JPH08245284A - Production of dense aluminous refractory - Google Patents

Abstract

PURPOSE: To efficiently produce dense aluminous refractories in a short time. CONSTITUTION: Glass phase-contg. refractories obtd. using alumina-silica stock and having 0.1-5wt.% silica content, 15-30% apparent porosity and 0.1-7wt.% glass phase content are heated as base materials at 1,000-1,230 deg.C in an oxygen- contg. atmosphere while keeping aluminum in contact with the surfaces of the base materials to allow the aluminum to react and penetrate into the pores in the base materials. The resultant dense aluminous refractories have a superior structure, superior strength, corrosion and wear resistances.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for producing a dense alumina refractory material, and more particularly to a method for producing a dense alumina refractory material in a short time and efficiently.

[0002]

2. Description of the Related Art As a method for densifying ceramics, (1) a higher molding pressure or firing temperature or a method using a rubber press (CIP) for shaping (2) pressure firing using HIP Method (3) Method of adding sintering accelerator (4) Method of impregnating a ceramic molded body with a liquid metal salt or tar, and extinguishing pores in the molded body by heat treatment (5) Ceramic preform -A method of filling the pores of a metal or a filler while oxidizing the metal (see JP-B-3-75508, JP-A-63-30376, JP-A-63-170256) (6) Mullite-containing ceramics There is known a method in which aluminum is reacted and permeated while being oxidized (see JP-A-6-135766).

[0003]

Among the above conventional methods (1)
The methods (4) to (4) are completely different from the method of the present invention, which will be described in detail later, and require the starting material to be finely pulverized or require a large apparatus.

The conventional method (5) can be highly densified,
Although it can be used at high temperature, it has a drawback that the production rate of the dense body is extremely slow, heating for a long time is required, and the production efficiency is poor. On the other hand, in the conventional method (6), the conventional method
As in the case of (5), it is possible to manufacture a dense body, but there is a drawback in that the reaction permeability greatly changes depending on the manufacturing conditions and it is difficult to obtain a stable product.

When such a dense body is used as a refractory, it is necessary to make it a large-sized product to some extent, and its production efficiency becomes a problem. However, if a large-sized product is produced by the above conventional method (5), There are problems that heating for a longer time is required, manufacturing efficiency is extremely poor, and a stable large-sized product cannot be obtained even by the conventional method (6).

The inventors of the present invention have conducted extensive research on a method of oxidizing aluminum into the pores of a refractory while oxidizing and reacting the aluminum to densify it. As a result, the alumina-silica in a very short time, which was not found in the conventional method. The present invention has been completed by finding a method capable of densifying a refractory-based material.

That is, the present invention aims to solve the above-mentioned conventional drawbacks and problems, and in particular, a dense alumina refractory material suitable for applications such as members requiring strength, corrosion resistance and wear resistance. It is an object of the present invention to provide a method capable of efficiently producing lactic acid in a short time. It is another object of the present invention to provide a method for producing a dense alumina refractory material, which can efficiently produce a large product in a shorter time than the conventional method.

[0008]

The present invention is characterized in that an alumina-silica-based glass phase-containing refractory material is used as a base material, aluminum is brought into contact with the surface of the base material, and heating is performed under predetermined conditions. Accordingly, the above-mentioned conventional drawbacks and problems are solved, and a method for producing a dense alumina refractory material as described above is provided.

That is, according to the present invention, "a silica-containing refractory material having a silica content of 0.1 to 5% by weight and an apparent porosity of 15 to 30% obtained by using an alumina-silica-based material is used as a base material, A method for producing a dense alumina refractory material, which comprises heating aluminum in an oxygen-containing atmosphere at 1000 to 1230 ° C. in a state where aluminum is brought into contact with the surface of the base material, and allowing the aluminum to react and permeate into the pores of the base material. . "(Claim 1).

In the present invention, the base material composed of the glass phase-containing refractory material is alumina-
It is a refractory obtained by firing a silica-based raw material (claim 2), and the glass phase content in the base material made of the glass phase-containing refractory is 0.1 to 7 weight relative to the weight of the base material. % (Claim 3) is a preferred embodiment of the present invention.

The method for producing a dense alumina refractory material according to the present invention will be described in detail below. The "reactive infiltration of aluminum" in the present invention means that aluminum penetrates into the pores of the base material and the aluminum Part of the aluminum reacts with oxygen in the atmosphere and the silica-based material in the base material to form aluminum oxide, which causes the base material to be densified by filling pores with aluminum and aluminum oxide. It is a thing. As described above, since aluminum oxide is formed at any time along with the permeation of aluminum, the expression “reactive permeation of aluminum” will be used for convenience in this specification.

Any raw material containing alumina and / or silica may be used as the alumina-silica-based raw material used in the present invention, and is not particularly limited in the present invention. Examples of this are silica stones, silica sand, porcelain stones, wax stones, clay, chamotte, shale shale, sillimanite,
Examples include bauxite, synthetic mullite, fused alumina, sintered alumina, and calcined alumina. Further, as other raw materials, each oxide, carbide, or nitride may be contained in an amount of 10% or less with respect to the weight of the base material for the purpose of providing a sintering accelerator or strength, and this is also included in the present invention. It is what is done.

The present invention uses, as a base material, a glass phase-containing refractory material produced by using the above-described alumina-silica-based raw material (or a mixture of this raw material with the other raw material described above). However, the proportion of silica (glass component + crystalline) in this matrix should be 0.1-5% by weight. The reason is that when the amount of silica is less than 0.1% by weight, the amount of the glass phase described below becomes too small, so that the function as a reaction inducer is not sufficiently exerted and reaction permeation hardly occurs.

On the other hand, when the amount of silica exceeds 5% by weight,
The amount of reaction products per unit area of the base material becomes too large,
This is not preferable because the reaction permeation passage of aluminum becomes small and the permeation rate decreases, and the reaction permeation time becomes long. Further, silica is reduced by the reaction of silica and aluminum, and metallic silicon is deposited. However, if the amount of silica is large, the amount of metallic silicon that is deposited is also large, and corrosion resistance decreases when used at high temperatures. The problem arises.

Further, when the amount of silica in the base material is large, excessive formation on the side surface of the base material and the like increases, and a step (processing step) for removing the excessively generated portion after reaction permeation is required, Problems such as a decrease in manufacturing efficiency occur.

The above reason will be further described with reference to FIG. FIG. 1 is a diagram schematically showing each cut surface of the sample before and after the reaction and permeation of aluminum into the base material. (A) is the sample before the reaction and the (B) is the sample after the reaction and the permeation. It is a figure which shows a sample. When the base material 2 shown in FIG. 1 (A) contains a large amount of silica component, the base material 2 is heated at 1000 to 1230 ° C. in an oxygen-containing atmosphere according to the present invention to react and permeate aluminum 1 (B). As shown in (), the number of extra portions 4 formed on the side surface of the densified refractory material 3 increases. A processing step for removing this portion 4 later is required, which lowers the manufacturing efficiency.

As described above, in the present invention, the lower limit of the amount of the silica component in the matrix made of the glass phase-containing refractory is 0.1% by weight, and the upper limit thereof is 5% by weight. It is what

Next, a method of manufacturing a base material made of a glass phase-containing refractory will be described. In the present invention, the glass phase must be distributed almost uniformly in the base material. That is, the manufacturing conditions of the base material composed of a glass phase-containing refractory "alumina-silica-based raw material particle size and composition, firing temperature and firing time during the production of the base material", the glass phase in the obtained base material It is necessary to combine the above manufacturing conditions so as to uniformly exist.

The reason for this is that if the glass phase does not exist in the base material, even if the base material contains a silica component in the form of crystalline mullite or cristobalite, the crystalline silica component alone is sufficient. This is because the reaction permeation of aluminum hardly occurs and the base material is difficult to be densified.

When a glass phase, which is more active than crystalline silica with respect to reaction permeation with aluminum, is present in the base material in an amount of 0.1% by weight or more, the glass phase serves as a reaction inducer, and aluminum is The base material can be densified in a short time by continuously reacting with the crystalline silica-based material and oxygen in the atmosphere. The glass phase in the base material is 0.1
If it is less than 10% by weight, the amount of the glass phase acting as the above-mentioned reaction inducer is small, the permeation of aluminum becomes non-uniform, and the densified portion is small or non-uniform, which is not preferable.

On the other hand, when the glass phase exceeds 7% by weight, the reaction permeation in the vicinity of the contact portion between the base metal and aluminum is very fast, but the subsequent continuous permeation is rather slow, and it becomes like a refractory. It takes a long time to obtain a product of a certain size, which is not preferable. Therefore,
In the present invention, the amount of the glass phase is preferably in the range of 0.1 to 7% by weight based on the weight of the base material.

In the present invention, as the particle size of the alumina-silica based raw material to be used, one prepared to have a particle size constitution suitable for the molding method adopted can be arbitrarily used. The molding method for producing the base material is not particularly limited in the present invention, and examples thereof include die press molding and rubber press.
(Isotropic hydrostatic press), extrusion molding, cast molding, slip casting, injection molding and the like can be arbitrarily used.

The base material used in the present invention is not particularly limited, but it is preferable to use a molded body of an alumina-silica-based raw material after firing. That is, when a glass or clay having a low melting point that vitrifies at a temperature at which aluminum is reacted and permeated (1000 ° C to 1230 ° C: see later) and melts and diffuses is used as a raw material, it does not need to be fired. Although reaction permeation is possible, even in this case, firing is preferable because reaction permeation proceeds more uniformly, the strength of the obtained dense body is high, and cracks are less likely to occur during reaction permeation. The firing temperature and firing time are arbitrary depending on the raw material used, but it is usually preferable to perform firing at 800 to 1800 ° C. for 1 hour to several hours.

As described above, the base material used in the present invention needs to be prepared so that the glass phase is substantially evenly distributed in the base material. It is necessary to adjust the rate to be 15 to 30%. The reason is that the apparent porosity of the base material has a great influence on the reaction permeation rate of aluminum.

This will be described with reference to FIG. Note that FIG. 2 is a graph showing the relationship between the ratio of the densified portion (area ratio) to the area of the original base material and the apparent porosity of the base material in the cut surface. Specifically, as a refractory base material, 1% by weight, 3% by weight, and 5% by weight of ball clay was mixed with sintered alumina, and the mixture was prepared to have a particle size ratio of Table 1 below.
Molded at pressure of MPa or 120MPa, 1500 ℃ or 1760 ℃
It was used after being fired for 3 hours. Then, the reaction was permeated under the same conditions as in Example 1 described later. 6 is a graph showing the influence of the apparent porosity of the base material on the area ratio of the densified portion in the cut surface in this case.

As shown in FIG. 2, the apparent porosity of the base metal is 15
If it is less than%, the reaction permeation rate of aluminum into the base material is rapidly reduced. On the other hand, if it exceeds 30%, the base material obtained by this reaction permeation may not be sufficiently densified, which is not preferable.

The present invention is characterized in that a base material made of the above-mentioned glass phase-containing refractory material is used, and aluminum is reactively permeated into the base material to be densified. The densification means will be described below.

In the present invention, first, it is necessary to bring aluminum into contact with part of the surface of the base material, and the reaction permeation of aluminum proceeds sequentially from this contact surface. This aluminum can be used in any shape such as aluminum powder, a plate-shaped body, and a lump-shaped body, and such aluminum is left to stand so as to come into contact with the refractory base material.

The heating conditions for the reaction and permeation of aluminum into the base material are 1000 to 1230 ° C. in an oxygen-containing atmosphere.
Need to heat in. The reason for this will be described with reference to FIG. Note that FIG. 3 is a graph showing the relationship between the heating temperature and the permeation thickness during reaction permeation. That is, 1 wt% of ball clay was mixed with the fused alumina raw material to prepare the particle size composition shown in Table 1 below, and a base material was prepared in the same manner as in Example 1 below.
At the top of this base material, at 100 MPa, width 100 mm, thickness 25 mm, length 160
FIG. 3 is a diagram showing a relationship between a reaction permeation temperature and a permeation thickness when an aluminum molded body having a shape of mm ”is placed and heated in an oxygen atmosphere at a predetermined temperature for 3 hours for reactive permeation.

As shown in FIG. 3, 1000 to 1230 ° C., especially 11
It can be understood that in the temperature range from 00 ° C to 1200 ° C, the permeation thickness (mm) due to the reaction permeation of aluminum is large. If it is less than 1000 ° C, the permeation thickness (mm) is small, and if it exceeds 1230 ° C, it is the same. Thus, FIG.
Therefore, in the present invention, the heating temperature during reaction osmosis is 10
The temperature is preferably 00 to 1230 ° C, more preferably 1100 to 1200 ° C.

On the other hand, as for the atmosphere during heating, when heating in an atmosphere containing no oxygen (for example, an argon atmosphere), aluminum oxide for densification is not generated, and a dense refractory cannot be obtained. The higher the oxygen content in the atmosphere, the larger the amount of aluminum oxide produced and the larger the amount of reaction permeation. Therefore, in the present invention, the oxygen content in the atmosphere is as high as possible, for example, 50% or more is preferable, and 80 is more preferable. % Or more.

[0032]

EXAMPLES Next, the present invention will be described in more detail with reference to examples of the present invention, comparative examples and conventional examples, but the present invention is not limited to the following examples.

Here, the following Examples 1 to 5 and Comparative Example 1
Table 1 shows the particle sizes of the base material-forming compounds used in Examples 1 to 6 together.

[0034]

[Table 1]

Example 1 Sintered alumina raw material was added with ball clay (particle size: 0.3 mm or less) in "0.5 wt%", "1 wt%" and "3 wt."
% "Was added to prepare the particle size composition shown in Table 1 above. Each composition was prepared at 60 MPa with a width of 100 mm, a thickness of 50 mm and a length of 16 mm.
After molding into a shape of 0 mm, it was fired at 1760 ° C for 3 hours to obtain a refractory brick base material.

The amount of silica in each base material is "0.3 wt%""0.6wt%""1.7wt%" according to the addition amount of ball clay "0.5 wt%""1wt%""3wt%"."Met. Also,
Regarding the amount of glass in each base material, as a result of obtaining the weight change by subjecting each base material to acid treatment, "0.2 wt%", "0.4 wt%", and "1.3 wt%" were also obtained according to the addition amount of the ball clay. %, On the other hand, the apparent porosity of each base material is also “21.0%”, “20.4%”, “1” depending on the addition amount of the ball clay.
9.5% ”.

On each of the obtained base materials, "aluminum powder compact molded at a width of 100 mm, a thickness of 25 mm and a length of 160 mm at 100 MPa" was placed, and heated in an oxygen atmosphere at 1150 ° C. for 3 hours,
It was then cooled. After cooling, it was bisected in the lengthwise direction, and the thickness (mm) of the portion densified by reaction permeation from the cut surface and the apparent porosity (%) of the densified refractory were measured. As a result, the "densified part thickness (mm)" and "apparent porosity (%)" are those of the addition of 0.5% by weight of ball clay "42 mm, 1.9%",
"47 mm, 1.5%" was obtained by adding 1 wt% of Lucre, and "39 mm, 0.9%" was obtained by adding 3 wt% of Bole.

(Example 2) 5 wt% of cristobalite was added to the raw material of fused alumina to prepare the particle size composition shown in Table 1 above. A base material was manufactured by the same method as in Example 1.
The amount of silica in the base material was 5.0 wt%, the amount of glass was 1.0 wt%, and the apparent porosity was 17.2%. As a result of reacting and permeating this base material under the same conditions as in Example 1, the thickness of the densified portion was 31 mm.
And the apparent porosity was 0.7%.

(Example 3) Sintered alumina: 30 wt% and pre-fired white bauxite: 70 wt% were mixed to prepare the particle size composition shown in Table 1. The silica content of the entire formulation is 4.2 wt%. This was molded into a shape having a width of 85 mm, a thickness of 35 mm, and a length of 110 mm at 100 MPa, and then fired at 1630 ° C. for 3 hours to obtain a refractory base material. The glass amount of this base material was 1.4 wt% and the apparent porosity was 17.5%.

On the above base material, "100 MPa, width 85 mm, thickness 20
mm powder, aluminum powder compact molded into a length of 110 mm "is placed at 1200 ° C in a mixed gas of 60% oxygen and 40% nitrogen.
Heated for 3 hours. As a result, the upper 24 mm of the base material was densified and its apparent porosity was 0.8%. The bending strength of the refractory base material is 30 MPa, but
It was MPa.

(Example 4) Pyrex glass was added to an alumina ball in an amount of 5% by weight to prepare a composition having a particle size shown in Table 1, which was formed into a shape having a width of 100 mm, a thickness of 45 mm and a length of 160 mm at a pressure of 100 MPa. After molding, it was fired at 1200 ° C for 3 hours to obtain a refractory base material. The amount of silica in this matrix was 4 wt%, the amount of glass was 1.6 wt%, and the apparent porosity was 27.5%. Place "aluminum powder compact molded into a shape with a width of 100 mm, a thickness of 20 mm and a length of 160 mm" on the base material and place it in an oxygen atmosphere.
Heated at 00 ° C. for 3 hours. As a result, the upper 30 mm was changed to a densified refractory, and the apparent porosity of that part was 1.0%.

(Example 5) 80 wt% of sintered alumina and 20 wt% of calcined alumina were mixed to prepare the particle size composition shown in Table 1.
5 wt% of soda silicate glass and 8 wt% of water were added to this to obtain a fluidized kneaded product. This kneaded product has an inner diameter of 120 mm and a height of 50 m.
It was cast by molding in a m-shaped cylindrical mold.

This molded body was dried at 110 ° C. and then at 1500 ° C. for 3 minutes.
It was fired for a period of time to obtain a base material. The amount of silica in this matrix is 1.5w
t%, the amount of glass was 0.6 wt%, and the apparent porosity was 18.2%. This base material is placed on "aluminum formed into a cylindrical shape with a diameter of 120 mm and a height of 20 mm", and at 1150 ° C in an oxygen atmosphere.
Heated for 3 hours. As a result, 35 mm from the contact surface with aluminum changed to a densified refractory, and the apparent porosity of that part was 1.2%.

(Comparative Example 1) 15 wt% of cristobalite and 1 wt% of ball clay were mixed with sintered alumina to prepare the particle size composition shown in Table 1, and a base material was prepared in the same manner as in Example 1. The amount of silica in the base material is 20.6wt%, the amount of glass is 5.5wt
%, The apparent porosity was 16.2%. Example 1 for this base material
As a result of reacting and permeating under the same conditions as above, the top 10 mm of the base material was densified.

In this Comparative Example 1, as compared with Example 1,
The densified portion was about 1/4, and there was a large amount of extra generation on the side surface of the base material as shown in FIG. 1, resulting in poor production efficiency. It is considered that this is because in Comparative Example 1, the amount of silica in the base material was excessive (20.6 wt%).

(Comparative Example 2) A ball clay was added to sintered alumina.
Was mixed in an amount of 5 wt% to prepare the particle size composition shown in Table 1. The silica content of the entire formulation is 2.8 wt%. This was CIP-molded into a shape similar to that of Example 1 at a pressure of 120 MPa and fired at 1760 ° C. for about 6 hours to obtain a base material. The glass amount of this base material was 2.0 wt% and the apparent porosity was 11.7%.

An "aluminum compact having a width of 100 mm, a thickness of 25 mm and a length of 160 mm" was placed on the upper part of the base material and reacted and permeated under the same conditions as in Example 1. As a result, the thickness of the densified portion was 8 mm, which was 1/4 or less of that in Example 1. The decrease in the production amount is considered to be due to the low apparent porosity of the base material.

(Comparative Example 3) 5% by weight of cristobalite was mixed with fused alumina to prepare the particle size composition shown in Table 1. The total amount of silica in the blend is 5 wt%. A base material was an unfired material that was molded into a width of 100 mm, a thickness of 50 mm, and a length of 160 mm at a pressure of 60 MPa.

At the top of this base material, at 100 MPa, width 100 mm, thickness 2
Aluminum molded body with a shape of 5 mm and length of 160 mm "
Was placed, and reaction permeation was carried out under the same conditions as in Example 1. As a result, since it was an unfired base material and a glass phase was not formed in this base material, reaction permeation hardly occurred and it was not densified.

(Comparative Example 4) Using a sintered alumina raw material having a grain size shown in Table 1, a pressure of 60 MPa, a width of 100 mm and a thickness of
The base material was formed into 50 mm and a length of 160 mm and fired at 1300 ° C. for 3 hours. The amount of silica in this base material was 0.03 wt% and the apparent porosity was 32.2%.

As a result of reacting and permeating aluminum into the base material, a permeation layer was formed only in 4 mm, and the permeation was uneven. It is considered that this is because the amount of silica in the base material is too small and the apparent porosity of the base material is too large.

(Comparative Example 5) 1 wt% of ball clay was mixed with a sintered alumina raw material to prepare a mixture having a particle size shown in Table 1, and a base material was prepared in the same manner as in Example 1. The amount of silica in the base material was 0.6 wt%, the amount of glass was 0.4 wt%, and the apparent porosity was 20.4%.

On top of this base material, put an "aluminum molded body having a width of 100 mm, a thickness of 25 mm, and a length of 160 mm at 100 MPa" and place it in an oxygen atmosphere at 800 ° C. and 1250 ° C. for 3 times, respectively.
Heated for hours. The part densified by reaction osmosis is 800
The thickness was 2 mm at a temperature of 1 ° C. and 11 mm at a temperature of 1250 ° C., and there were few densified portions as compared with Example 1. This is because the reaction permeation temperature was not appropriate.

(Comparative Example 6) 1 wt% of ball clay was mixed with a fused alumina raw material to prepare a particle size composition shown in Table 1, and a base material was prepared in the same manner as in Example 1. The amount of silica in the base material was 0.6 wt%, the amount of glass was 0.4 wt%, and the apparent porosity was 20.8%.

At the top of this base material, at 100 MPa, width 100 mm, thickness 2
Aluminum molded body with a shape of 5 mm and length of 160 mm "
And was heated in an argon atmosphere at 1150 ° C. for 3 hours. As a result, almost no reaction permeation occurred and no densification occurred. This is because aluminum oxide was not formed because the atmosphere was argon.

(Comparative Example 7-Conventional Example) In the method described in JP-A-63-30376, JP-A-63-170256 and JP-A-3-75508, which are disclosed in the above-mentioned conventional method (5). When densifying by using aluminum oxidation, a minimum holding time of 18 hours is required. For example, in Example 1 described in JP-A-63-30376, it is 66 hours at 1000 ° C. to densify a preform having a thickness of 4.8 mm, and in Example 3 described therein, the thickness is For densifying a 44mm preform
It is held at 1000 ° C for 144 hours, and it is clear that it takes a long time to manufacture.

Here, the above Examples 1 to 5 and Comparative Examples 1 to 6
The thickness of the densified part of the base material and the densified refractory used in
m) and apparent porosity (%) are summarized in Tables 2 and 3.

[0058]

[Table 2]

[0059]

[Table 3]

[0060]

As described in detail above, the present invention has a silica content of 0.
A glass phase-containing refractory having an apparent porosity of 15 to 30% at 1 to 5% is used as a base material, and aluminum is brought into contact with the surface of the base material, and heated at 1000 to 1230 ° C. in an oxygen-containing atmosphere. This is advantageous in that a dense alumina refractory can be obtained efficiently in a short time.
Further, the dense alumina refractory produced by the present invention is suitable for a portion requiring excellent structure, strength, corrosion resistance, wear resistance, etc., such as a slide plate, a pig-iron steel sleeve and the like. .

[Brief description of drawings]

FIG. 1 is a diagram schematically showing each cut surface of a sample before and after the reaction and permeation of aluminum into a base material, where (A) is a sample before the reaction and permeation, and (B) is a sample after the reaction and permeation. FIG.

FIG. 2 is a diagram showing a relationship between a ratio (area ratio) of a densified portion to an area of an original base material and an apparent porosity of the base material in a cut surface.

FIG. 3 is a diagram showing a relationship between a heating temperature and a permeation thickness during reactive permeation of aluminum.

[Explanation of symbols]

 1 Aluminum 2 Base material 3 Densified refractory 4 Extra parts

Claims (3)

[Claims] 1. A silica content obtained by using an alumina-silica raw material: 0.1 to 5% by weight, and an apparent porosity: 15 to 30%.
1000 to 1230 in an oxygen-containing atmosphere with the glass phase-containing refractory as a base material and aluminum in contact with the surface of the base material.
A method for producing a dense alumina refractory material, which comprises heating at 0 ° C. to allow aluminum to react and permeate into the pores of the base material. 2. The dense alumina refractory according to claim 1, wherein the base material made of the glass phase-containing refractory is a refractory obtained by firing an alumina-silica-based raw material. Production method. 3. The dense glass according to claim 1, wherein the glass phase content of the base material made of the glass phase-containing refractory is 0.1 to 7% by weight based on the weight of the base material. Alumina refractory manufacturing method.