JP4612331B2 - Refractory material for float bath and float bath - Google Patents

Description

  The present invention relates to a refractory material used in a float bath that is a molten glass tank for producing float glass, and a float bath lined with the refractory material.

  The float bath is composed of a refractory brick lined on a metal frame, which contains molten tin or a tin alloy, forms a horizontal metal bath surface, and melts on the metal bath surface. This is an apparatus for continuously forming a flat glass plate having a smooth surface by causing glass to flow out into a strip-shaped plate glass and then moving along the bath surface while floating on a metal bath. The upper space of the float bath is covered with a cover to form a sealed space, and in order to prevent oxidation of molten tin, the sealed space is filled with a reducing gas mainly composed of nitrogen and hydrogen. Yes.

Patent Document 1 describes that the following general performance is required for the lining refractory brick of the float bath.
a. Because the surface of the lining refractory brick is in direct contact with the molten metal, it must have corrosion resistance to the molten metal.
b. Na ₂ O and K ₂ O, which are alkali components contained in the plate glass that floats forward on the surface of the molten metal, reach the lining refractory brick through the molten metal, and are alkali-resistant.
c. Since the sealed space of the float bath is filled with the nitrogen and hydrogen, it has a reduction-resistant atmosphere.
d. Must have spalling resistance and resistance to foaming to withstand temperature fluctuations in the float bath.

Patent Document 1 discloses that alkali (Na ₂ O and K ₂ O) contained in a plate glass by adding 0.5 to 2% by weight of MgO and CaO to a conventional alumina silica chamotte brick as the lining refractory brick. Float bath-lined refractory bricks are described in which the flaking phenomenon (b) described above, which acts on the lining refractory brick and peels the surface, is less likely to occur.

JP 7-109129 A

  The present invention is a novel float bath refractory material having a performance equivalent to or higher than that of a conventional alumina silica-based chamotte brick used as a lining refractory brick for a float bath, and having high thermal shock resistance. The purpose is to provide a float bath lined with wood.

The present inventor has particular titanium magnesium aluminum sintered body is excellent in heat resistance and corrosion resistance against molten metal float bath, the temperature change in order to have a sufficient heat resistance, lightweight and low thermal expansion coefficient Therefore, the present inventors have found that it is extremely excellent as a lining refractory material for a float bath.

That is, the present invention provides the following refractory material for float bath and float bath.
(1) the composition _{formula: M g x Al 2 (1} -x) Ti (1 + x) O 5 ( wherein, 0.2 ≦ x <1) metal component ratio in the represented Ruchi Tan aluminum magnesium 100 parts by mass with a mixture (component X) containing an Al-containing compound, a Ti-containing compound and an Mg-containing compound in the same metal component ratio as the oxide equivalent, and a composition formula: (Na _y K _1-y ) AlSi ₃ O ₈ (wherein, 0 ≦ y ≦ 1) an alkali length stone represented by raw material mixture of (Y of component) containing a 1 to 10 parts by mass in terms of oxide amount, calcined at 1000 to 1700 ° C. float buses refractory material consisting of the titanium magnesium aluminum sintered body.
(2) (1) above float bath being lined with a float bath refractory material.

  The refractory material for a float bath according to the present invention is excellent in heat resistance and corrosion resistance to the molten metal in the float bath, has a small thermal expansion coefficient, and also has excellent thermal shock resistance, and is non-wetting to a molten metal such as tin. Therefore, by lining the float bath with this refractory material, it becomes possible to stably operate the float bath over a long period of time to produce float glass.

As described above, the refractory material for a float bath according to the present invention is represented by the composition formula : M g _x Al _{2 (1-x)} Ti _{(1 + x)} O ₅ (where 0.2 ≦ x <1 ). I by including the same metal component ratio and the metal component ratio in Ruchi Tan magnesium aluminum, Al-containing compound, and 100 parts by weight of a mixture comprising a Ti-containing compound and M g containing compound (X component) as the oxide equivalent weight , composition formula: and _{(Na y K 1-y)} AlSi 3 O 8 ( wherein, 0 ≦ y ≦ 1) 1~10 parts by weight of the alkali-length stone represented by a (called Y component) as the oxide equivalent weight, the raw material mixture containing a titanium magnesium aluminum sintered body obtained by firing at 1000 to 1700 ° C..

Forming an X component in said, Al-containing compound, Ti-containing compound and M g containing compound by firing the composition _{formula: M g x Al 2 (1} -x) Ti (1 + x) O 5 ( wherein, if a component for forming a Ruchi Tan magnesium aluminum represented by 0.2 ≦ x <1) can be used without particular limitation. The Mg-containing compound, Al-containing compound, and Ti-containing compound may not be separate compounds, but may be a compound containing two or more metal components. These compounds are usually selected from those used as raw materials for various ceramics such as alumina ceramics, titania ceramics, magnesia ceramics, aluminum titanate ceramics, magnesium titanate ceramics, spinel ceramics, aluminum magnesium titanate ceramics, etc. Can be used. Specific examples of such a compound include two or more kinds of oxides such as Al ₂ O ₃ , TiO ₂ , and MgO, MgAl ₂ O ₄ , Al ₂ TiO ₅ , and spinel structures containing Mg and Ti. Examples thereof include composite oxides containing metal components, compounds containing one or more metal components selected from the group consisting of Al, Ti and Mg (carbonates, nitrates, sulfates, etc.).

The mixing ratio of the Al-containing compound, Ti-containing compound, and Mg-containing compound is such that the ratio of the metal components contained in these compounds is the above-described composition formula : M g _x Al _{2 (1-x)} Ti _{(1 + x )} Same as the metal component ratio of Mg, Al and Ti in aluminum magnesium titanate represented by O ₅ (wherein 0.2 ≦ x <1, preferably 0.2 ≦ x ≦ 0.8) Ratio, preferably substantially the same ratio. By using a mixture of the above compound in such a ratio, it is possible to obtain a Ruchi Tan magnesium aluminum having a similar metal component ratio and the metal component ratio in the mixture used as the starting material.

The X components described above, Y components to be mixed is an alkali feldspar. Y alkali feldspar is Ingredient is expressed by the formula is those represented by _{(Na y K 1-y)} AlSi 3 O 8 are used. In the formula, y satisfies 0 ≦ y ≦ 1, preferably 0.1 ≦ y ≦ 1, and particularly preferably 0.15 ≦ y ≦ 0.85. Alkali feldspar has a low melting point having a y value of this range is particularly effective in promoting sintering of titanium magnesium aluminum.

The mixing ratio of the X component and the Y component is important, and the Y component is 1 to 10 parts by mass relative to 100 parts by mass of the X component. Note that each of the X component and the Y component is a ratio as an oxide, and when a raw material other than the oxide is used, the value is converted to an oxide. When the Y component with respect to 100 parts by mass of the X component is smaller than 1 part by mass, the effect of adding the Y component is small, and the characteristics of the sintered body may not be sufficiently improved. Conversely, if it exceeds 10 parts by weight, which exceeds greatly the solubility limit of S i elemental to titanium magnesium aluminum crystals, as excess oxide alone the added excess component in the sintered body It is unsuitable because it results in a particularly large thermal expansion coefficient. Especially, 3-7 mass parts is suitable for Y component with respect to 100 mass parts of X components.

In the present invention, the X component is a metal component ratio in aluminum magnesium titanate represented by Mg _x Al _{2 (1-x)} Ti _{(1 + x)} O ₅ (where 0.2 ≦ x <1 ) It is a mixture containing an Al-containing compound, a Ti-containing compound and an Mg-containing compound, which are contained in the same metal component ratio, and the Y component has a composition formula: (Na _y K _1-y ) AlSi ₃ O ₈ (wherein The alkali feldspar represented by 0 ≦ y ≦ 1) is preferable because an aluminum magnesium titanate sintered body having particularly excellent characteristics can be obtained.

In the present invention, in addition to the above-mentioned X component and Y component, other sintering aids can be used as necessary, and the properties of the resulting sintered body can be improved. Other sintering aids such _{as, SiO 2, ZrO 2, FeO} 3, CaO, and the like Y ₂ O _3.

  The raw material mixture containing the X component and the Y component is sufficiently mixed and pulverized. The mixing and pulverization of the raw material mixture is not particularly limited and is performed according to a known method. For example, a ball mill, a medium stirring mill, or the like may be used. The degree of pulverization of the raw material mixture is not particularly limited, but the average particle size is preferably 30 μm or less, particularly preferably 8 to 15 μm. This is preferably as small as possible as long as secondary particles are not formed.

  Preferably, a molding aid can be blended in the raw material mixture. As molding aids, known ones such as binders, mold release agents, antifoaming agents, and peptizers can be used. As the binder, polyvinyl alcohol, microwax emulsion, methylcellulose, carboxymethylcellulose and the like are preferable. As the releasing agent, stearic acid emulsion and the like are preferable, as the antifoaming agent, n-octyl alcohol, octylphenoxyethanol and the like are preferable, and as the peptizer, diethylamine, triethylamine and the like are preferable.

  The amount of the molding aid used is not particularly limited, but in the case of the present invention, both are solids with respect to a total amount of 100 parts by mass of the X component and Y component (converted as oxides) used as raw materials. The following ranges are preferable in terms of conversion. That is, the binder is preferably about 0.2 to 0.6 parts by weight, the release agent is preferably about 0.2 to 0.7 parts by weight, and the antifoaming agent is preferably 0.5 to 1.5 parts by weight. It is preferable to use about 0.5 to 1.5 parts by weight of peptizer and peptizer.

The raw material mixture to which the molding aid is added is mixed, kneaded, and plasticized so as to be moldable, and formed into a lining refractory material by casting or press molding. As this molding method, a known method can be used. The shaped body is preferably dried and then fired at 1000 to 1700 ° C, preferably 1250 to 1700 ° C, more preferably 1300 to 1450 ° C. There is no particular limitation on the firing atmosphere, and any of an oxygen-containing atmosphere such as air, a reducing atmosphere, and an inert atmosphere that are usually employed may be used. The firing time may be fired until the sintering proceeds sufficiently, and usually about 1 to 20 hours is employed.

There is no restriction | limiting in particular also about the temperature increase rate and temperature decrease rate in the case of the said baking, What is necessary is just to set suitably the conditions which a crack etc. do not enter in the obtained sintered compact. For example, it is preferable to gradually raise the temperature without rapidly raising the temperature in order to sufficiently remove moisture, binders and other molding aids contained in the raw material mixture. Moreover, before heating to the above-described firing temperature, firing is preferably performed at a moderate temperature rise of about 10 to 30 hours, if necessary, preferably in a temperature range of about 500 to 1000 ° C. In this case, titanium aluminum magnesium, the sintered body of the stress which causes cracking at the time of forming can be reduced, dense and uniform sintering by suppressing the generation of cracks in the sintered body A ligation can be obtained.

A sintered body obtained in this manner, the Ruchi Tan magnesium aluminum formed from the X component as a basic component, a Y component, Si Ingredients contained in the alkali feldspar is titanium magnesium aluminum crystal lattice It becomes a solid solution. As described above, such a sintered body has a high heat resistance and a low thermal expansion coefficient, and has a stable crystal structure, so that the sintered body has excellent thermal decomposition resistance. When the fireproof material for a float bath of the present invention is manufactured from this fired body, normally, six surfaces of a rectangular parallelepiped formed of the sintered body are polished to a predetermined size to obtain a flat and smooth surface, and the float bath is further processed. Drilling for mounting and fixing to the metal casing.

Ceramic material composed of a sintered body of the upper Eat Tan aluminum magnesium, heat resistance and excellent corrosion resistance, and in order to have a small thermal expansion coefficient and excellent thermal shock resistance, a float bath refractory material of the present invention It is suitable as. In addition, since the ceramic material has a melting point of 1700 ° C. or higher, it has sufficient heat resistance to, for example, molten tin heated to about 600 to 1050 ° C. in a float bath. In addition, the thermal expansion coefficient at room temperature is as small as about 2.0 × 10 ⁻⁶ K ⁻¹ or less, and this thermal expansion coefficient hardly changes in the temperature range from room temperature to the molten tin temperature. can get. Furthermore, as a chemical characteristic, no decomposition or reaction occurs even when contacted with high-temperature molten tin.
Thus, the refractory material for the float bath of the present invention has sufficient performance required for the refractory material for the lining of the float bath and is excellent in non-wetting property against the molten metal. Ru suitable der as lining for refractory material.

  Hereinafter, embodiments of the float bath of the present invention will be described with reference to the drawings. However, the following drawings are illustrated for facilitating understanding of the float bath, and the present invention is not limited to this. Since the basic structure of the float bath is substantially the same as a known float bath, a detailed description thereof will be omitted.

  FIG. 1 shows a longitudinal sectional view of a float bath. As shown in FIG. 1, the float bath is constituted by a rectangular metal casing 2 that extends long in the forming direction of the glass sheet, and a refractory material 1 for the float bath is lined. To form a flat molten metal bath surface. The molten metal 3 is exemplified by tin or a tin alloy, but usually tin is used. The upper part of the float bath is covered with a cover 4, and the space 7 above the molten metal 3 is filled with a mixed gas of nitrogen and hydrogen to prevent oxidation of the molten metal 3.

  When the float bath is lined with the refractory material 1 for the float bath of the present invention, in the float bath of FIG. 1, both the bottom portion and the side portion of the casing 2 are lined with the refractory material 1 for the float bath. It is also possible to line only one or only a part of the portion with the refractory material 1 for the float bath, and line the other or the remaining portion with a conventional refractory brick for lining (for example, alumina silica-based chamotte). Moreover, you may interpose the conventional refractory brick for lining between the casing 2 and the refractory material 1 for float baths. In addition, the magnitude | size of a float bath changes with the magnitude | size (melting capability) of a glass melting tank, the width | variety of the plate glass to shape | mold, etc. similarly to the known float bath, and is not specified.

  The thickness of the refractory material 1 for a float bath of the present invention is required to be about 25 mm or more, preferably 200 mm or more, and about 300 mm in a large size. When the thickness is less than 25 mm, there is a possibility that sufficient strength cannot be obtained particularly when the inner side of the casing 2 is lined. Moreover, although the magnitude | size of the refractory material 1 for float baths is not specified, the general purpose magnitude | size is about 500-1000 mm x 300-800 mm (horizontal x length). Accordingly, the refractory material 1 for a float bath is generally formed as a rectangular parallelepiped in combination with the thickness.

  The method of manufacturing plate glass with the float bath is the same as the conventional float method. When this is outlined according to FIG. 1, the molten glass 6 supplied from a glass melting tank (not shown) flows down onto the molten metal 3 in the float bath, and the molten glass that has flowed down on the molten metal bath surface is directed downstream. The glass strip 5 is stretched to form a glass strip 5, which is further stretched while floating and moving along the surface of the molten metal bath to obtain a glass plate having a predetermined plate thickness. The formed strip-shaped glass 5 is taken out while being lifted by the lift roll 8 from the opening at the rear end of the float bath, conveyed in the direction of the arrow, gradually cooled in a slow cooling furnace (not shown), and then cut.

  In the float method described above, the molten metal bath in the float bath has a temperature gradient along the forming direction from the inlet side of the molten glass 6, and the temperature near the inlet of the float bath is the highest and gradually decreases toward the downstream. It is low. This temperature mainly varies depending on the composition of the plate glass. For example, in the case of soda lime glass, the temperature is adjusted to about 1050 ° C. near the inlet of the float bath and about 600 ° C. near the take-out outlet. Due to this temperature gradient, the belt-like glass 5 is gradually cooled as it advances on the metal bath surface, and reaches a temperature that does not deform near the take-out outlet.

  Hereinafter, although the performance of the refractory material for a float bath of the present invention is evaluated by examples, it is needless to say that the present invention should not be construed as being limited thereto.

Example 1 (Reference example)
For 100 parts by mass of a mixture composed of 56.1% by mass (50 mol%) of easily sinterable α-type alumina and 43.9% by mass (50 mol%) of anatase type titanium oxide, (Na _0.6 K _0.4 ) 4 parts by mass of alkali feldspar represented by AlSi ₃ O ₈ , 0.25 parts by mass of polyvinyl alcohol as a binder, 1 part by mass of diethylamine as a peptizer, 0.5 mass of polypropylene glycol as an antifoaming agent Part was added and mixed with a ball mill for 3 hours, and then dried with a 120 ° C. dryer for 12 hours or more to obtain a raw material powder.

  The obtained raw material powder was pulverized to an average particle size of 10 μm or less, and a 100 × 600 × 400 mm (thickness × width × length) rectangular parallelepiped (sample) was formed using a press molding machine (manufactured by Taiheiyo Tech). The molded body was dried and then fired in the air at 1500 ° C. for 4 hours.

Example 2 (Reference example)
With respect to 100 parts by mass of a mixture composed of 56.1% by mass (50 mol%) of easily sinterable α-type alumina and 43.9% by mass (50 mol%) of anatase type titanium oxide, (Na _0.6 K _0.4 ) 4 parts by mass of an alkali feldspar represented by AlSi ₃ O ₈ , 6 parts by mass of a spinel compound represented by the chemical formula: MgAl ₂ O ₄ , 0.25 parts by mass of polyvinyl alcohol as a binder, and 1 of diethylamine as a peptizer 0.5 parts by mass of polypropylene glycol as a part by mass and an antifoaming agent were added, mixed for 3 hours by a ball mill, and then dried at 120 ° C. by a dryer for 12 hours or more to obtain a raw material powder.

  Using the obtained raw material powder, a sample having the same dimensions was obtained by performing pulverization, molding, drying, and firing in the same manner as in Example 1.

Example 3 (Example)
26.7 mass% (20 mol%) of easily sinterable α-type alumina, 62.8 mass% (60 mol%) of anatase type titanium oxide, and periclase type magnesium oxide existing as a natural mineral 4 parts by mass of alkali feldspar represented by (Na _0.6 K _0.4 ) AlSi ₃ O ₈ and 0.25 mass of polyvinyl alcohol as a binder with respect to 100 parts by mass of a mixture consisting of 10.5% by mass (20 mol%). 1 part by weight of diethylamine as a peptizer and 0.5 parts by weight of polypropylene glycol as an antifoaming agent were mixed for 3 hours by a ball mill and then dried by a 120 ° C. dryer for 12 hours or more to obtain a raw material powder. .

Using the obtained raw material powder, a sample having the same dimensions was obtained by performing pulverization, molding, drying and firing in the same manner as in Example 1.

Example 4 (comparative example)
26.7 mass% (20 mol%) of easily sinterable α-type alumina, 62.8 mass% (60 mol%) of anatase type titanium oxide, and periclase type magnesium oxide existing as a natural mineral For 100 parts by mass of a mixture consisting of 10.5% by mass (20 mol%), 0.25 parts by mass of polyvinyl alcohol as a binder, 1 part by mass of diethylamine as a peptizer, 0.5% of polypropylene glycol as an antifoaming agent Mass parts were added and mixed for 3 hours in a ball mill, and then dried in a dryer at 120 ° C. for 12 hours or more to obtain a raw material powder.

Using the obtained raw material powder, a sample having the same dimensions was obtained by performing pulverization, molding, drying and firing in the same manner as in Example 1.
[Characteristic test of sample]
For the samples obtained in Examples 1 to 4 above, the thermal expansion coefficient (× 10 ⁻⁶ K ⁻¹ ) from room temperature to 800 ° C., thermal shock resistance (° C.) by submerged dropping method, softening temperature (° C.), and 3 The point bending strength (MPa) was measured and the result is shown in Table 1. The thermal expansion coefficient was measured by a method according to JISR1618, the thermal shock resistance was measured by JISR1648, the softening temperature was measured by JISR2209, and the three-point bending strength was measured by a method based on JISR1601.

  The three-point bending strength was measured by cutting a test piece having a size of 3 mm × 4 mm × 40 mm from each sample.

表１から明らかのように例３の試料は、耐熱性がよく、低熱膨張であり、耐熱衝撃性が高く、さらに高い機械的強度を有しており、フロートバス用耐火材として優れた特性を有している。これに対し、例４の試料は実用には不充分である低い機械的強度である。

As is clear from Table 1, the sample of Example 3 has good heat resistance, low thermal expansion, high thermal shock resistance, high mechanical strength, and excellent characteristics as a refractory material for float baths. Have. In contrast, the sample of Example 4 has a low mechanical strength that is insufficient for practical use.

It is a schematic longitudinal cross-sectional view of the float bath part in a float glass process.

1: Refractory material for float bath 2: Metal casing 3: Molten metal 4: Cover 5: Strip glass 6: Molten glass 7: Space 8: Lift roll

Claims (2)

Composition _{formula: M g x Al 2 (1} -x) Ti (1 + x) O 5 ( wherein, 0.2 ≦ x <1) similar to the metal component and the metal component ratio in the titanium phosphate magnesium aluminum you express in 100 parts by mass of a mixture (component X) containing an Al-containing compound, a Ti-containing compound and an Mg-containing compound in terms of oxide, and a composition formula: (Na _y K _1-y ) AlSi ₃ O ₈ (wherein, 0 ≦ y ≦ 1) alkali length stone represented by a raw material mixture containing a 1 to 10 parts by mass in terms of oxide amount (Y component), titanium acid calcined at 1000 to 1700 ° C. A refractory material for a float bath, which is formed of an aluminum magnesium sintered body. A float bath lining with the refractory material for a float bath according to claim 1.

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