is a transparent electrode, TFT (Si , SiOx, SiNx, Ta, Mo, W, Al).

As a method for treating a waste liquid crystal panel, there is an invention proposed in Japanese Patent Application Laid-Open No. 2007-12559.
This prior invention consists of 1) crushing step of liquid crystal panel, 2) organic matter decomposition step, 3) metal and metal thin film peeling step, 4) glass cullet separation step, and 5) oxide semiconductor separation step. After being crushed, it is mixed with an oxide semiconductor powder typified by titanium oxide, and this is stirred and heated to 350 to 400 ° C. to completely decompose and remove organic substances such as liquid crystals.

Subsequently, the crushed material of the liquid crystal panel obtained by decomposing the organic material is immersed in an acidic aqueous solution such as hydrochloric acid, and the metal and the metal thin film such as the transparent electrode remaining on the crushed material are dissolved and separated. Next, after separating into a mixture of a glass cullet, a metal solution, and an oxide semiconductor powder, the metal solution and the oxide semiconductor powder are separated, and the oxide semiconductor powder is reused. Finally, tin or indium is chemically or electrochemically separated and recovered from the metal solution.
JP 2007-12559 A

In view of the current situation where final disposal sites are tight, processing methods other than landfill are required as processing methods for waste liquid crystal panels, and processing methods that are as simple as possible are desirable.
Secondly, ITO used for the transparent electrode contains indium, which is a rare metal, and therefore needs to be recovered. In addition, it is desirable that alkali-free glass can also be diverted.
Third, since liquid crystals are difficult to decompose naturally, it is preferable to perform thermal decomposition treatment or combustion treatment rather than landfill.

  However, if dissolution and stripping with an acidic solution is used to remove metals such as transparent electrodes and metal thin films, acid remains in the recovered glass cullet and there are restrictions on reuse, and extensive cleaning is required when removing the acid. There is a problem that a process is required and causes a cost increase.

To solve this problem,
According to the first aspect of the present invention, the pulverized product of the liquid crystal panel is supplied into a flame formed of a fuel and a combustion-supporting gas, and heated to burn organic matter contained in the liquid crystal panel, and indium oxide is produced. The liquid crystal panel processing method is characterized by collecting.

  The invention according to claim 2 introduces dilution air into the heating furnace in which the flame is formed, and adjusts the dilution air introduction amount to adjust the atmospheric temperature in the heating furnace to 1400 ° C. or less, and By introducing diluted air between the cyclone connected to the rear stage of the heating furnace and the bag filter connected to the subsequent stage, and adjusting the amount of diluted air introduced, the airflow temperature at the bag filter inlet is 850 ° C. The liquid crystal panel processing method according to claim 1, wherein adjustment is performed as follows.

The invention according to claim 3 is a heating furnace, a burner installed on the ceiling of the heating furnace, a raw material feeder for storing liquid crystal panel pulverized powder connected to the burner, and a cyclone connected to a subsequent stage of the heating furnace. And a bag filter connected to the latter stage of the cyclone,
A dilution air introduction port for adjusting the temperature inside the heating furnace is provided in the heating furnace, and a dilution air introduction port for adjusting the airflow temperature at the bag filter inlet is provided between the cyclone and the bag filter, This is a liquid crystal panel processing apparatus.

According to the present invention, the waste liquid crystal panel can be processed by a simple process of allowing the waste liquid crystal panel pulverized powder to pass through the flame without performing the landfill process.
Further, indium oxide forming a transparent electrode can be easily recovered by the principle of volatile smelting, and glass cullet does not contain an acid, so that it can be recycled as a non-ferrous smelting process or a cement raw material. Furthermore, liquid crystals and other organic substances are completely burned and decomposed in the combustion flame.

FIG. 1 shows an example of a liquid crystal panel processing apparatus of the present invention.
In FIG. 1, the code | symbol 1 shows a heating furnace. The heating furnace 1 is a cylindrical vertical furnace, and a burner 2 is provided at the center of the ceiling with its tip end facing downward.
The burner 2 is supplied with a fuel such as liquefied petroleum gas (LPG) with a flow rate adjusted from a fuel supply source 3.

The burner 2 is supplied with a combustion-supporting gas (oxidant) such as air, oxygen-enriched air, oxygen, etc., from the combustion-supporting gas supply source 4 with its flow rate adjusted.
The code | symbol 5 in a figure shows a raw material feeder. The raw material feeder 5 stores a pulverized product obtained by pulverizing a waste liquid crystal panel. The pulverized product is scraped out by a certain amount per hour and is carried on a carrier gas such as air through the pipe 6 and sent to the burner 2. It is like that. The transfer gas is fed from the transfer gas supply source 7 to the burner 2 with the flow rate adjusted.

  A pilot burner 8 is provided on the side of the burner 2 of the heating furnace 1. The pilot burner 8 also has a flow rate adjusted for a fuel such as LPG from a fuel supply source (not shown) and a combustion-supporting gas such as air, oxygen-enriched air, and oxygen from a fuel-supply gas supply source (not shown). Configured to be supplied.

The body portion of the heating furnace 1 is provided with a plurality of introduction ports 9, 9... For introducing dilution air therein, and dilution air is introduced through these introduction ports 9, 9. It is sent from the outside into the heating furnace 1 so that the atmosphere temperature inside the heating furnace 1 can be adjusted.
The heating furnace 1 is provided with temperature sensors 10 and 10 for measuring the internal atmosphere temperature.

A duct 11 having a heat insulating structure is connected to the bottom of the heating furnace 1, and a combustion product gas accompanied by solid content from the heating furnace 1 is sent to the cyclone 12 through the duct 11. The upper part of the cyclone 12 has a heat insulating structure. In the cyclone 12, the glass cullet in the combustion exhaust gas is removed.
The gas from the cyclone 12 is sent to the bag filter 14 through the duct 13, where indium oxide is further collected.

  A temperature sensor 15 is attached near the outlet of the cyclone 12 so that the temperature of the gas derived from the cyclone 12 is measured. A dilution air introduction port 16 is provided in the middle of the duct 13, and dilution air is sent from the port 16 into the duct 13. A temperature sensor 17 is attached to the downstream side of the diluted air introduction port 16 of the duct 13 to measure the temperature of the gas introduced into the bag filter 14.

  The gas derived from the bag filter 14 is sent to an exhaust gas purification device 18 where harmful substances in the gas are removed and then sucked into a suction blower 19 and discharged out of the system. .

FIG. 2 shows the structure of the burner 2.
The burner 2 of this example has a quintuple tube structure, and a raw material supply pipe 21 is arranged at the center. A fuel supply pipe 22 and a combustion-supporting gas supply pipe are coaxially arranged outside the raw material supply pipe 21. 23, a water supply pipe 24 and a drain pipe 25 are sequentially arranged.

The front end opening of the raw material supply pipe 21 is a raw material ejection nozzle 26 from which the crushed waste liquid crystal panel that has been transported on the transportation gas is ejected.
The front opening of the fuel supply pipe 22 is a fuel ejection nozzle 27, and fuel such as LPG supplied from the fuel injection nozzle 27 to the fuel supply pipe 22 through the fuel supply port 22A is ejected. Yes.

Further, the front end opening of the combustion-supporting gas supply pipe 23 is an oxygen ejection nozzle 28, which is sent from the oxygen ejection nozzle 28 to the combustion-supporting gas supply pipe 23 through the combustion-supporting gas supply port 23 </ b> A. Combustion gases such as air, oxygen-enriched air, and oxygen are ejected.
A cooling medium such as cooling water is fed into the water supply pipe 24 via the water supply port 24A, and this cooling medium flows toward the tip end side of the burner 2 and is folded at the tip end portion to flow in the reverse direction through the drain pipe 25 to be drained. It flows out to the outside through the port 25A, so that the raw material supply pipe 21, fuel supply pipe 22 and combustion-supporting gas supply pipe 23 arranged on the center side can be cooled.

Moreover, in the burner 2 of this example, the front end surfaces of the raw material jet nozzle 26, the fuel jet nozzle 27, and the oxygen jet nozzle 28 are flush with each other so that they are flush with each other. The tip portion is also coplanar.
The burner 2 is attached to the center of the ceiling of the heating furnace 1 so that the front end faces the inside of the heating furnace 1, and the rear end is arranged to be located outside the heating furnace 1.

  FIG. 3 shows the structure of another example of the burner 2. In the burner 2 of this example, the form of the tip is different from the previous one, and the other parts are the same as the burner 2 shown in FIG. Is omitted.

In this example, the position of the opening of the raw material ejection nozzle 26 is located slightly inward on the base side of the burner 2. In addition, the positions of the openings of the fuel injection nozzle 27 and the oxygen injection nozzle 28 are also slightly inward, but are positioned forward of the position of the opening of the raw material injection nozzle 26.
As a result, a combustion chamber 29 is formed at the tip of the burner 2.

The combustion chamber 29 is composed of a frustoconical portion that expands toward the front end side of the burner 2 and a cylindrical portion up to the front end portion of the raw material ejection nozzle 26.
With this configuration, a flame is formed in the combustion chamber 29.
In the burner 2 shown in FIGS. 2 and 3, the raw material supply pipe 21, the fuel supply pipe 22, and the combustion-supporting gas supply pipe 23 are arranged from the center of the burner toward the radially outer side. May be appropriately changed. For example, the fuel supply pipe, the raw material supply pipe, and the combustion-supporting gas supply pipe may be arranged in this order from the center.

In the burner shown in FIG. 2, the flame temperature is relatively low due to its structure, while the dispersion of the pulverized material in the flame is improved. For this reason, it is suitable for the treatment of the pulverized waste liquid crystal panel having a small average particle diameter, which has a poor dispersibility and requires a small amount of heat for raising the temperature of the particles.
In the burner shown in FIG. 3, the mixing of the fuel and the combustion-supporting gas in the combustion chamber 29 is improved, the flame temperature is relatively high, and the dispersion of the pulverized material in the flame is relatively poor. Become. For this reason, it is suitable for the treatment of the pulverized waste liquid crystal panel having a large average particle diameter that has good dispersibility and requires a large amount of heat for increasing the temperature of the particles.

Next, a processing method using the above-described processing apparatus will be described.
First, the waste liquid crystal panel is pulverized to a particle size of 32 mesh (500 μm) or less by a pulverizer to obtain a pulverized waste liquid crystal panel, which is stored in the raw material feeder 5. When the particle size of the pulverized product is larger than 32 mesh, the pneumatic conveyance that conveys the pulverized product with the gas for conveyance becomes impossible.
Examples of the waste liquid crystal panel include a panel used as a liquid crystal television receiver and recovered, and a defective panel generated in a production process.

  The fuel and the combustion-supporting gas whose flow rate is adjusted are supplied to the pilot burner 8, and the ignition is ignited using an ignition source such as a spark plug. Then, the fuel whose flow rate is adjusted from the fuel supply source 3 and the fuel-supporting gas whose flow rate is adjusted from the combustion-supporting gas supply source 4 are supplied to the burner 2, and a flame is formed at the tip of the burner 2 by the seed fire.

Next, conveying gas such as air, oxygen-enriched air, oxygen, or the like from the conveying gas supply source 7 is sent to the raw material feeder 5, and a certain amount of waste liquid crystal panel pulverized material per hour is gasified from the raw material feeder 5 to the burner 2. The material is fed and conveyed, and is fed into the flame from the raw material ejection nozzle 26 of the burner 2, and the pulverized waste liquid crystal panel is heated in the flame.
During operation, the temperature sensor 10 and 10 are used to monitor the temperature in the heating furnace 1 and the amount of diluted air introduced from the introduction ports 9, 9... Is maintained so that the furnace temperature is maintained at 850 ° C. or higher and 1400 ° C. or lower. adjust.

  The waste liquid crystal panel pulverized product heated in the flame completely burns and decomposes organic substances such as liquid crystal and plastic at a temperature of less than 850 ° C., and indium oxide sublimates into a gaseous state at 850 ° C. or higher. The glass cullet is discharged from the heating furnace 2 together with the combustion product gas and gaseous indium oxide without melting because of the temperature of 1400 ° C. or lower.

When the temperature in the heating furnace 2 is less than 850 ° C., indium oxide is not sublimated, and the combustion and decomposition of organic substances are insufficient. On the other hand, when the temperature exceeds 1400 ° C., the glass cullet is softened, and the combustion product gas and the sublimated gaseous indium oxide may be taken into the glass.
Thus, by maintaining the atmospheric temperature in the heating furnace 2 at 850 ° C. or more and 1400 ° C. or less, the glass cullet and the gaseous indium oxide can be used without the combustion product gas and the sublimated gaseous indium oxide being taken into the glass. It can be discharged out of the heating furnace 2.

Combustion product gas accompanied by glass cullet, indium oxide or the like from the bottom of the heating furnace 2 passes through the duct 11 having a heat insulating structure and is introduced into the cyclone 12.
In the cyclone 12, the glass cullet is separated and collected. The atmospheric temperature in the cyclone 12 is controlled to be 850 ° C. or higher so that gaseous indium oxide is not condensed in the cyclone 12. For this reason, the temperature of the gas discharged from the heating furnace 1 is controlled so that the temperature at the outlet is maintained at 850 ° C. or higher by monitoring the temperature of the gas at the outlet of the cyclone 12 with the temperature sensor 15.

The gas led out from the upper part of the cyclone 12 is introduced into the bag filter 14 through the duct 13. At this time, the temperature of the gas introduced into the bag filter 14 is monitored by the temperature sensor 17, and when the temperature exceeds 850 ° C., the dilution air is sent from the dilution air introduction port 16 to the duct 13, and the temperature is It adjusts so that it may become 850 degrees C or less.
When the temperature of the gas becomes 850 ° C. or lower, the gaseous indium oxide contained in the combustion product gas is condensed into a solid and collected by the bag filter 14.

The gas derived from the bag filter 14 is sent to the exhaust gas treatment device 18, where harmful substances in the gas are removed, sucked by the suction blower 19, and discharged out of the system.
Thus, the glass cullet is collected and collected by the cyclone 12, the indium oxide is collected and collected by the bag filter 14, and the organic matter is combusted and decomposed.

  According to such a processing method, processing can be performed by a simple process of sending waste liquid crystal panel pulverized material into the flame, and organic substances such as liquid crystals, color filters, and sealing materials in the waste liquid crystal panel pulverized material are completely burned. Then, the glass such as the glass substrate is recovered as a glass cullet that is not contaminated with impurities, and can be reused as a nonferrous smelting process or a cement raw material. Further, indium which is a rare metal is recovered as indium oxide without waste and can be reused.

  For this reason, the processing method of the present invention can reduce the processing cost compared to the method of burying the waste liquid crystal panel crushed material in the final disposal site, and is simpler than the processing method proposed in the previous invention. There is an advantage that glass and indium oxide can be recycled in the process.

Other than the above-described embodiment will be described as the waste liquid crystal panel pulverized product in the present invention.
The amount of indium contained in the waste liquid crystal panel is as small as 200 to 750 mg per kg. On the other hand, in the manufacturing process of the liquid crystal panel, especially the ITO sputtering process, ITO cleaning waste liquid adhering to jigs and the like is generated. By impregnating the waste liquid crystal panel powder with this cleaning waste liquid, more oxidation can be achieved. Indium can be recovered.

Example 1
The waste liquid crystal panel was pulverized to 32 mesh or less with a high-speed impact screen pulverizer and stored in a raw material feeder. After igniting the pilot burner, the burner was supplied with propane gas 125 Nm ³ / h, oxygen gas 625 Nm ³ / h as fuel, and air 483 Nm ³ / h as carrier gas, and ignited. Waste liquid crystal panel pulverized powder 625 kg / h was supplied from the raw material feeder.

The operation was continued to maintain the furnace temperature at 1,400 ° C or lower while adjusting the dilution air amount, and to maintain the bag filter inlet temperature at 850 ° C or lower while adjusting the dilution air amount after the cyclone. .
As a result of operating for 24 hours, the amount of recovered indium oxide was 5.5 kg, the amount of glass cullet was 15 tons, and the recovery rate was almost 100%. Moreover, the obtained indium oxide was reusable quality as an ITO raw material.

  The obtained glass cullet does not contain an acid component and is difficult to reuse as a glass raw material. However, it is reusable as a roadbed material, a non-ferrous smelting flux, or a cement material. It was.

(Example 2)
The waste liquid crystal panel was pulverized to 32 mesh or less with a high-speed impact screen pulverizer, impregnated with ITO cleaning waste liquid, and dried, and stored in a raw material feeder. As a result of performing a treatment operation under the same conditions as in Example 1 and operating for 24 hours, the amount of recovered indium oxide increased to 44 kg. The quality of the recovered indium oxide and glass cullet was also the same.

It is a schematic block diagram which shows an example of the processing apparatus of this invention. It is a schematic block diagram which shows the structure of the burner used in this invention. It is a schematic block diagram which shows the structure of the other example of the burner used in this invention.

Explanation of symbols

1 ... Heating furnace 2 ... Burner 5 ... Raw material feeder 9 ... Introduction port 12 ... Cyclone 14 ... Bag filter 16 ... Dilution air introduction port

Claims (3)

   Liquid crystal panel is characterized in that the pulverized material of the liquid crystal panel is supplied into a flame formed of a fuel and a combustion-supporting gas and heated to burn organic substances contained in the liquid crystal panel and recover indium oxide. Panel processing method.    By introducing dilution air into the heating furnace in which the flame was formed and adjusting the amount of dilution air introduced, the atmosphere temperature in the heating furnace was adjusted to 1400 ° C. or lower and connected to the subsequent stage of the heating furnace. A feature is that the air flow temperature at the bag filter inlet is adjusted to 850 ° C. or less by introducing diluted air between the cyclone and the bag filter connected to the subsequent stage and adjusting the amount of diluted air introduced. A processing method for a liquid crystal panel according to claim 1. A heating furnace, a burner installed downward on the ceiling of the heating furnace, a raw material feeder for storing liquid crystal panel pulverized powder connected to the burner, a cyclone connected to the subsequent stage of the heating furnace, and a subsequent stage of the cyclone Have a bug filter,
A dilution air introduction port for adjusting the temperature inside the heating furnace is provided in the heating furnace, and a dilution air introduction port for adjusting the airflow temperature at the bag filter inlet is provided between the cyclone and the bag filter, Liquid crystal panel processing equipment.

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