CN107522387A - Melting furnaces for TFT glass - Google Patents

Abstract

The invention provides a melting furnace for TFT glass, comprising: a cold-top all-electric melting furnace and a clarification tank arranged sequentially; The ascending channel is connected with the feeding port of the clarification tank; the upper part of the cold-top all-electric melting furnace is provided with a feeding port for adding TFT glass batch materials, and the inside of the cold-top all-electric melting furnace is equipped with multiple kiln electrodes The inside of the clarification tank is equipped with multiple pool electrodes and multiple flame heating spray guns, and the clarifier tank is provided with a smoke exhaust port for the exhaust of the smoke; Bubble devices are located behind all electrodes in the cell. The melting furnace of the present invention separates the process of melting from high-temperature clarification and homogenization, which can not only effectively reduce the high volatilization of boron and the defects caused by the melting of TFT glass batch materials, but also effectively clarify the glass liquid of TFT glass And homogenization, so as to avoid the occurrence of defects such as streaks in the product, and significantly improve the product quality.

Description

Furnaces for TFT glass

technical field

The invention relates to the technical field of glass production, in particular to a melting furnace for TFT glass.

Background technique

TFT glass belongs to "high boron, high alumina and alkali-free" glass. The composition of TFT glass is boroaluminosilicate glass with boron oxide content of 8-12%. It is easy to produce problems such as phase separation and delamination. The melting temperature of boroaluminosilicate glass is more than 170°C higher than that of ordinary float glass. Usually, the fusion heating and melting method of thermal power combined with oxygen combustion and electric melting is used, but the volatilization rate of boron is as high as 7-10 %, leading to the accumulation of silicon dioxide with a lighter density on the surface of the glass liquid. This silicon-rich material not only has a high melting point and is difficult to melt, but also has a high viscosity, and a large number of microbubbles are gathered in it, which is difficult to discharge. The glass with a silica layer must be strictly controlled during melting, otherwise it will be difficult to completely disappear even after repeated high-temperature circulation convection in the furnace, and eventually defects such as streaks and microbubbles will be formed in the glass plate, which is of great importance to the glass. TFT glass whose quality is required to reach the grade of optical glass is completely unacceptable. In the production of TFT glass, there are often defects such as streaks and micro-bubbles that seriously affect the yield of the glass.

Chinese utility model patent "Full Borosilicate Float Glass Melting Furnace with Vertical Cold Roof", authorized announcement number CN2878376, in this patent, the interior of the glass melting furnace includes the melting zone and the clarification zone, and the long side of the glass melting furnace There is a feed port on the upper part of the furnace wall on one side; the melting zone is located above the clarification zone; the lower part of the side wall of the clarification zone is provided with a flow hole, and the flow holes of the glass melting furnace are respectively connected to one end of the ascending channel for feeding The other end of the ascending channel is connected to the feeding channel.

Since the electric melting furnace adopts a vertical melting method, the volatilized boron oxide can be condensed on the top of the cold top electric melting furnace, which greatly reduces the volatilization of boron in the melting furnace, and its volatilization rate is generally only 1-2%. However, the all-electric melting furnace also has its own defects: (1) the vertical melting method of the electric melting furnace is not conducive to the elimination of microbubbles in the molten glass; (2) the maximum scale of the full-electric melting furnace for the production of high borosilicate generally does not exceed 30 tons / day, otherwise the temperature uniformity in the kiln will be affected, and defects such as stripes will also occur; (3) When the electrode layout or temperature system in the kiln is slightly improper, the uniformity of the product will be greatly affected, and the product qualification rate will be low.

Contents of the invention

In view of the above-mentioned shortcomings of the prior art, the object of the present invention is to provide a melting furnace for TFT glass to solve the above-mentioned problems in the prior art.

In order to achieve the above purpose and other related purposes, the present invention provides a melting furnace for TFT glass, comprising: a cold top full electric melting furnace and a clarification tank arranged in sequence; the bottom of the cold top full electric melting furnace is provided with a flow A liquid hole, the outlet end of the liquid flow hole communicates with the lower end of a vertically arranged ascending channel, and the upper end of the ascending channel communicates with the feed port of the clarification tank; the upper part of the cold-top all-electric melting furnace There is a feed port for adding TFT glass batch materials, and the inside of the cold-top all-electric melting furnace is equipped with a plurality of kiln electrodes; the inside of the clarification tank is equipped with a plurality of electrodes in the pool and a plurality of flame heating spray guns, The clarifier is provided with a smoke outlet for exhausting smoke, and all the flame heating spray guns are arranged on the upper part of the clarifier; along the flow of the molten glass batch of the TFT glass in the clarifier Direction, the bottom brick of the clarification tank is provided with a bubbling device and a kiln ridge in sequence, and the bubbling device is arranged behind all the electrodes in the tank.

Preferably, the bottom brick of the kiln body and the side wall of the kiln body of the cold-top all-electric melting furnace are planar structures, or the bottom bricks of the kiln body and the side walls of the kiln body of the cold-roof all-electric melting furnace are of a stepped structure.

Preferably, all of the kiln electrodes are inserted on the bottom brick of the kiln body of the cold-top all-electric melting furnace, or all of the kiln electrodes are inserted into the kiln body of the cold-top all-electric melting furnace on the side wall.

Preferably, all the electrodes in the pool are inserted on the bottom brick of the tank body of the clarification tank, or all the electrodes in the pool are inserted on the side wall of the tank body of the clarification tank, or all the electrodes in the tank are inserted The electrodes are divided into bottom electrodes inserted on the bottom brick of the clarifier tank and side electrodes inserted on the side wall of the clarifier tank.

Preferably, all of the flame heating spray guns are arranged on the upper part of the clarification tank; the nozzles of all the flame heating spray guns are arranged on the side wall of the tank body of the clarification tank, or all of the flame heating spray guns The nozzle is arranged on the top of the tank body of the clarification tank.

Preferably, along the flow direction of the molten glass of the TFT glass, an outlet is provided on the side wall of the tank body at the rear end of the clarification tank, and the outlet is connected to a platinum forehearth.

Further, the clarification tank is also provided with a heterogeneous glass liquid surface overflow device, and the heterogeneous glass liquid surface overflow device is connected to the side walls of the tank body on both sides of the front end of the discharge port of the clarification tank.

Furthermore, the material extraction height of the outlet of the clarification tank is lower than the liquid level of the liquid glass of the TFT glass in the clarification tank.

Further, the bottom brick of the clarification tank is provided with a first bottom discharge device, the first bottom discharge device is behind all the electrodes in the tank, and the first bottom discharge device The device is in front of the bubbling device and in front of the outlet of the clarification tank.

Preferably, the bottom brick of the clarification tank is provided with a second bottom discharge device, and the second bottom discharge device is behind the kiln sill.

Preferably, an intermediate discharge device is provided at the bottom of the ascending channel.

As mentioned above, the melting furnace for TFT glass according to the present invention has the following beneficial effects:

The melting furnace of the present invention separates the process of melting from high-temperature clarification and homogenization, which can effectively reduce the high volatilization of boron and the defects caused by the melting of TFT glass batch materials, and can effectively clarify the glass liquid of TFT glass And homogenization, so as to avoid the occurrence of defects such as streaks in the product, and significantly improve product quality; the bubbling device in the clarification tank and the setting of the kiln ridge greatly increase the escape speed of the microbubbles in the glass liquid of TFT glass, The clarification efficiency of the molten glass of TFT glass is accelerated, and the bubbling device also accelerates the convection of the molten glass of TFT glass. The setting of the kiln sill increases the temperature of the molten glass of TFT glass. Efficiency is also significantly improved, and the scale of the cold-top all-electric melting furnace of the present invention is not affected by the quality of molten glass of TFT glass that is melted, so a larger scale can be realized.

Description of drawings

FIG. 1 is a schematic diagram of a vertical cross-sectional structure of a melting furnace for TFT glass in this embodiment.

FIG. 2 is a schematic top view of the melting furnace for TFT glass in this embodiment.

Explanation of reference numbers

100 cold top full electric melting furnace

110 Kiln liquid inlet

120 kiln electrode

200 clarifier

201 smoke vent

210 cell electrode

220 Flame Heated Spray Gun

230 Heterogeneous glass liquid surface overflow device

241 First bottom discharge device

242 Second bottom discharge device

300 Fluid Hole

310 anti-blocking electrode

400 ascending road

410 side insert electrode

420 Intermediate discharge device

250 bubbler

600 Outlet

700 Platinum Forehearth

800 kiln ridge

detailed description

The implementation of the present invention will be illustrated by specific specific examples below, and those skilled in the art can easily understand other advantages and effects of the present invention from the contents disclosed in this specification.

Please refer to attached picture. It should be noted that the structures, proportions, sizes, etc. shown in the drawings attached to this specification are only used to match the content disclosed in the specification, for those who are familiar with this technology to understand and read, and are not used to limit the implementation of the present invention. Limiting conditions, so there is no technical substantive meaning, any modification of structure, change of proportional relationship or adjustment of size, without affecting the effect and purpose of the present invention, should still fall within the scope of the present invention. The disclosed technical content must be within the scope covered. At the same time, terms such as "upper", "lower", "left", "right", "middle" and "one" quoted in this specification are only for the convenience of description and are not used to limit this specification. The practicable scope of the invention and the change or adjustment of its relative relationship shall also be regarded as the practicable scope of the present invention without any substantial change in the technical content.

As shown in Figures 1 to 2, the melting furnace for TFT glass in this embodiment includes: a cold-top all-electric melting furnace 100 and a clarification tank 200 arranged in sequence;

The bottom of the cold roof all-electric melting furnace 100 is provided with a liquid flow hole 300, the outlet end of the liquid flow hole 300 communicates with the lower end of a vertically arranged ascending channel 400, and the upper end of the ascending channel 400 is connected to the The feed port 110 of the clarifier 200 is communicated;

The upper part of the cold-top all-electric melting furnace 100 is provided with a feed port 110 for adding TFT glass batch materials, and the inside of the cold-top all-electric melting furnace 100 is provided with a plurality of kiln electrodes 120;

The interior of the clarification tank 200 is provided with a plurality of electrodes 210 in the pool and a plurality of flame heating spray guns 220. The clarification tank 200 is provided with a smoke exhaust port 201 for exhausting smoke, and all the flame heating spray guns 220 are arranged on The upper part of the clarifier 200;

Along the flow direction of the molten glass of the TFT glass in the clarification tank 200, a bubbling device 500 and a kiln ridge 800 are sequentially arranged on the bottom brick of the tank body of the clarification tank 200, and the bubbling device 500 is set behind all electrodes 210 in the cell.

In the present invention, the cold-top all-electric melting furnace 100 adopts a vertical melting mechanism. After the cold-top all-electric melting furnace 100 forms a cold roof, the temperature of the top is lower, so the heat dissipation of the cold-top all-electric melting furnace 100 is greatly reduced, and the thermal efficiency is remarkable. Improvement, while the low temperature also suppresses the volatilization of volatiles;

In the existing vertical cold-roof melting borosilicate float glass duplex type all-electric melting furnace, the forming liquid flows vertically from the top to the bottom, and the bubble removal process in the molten glass is a bottom-up buoyancy process. That is, the escape process of the bubbles is opposite to the flow direction of the formed glass liquid flow, which increases the stroke and resistance of the bubbles in the glass liquid, which is not conducive to the discharge of the bubbles; The cold roof structure of the all-electric melting furnace is not conducive to the escape of air bubbles due to the low temperature and high viscosity of the glass liquid at the top. It also limits the clarification of the microbubbles in the glass liquid.

The melting furnace of the present invention separates the melting process of the molten glass of TFT glass from the clarification and homogenization process, and the melting process of the TFT glass batch material is mainly completed in the cold-top all-electric melting furnace 100, which does not require cold-top full-electric melting The clarification quality of the molten glass of the TFT glass melted in the kiln 100, so the melting temperature of the cold-top all-electric melting furnace 100 can be lower than the melting temperature of the existing single all-electric melting furnace, the purpose is not to melt the all-electric melting furnace The bubbles in the molten glass of TFT glass are all released prematurely, but the bubbles in the molten glass of TFT glass are kept in the TFT glass batch as much as possible;

The molten glass of the melted TFT glass enters the clarification tank 200 through the flow hole 300 and the ascending channel 400, and then undergoes high-temperature clarification and homogenization. The melting temperature is 50-120°C higher, so the inside of the clarification tank 200 needs to be equipped with multiple pool electrodes 210 and multiple flame heating spray guns 220, that is, the heating in the clarification tank 200 adopts thermal and electric hybrid heating;

The bubbling device 500 is arranged behind the electrode 210 in the pool, and the bubbling medium is blown into the molten glass of the TFT glass inside the clarification tank 200 through the bubbling nozzle of the bubbling device 500, so that bubbles can be formed in the molten glass of the TFT glass, and then As the temperature of the molten glass of TFT glass continues to increase, the bubbles also expand and float continuously. During the process of rising, the surrounding small bubbles are continuously adsorbed on the surface due to the effect of surface tension, forming the precipitation in the molten glass of TFT glass. The "bubble nucleus" and power of the bubbles, thereby promoting the efficient clarification of the molten glass of TFT glass. Since the premature release of the bubbles in the molten glass is suppressed in the cold-top all-electric melting furnace 100, the TFT in the clarification tank 200 The bubbles in the molten glass of the glass are released more easily through high temperature and bubbling, and the clarification and homogenization effect is better than that achieved by the existing vertical cold top melting borosilicate float glass double-split all-electric melting furnace. better quality;

After the bubbling device 500, a kiln sill 800 is also provided in the clarification tank 200. The setting of this kiln sill 800 can not only force the molten glass of high-temperature TFT glass to flow through the top of the kiln sill 800, but also the molten glass of TFT glass Flame heating with a higher surface temperature can be obtained, and at the same time, the surface flow layer of the molten glass flowing through the TFT glass above the kiln sill 800 becomes shallower, which promotes the rapid release of microbubbles in the molten glass of the TFT glass.

The bottom bricks and side walls of the kiln body of the cold-top all-electric melting furnace 100 are planar structures, or the bottom bricks and side walls of the kiln body of the cold-top all-electric melting furnace 100 are stepped structures. When the bottom brick of the kiln body and the side wall of the kiln body of the cold-top all-electric melting furnace 100 are stepped structures, the scale of the cold-top all-electric melting furnace 100 is large, and the depth of the cold-top all-electric melting furnace 100 can reach 1.8-3m; When the bottom brick of the kiln body and the side wall of the kiln body of the cold top all-electric melting furnace 100 are planar structures, the scale of the cold-top all-electric melting furnace 100 is small, and the cold-top all-electric melting furnace 100 is a non-step structure, and the cold top all-electric melting furnace 100 is a non-step structure. The depth of the electric melting furnace 100 is less than 1.8m.

All the kiln electrodes 120 are inserted on the bottom brick of the kiln body of the cold top full electric melting furnace 100, or all the kiln electrodes 120 are inserted in the kiln of the cold top full electric melting furnace 100 on the side wall of the body. The kiln electrode 120 heats the molten glass of TFT glass in the cold-roof all-electric melting furnace 100 . In this embodiment, all the kiln electrodes 120 are inserted on the kiln body bottom bricks of the melting furnace.

In this embodiment, the structure of the cold top full electric melting furnace 100 is determined according to the production scale, and the cross section of the cold top full electric melting furnace 100 is hexagonal, rectangular or circular; the depth of the cold top full electric melting furnace 100 can be 1.5 ~ 2.8m.

All of the electrodes 210 in the pool are inserted on the bottom brick of the clarifier 200, or all the electrodes 210 in the pool are inserted on the side wall of the clarifier 200, or all of the The electrodes 210 in the tank are divided into bottom electrodes inserted on the bottom brick of the clarification tank 200 and side electrodes inserted on the side walls of the tank body of the clarification tank 200 . The electrode 210 in the tank heats the molten glass of the TFT glass in the clarification tank 200 . In this embodiment, all the electrodes 210 in the tank are inserted on the bottom brick of the tank body of the clarification tank 200 .

All the flame heating spray guns 220 are arranged on the top of the clarification tank 200; the nozzles of all the flame heating spray guns 220 are arranged on the side wall of the tank body of the clarification tank 200 to heat the molten glass of the TFT glass; The nozzle of the flame heating spray gun 220 is arranged on the top of the tank body of the clarification tank 200 to heat the molten glass of the TFT glass. The heating method of the flame heating spray gun 220 adopts all-oxygen or oxygen-enriched combustion-supporting heating. All nozzles are staggered or symmetrically arranged. In this implementation, the nozzles of all the flame heating spray guns 220 are arranged on the side wall of the tank body in the upper space of the clarification tank 200 .

The bubbling medium used in the bubbling device 500 is gas such as high pressure oxygen, compressed air, argon or nitrogen. In this embodiment, the bubbling medium is high pressure oxygen.

Along the flow direction of the molten glass of the TFT glass, a discharge port 600 is provided on the side wall of the rear end of the clarification tank 200 , and the discharge port 600 is connected to a platinum channel 700 . Due to the high quality requirements of TFT glass, the molten glass of TFT glass flows out through the discharge port 600 and enters the platinum forehearth 700 system for more accurate and efficient high-temperature clarification, forced homogenization and cooling processes. With the invention of the melting furnace, the defects of the final TFT glass substrate from melting will be significantly reduced, and the yield rate will be improved. In this implementation, the outlet 600 is also made of platinum material, which is actually consistent with the material of the connected platinum channel 700 . Due to the high clarification efficiency of the molten glass of TFT glass in the melting furnace of the present invention, the platinum forehearth 700 system after the molten glass of TFT glass flows out of the discharge port 600 does not need to be equipped with a high-temperature clarification function, and only needs to be equipped with homogenization and temperature adjustment cooling function, which can greatly save the investment cost of the subsequent platinum forehearth 700 and prolong the service life of the platinum forehearth 700.

In this embodiment, the discharge port 600 is located at the lower part of the clarification tank 200 . The clarification tank 200 is also provided with a heterogeneous glass liquid surface overflow device 240 , and the heterogeneous glass liquid surface overflow device 240 is connected to the side walls of the tank body on both sides of the front end of the discharge port 600 of the clarification tank 200 . The purpose of setting the overflow device on the inner surface of the pool is to discharge the silicon-rich inhomogeneous molten glass remaining on the surface of the molten glass of the TFT glass.

The feeding height of the outlet 600 of the clarification tank 200 is lower than the liquid level of the molten glass of TFT glass in the clarification tank 200 . This structure can make the glass liquid of TFT glass with better quality be discharged after the silicon-rich glass liquid remaining on the surface layer in the TFT glass liquid is discharged.

The horizontal height of the top surface of the kiln ridge 800 is 75-200mm lower than the liquid level of the molten glass of the TFT glass, and this structure greatly shortens the distance for the bubbles to float up.

In order to obtain satisfactory glass quality, a first bottom discharge device 241 is provided on the bottom brick of the clarification tank 200, and the first bottom discharge device 241 is located behind all the electrodes 210 in the tank, And the first bottom discharge device 241 is in front of the bubbling device 500 . When the present invention is used, according to the requirements of product quality, the first bottom unloading device 241 is opened to discharge the impurities at the bottom of the molten glass of TFT glass. The first bottom unloading device 241 is arranged before the bubbling device 500 so that the molten glass of the TFT glass can discharge impurities before flowing through the kiln sill 800 .

The bottom brick of the clarifier 200 is provided with a second bottom discharge device 242, the second bottom discharge device 242 is located behind the kiln ridge 800, and is located at the outlet 600 of the clarifier 200. ahead. When the present invention is used, according to the requirements of product quality, the second bottom unloading device 242 is opened to discharge the impurities at the bottom of the molten glass of TFT glass. The second bottom unloading device 242 is arranged behind the kiln ridge 800 and before the outlet 600 ; the molten glass of the TFT glass discharges impurities before entering and exiting the platinum forehearth 700 .

An intermediate discharge device 420 is provided at the bottom of the ascending channel 400 to discharge impurities at the bottom of the molten glass of the TFT glass.

In order to prevent the liquid flow hole 300 from freezing when it is put into production or when the lead plate is stopped, anti-blocking electrodes are respectively arranged on the inlet and outlet ends of the flow hole 300; the anti-blocking electrodes heat the glass liquid of the TFT glass. In order to slow down the temperature drop of the TFT glass molten glass in the ascending channel 400 , side-inserted electrodes are arranged on the ascending side wall of the ascending channel 400 , and the side-inserted electrodes heat the TFT glass molten glass.

The melting furnace of the present invention separates the process of melting from high-temperature clarification and homogenization, which can effectively reduce the high volatilization of boron and the defects caused by the melting of TFT glass batch materials, and can effectively clarify the glass liquid of TFT glass and homogenization, thereby avoiding the occurrence of defects such as streaks in the product, and significantly improving product quality; the setting of the bubbling device 500 and the kiln ridge 800 in the clarification tank 200 greatly improves the microbubbles in the glass liquid of TFT glass. The escape speed accelerates the clarification efficiency of the molten glass of the TFT glass, while the bubbling device 500 also accelerates the convection of the molten glass of the TFT glass, and the setting of the kiln ridge 800 improves the temperature of the molten glass of the TFT glass. In this way, the TFT glass The homogenization efficiency of the molten glass is also significantly improved, and the scale of the cold-top all-electric melting furnace 100 of the present invention is not affected by the quality of the molten glass of the melted TFT glass, so a larger scale can be realized.

To sum up, the present invention effectively overcomes various shortcomings in the prior art and has high industrial application value.

The above-mentioned embodiments only illustrate the principles and effects of the present invention, but are not intended to limit the present invention. Anyone skilled in the art can modify or change the above-mentioned embodiments without departing from the spirit and scope of the present invention. Therefore, all equivalent modifications or changes made by those skilled in the art without departing from the spirit and technical ideas disclosed in the present invention should still be covered by the claims of the present invention.

Claims (11)

1. A melting furnace for TFT glass, characterized in that it comprises: a cold-top all-electric melting furnace (100) and a clarifying tank (200) arranged in sequence; The bottom of the cold roof all-electric melting furnace (100) is provided with a liquid flow hole (300), and the outlet end of the liquid flow hole (300) communicates with the lower end of a vertically arranged ascending channel (400). The upper end of the ascending channel (400) communicates with the feed inlet of the clarifier (200); The upper part of the cold-top all-electric melting furnace (100) is provided with a feed port (110) for adding TFT glass batch materials, and the inside of the cold-top all-electric melting furnace (100) is provided with a plurality of kiln electrodes ( 120); The inside of the clarification tank (200) is provided with a plurality of electrodes (210) and a plurality of flame heating spray guns (220), and the clarification tank (200) is provided with a smoke outlet (201) for exhausting the smoke, All the flame heating spray guns (220) are arranged on the upper part of the clarification tank (200); Along the flow direction of the molten glass of the TFT glass in the clarification tank (200), a bubbling device (500) and a kiln ridge (800) are sequentially arranged on the bottom brick of the tank body of the clarification tank (200) , the bubbling device (500) is arranged behind all the electrodes (210) in the cell. 2. The melting furnace for TFT glass according to claim 1, characterized in that: the bottom brick of the kiln body and the side wall of the kiln body of the cold roof all-electric melting furnace (100) are planar structures, or the cold roof The bottom brick of the kiln body and the side wall of the kiln body of the top all-electric melting furnace (100) are stepped structures. 3. The melting furnace for TFT glass according to claim 1, characterized in that: all the kiln electrodes (120) are inserted into the kiln bottom bricks of the cold-roof all-electric melting furnace (100) or all of the kiln electrodes (120) are inserted on the side wall of the kiln body of the cold-top all-electric melting furnace (100). 4. The melting furnace for TFT glass according to claim 1, characterized in that: all electrodes (210) in the pool are inserted on the bottom bricks of the clarification tank (200), or all The electrodes (210) in the pool are inserted on the side wall of the clarification tank (200), or all the electrodes (210) in the pool are divided into the bottom of the tank body of the clarification tank (200). The bottom electrode on the brick and the side electrode inserted on the side wall of the clarification tank (200). 5. The melting furnace for TFT glass according to claim 1, characterized in that: all of the flame heating spray guns (220) are arranged on the upper part of the clarification tank (200); all of the flame heating spray guns The nozzles of (220) are arranged on the side wall of the clarification tank (200), or all the nozzles of the flame heating spray guns (220) are arranged on the top of the tank body of the clarification tank (200). 6. The melting furnace for TFT glass according to claim 1, characterized in that: along the flow direction of the molten glass of the TFT glass, on the side wall of the tank body at the rear end of the clarification tank (200) A discharge port (600) is provided, and the discharge port (600) is connected to a platinum forehearth (700). 7. The melting furnace for TFT glass according to claim 6, characterized in that: the clarification tank (200) is also provided with a heterogeneous glass liquid surface overflow device (230), and the heterogeneous glass liquid The surface overflow device (230) is connected with the side walls of the tank body on both sides of the front end of the discharge port (600) of the clarification tank (200). 8. The melting furnace for TFT glass according to claim 7, characterized in that: the discharge port (600) of the clarification tank (200) has a material taking height lower than that of the TFT glass in the clarification tank (200). The level of the glass liquid level of the glass. 9. The melting furnace for TFT glass according to claim 1, characterized in that: the bottom brick of the clarification tank (200) is provided with a first bottom discharge device (241), the first The bottom discharge device (241) is located behind all the electrodes (210) in the cell, and the first bottom discharge device (241) is located in front of the bubbling device (250). 10. The melting furnace for TFT glass according to claim 1, characterized in that: the bottom brick of the clarification tank (200) is provided with a second bottom discharge device (242), the second The bottom discharge device (242) is located behind the kiln ridge (800) and in front of the discharge port (600) of the clarification tank (200). 11. The melting furnace for TFT glass according to claim 1, characterized in that: an intermediate discharge device (420) is provided at the bottom of the ascending channel (400).