JP2021046334A - Apparatus and method for producing float glass - Google Patents

Abstract

To provide an apparatus for producing a float glass which is excellent in corrosion resistance to a molten glass and on which tiles in which cracks are difficult to occur during the rise of temperature are arranged.SOLUTION: An apparatus 1 of this invention for producing a float glass includes a bath 10 for housing a molten metal M, and a spout lip 14 for supplying a molten glass G on the molten metal M, wherein: tiles 20 that come into contact with the molten glass G on the molten metal M are arranged below the spout lip 14; and at least some of the tiles 20 are a refractory comprising, by mass, 90% or more of zircon (ZrSiO4).SELECTED DRAWING: Figure 1

Description

The present invention relates to a float glass manufacturing apparatus and a float glass manufacturing method.

The float glass manufacturing apparatus continuously supplies molten glass onto the molten metal in the bathtub and causes it to flow in the downstream direction to form a strip-shaped glass ribbon. The space above the bathtub is divided into a spout space on the upstream side and a main space on the downstream side by a partition wall (front lintel). The main space is sufficiently larger than the spout space and is filled with a reducing gas to prevent oxidation of the molten metal.

In the spout space, the molten glass supplied on the molten metal forms a main stream (front flow) flowing in the downstream direction and a tributary stream (back flow) flowing back toward the wet back tile provided below the spout trip. To do. The tributary flows backward toward the wet back tile, splits left and right along the wet back tile, then flows downstream along the left and right restrictor tiles, and joins the widthwise end of the main stream (patented). See FIG. 3 in Document 1).

In Patent Document 1, at least one of spout trip, side jam sandwiching spout trip, wet back tile and restrictor tile is mainly composed _{of ZrO 2} of 85% or more and 97% or less in _{weight%, and the rest is SiO 2.} It is disclosed that it is composed of an electroformed refractory that is glassy. Such electroformed refractories have excellent corrosion resistance to molten glass.

International Publication No. 2014/203569

However, in the above electroformed refractory, when the temperature is raised from room temperature to at least 1200 ° C. when the production of float glass is started, _{the crystal phase of ZrO 2} changes from monoclinic to tetragonal at 1100 to 1200 ° C. However, cracks are likely to occur due to large volume shrinkage. In particular, wet back tiles and restrictor tiles have a vigorous flow of the above-mentioned tributaries, and therefore, if cracks occur, they may be damaged.

On the other hand, the _{electroformed refractory having an Al 2} O ₃ content of about 95% by mass does not undergo the above-mentioned volume shrinkage when the temperature is raised, but has corrosion resistance to molten glass as compared with the electroformed refractory disclosed in Patent Document 1. Is inferior.

The present invention has been made in view of the above problems, and provides a float glass manufacturing apparatus and a float glass manufacturing method in which tiles having excellent corrosion resistance to molten glass and which are less likely to crack when the temperature rises are arranged. The purpose is.

The float glass manufacturing apparatus of the present invention is a float glass manufacturing apparatus including a bathtub for accommodating a molten metal and a spout trip for supplying molten glass on the molten metal, and below the spout trip is the molten glass. A tile that comes into contact with the molten glass on the metal is arranged, and at least a part of the tile is a refractory material containing 90% or more _{of zircon (ZrSiO 4) in mass%.}

Further, the float glass manufacturing apparatus of the present invention is a float glass manufacturing apparatus including a bathtub for accommodating the molten metal and a spout trip for supplying the molten glass on the molten metal. the tile in contact with the molten glass on the molten metal is disposed, at least a portion of the tile, ZrO ₂ and 60% by mass%, a refractory material containing SiO ₂ 2.5% or more, the The refractory is characterized by containing stabilized zirconia, which is a solid solution of the _{ZrO 2} and _{at least one selected from Y 2} O ₃ , Ca _{O and Ce O 2.}

The float glass manufacturing method of the present invention is a float glass manufacturing method in which molten glass flowing on a spout trip is continuously supplied onto a molten metal in a bathtub, and below the spout trip is on the molten metal. A tile that comes into contact with the molten glass is arranged, and at least a part of the tile is a refractory material containing 90% or more _{of zircon (ZrSiO 4) in mass%.}

Further, the float glass manufacturing method of the present invention is a float glass manufacturing method in which molten glass flowing on a spout trip is continuously supplied onto a molten metal in a bathtub, and the molten metal is below the spout trip. tile in contact with the molten glass above is disposed, at least a portion of the tile, ZrO ₂ and 60% by mass%, a refractory material containing SiO ₂ 2.5% or more, the refractory , The ZrO ₂ is characterized by containing stabilized zirconia, which is a solid solution of _{ZrO 2 and at least one selected from Y 2} O ₃ , Ca _{O and Ce O 2.}

The present invention can provide a float glass manufacturing apparatus and a float glass manufacturing method in which tiles having excellent corrosion resistance to molten glass and less likely to crack when the temperature rises are arranged.

It is sectional drawing which shows the main part of the float glass manufacturing apparatus by one Embodiment of this invention. It is sectional drawing along the line II-II of FIG. It is a top view which shows the flow of the molten glass in the bathtub of FIG. It is a figure which shows the change of the coefficient of thermal expansion in the process of raising temperature of the refractory of an Example. It is a figure for demonstrating the method of the corrosion resistance test of an Example. It is a figure which shows the heat treatment condition in the thermal shock test of an Example.

Hereinafter, embodiments for carrying out the present invention will be described with reference to the drawings.

[Float glass manufacturing equipment]
FIG. 1 is a cross-sectional view showing a main part of a float glass manufacturing apparatus according to an embodiment of the present invention. FIG. 2 is a cross-sectional view taken along the line II-II of FIG. FIG. 3 is a plan view showing the flow of molten glass in the bathtub of FIG.

The float glass manufacturing apparatus 1 continuously supplies the molten glass G onto the molten metal M in the bathtub 10, and causes the supplied molten glass G to flow on the molten metal M to form a strip-shaped glass ribbon. The float glass manufacturing apparatus 1 has a bathtub 10, a spout trip 14, side jams 16, 17, twill 18, wet back tiles 22, restrictor tiles 24, 25, partition walls 26, a heating source 27, and a tile heating source 29.

The bathtub 10 accommodates the molten metal M. As the molten metal M, for example, molten tin is used. In addition to molten tin, a molten tin alloy or the like can also be used, and the molten metal M may be any as long as it can float the molten glass G.

As shown in FIG. 1, for example, the bathtub 10 melts the box-shaped metal casing 11 opened upward, the side brick 12 that protects the side wall of the metal casing 11 from the molten metal M, and the bottom wall of the metal casing 11. It has a bottom brick 13 that protects it from the metal M.

As shown in FIG. 1, the spout trip 14 forms a supply path for supplying the molten glass G on the molten metal M in the bathtub 10. As shown in FIG. 2, the side jams 16 and 17 are provided so as to sandwich the spout trip 14, and prevent the molten glass G flowing on the spout trip 14 from spilling to the left and right (Y direction in FIG. 2).

It is preferable that the spout trip 14 and the side jams 16 and 17 are _{electroformed refractories in which ZrO 2} is 85% or more and 97% or less in weight% and the balance is glassy mainly composed of _{SiO 2. ZrO 2 of} electroformed refractory exists mainly as baddeleyite crystals. The rest of the electroformed refractory exists at the grain boundaries of _{the ZrO 2 baddeleyite crystals, which densifies the electroformed refractory.} The remaining vitreous material contains _{Al 2} O ₃ , Na ₂ O, and the like in addition to _{SiO 2.} This electroformed refractory is called a high zirconia electroformed refractory and has excellent corrosion resistance to molten glass.

The twill 18 is movable up and down with respect to the spout trip 14, and adjusts the flow rate of the molten glass G flowing on the spout trip 14. The narrower the distance between the twill 18 on the side in contact with the molten glass G and the spout trip 14, the smaller the flow rate of the molten glass G flowing on the spout trip 14.

The twill 18 is made of a refractory material. The twill 18 may be formed with a protective film 19 that prevents contact between the twill 18 and the molten glass G. The protective film 19 is formed of, for example, platinum or a platinum alloy.

The tile 20 is disposed below the spout trip 14 and comes into contact with the molten glass G on the molten metal M. The tile 20 has a wet back tile 22 and restrictor tiles 24 and 25 extending downstream from the wet back tile 22. In the present embodiment, as shown in FIG. 3, the restrictor tiles 24 and 25 extend obliquely downstream from the wet back tile 22 and expand downstream.

At least a part of the tile 20 of the present invention is _{a refractory material containing 90% or more of zircon (ZrSiO 4} ) in mass% (hereinafter, referred to as “first refractory material”). The first refractory is different from the high zirconia electrocast refractory, and when the production of float glass is started, when the temperature is raised from room temperature to at least 1200 ° C., the crystal phase _{of ZrO 2 is formed at 1100 to 1200 ° C.} There is no problem that the refractory is cracked due to a large volume shrinkage due to the transition from monoclinic to tetragonal. This is because zircon (ZrSiO ₄ ) has a single crystal structure in which Zr, Si, and O are integrated, and does not exist as a monoclinic crystal of _{ZrO 2 in the first place.} Depending on the type of glass to be manufactured, the temperature of the tile 20 may be raised to 1300 ° C. or higher.

The first refractory has excellent corrosion resistance to molten glass, and contains zircon (ZrSiO ₄ ) in a mass% of preferably 92% or more, more preferably 95% or more, still more preferably 98% or more. Further, the first refractory is preferably a zircon refractory containing, for example, Al ₂ O ₃ or Fe ₂ O _{3 in addition to zircon (ZrSiO 4} ).

In the present embodiment, the fact that at least a part of the tile 20 is the first refractory is not limited to the case where all of the wet back tiles 22 and all of the restrictor tiles 24 and 25 are the first refractories. This includes the case where all or part of the wet back tile 22 is the first refractory, and the case where all or part of the restrictor tiles 24 and 25 is the first refractory. The restrictor tiles 24 and 25 are longer than the wet back tile 22 (see FIG. 3) and are easily affected by the volume shrinkage, so that they are preferably the first refractory material. The same applies to the second refractory material described later.

By the way, in the portion where the tile 20 and the molten glass G come into contact with each other, the molten glass G tends to stay, so that the molten glass tends to be devitrified. When the tile 20 is a high zirconia electrocast refractory, the Na ₂ O content of the high zirconia refractory is, for example, 0.4% by mass, so that the molten glass reacts with the electrocast refractory. _{Then, Na 2} O is likely to be mixed in the molten glass, and devitrification may occur.

Therefore, the Na ₂ O content of the first refractory is preferably 0.1% by mass or less. If the Na ₂ O content is 0.1% by mass or less, even if the molten glass reacts with the first refractory, Na ₂ O is less likely to be mixed into the molten glass. When this is done, devitrification is unlikely to occur. Here, devitrification is likely to occur in the portion where the molten glass G is in contact with the restrictor tiles 24 and 25 and in the vicinity thereof. Therefore, _{the first refractory having a Na 2} O content of 0.1% by mass or less is suitable for the restrictor tiles 24 and 25 in order to suppress the occurrence of devitrification. _{The Na 2} O content of the first refractory is more preferably 0.07% by mass or less, still more preferably 0.04% by mass or less.

The non-alkali glass refers to glass that does not substantially contain alkali metal oxides such as _{Na 2} O and K _{2 O.} Here, the fact that the alkali metal oxide is substantially not contained means that the total content of the alkali metal oxide is 0.1% by mass or less.

The porosity of the first refractory is preferably 1% or less. When the porosity is 1% or less, the refractory becomes dense and the compressive strength becomes high, so that even if the tile 20 and the molten glass G come into contact with each other, the tile 20 is unlikely to be damaged. In this case, the bulk specific gravity is, for example, 4.0 or more. The porosity of the first refractory is more preferably 0.9% or less, still more preferably 0.8% or less. The porosity and bulk specific gravity in the present specification were measured according to JIS R2205, "Method for measuring apparent porosity, water absorption rate, and specific gravity of refractory bricks".

At least a portion of the tile 20 of the present invention, ZrO ₂ and 60% by mass%, refractories containing SiO ₂ 2.5% or more (hereinafter, referred to as a "second refractory".) Is. The second refractory contains stabilized zirconia, which is a solid solution of _{ZrO 2} and _{at least one selected from Y 2} O ₃ , Ca _{O and CeO 2.} In the second refractory, when the temperature is raised from room temperature to at least 1200 ° C., _{the crystal phase of ZrO 2} shifts from monoclinic to tetragonal at 1100 to 1200 ° C., causing large volume shrinkage and cracking in the refractory. There is no problem that occurs. This is because, stabilized zirconia, by solid solution and Y ₂ O ₃ and CaO to ZrO _2, and which was stabilized to room temperature remains tetragonal ZrO _2, from monoclinic in the course of raising the temperature This is because it does not transfer to tetragonal crystals.

ZrO ₂ (zirconia) has high corrosion resistance to molten glass, and the ZrO ₂ component contained in the second refractory is preferably 60 to 92%, more preferably 65% or more, and further 75% or more. preferable.

SiO ₂ is a component that acts as a binder by forming a glass phase and improves corrosion resistance and strength. _{The SiO 2} contained in the second refractory is preferably 2.5 to 12%, more preferably 3.0 to 11%. If it is 2.5% or more, the effect as a binder is high, and the strength and corrosion resistance are improved. If it is 12% or less, the bond between the zirconia particles is not inhibited, so that the corrosion resistance to the molten glass is unlikely to decrease.

The second refractory contains _{0.3 to 4% of Al 2} O ₃ , 0.1 to 10% of Ca O _{, 0 to 18% of Y 2 O 3,} and 0 to 18% of CeO ₂ in mass%. In addition, it is preferably a sintered refractory having a mass ratio of 0.05 to 0.8 represented by _{Al 2} O ₃ / SiO _2.

Al ₂ O ₃ is a component that forms a glass phase together with _{SiO 2 and acts as a binder.} Al ₂ O ₃ has the effect of lowering the vitrification temperature of _{SiO 2.} When _{the content of Al 2} O ₃ is 0.3% or more, the vitrification temperature becomes low, so that the firing temperature becomes low, and the production cost of refractories can be reduced. When fired at a temperature lower than the vitrification temperature, the function as a binder is not exhibited, and the corrosion resistance and strength are lowered. When _{the content of Al 2} O ₃ is 4.0% or less, even if the vitrification temperature is lowered and the glass is deformed during firing, the corrosion resistance to the molten glass is unlikely to be lowered. The content of Al ₂ O ₃ is more preferably 0.4 to 3.5% in the sintered refractory.

The porosity of the second refractory is preferably 3 to 50% by volume. If the porosity is 3% by volume or more, it is difficult for cracks to develop when cracks occur, and it is difficult for large cracks to occur. If the pores are 50% by volume or less, it is difficult for the molten glass to penetrate into the inside of the sintered body furnace material, and the corrosion resistance is not easily lowered. The porosity is more preferably 3.5 to 45% by volume, even more preferably 4 to 35% by volume.

_{The Na 2} O content of the second refractory is preferably 0.1% by mass or less. The reason is the same as that of the first refractory mentioned above.

As described above, the first refractory and the second refractory are excellent in corrosion resistance to molten glass, and cracks are unlikely to occur when the temperature rises. In addition, devitrification of molten glass is unlikely to occur. Therefore, if at least a part of the tile 20 is a first refractory or a second refractory, it is possible to stably supply high quality float glass after starting the production of the float glass.

As shown in FIG. 1, the partition wall 26 partitions the upper space 30 of the bathtub 10 into a spout space 32 on the upstream side and a main space 34 on the downstream side. The partition wall 26 is made of a refractory material.

The spout space 32 includes a molten glass inflow space 32a. The molten glass inflow space 32a is formed between the twill 18 and the partition wall 26, and is formed above the molten glass G.

As shown in FIG. 3, the molten glass G supplied onto the molten metal M in the spout space 32 forms a main stream 42 flowing in the downstream direction and a tributary 44 flowing in the upstream direction toward the wet back tile 22. .. The tributary 44 flows backward toward the wet back tile 22, is divided into left and right along the wet back tile 22, and then flows downstream along the left and right restrictor tiles 24 and 25, and flows in the width direction of the main stream 42. Join the end. Therefore, the foreign components in the molten glass G generated by the contact of the molten glass G with the refractory collect at both side edges of the glass ribbon. Then, both side edges of the glass ribbon are cut off after slow cooling to form a product, so that a high-quality float glass can be obtained.

The temperature range of the molten glass G in the spout space 32 is, for example ^{, a range corresponding to, for example, 103.8} to ^4.65 dPa · s in terms of the viscosity of the molten glass G, and preferably 10 in terms of the viscosity of the molten glass G. It is a range corresponding to ^4.1 to ^{4.3 dPa · s.}

The main space 34 is sufficiently larger than the spout space 32. The main space 34 is filled with a reducing gas in order to prevent oxidation of the molten metal M. The reducing gas is, for example, a mixed gas of nitrogen gas and hydrogen gas, and contains 85 to 98.5% by volume of nitrogen gas and 1.5 to 15% by volume of hydrogen gas. The reducing gas is supplied from the joint of the roof brick of the main space 34 and the hole of the heater portion.

The heating source 27 is arranged in the molten glass inflow space 32a of the spout space 32 and heats the molten glass G. As shown in FIG. 1, the heating source 27 is preferably arranged on the downstream side of the spout trip 14. This is because not only the molten glass G flowing on the spout trip 14 but also the molten glass G flowing on the molten metal M can be heated.

The heating source 27 has a heat generating portion 28 parallel to the width direction of the molten glass G (Y direction in FIG. 2) and a feeding portion for supplying power to the heat generating portion 28. The heat generating portion 28 heats the molten glass G passing below over the entire width direction.

The tile heating source 29 is placed on, for example, the wet back tile 22. The tile heating source 29 heats the molten glass G on the molten metal M by heating the wet back tile 22. As a result, the fluidity of the tributary 44 is increased and the flow of the tributary 44 is stabilized, so that the flow of the molten glass G is stabilized when the tributary 44 merges with the main stream 42. The tile heating source 29 may be embedded inside the wet back tile 22.

The tile heating source 29 may heat the molten glass G around the wet back tile 22 to a temperature 10 to 50 ° C. higher than the devitrification temperature of the glass. This makes it possible to prevent devitrification of the molten glass G around the wet back tile 22.

The heating source 27 and the tile heating source 29 may be composed of an electric heater, for example, a SiC heater. Instead of the SiC heater, a ceramic heater in which a metal heating element is embedded in a ceramic such as _{Al 2} O ₃ or Si ₃ N _{4 can also be used.}

[Float glass manufacturing method]
In the float glass manufacturing method, as shown in FIG. 1, the molten glass G flowing on the spout trip 14 is continuously supplied onto the molten metal M in the bathtub 10 by adjusting the flow rate with the twill 18, and the molten glass G is melted. It is made to flow on the metal M and passes between the partition wall 26 and the molten metal M. ^{In the range corresponding to 10 4.5} to 10 ^7.5 dPa · s in terms of viscosity of the molten glass G in the main space 34, the glass ribbon is pressed in a predetermined direction (X in FIG. 1) while the both side edges are pressed by the top roll. It is made to flow in the direction) and formed to a predetermined plate thickness. The glass ribbon formed to a predetermined plate thickness in the main space 34 is pulled up from the molten metal M in the downstream region of the main space 34, then slowly cooled in the slow cooling furnace, and cut into a predetermined size. In this way, a float glass is obtained.

The space above the bathtub 10 is divided into a spout space 32 and a main space 34 by a partition wall 26, and a tile 20 in contact with the molten glass G on the molten metal M is arranged below the spout trip 14.

At least a part of the tile 20 of the present invention is a first refractory containing 90% or more _{of zircon (ZrSiO 4) in mass%.}

At least a portion of the tile 20 of the present invention, ZrO ₂ and 60% by mass%, a second refractory containing SiO ₂ 2.5% or more. The second refractory contains stabilized zirconia, which is a solid solution of _{ZrO 2} and _{at least one selected from Y 2} O ₃ , Ca _{O and CeO 2.}

_{The Na 2} O content of the first refractory or the second refractory is preferably 0.1% by mass or less.

The first refractory and the second refractory are excellent in corrosion resistance to molten glass, and cracks are unlikely to occur when the temperature rises. In addition, devitrification of molten glass is unlikely to occur. Therefore, if at least a part of the tile 20 is a first refractory or a second refractory, it is possible to stably supply high quality float glass after starting the production of the float glass.

The use of the float glass is not particularly limited, but is used as a glass substrate for a display such as a liquid crystal panel or an organic EL panel. In this case, the plate thickness at the center of the glass ribbon in the width direction (Y direction in FIG. 2) is preferably 0.75 mm or less, more preferably 0.55 mm or less, and even more preferably 0.45 mm or less. The width direction of the glass ribbon is a direction orthogonal to the flowing direction of the glass ribbon. The central portion in the width direction of the glass ribbon is a range within 25% in the width direction from the center in the width direction of the glass ribbon. The plate thickness at the central portion in the width direction of the glass ribbon is measured after the glass ribbon slowly cooled in the slow cooling furnace is cooled to room temperature and cut to a predetermined size.

Examples of the type of float glass include non-alkali glass, aluminosilicate glass, borosilicate glass, and soda lime glass.

_{Float glass contains SiO 2} : 54 to 66%, Al ₂ O ₃ : 10 to 23%, B ₂ O ₃ : 6 to 12%, MgO + CaO + SrO + BaO: 8 to 26% in terms of mass% based on oxides. A non-alkali glass substrate is preferable.

Float glass has a mass% representation based on oxides to have a high strain point, SiO ₂ : 54 to 68%, Al ₂ O ₃ : 10 to 25%, B ₂ O ₃ : 0.1 to 5. A non-alkali glass substrate containing 5%, MgO + CaO + SrO + BaO: 8 to 26% is preferable.

Examples of the present invention will be described. Examples 1 and 2 are examples, and examples 3 and 4 are comparative examples. The refractory of Example 1 corresponds to the first refractory, and the refractory of Example 2 corresponds to the second refractory.

Refractories Example 1, 98.6% zircon (ZrSiO ₄₎ by mass%, the Al ₂ O ₃ 0.2%, the Fe ₂ O ₃ contained 0.06%, porosity of 0.7% It is a zircon refractory (manufactured by AGC Ceramics Co., Ltd., trade name: G-ZRHD-65S) having a bulk specific gravity of 4.34.

The refractory of Example 2 is 84.3% _{ZrO 2} , 9.3% _{Y 2} O ₃ , 5.0% _{SiO 2 , 1.0% Al 2} O ₃ , and 0. CaO in mass%. A stabilized zirconia sintered refractory containing 4%, _{having a mass ratio of 0.20 in Al 2} O ₃ / SiO ₂ , a porosity of 12.5%, and a bulk specific gravity of 4.8. is there.

_{The Na 2} O content of the refractories of Examples 1 and 2 is 0.1% by mass or less.

The refractory of Example 3 is a high zirconia electroformed refractory containing 94.5 _{% of ZrO 2} , 4% of _{SiO 2 , 0.8% of Al 2} O ₃ and 0.4% of Na _{2 O in mass%.} A product (manufactured by AGC Ceramics Co., Ltd., trade name: ZB-X9510).

The refractory of Example 4 is an alumina electroformed refractory containing 95% _{Al 2} O ₃ , 0.8% _{SiO 2 and 3.5% Na 2} O in mass% (manufactured by AGC Ceramics Co., Ltd., trade name). : MB-G).

(Thermal expansion characteristics)
FIG. 4 is a diagram showing a change in the coefficient of thermal expansion in the process of raising the temperature of the refractory of the example. The thermal expansion characteristics shown in FIG. 4 are obtained by using a columnar test piece having a diameter of 10 mm and a height of 20 mm for the refractories of Examples 1 to 4 and using TMA (manufactured by Rigaku Co., Ltd., device name: Thermo plus EVO TMA8310). The coefficient of thermal expansion in the heating process from room temperature to 1400 ° C. (Example 2) or 1500 ° C. (Example 1, Example 3 and Example 4) was measured.

In Examples 1, 2 and 4, the coefficient of thermal expansion linearly increases from room temperature to 1400 ° C. or 1500 ° C., and no volume shrinkage occurs at 1100 to 1200 ° C. From this result, it can be seen that in Examples 1 and 2, _{the phenomenon that the crystal phase of ZrO 2} changes from monoclinic to tetragonal (so-called phase transition) does not occur. Since the refractory of Example 4 _{does not contain ZrO 2} in the first place, the above-mentioned phase transition does not occur.

In Example 3, the coefficient of thermal expansion sharply decreases in the process of raising the temperature from 1100 to 1200 ° C., and a large volume shrinkage occurs at 1100 to 1200 ° C. From this result, it can be seen that the above-mentioned phase transition has occurred in Example 3.

(Corrosion resistance test)
FIG. 5 is a diagram for explaining a method of corrosion resistance test of Examples. For the refractories of Examples 1 to 4, a columnar test piece having a diameter of 20 mm and a height of 80 mm was used. A cullet of non-alkali glass (manufactured by AGC, trade name: AN100) was housed in a platinum crucible 130 and melted at 1400 ° C. or higher to obtain molten glass 120. The test pieces 110 of Examples 1 to 4 were immersed in molten glass 120 at 1450 ° C. for 50 hours, cooled at 300 ° C./h, and taken out from the platinum crucible 130. The test piece 110 was obtained by observing a cross section cut along the length direction with an optical microscope (manufactured by Nikon Corporation, device name: Profile Projector V-12B), and based on the amount of erosion of the test piece 110, the refractory of Examples 1 to 4 The erosion rate was calculated.

The erosion rates of Examples 1 to 3 were 0.06 mm / day, 0.04 mm / day, and 0.03 mm / day, respectively. From this result, it can be seen that the refractories of Examples 1 to 3 have excellent corrosion resistance against high-temperature molten glass.

The erosion rate of Example 4 was 0.23 mm / day. From this result, it can be seen that the refractory of Example 4 is inferior in corrosion resistance to molten glass as compared with the refractory of Examples 1 to 3.

(Thermal impact test)
FIG. 6 is a diagram showing heat treatment conditions in the thermal shock test of Examples. For the refractories of Examples 1 to 4, a rectangular parallelepiped test piece of 90 mm × 50 mm × 30 mm was used. The refractory of Examples 1 to 4 is placed in an electric furnace (manufactured by Motoyama Co., Ltd., device name: NH-2035D), the temperature is raised from room temperature to 900 ° C. at 100 ° C./h, and the temperature is maintained at 900 ° C. for 1 hour. Then, a heat treatment cycle is performed in which the temperature is raised from 900 ° C. to 1200 ° C. at 100 ° C./h and held at 1200 ° C. for 1 hour, the temperature is lowered from 1200 ° C. to 900 ° C. at 100 ° C./h, and the temperature is held at 900 ° C. for 1 hour. Repeat 3 times. Then, the temperature was lowered from 900 ° C. to room temperature at 100 ° C./h, and the test piece was taken out from the electric furnace.

No cracks or cracks were visually confirmed in the test pieces of Examples 1, 2 and 4. From this result, the refractories of Examples 1, 2 and 4 are those in which cracks do not occur or cracks are unlikely to occur when the temperature is raised from room temperature to at least 1200 ° C. when the production of float glass is started. Can be evaluated as.

The test piece of Example 3 was visually confirmed to have cracks. From this result, it can be evaluated that the refractory of Example 3 may have cracks when the temperature is raised from room temperature to at least 1200 ° C. when the production of float glass is started.

(Summary)
Since the refractories of Examples 1 and 2 obtained good results in all of the thermal expansion characteristics, the corrosion resistance test and the thermal shock test, they are excellent in corrosion resistance to molten glass and cracks are unlikely to occur at the time of temperature rise. It is suitable for application to the required tiles.

Although the float glass manufacturing apparatus and the embodiment of the float glass manufacturing method have been described above, the present invention is not limited to the above-mentioned embodiments and the like, and is within the scope of the gist of the present invention described in the claims. , Various modifications and improvements are possible.

Float glass produced can be used for construction, vehicles, flat panel displays, cover glass, or various other uses.

1 Float glass manufacturing equipment 10 Bathtub 14 Spout trip 16, 17 Side jam 18 Twill 20 Tile 22 Wet back tile 24, 25 Restrictor tile 26 Partition wall 27 Heat source 28 Heat generation part 29 Tile heat source 30 Upper space of bathtub 32 Spout space 32a Float glass inflow space 34 Main space G Float glass M Float metal

Claims (10)

A float glass manufacturing apparatus including a bathtub for accommodating molten metal and a spout trip for supplying molten glass on the molten metal.
Below the spout trip, tiles in contact with the molten glass on the molten metal are arranged.
A float glass manufacturing apparatus, wherein at least a part of the tile is a refractory material containing 90% or more _{of zircon (ZrSiO 4) in mass%.} A float glass manufacturing apparatus including a bathtub for accommodating molten metal and a spout trip for supplying molten glass on the molten metal.
Below the spout trip, tiles in contact with the molten glass on the molten metal are arranged.
At least a portion of the tile, ZrO ₂ and 60% by mass%, a refractory material containing SiO ₂ 2.5% or more,
The float glass manufacturing apparatus, wherein the refractory contains stabilized zirconia, which is a solid solution of _{ZrO 2} and _{at least one selected from Y 2} O ₃ , Ca _{O and CeO 2.} The float glass manufacturing apparatus according to claim 1, wherein the refractory has a porosity of 1% or less. The float glass manufacturing apparatus according to any one of claims 1 to 3, wherein the Na _{2 O content of the refractory is 0.1% by mass or less.} The tile has a wet back tile and a restrictor tile extending downstream from the wet back tile.
The float glass manufacturing apparatus according to any one of claims 1 to 4, wherein the restrictor tile is made of the refractory material. A float glass manufacturing method in which molten glass flowing on a spout trip is continuously supplied onto the molten metal in a bathtub.
Below the spout trip, tiles in contact with the molten glass on the molten metal are arranged.
A method for producing float glass, wherein at least a part of the tile is a refractory material containing 90% or more _{of zircon (ZrSiO 4) in mass%.} A float glass manufacturing method in which molten glass flowing on a spout trip is continuously supplied onto the molten metal in a bathtub.
Below the spout trip, tiles in contact with the molten glass on the molten metal are arranged.
At least a portion of the tile, ZrO ₂ and 60% by mass%, a refractory material containing SiO ₂ 2.5% or more,
The method for producing float glass, wherein the refractory contains stabilized zirconia, which is a solid solution of _{ZrO 2} and _{at least one selected from Y 2} O ₃ , Ca _{O and CeO 2.} The float glass production method according to claim 6 or 7, wherein the Na _{2 O content of the refractory is 0.1% by mass or less. Float glass contains SiO 2} : 54 to 66%, Al ₂ O ₃ : 10 to 23%, B ₂ O ₃ : 6 to 12%, MgO + CaO + SrO + BaO: 8 to 26% in terms of mass% based on oxides. The float glass manufacturing method according to any one of claims 6 to 8, which is a non-alkali glass substrate. Float glass is expressed in terms of mass% based on oxides, SiO ₂ : 54 to 68%, Al ₂ O ₃ : 10 to 25%, B ₂ O ₃ : 0.1 to 5.5%, MgO + CaO + SrO + BaO: 8 to 26. The float glass manufacturing method according to any one of claims 6 to 8, which is a non-alkali glass substrate containing%.

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