JP2000095528A - Refractory for molten glass feeder - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain refractories that maintain thermal shock resistance and have enhanced anti-corrosion characteristics such as infiltration and reaction resistances by forming a thermally sprayed ceramic coating film on the surface of a substrate consisting of specified proportions of alumina and silica. SOLUTION: A substrate consisting of 55-85 wt.% alumina and 15-45 wt.% silica is used. Starting materials such as alumina powder and silica powder are mixed, blended with an organic binder, or the like, and kneaded with water and the resultant slurry is cast in a prescribed shape, dried and fired to obtain the substrate. A thermally sprayed ceramic coating film comprising alumina, mullite, zirconia, zircon or alumina-silica-zirconia is preferably formed on the substrate by gas plasma spraying or water plasma spraying. the coating film has >=50 μm thickness and <=15% porosity.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a refractory for a molten glass feeder used in the glass manufacturing industry.
More specifically, the present invention relates to a refractory for a glass feeder used for a constituent member of a molten glass feeder such as an orifice ring, a spout, a plunger, a stirrer, and a tube.

[0002]

2. Description of the Related Art In the glass manufacturing industry, particularly in the manufacturing industry of general-purpose glass molded articles produced in large quantities such as plate glass, bottle glass, tableware, etc., recently, most of the manufacturing steps have been automated and generally transferred from a melting tank. The molten glass that has been subjected to the homogenous stirring step is supplied to the next processing step via a molten glass feeder. For example, as shown in FIG. 3, the molten glass feeder typically includes a spout 2 for temporarily retaining molten glass 6, an orifice 3 provided at a bottom outlet of the spout 2, and a molten glass feeder. It is composed of members such as a plunger 5 for adjusting the flow rate and a tube 4 for adjusting the temperature of the molten glass.

Next, the operation of the molten glass feeder shown in FIG. 3 will be described. First, the molten glass that has passed through the homogenizing step (not shown) from the melting tank flows into the spout 2 of the molten glass feeder from, for example, the forehearth 1. The molten glass 6 retained in the spout 2 passes through a gap between the spout 2 and the spout 2 below the tube 4, and is led out from an orifice 3 having a predetermined diameter provided at a bottom outlet of the spout 2. At this time, a predetermined amount of the glass gob is discharged from the orifice 3 by the plunger 5 which is moved up and down by an elevating means (not shown), and is sent to the next-step bin manufacturing apparatus.

Most of these members constituting the molten glass feeder are formed of refractory. Generally, these members are formed by kneading a refractory raw material such as alumina / mullite or alumina / zircon and an organic binder together with water to form a slurry, and then casting the same using a gypsum mold. It is manufactured by molding into a predetermined shape, followed by drying and firing. In the production of each of these members, the composition is appropriately adjusted according to various characteristics such as strength characteristics, corrosion resistance, and thermal shock resistance required individually for each member such as an orifice ring, spout, plunger, stirrer, and tube. You.

[0005]

However, the members constituting the molten glass feeder made of such a refractory are used due to peeling due to infiltration of the molten glass that comes into contact with the molten glass and melting due to a reaction at a high temperature. In the past, considerable wear occurred and its use lasted for a long period of time, so that its durability was not always sufficient in the past. In order to improve the durability of the refractory, attempts have been made to make the structure of the refractory dense so as to improve exfoliation due to infiltration of molten glass and erosion due to reaction. However, when the structure of the refractory is simply densified, thermal shock resistance, which is another requirement required for this type of refractory, is reduced, and cracks or cracks are easily generated on the surface. There has been a problem that a new inconvenience is caused that the refractory cannot be used satisfactorily in practical use.

As described above, the thermal shock resistance of this type of refractory and the corrosion resistance such as infiltration resistance and reaction resistance have a trade-off relationship, and a refractory for a molten glass feeder excellent in both of these characteristics is required. , Despite the desire for its appearance,
Its realization has traditionally been very difficult.

The present invention has been made to solve the above-mentioned technical problems, and has a thermal shock resistance equal to or higher than that of a conventional product, and has corrosion resistance such as infiltration resistance and reaction resistance. It is an object of the present invention to provide a refractory for a molten glass feeder having an improved refractory.

[0008]

According to the refractory for a molten glass feeder according to the present invention, 55% by weight to 8% of alumina is used.
A ceramic sprayed coating is formed on the surface of a substrate composed of 5% by weight and 15% by weight to 45% by weight of silica. Here, the ceramic sprayed coating is any of alumina, mullite, zirconia, zircon,
Alternatively, the ceramic sprayed coating is preferably made of alumina, silica, and zirconia, and the ceramic sprayed coating is preferably a sprayed coating formed by a gas plasma spraying method or a water plasma spraying method. Further, the thickness of the ceramic sprayed coating is desirably 50 μm or more, and the porosity of the ceramic sprayed coating is desirably 15% or less.

As described above, the present invention is directed to a refractory for a molten glass feeder, which is characterized by a combination of a specific composition of an alumina / silica-based refractory base material and a specific thermal spray coating. That is, alumina (Al ₂ O ₃ ) components 55 to 85
Alumina / silica refractory having a specific composition comprising 15 to 45% by weight of a silica (SiO ₂ ) component as a base material, and preferably a surface of alumina, mullite, zirconia or zircon on the surface of the refractory base material. Alternatively, a ceramic material for forming a sprayed film made of alumina, silica, and zirconia was sprayed using a spraying method such as a gas plasma method or a water plasma method to form a coating layer having a predetermined thickness on the surface of the base material. The refractory for a molten glass feeder member is a remarkable feature in the structure.

In the combination of the alumina / silica-based refractory substrate having the specific composition and the specific sprayed coating, the alumina / silica substrate used in the present invention contains 55% by weight or more of an alumina component. Al ₂ O
₃ ) Good affinity with thermal sprayed film forming substances containing mullite (Al ₆ Si ₂ O ₁₃ ), zirconia (ZrO ₂ ), zircon (ZrSiO ₄ ), etc. Further, since the coefficient of thermal expansion is relatively similar to that of the material for forming a sprayed film, it has excellent adhesion to a formed film and has a characteristic that a strong film can be formed.

Further, since the base material contains a large amount of alumina, the base material itself has excellent resistance to reaction with molten glass at a high temperature, and when used as a molten glass feeder member,
For example, even if a small amount of molten glass infiltrates into the base material through the thermal spray coating layer, which is a surface layer, the molten glass does not violently react and thereby exhibit sufficient resistance. In addition, since the silica component is contained in an amount of 15 to 45% by weight, the base material structure forms a mullite structure, and thus is strong against heat shock and excellent in heat shock resistance. In addition, since the material for forming a ceramic sprayed coating layer of the present invention is excellent in corrosion resistance such as high-temperature reaction resistance to molten glass and resistance to infiltration and peeling, the molten glass feeder member coated therewith is formed by the infiltration of molten glass. It shows excellent resistance to erosion caused by peeling and reaction.

This thermal spray coating layer is preferably formed in a layer thickness of 50 μm or more from the viewpoint of sufficiently exerting the above-mentioned durability effect. Further, the thermal spray coating layer preferably has a porosity as small as possible from the viewpoint of molten glass infiltration resistance, and preferably 15% or less.

[0013]

BEST MODE FOR CARRYING OUT THE INVENTION The present invention provides an alumina
The present invention relates to a refractory for a molten glass feeder in which a silica refractory is used as a base material and a ceramic sprayed coating layer of a predetermined thickness such as alumina or zirconia is formed on the surface of the base material. In the present invention, the target molten glass filler
The refractory for the laser, that is, the molten glass feeder member is not necessarily limited to the one described below, but constitutes a molten glass feeder such as an orifice ring, a spout, a plunger, a stirrer, a tube, and the like. Members can be mentioned. In the present invention, alumina (Al ₂ O) is used as a base material constituting the member.
₃ ) A silica-alumina refractory material comprising 55 to 85% by weight of a component, 15 to 45% by weight of a silica (SiO ₂ ) component, more preferably 65 to 80% by weight of an alumina component, and 20 to 35% by weight of a silica component. A material obtained by molding this material into a desired shape of a target member and firing the material is used.

More specifically, for example, alumina powder,
Raw materials such as silica powder are mixed in the above composition ratio, a predetermined amount of an organic binder and the like are added and kneaded together with water to form a slurry, and then molded into a predetermined shape by a casting method using a gypsum mold or the like. Then, after drying, firing is performed to obtain a substrate having a predetermined shape.

In the refractory for a glass feeder according to the present invention, it is important that the composition of the alumina component and the silica component is within the above range, and the alumina component in the base material is 55% by weight.
If the amount is less than 45%, that is, if the silica component exceeds 45% by weight, the reaction with the molten glass component becomes remarkable when it comes into contact with the molten glass. As a result, when the obtained refractory is used, the refractory reacts violently with the molten glass slightly penetrating through the thermal spray coating on the surface and melts, so that sufficient corrosion resistance cannot be maintained as a refractory for a glass feeder.

On the other hand, when the alumina component exceeds 85% by weight, that is, when the silica component is less than 15% by weight, cracks are likely to occur due to heat shock or the like when the obtained refractory is used, and the glass feeder is used. It cannot maintain sufficient thermal shock resistance as a refractory for use.

In the present invention, the surface of the substrate is coated with a ceramic sprayed coating having a predetermined thickness. The material for forming a film is not necessarily limited to those described below. For example, any of alumina, mullite, zirconia, and zircon excellent in high-temperature corrosion resistance to molten glass or the like, or alumina, silica, zirconia, or the like It is preferable to use The thermal spraying method is not necessarily limited to the method described below. For example, a gas flame thermal spraying method, a plasma arc thermal spraying method, a gas explosive thermal spraying method, a linear explosive thermal spraying method, or the like can be used. Various plasma spraying methods using gas plasma, water plasma or the like are preferably used.

The thickness of the thermal spray coating is preferably at least 50 μm, particularly preferably at least 300 μm. The coating thickness is 5
When the thickness is less than 0 μm, pinholes are generated, the film is easily worn or peeled, and it is somewhat difficult to completely prevent infiltration of molten glass and reaction with glass. The porosity of the thermal spray coating is preferably 15% or less, more preferably 10% or less, from the viewpoint of infiltration resistance and corrosion resistance.

[0019]

EXAMPLES Example 1 A refractory base material having a composition of 80% by weight of alumina (Al ₂ O ₃ ) component and 20% by weight of silica (SiO ₂ ) component and having an apparent porosity of 21.5% was used. This was prepared and processed into a crucible-shaped substrate 7 having a cylindrical hole having a diameter of 35 mm and a depth of 35 mm formed on one side of a cube having a side of 65 mm as shown in FIG. Alumina is sprayed on the inner surface of the cylindrical hole of the crucible-shaped substrate and the surface provided with the hole using a gas plasma apparatus, and the sprayed surface is coated with a film having a thickness of 3 mm.
An alumina sprayed coating 8 having a thickness of 00 μm and a porosity of 3.0% was formed. Into the cylindrical hole of the crucible-shaped refractory 7 on which the thermal spray coating 8 is formed, 20 g of crushed bottle glass and sized to 16 to 32 mesh are put.
Heated for hours.

After the crucible-shaped refractory was cooled, the refractory was cut, and the amount of molten glass in the hole into the refractory and the amount of erosion were measured (corrosion resistance evaluation test: see FIGS. 1 and 2). . Here, the amount of erosion is the amount of erosion at the bottom of the columnar hole of the crucible-shaped refractory 7 as shown in FIG. 2, and the amount of infiltration is the amount of erosion at the bottom of the columnar hole of the refractory 7 as shown in FIG. The amount of infiltration was measured.

Separately, J made of the same material as the above base material
IS average shape (length 230mm, width 114mm, thickness 65
mm), a sample in which alumina was sprayed to a thickness of 300 μm on the entire surface of the sample was prepared. This operation was performed by inserting half of the length in an electric furnace heated to 1200 ° C., holding for 15 minutes, and then taking out from the furnace and allowing to cool for 15 minutes until the cracks occurred in the sample plate. The thermal shock resistance was evaluated by examining the number of repetitions until crack generation (thermal shock resistance evaluation test). Table 1 also shows these evaluation results.

[Examples 2 to 6] Using the base materials having the compositions and apparent porosity shown in Table 1 respectively, crucible-shaped base materials and JIS regular-shaped base materials similar to those in Example 1 were prepared. And the like were sprayed in the same manner as in Example 1 using the sprayed materials shown in Table 1, respectively, to form a sprayed coating having the thickness shown in Table 1 on the crucible refractory and the sample plate. Then, these crucible refractories and sample plates were prepared in Example 1.
And a corrosion resistance evaluation test and an impact resistance evaluation test were performed. Table 1 shows the results.

Comparative Example 1 A crucible-shaped refractory and a sample plate similar to those in Example 1 were prepared using a substrate having the same composition and apparent porosity as in Example 1 except that the thermal spray coating was not formed on the substrate. Then, a corrosion resistance evaluation test and an impact resistance evaluation test were performed in the same manner as in Example 1. Table 2 shows the results. “Comparative Example 2” Alumina (Al ₂
O ₃ ) component 90% by weight, silica (SiO ₂ ) component 1
A crucible-shaped refractory and a sample plate were formed in the same manner as in Example 1 except that a base material having a composition of 0% by weight and an apparent porosity of 20.3% was used. In the same manner as in Example 1, a corrosion resistance evaluation test and an impact resistance evaluation test were performed. Table 2 shows the results. Comparative Example 3 Except for using a refractory base material having a composition of 50% by weight of an alumina (Al ₂ O ₃ ) component and 50% by weight of a silica (SiO ₂ ) component and having an apparent porosity of 19.3%. A crucible-shaped refractory and a sample plate on which a thermal spray coating was formed were produced in the same manner as in Example 1, and a corrosion resistance evaluation test and an impact resistance evaluation test were performed as in Example 1. Table 2 shows the results.
Shown in

Reference Examples 1 to 3 A crucible shape similar to that of Example 1 was obtained using a substrate having the same composition and apparent porosity as that of Example 1 except that the thickness of the sprayed coating formed was as thin as 30 μm. A refractory and a sample plate were prepared, and a corrosion resistance evaluation test and an impact resistance evaluation test were performed in the same manner as in Example 1 (Reference Example 1). Similarly, a crucible-shaped refractory and a sample plate similar to those in Example 4 were prepared using a substrate having the same composition and apparent porosity as in Example 4 except that the thickness of the thermal spray coating was as thin as 30 μm. In the same manner as in Example 4, a corrosion resistance evaluation test and an impact resistance evaluation test were performed (Reference Example 2). Further, a crucible-shaped refractory and a sample plate similar to those in Example 1 manufactured using a commercially available alumina-silica-zircon base material that does not form a sprayed film,
A corrosion resistance evaluation test and an impact resistance evaluation test were performed in the same manner as in Example 1 (Reference Example 3). Table 2 shows the evaluation results.

[0025]

[Table 1]

[0026]

[Table 2]

In Tables 1 and 2, ASZ indicates alumina / silica / zirconia, G indicates gas plasma, and W indicates water plasma.

As is clear from the above Examples and Comparative Examples of the present invention, the molten glass filler of the present invention is shown.
Crucible-shaped refractory made of refractory for
The amount of erosion (wall thickness of eroded wall: mm) after being stored and retained at 200 ° C. for 48 hours is 0, and the amount of infiltration (wall thickness of infiltrated molten glass: mm) is 1.0 mm at the maximum. (See Examples 1 to 6). Further, the number of times of repeated heating until the occurrence of cracks indicating thermal shock resistance (number of times of 1200 ° C. heating to ordinary temperature cooling cycle) is 10 or more (Example 1).
To 6).

On the other hand, in the crucible-shaped refractory made of the alumina / silica refractory substrate having no thermal spray coating layer according to the present invention (Comparative Example 1), the amount of erosion is 3.0 mm and the amount of infiltration is 11 .5 mm, both of which are larger than the examples of the present invention. Further, even if the refractory in the form of a crucible provided with the thermal spray coating layer of the present invention has a base material refractory composition outside the range specified in the present invention, the amount of erosion or infiltration is large ( Comparative Example 3, alumina component: 50% by weight, erosion amount: 3.0
mm, infiltration amount 12.0 mm) or poor thermal shock resistance (Comparative Example 2, alumina component: 90% by weight, number of times until crack generation 8 times).

As described above, the above-mentioned excellent properties of the refractory for a molten glass feeder of the present invention are attained by combining an alumina-silica refractory base material having a specific composition range specified by the present invention with a ceramic sprayed coating. And its effects are particularly critical to the substrate composition.

[0031]

According to the present invention, there is provided a ceramic-sprayed coating layer of a predetermined thickness such as alumina, zirconia or the like formed on the surface of an alumina-silica refractory having the above specific composition as defined in the present invention. Due to its specific constitution, the refractory for molten glass feeder can improve both the thermal shock resistance and the corrosion resistance such as infiltration resistance and reaction resistance, which have been very difficult to improve conventionally. it can.

[Brief description of the drawings]

FIG. 1 is a schematic view of a crucible-shaped refractory used in Examples and Comparative Examples of the present invention.

FIG. 2 is a schematic diagram for explaining a measurement position of a erosion amount and an infiltration amount after a corrosion resistance evaluation test of the sample of FIG. 1;

FIG. 3 is a schematic diagram for explaining a general configuration of a molten glass feeder.

[Explanation of symbols]

 REFERENCE SIGNS LIST 1 Foreheart (introduction gutter) 2 Spout 3 Orifice 4 Tube 5 Plunger 6 Molten glass 7 Crucible-shaped refractory 8 Thermal spray coating 8 Crucible-shaped refractory A Melting amount (measuring position) B Infiltration amount (measuring position) )

Claims (5)

[Claims] 1. A refractory for a molten glass feeder, characterized in that a ceramic sprayed coating is formed on the surface of a substrate comprising 55% to 85% by weight of alumina and 15% to 45% by weight of silica. . 2. The refractory for a molten glass feeder according to claim 1, wherein the ceramic sprayed coating is made of one of alumina, mullite, zirconia, and zircon, or alumina / silica / zirconia. 3. The refractory for a molten glass feeder according to claim 2, wherein the ceramic sprayed coating is a sprayed coating formed by a gas plasma spraying method or a water plasma spraying method. 4. The ceramic sprayed coating having a thickness of 50
4. The method according to claim 1, wherein the thickness is not less than μm.
A refractory for a molten glass feeder according to any one of the above. 5. The porosity of the ceramic sprayed coating layer is as follows:
The refractory for a molten glass feeder according to any one of claims 1 to 4, wherein the content is 15% or less.