KR20210033421A - Float glass manufacturing device and float glass manufacturing method - Google Patents

Abstract

Provided is a float glass manufacturing apparatus which is excellent in the corrosion resistance to molten glass, and in which a tile hard to crack at the time of temperature rise is disposed. A float glass manufacturing apparatus (1) of the present invention is equipped with a bathtub (10) which accommodates a molten metal M, and a spout lip (14) which supplies molten glass G on the molten metal M. On a lower part of the spout lip (14), a tile (20) in contact with the molten glass G on the molten metal M is arranged, and at least one part of the tile (20) is a refractory material containing 90 wt% or more of zircon (ZrSiO_4).

Description

A float glass manufacturing apparatus and a float glass manufacturing method TECHNICAL FIELD [FLOAT GLASS MANUFACTURING DEVICE AND FLOAT GLASS MANUFACTURING METHOD}

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

A float glass manufacturing apparatus continuously supplies molten glass onto a molten metal in a bathtub, flows in a downstream direction, and molds it into a strip plate-shaped glass ribbon. The upper space of the bathtub is partitioned by a partition wall (front lintel) into an upstream spout space and a downstream main space. The main space is sufficiently larger than the spout space and is filled with a reducing gas in order to prevent oxidation of the molten metal.

In the spout space, the molten glass supplied onto the molten metal forms a main stream (front flow) flowing in the downstream direction and a branch stream (back flow) flowing back toward the wet back tile provided below the spout lip. The branch flows countercurrently toward the wet back tile, and flows dividedly left and right along the wet back tile, then flows downstream along the left and right restrictor tiles and joins the end of the main stream in the width direction (Fig. 3 of Patent Document 1). Reference).

In Patent Document 1, at least one of the spout lip, the side jam between the spout lip, the wet back tile, and the restrictor tile, ZrO ₂ is 85% or more and 97% or less in _{weight%, and the remainder is SiO 2} It is disclosed that it is composed of a glassy electric pole refractory material. Such electric cast refractory material is excellent in corrosion resistance to molten glass.

International Publication No. 2014/203569

However, the electric pole refractory material, when the temperature was raised from room temperature to at least 1200°C when starting the production of float glass, _{the crystal phase of ZrO 2} at 1100 to 1200°C transitions from monoclinic to tetragonal, resulting in large volume shrinkage. By doing so, cracks are liable to occur. In particular, the wet back tile and the restrictor tile are likely to be damaged when a crack occurs because the branch flow is active.

On the other hand, the electric _{cast refractory material having an Al 2} O _{3 content of} about 95% in terms of mass% does not cause the volume shrinkage at the time of heating, but the corrosion resistance to molten glass is inferior to the electric cast refractory material disclosed in Patent Document 1.

The present invention has been made in view of the above problems, and has excellent corrosion resistance to molten glass, and it is an object of the present invention to provide a float glass manufacturing apparatus and a float glass manufacturing method in which a tile that is less likely to crack when heated is disposed. do.

The float glass manufacturing apparatus of the present invention is a float glass manufacturing apparatus including a bath for accommodating molten metal and a spout lip for supplying molten glass onto the molten metal, and below the spout lip, the molten metal phase is melted. A tile in contact with glass is disposed, and at least a part of the tile is characterized in that it is a refractory material containing 90% or more _{of zircon (ZrSiO 4) by mass.}

In addition, the float glass manufacturing apparatus of the present invention is a float glass manufacturing apparatus including a bath for accommodating molten metal and a spout lip for supplying molten glass onto the molten metal, and below the spout lip, the molten metal arranged a tile in contact with on the molten glass, at least a portion of the tile is a refractory containing at least 60% of ZrO _2, in mass%, at least 2.5% SiO _2, wherein the refractory material, and said ZrO _2, Y ₂ It is characterized in that it contains stabilized zirconia, which is at least one _{solid solution selected from O 3} , CaO and CeO _2.

The float glass manufacturing method of the present invention is a float glass manufacturing method in which molten glass flowing over a spout lip is continuously supplied onto a molten metal in a bath, and below the spout lip, a tile in contact with the molten glass on the molten metal Is disposed, and at least a part of the tile is a refractory material containing 90% or more _{of zircon (ZrSiO 4) by mass.}

In addition, the float glass manufacturing method of the present invention is a float glass manufacturing method in which molten glass flowing on a spout lip is continuously supplied onto a molten metal in a bath, and below the spout lip, the molten glass on the molten metal is in contact. tiles are placed, at least a portion of the tile that is more than 60% of ZrO ₂ in terms of percent by mass, and the refractory material containing SiO ₂ at least 2.5%, said refractory, and said ZrO _2, Y ₂ O _3, CaO, and It is characterized in that it contains stabilized zirconia, which is at least one solid solution _{selected from CeO 2.}

The present invention is excellent in corrosion resistance to molten glass and can provide a float glass manufacturing apparatus and a float glass manufacturing method in which a tile that is less likely to generate cracks at the time of temperature rise is disposed.

1 is a cross-sectional view showing a main part of a float glass manufacturing apparatus according to an embodiment of the present invention.
2 is a cross-sectional view taken along line II-II of FIG. 1;
Fig. 3 is a plan view showing a flow of molten glass in the bath of Fig. 1;
Fig. 4 is a diagram showing a change in the coefficient of thermal expansion in a process of increasing the temperature of the refractory material in Examples.
Fig. 5 is a diagram for explaining a method of a corrosion resistance test in Examples.
6 is a diagram showing heat treatment conditions in a thermal shock test in Examples.

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

[Float Glass Manufacturing Equipment]

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 line II-II of FIG. 1. 3 is a plan view showing a flow of molten glass in the bath of FIG. 1.

The float glass manufacturing apparatus 1 continuously supplies the molten glass G onto the molten metal M in the bathtub 10, flows the supplied molten glass G on the molten metal M, and molds it into a strip-shaped glass ribbon. Float glass manufacturing apparatus 1, bathtub 10, spout lip 14, side jam 16, 17, twill 18, wet back tile 22, restrictor tile 24, 25, partition It has a wall 26, a heating source 27 and a tile heating source 29.

The bathtub 10 accommodates molten metal M. As the molten metal M, molten tin is used, for example. In addition to molten tin, molten tin alloys and the like can also be used, and the molten metal M may be anything that can float the molten glass G.

The bathtub 10 includes a box-shaped metal casing 11 opened upward, for example, as shown in FIG. 1, a side brick 12 protecting the sidewall of the metal casing 11 from molten metal M, and , It has a bottom brick 13 which protects the bottom wall of the metal casing 11 from molten metal M.

As shown in FIG. 1, the spout lip 14 forms a supply path for supplying the molten glass G onto the molten metal M in the bathtub 10. The side jams 16 and 17 are provided with the spout lip 14 interposed therebetween, as shown in Fig. 2, and the molten glass G flowing over the spout lip 14 flows left and right (Y direction in Fig. 2). Prevent overflow.

It is preferable that the spout lip 14 and the side jams 16, 17 are glassy electric pole refractory materials whose _{ZrO 2} is 85% or more and 97% or less in _{weight%, and the remainder is SiO 2 as a main body. ZrO 2} of the electric pole refractory material mainly exists as a badelite crystal. The balance of the electric pole refractory exists in the grain boundary of the bardelite crystal of ZrO _{2, and the electric pole refractory is densified.} In addition to _{SiO 2 , Al 2} O ₃ , Na ₂ O, and the like are contained in the glass material of the remainder. This electric pole refractory is called a high zirconia electric pole refractory, and is excellent in corrosion resistance to molten glass.

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

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

The tile 20 is disposed below the spout lip 14 and contacts 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, the restrictor tiles 24 and 25 obliquely extend downward from the wet back tile 22 as shown in FIG. 3 and are expanded and opened downward.

At least a part of the tile 20 of the present invention is _{a refractory material containing 90% or more of zircon (ZrSiO 4} ) by mass (hereinafter referred to as "first refractory material"). In the first refractory material, unlike high zirconia-based electric pole refractory material, when the temperature of the float glass is increased from room temperature to at least 1200°C, _{the crystal phase of ZrO 2} transitions from monoclinic to tetragonal crystal at 1100 to 1200°C. Thus, there is no problem that large volume shrinkage occurs and cracks occur in the refractory. 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.} In addition, 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 material is excellent in corrosion resistance to molten glass, and contains zircon (ZrSiO ₄ ) by mass% of preferably 92% or more, more preferably 95% or more, and even more preferably 98% or more. In addition, the first refractory material is preferably a zirconic refractory material containing, for example, Al ₂ O ₃ or Fe ₂ O _{3 in addition to zircon (ZrSiO 4 ).}

In the present embodiment, that at least a part of the tile 20 is the first refractory material is not limited to the case where all of the wet back tile 22 and all of the restrictor tiles 24 and 25 are the first refractory material, This includes a case where all or a part of the wet back tile 22 is a first refractory material, or a case in which all or a part of the restrictor tiles 24 and 25 is a first refractory material. In addition, the restrictor tiles 24 and 25 are longer than the wet back tiles 22 (see Fig. 3), and are susceptible to the volume contraction, so that they are preferably the first refractory materials. The same is true for the second refractory to be described later.

By the way, in the part where the tile 20 and the molten glass G contact, since molten glass G easily stays, there exists a tendency for the devitrification of the molten glass to easily generate|occur|produce. And, in the case where the tile 20 is a high zirconia electric pole refractory, the Na ₂ O content of the high zirconia electric pole refractory is, for example, 0.4% by mass. When the molten glass and the electric pole refractory react, Na ₂ O in the molten glass There was a risk of mismatch due to being easily mixed.

_{Therefore, it is preferable that the Na 2} O content of the first refractory material is 0.1% by mass or less. When the Na ₂ O content is 0.1% by mass or less, even if the molten glass and the first refractory react, Na ₂ O is less likely to be mixed in the molten glass, and thus devitrification is less likely to occur particularly in the case of producing an alkali-free glass. Here, in the portion where the molten glass G contacts the restrictor tiles 24 and 25 and the vicinity thereof, devitrification is likely to occur. Therefore, _{the 1st refractory material whose Na 2} O content is 0.1 mass% or less is suitable for the restrictor tiles 24 and 25 in suppressing the occurrence of devitrification. _{The Na 2} O content of the first refractory material is more preferably 0.07% by mass or less, and still more preferably 0.04% by mass or less.

In addition, alkali-free glass means glass which does not contain alkali metal oxides, such as _{Na 2} O and K _{2 O substantially.} Here, "substantially not containing an alkali metal oxide" means that the total amount of the content of the alkali metal oxide is 0.1% by mass or less.

It is preferable that the porosity of the first refractory is 1% or less. If the porosity is 1% or less, the refractory becomes dense and the compressive strength increases, so that even if the tile 20 and the molten glass G contact each other, the tile 20 is unlikely to be damaged. In this case, the bulk specific gravity is 4.0 or more, for example. The porosity of the first refractory material is more preferably 0.9% or less, and still more preferably 0.8% or less. In addition, the porosity and bulk specific gravity in this specification were measured according to "Measurement method of apparent porosity, water absorption rate and specific gravity of refractory brick" of JIS R2205.

At least a portion of the tiles 20 of the present invention is a refractory material (hereinafter referred to as "the second refractory material") containing 60% or more of ZrO _2, by mass%, at least 2.5% SiO _2. The second refractory material contains ZrO ₂ and stabilized zirconia, which is at least one _{solid solution selected from Y 2} O ₃ , CaO and CeO _2. In the second refractory material, when the temperature is raised from room temperature to at least 1200°C, _{the crystal phase of ZrO 2} transitions from monoclinic to tetragonal at 1100 to 1200°C, resulting in large volume shrinkage, and there is no problem that cracking occurs in the refractory. Because, stabilized zirconia, by employing a Y ₂ O ₃ and CaO, such as the ZrO _2, will stabilized to tetragonal state as room temperature of ZrO _2, there is no thing transferred to the tetragonal from monoclinic in the course of the temperature increase .

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 even more preferably 75% or more.

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

The second refractory contains _{0.3 to 4% of Al 2} O ₃ , 0.1 to 10% of CaO _{, 0 to 18% of Y 2} O ₃ , 0 to 18% of CeO ₂ by mass %, and further contains Al ₂ O It is preferable that it is a sintered refractory material whose mass ratio represented by ₃ /SiO _{2 is 0.05 to 0.8.}

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, since the vitrification temperature is lowered, the firing temperature is lowered, and the production cost of the refractory material can be reduced. Further, when firing at a temperature lower than the vitrification temperature, the function as a binder is not exhibited, and corrosion resistance and strength are deteriorated. When _{the content of Al 2} O ₃ is 4.0% or less, the vitrification temperature is lowered and the corrosion resistance to molten glass is hardly lowered even if it is deformed at the time of firing. The content of Al ₂ O ₃ is more preferably 0.4 to 3.5% in the sintered refractory.

It is preferable that the porosity of the second refractory is 3 to 50% by volume. When the porosity is 3% by volume or more, it is difficult to develop when cracking occurs, and it is difficult to lead to large cracks. If the pores are 50% by volume or less, the molten glass is difficult to penetrate into the furnace material of the sintered body, and corrosion resistance is difficult to decrease. The porosity is more preferably 3.5 to 45% by volume, and still more preferably 4 to 35% by volume.

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

As described above, the first refractory material and the second refractory material are excellent in corrosion resistance to molten glass, and cracks are less likely to occur at elevated temperature. Moreover, it is difficult to generate devitrification of molten glass. Therefore, if at least a part of the tile 20 is a first refractory material or a second refractory material, a float glass having good quality can be stably supplied after starting the manufacture of the float glass.

The partition wall 26 divides the upper space 30 of the bathtub 10 into an upstream spout space 32 and a downstream main space 34 as shown in FIG. 1. The partition wall 26 is made of 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.

The molten glass G supplied from the spout space 32 onto the molten metal M is, as shown in FIG. 3, a main stream 42 flowing in the downstream direction and a branch flowing in the upstream direction toward the wet back tile 22. Form 44. The branch 44 flows backwards toward the wet back tile 22, divides and flows left and right along the wet back tile 22, and then flows downstream along the left and right restrictor tiles 24, 25, and the main stream Joins the end of 42 in the width direction. Therefore, the foreign components in the molten glass G generated by contacting the molten glass G with the refractory material are collected in the edge portions of both side portions of the glass ribbon. And since both side edge portions of the glass ribbon are cut off after slow cooling and do not become a product, a float glass with good quality is obtained.

Temperature range of the molten glass G in the spout area 32 is in a range corresponding to the viscosity of the molten glass G in terms of, for example ^3.8 to 10 ⁶⁵ dPa · s in a ^4. 10, preferably in terms of the viscosity of the molten glass G It is in the range corresponding ^{to 10 4.1} to 10 ^{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 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 vol% of nitrogen gas and 1.5 to 15 vol% of hydrogen gas. The reducing gas is supplied from the joint of the roof brick in the main space 34 and the hole in the heater part.

The heating source 27 is disposed in the molten glass inflow space 32a in the spout space 32 to heat the molten glass G. The heating source 27 is preferably disposed downstream of the spout lip 14 as shown in FIG. 1. This is because not only the molten glass G flowing over the spout lip 14 but also the molten glass G flowing over 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 power feeding portion that feeds power to the heat generating portion 28. The heat generating part 28 heats the molten glass G passing downward over the entire width direction.

The tile heating source 29 is mounted on the wet back tile 22, for example. The tile heating source 29 heats the molten glass G on the molten metal M by heating the wet back tile 22. Thereby, since the flow of the branch 44 becomes high and the flow of the branch 44 is stabilized, when the branch 44 merges with the main stream 42, the flow of the molten glass G is stabilized. In addition, the tile heating source 29 may be embedded in 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. Thereby, the devitrification of the molten glass G around the wet back tile 22 can be prevented.

The heating source 27 and the tile heating source 29 may be constituted by 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 be used.}

[Method of manufacturing float glass]

In the float glass manufacturing method, as shown in FIG. 1, the molten glass G flowing over the spout lip 14 is continuously supplied to the molten metal M in the bath 10 by adjusting the flow rate with the twill 18, and melting. The glass G is flowed over the molten metal M and passed between the partition wall 26 and the molten metal M. In the range corresponding to the main space 34 of the molten glass G in terms of a viscosity of 10 ^4.5 to 10 ^{7. 5} dPa · s of, the glass ribbon (X direction in Fig. 1), both side edge portion top roll pressed As predetermined direction It is made to flow and is molded into a predetermined plate thickness. The glass ribbon molded 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 a slow cooling furnace, and cut to a predetermined size. . In this way, a float glass is obtained.

The upper space of the bathtub 10 is divided into a spout space 32 and a main space 34 by a partition wall 26, and below the spout lip 14, it is in contact with the molten glass G on the molten metal M. Tile 20 is placed.

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

At least a portion of the tile 20 of this invention is at least 60% of ZrO ₂ in terms of percent by mass, the second refractory material containing SiO ₂ at least 2.5%. The second refractory material contains ZrO ₂ and stabilized zirconia, which is at least one _{solid solution selected from Y 2} O ₃ , CaO and CeO _2.

_{It is preferable that the Na 2} O content of the first refractory material or the second refractory material is 0.1% by mass or less.

The first refractory material and the second refractory material are excellent in corrosion resistance to molten glass, and cracks are less likely to occur at elevated temperature. Moreover, it is difficult to generate devitrification of molten glass. Therefore, if at least a part of the tile 20 is a first refractory material or a second refractory material, a float glass having good quality can be stably supplied after starting the manufacture of the float glass.

The use of the float glass is not particularly limited, but is used as, for example, a glass substrate for displays such as a liquid crystal panel or an organic EL panel. In this case, the plate thickness in the central part of the width direction (Y direction in FIG. 2) of the glass ribbon is preferably 0.75 mm or less, more preferably 0.55 mm or less, and still more preferably 0.45 mm or less. In addition, the width direction of a glass ribbon is a direction orthogonal to the flow direction of a glass ribbon. The center part in the width direction of a glass ribbon is a range within 25% in the said width direction from the center of a width direction of a glass ribbon. The plate thickness in the central part of the width direction of the glass ribbon is measured after cooling the glass ribbon slowly cooled in a slow cooling furnace to room temperature and cutting it into a predetermined dimension.

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

Float glass, in terms of oxide-based mass%, 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 It is preferable that it is an alkali-free glass substrate containing 26%.

Float glass, in order to have a high distortion point, is expressed by mass% based on oxide, 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: It is preferable that it is an alkali-free glass substrate containing 8-26%.

[Example]

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

The refractory of Example 1 contains 98.6 _{% of zircon (ZrSiO 4} ), 0.2% of _{Al 2} O _{3 , and 0.06% of Fe 2} O ₃ by mass, and has a porosity of 0.7% and a volume specific gravity of 4.34. (AGC Ceramics, brand name: G-ZRHD-65S).

The refractory material of Example 2 contains 84.3 _{% of ZrO 2} , 9.3% of _{Y 2} O _{3 , 5.0% of SiO 2} , 1.0% of Al ₂ O ₃ , 0.4% of CaO by mass %, and Al ₂ O ₃ /SiO _It is a stabilized zirconia sintered refractory material having a mass ratio represented by 2 of 0.20, a porosity of 12.5%, and a volume specific gravity of 4.8.

In addition, the refractory Na ₂ O content of Examples 1 and 2 is 0.1% by mass or less.

The refractory material of Example 3 is a high-zirconia electric cast refractory material 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% (manufactured by AGC Ceramics, brand name: ZB -X9510).

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

(Thermal expansion characteristics)

Fig. 4 is a diagram showing a change in the coefficient of thermal expansion in a process of increasing the temperature of the refractory according to the example. The thermal expansion properties shown in Fig. 4 are, for the refractory materials of Examples 1 to 4, a cylindrical test piece having a diameter of 10 mm x a height of 20 mm was used, and at room temperature by TMA (manufactured by Rigaku Corporation, device name: Thermo plus EVO TMA8310). The coefficient of thermal expansion in the process of heating up 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 increased from room temperature to 1400°C or 1500°C, and volume contraction did not occur 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} transitions from monoclinic to tetragonal (so-called phase transition) did not occur. In addition, since the refractory material of Example 4 _{does not initially contain ZrO 2} , the phase transition does not occur.

In Example 3, the coefficient of thermal expansion was rapidly lowered in the process of increasing the temperature of 1100 to 1200°C, so that a large volume contraction occurred at 1100 to 1200°C. From this result, it can be seen that in Example 3, the phase transition occurred.

(Corrosion resistance test)

5 is a diagram for explaining a method of a corrosion resistance test in Examples. For the refractory materials of Examples 1 to 4, cylindrical test pieces having a diameter of 20 mm and a height of 80 mm were used. A collet of alkali-free glass (manufactured by AGC, brand name: AN100) was accommodated in a platinum crucible 130, and melted at 1400°C or higher to obtain a molten glass 120. The test pieces 110 of Examples 1 to 4 were immersed in the molten glass 120 at 1450°C for 50 hours, then cooled at 300°C/h and taken out from the platinum crucible 130. The test piece 110 observes the cross section cut along the longitudinal direction with an optical microscope (manufactured by Nikon, device name: Profile Projector V-12B), and calculates the refractory erosion rate of Examples 1 to 4 from the amount of erosion of the test piece 110. I did.

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 refractory materials of Examples 1 to 3 are excellent in corrosion resistance with respect to 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 material of Example 4 is inferior in corrosion resistance to molten glass as compared with the refractory material of Examples 1 to 3.

(Thermal shock test)

6 is a diagram showing heat treatment conditions in a thermal shock test in Examples. For the refractory materials of Examples 1 to 4, a rectangular parallelepiped test piece of 90 mm x 50 mm x 30 mm was used. The refractory materials of Examples 1 to 4 were loaded in an electric furnace (manufactured by Motoyama, apparatus name: NH-2035D), the temperature was raised from room temperature to 900°C at 100°C/h, and maintained at 900°C for 1 hour. Then, the temperature was raised from 900°C to 1200°C at 100°C/h, maintained at 1200°C for 1 hour, lowered from 1200°C to 900°C at 100°C/h, and maintained at 900°C for 1 hour 3 times. Repeat. 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.

In the test pieces of Examples 1, 2, and 4, no cracks or cracks were observed visually. From this result, the refractory materials of Examples 1, 2, and 4 can be evaluated as having no cracks or difficult to generate cracks when the temperature is raised from room temperature to at least 1200°C when starting the manufacture of float glass. have.

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

(theorem)

The refractory materials of Examples 1 and 2 obtained good results in any of the thermal expansion properties, corrosion resistance test, and thermal shock test, so it is required to have excellent corrosion resistance to molten glass and to be less likely to generate cracks at elevated temperature. It is suitable for application to tiles.

As described above, embodiments of the float glass manufacturing apparatus and the float glass manufacturing method have been described, but the present invention is not limited to the above embodiments, and various modifications and improvements are possible within the scope of the gist of the present invention described in the claims. Do.

Examples of the use of the produced float glass include construction, vehicle, flat panel display, cover glass, and other various uses.

1: Float glass manufacturing equipment
10: bathtub
14: spout lip
16, 17: side jam
18: Twill
20: tile
22: wet back tile
24, 25: Restrictor tiles
26: partition wall
27: heating source
28: heating part
29: tile heating source
30: space above the bathtub
32: spout space
32a: molten glass inflow space
34: main space
G: molten glass
M: molten metal

Claims (10)

It is a float glass manufacturing apparatus comprising a bath for accommodating molten metal and a spout lip for supplying molten glass onto the molten metal,
Below the spout lip, a tile in contact with the molten glass on the molten metal is disposed,
At least a part of the tile is a refractory material containing 90% or more _{of zircon (ZrSiO 4) by mass.} It is a float glass manufacturing apparatus comprising a bath for accommodating molten metal and a spout lip for supplying molten glass onto the molten metal,
Below the spout lip, a tile in contact with the molten glass on the molten metal is disposed,
At least a portion of the tile is not less than 60% of ZrO ₂ in terms of percent by mass, the refractory containing at least 2.5% SiO _2,
The refractory material comprises the ZrO ₂ and stabilized zirconia, which is at least one _{solid solution selected from Y 2} O ₃ , CaO and CeO _2. The method of claim 1,
Float glass manufacturing apparatus in which the porosity of the refractory material is 1% or less. The method according to any one of claims 1 to 3,
_{A float glass manufacturing apparatus in which the Na 2} O content of the refractory material is 0.1% by mass or less. The method according to any one of claims 1 to 3,
The tile has a wet back tile and a restrictor tile extending downstream from the wet back tile,
The restrictor tile is a float glass manufacturing apparatus containing the refractory material. It is a float glass manufacturing method in which molten glass flowing over a spout lip is continuously supplied onto a molten metal in a bath,
Below the spout lip, a tile in contact with the molten glass on the molten metal is disposed,
At least part of the tile is a refractory material containing 90% or more _{of zircon (ZrSiO 4) by mass.} It is a float glass manufacturing method in which molten glass flowing over a spout lip is continuously supplied onto a molten metal in a bath,
Below the spout lip, a tile in contact with the molten glass on the molten metal is disposed,
At least a portion of the tile is not less than 60% of ZrO ₂ in terms of percent by mass, the refractory containing at least 2.5% SiO _2,
The refractory material comprises the ZrO ₂ and stabilized zirconia, which is at least one _{solid solution selected from Y 2} O ₃ , CaO and CeO _2. The method according to claim 6 or 7,
The method for producing a float glass, wherein the refractory material has a Na ₂ O content of 0.1 mass% or less. The method according to claim 6 or 7,
Float glass, in terms of oxide-based mass%, 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 Float glass manufacturing method which is an alkali-free glass substrate containing 26%. The method according to claim 6 or 7,
Float glass, in terms of oxide-based mass%, 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 Float glass manufacturing method which is an alkali-free glass substrate containing 26%.

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