JPH06345532A - High zirconia fusion casting refractory and production thereof - Google Patents

Abstract

PURPOSE:To obtain a high zirconia fusion casting refractory having a thick thickness and less unevenness in the chemical composition and the structure by mixing a specific composition of glass raw material and ZrO2 raw material, fusing them in an arc electric furnace and casting it into a casting mold. CONSTITUTION:A mixed raw material with the glass raw material having a chemical composition of matrix glass constituting the fused casting refractory and the ZrO2 raw material, is prepared. Thereafter the mixed raw material is fused in an arc electric furnace to cast it into the casting mold. Thus, the high zirconia fused casting refractory containing 80-95wt.% ZrO2, having >=200mm thickness, and being <=8% of an average analysis value in the max. value of a deviation from the average analysis value against analysis values of each of chemical components contained >=0.4wt.% in samples extracted from five places of the refractory mutually apart >=70mm, is obtained. The obtained refractory has a stable high quality and reliability and a glass kiln produced by using the refractory has excellent durability and reliability.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a high zirconia fused cast refractory which is mainly used for walls contacting with molten glass in a glass kiln and a method for producing the same.

[0002]

2. Description of the Related Art In a molten cast refractory, a mixed raw material of a refractory prepared to have a predetermined chemical composition is put into an arc electric furnace, and the molten metal obtained by the arc melting is used as a heat insulating material having a required internal dimension. It is manufactured by pouring it into an embedded mold, cooling it to room temperature and solidifying it, and it has a dense and developed crystal structure, and is an ordinary bonded refractory (fire brick).
In comparison with, it is a refractory that exhibits excellent corrosion resistance especially to molten glass.

Among such melt-cast refractories, a refractory containing a relatively large amount of ZrO ₂ is preferably used in a glass kiln because of its excellent corrosion resistance, and a typical one is a glass kiln. , ZrO ₂ -A containing 33 to 40% by weight of ZrO ₂
There are 1 ₂ O ₃ —SiO ₂ based melt cast refractories and high zirconia melt cast refractories containing 80-95 wt% ZrO ₂ .

Here, ZrO ₂ --Al ₂ O ₃ --SiO ₂
System melt-cast refractories have ZrO ₂ crystals (monoclinic ZrO ₂ crystals at room temperature, called baddelite) and α-A in the structure.
It contains a l ₂ O ₃ crystal (also referred to as corundum) and has a dense structure in which a space between these crystals is filled with a matrix glass. On the one hand the high zirconia fused cast refractory is composed of a majority ZrO ₂ crystals, between ZrO ₂ crystal has a dense tissue filled with a small amount of the matrix glass of 20 wt% or less.

These ZrO ₂ crystals have the property of undergoing reversible crystal transformation from monoclinic to tetragonal at around 1100 ° C., and exhibit anisotropy in volume expansion and contraction accompanying this crystal transformation. As a result, when a molten cast refractory containing a large amount of ZrO ₂ crystals is subjected to a temperature cycle of passing through this temperature range, expansion and contraction of the crystal volume is repeated to show residual expansion, and this residual expansion is integrated to form a refractory. As the volume increases, cracks occur, and the cracks may eventually destroy the outer shape of the refractory.

With respect to the existence of this residual expansion and the problem of thermal cycle resistance which prevents the refractory from collapsing due to the integration of the residual expansion, the temperature of the matrix glass near 1100 ° C. at which the crystal transformation of ZrO ₂ crystal occurs. Can be solved by adjusting the composition of the matrix glass so as to maintain an appropriate softness. The properties of this matrix glass are particularly important in a high zirconia melt-cast refractory having a high content of ZrO ₂ crystals and a relatively low content of matrix glass in order to reduce the cumulative tendency of residual expansion.

In Japanese Patent Publication No. 47-15689, an attempt is made to add a rare earth oxide to a refractory to stabilize the ZrO ₂ crystal (convert it into a cubic crystal so as not to undergo crystal transformation) and reduce the volume change accompanying the crystal transformation. However, there is a problem that thermal shock resistance and corrosion resistance are impaired because the thermal expansion coefficient of refractory becomes large, and this method is not actually adopted in these melt-cast bricks.

As a method for adjusting the properties of the matrix glass of a high-zirconia melt-cast refractory material, Japanese Patent Laid-Open No.
In 85610, a matrix glass having SiO ₂ as a main component and Al ₂ O ₃ added with a CuO component or a B ₂ O ₃ component to adjust its viscosity, and has a proper viscosity at a grain boundary of a ZrO ₂ crystal. Exist and make ZrO
₂ Absorbs crystal expansion and contraction.

Similarly, in Japanese Patent Laid-Open No. 53-121012, S
CaO and MgO components are added to a matrix glass containing iO ₂ as a main component, and in Japanese Patent Publication No. 59-12619, SiO is added.
The P ₂ O ₅ added ₂ as a main component in the matrix glass containing Al ₂ O _3, Kokoku 2-40018 and JP-1-
In 100068, P ₂ O ₅ and B ₂ O ₃ were added to a matrix glass containing SiO ₂ as a main component and containing Al ₂ O ₃ ,
In Japanese Patent Application Laid-Open No. 63-285173, SiO ₂ is the main component and A
In matrix glass containing l ₂ O ₃ , K ₂ O, SrO, BaO, Rb ₂ O and Cs ₂ which are alkali metal or alkaline earth metal oxides having a large ionic radius with B ₂ O ₃
O and the like are added to adjust the viscosity of the matrix glass to cast a melt-cast refractory without cracks.

Further, JP-A-3-218980 and JP-A-3-218980.
-28175, a matrix glass having an appropriate viscosity is obtained by adding Na ₂ O to a matrix glass containing SiO ₂ as a main component and containing Al ₂ O _3, and a high zirconia melt cast refractory without cracks is cast. The composition of the matrix glass is devised so that the properties of the matrix glass are not altered by the precipitation of zircon crystals in the matrix glass, and the phenomenon of chipping of the refractory surface is prevented.

As described above, many high-zirconia melt-cast refractories containing 80% by weight or more of ZrO ₂ crystals have been proposed, and these high-zirconia melt-cast refractories have a corrosion resistance to molten glass. Since it is excellent, does not stain the molten glass, and has a low foaming (blister) property, it is widely used as a refractory material in a portion of the glass kiln where corrosion resistance in contact with molten glass is particularly required.

Further, Japanese Patent Laid-Open Nos. 4-193088 and 4
193766 proposes a high zirconia fused cast refractory suitable for electric melting kiln of glass that has a large electric resistivity of refractory in the operating temperature range, and is currently in the field of special glass. Its uses are expanding.

[0013]

However, in the conventional method for producing a high-zirconia melt-cast refractory, the raw material in the powder mixture charged into the arc electric furnace is a crystal having various melting points and vapor pressures. Since the components and the raw materials of the matrix glass components are mixed, some of the raw material components are scattered during the arc melting, particularly, the alkali metal oxides, P ₂ O ₅ , and B ₂ which are the components of the matrix glass. O ₃ , Si
It is known that the chemical composition deviates from the target composition because it is necessary to melt and homogenize over time so that the unmelted raw material does not remain because the O ₂ component or the like is scattered or evaporated. There is.

For this reason, conventionally, a method of melting a raw material mixture to which a large amount of chemical components, which are expected to scatter and decrease, is added in advance. However, if melting is performed for a long time for homogenization, the reaction between the melted raw material and the lining material of the arc electric furnace will proceed, and there will also be the effects of the residual hot water in each casting batch. There is considerable variation in the chemical composition from batch to batch, and it is very difficult to obtain a melt cast refractory having a predetermined target composition limited to a narrow range.

During melting of the refractory raw material and casting of the molten metal, some chemical components are scattered and evaporated, and the large difference in specific gravity between the ZrO ₂ crystal and the matrix glass causes gravity to occur in the molten metal. It is presumed that the sedimentation phenomenon occurs and the distribution of the components in the molten metal becomes non-uniform, and the chemical composition varies inside the cast melt-cast refractory, especially in the matrix glass.

The variations in the chemical composition inside the melt-cast refractory and the variations in the chemical composition for each batch of the cast refractory cause variations in the chemical composition inside the melt-cast refractory and between the lots of the melt-cast refractory. This is a cause of cracking during cooling and solidification of molten cast refractories, which is one of the causes of lowering the casting yield of refractory, and when used in glass kilns, chipping and heat cycle stability It is recognized that there are variations in the usage characteristics such as properties, and it causes troubles such as gravel due to refractory in the glass.

For this reason, there is little variation in the chemical composition inside the melt-cast refractory, and even when it is used for the wall surface of various glass kilns, the high-zirconia melt-cast refractory has high reliability with no variation in the usage characteristics. Users of glass kilns strongly demand the provision of goods. If a highly zirconia-based molten cast refractory having such a small variation can be cast with good reproducibility, the yield of the molten cast refractory at the time of casting the refractory should be significantly improved.

[0018]

The present invention has been made to achieve the above-mentioned objects, and the high zirconia melt-cast refractory material of the present invention contains 80 to 95% by weight of ZrO ₂ .
A melt-cast refractory having a wall thickness of 200 mm or more, which is an analytical value of each chemical component contained in 0.4% by weight or more in a sample taken out from 5 points separated by 70 mm or more from each other. The deviation is 8% or less of the average analysis value based on each average analysis value.

If a high zirconia melt-cast refractory can be cast without variations in chemical composition, the composition of the matrix glass will be stable and the expansion and contraction due to the crystal transformation of the ZrO ₂ crystal will be reliably absorbed by the matrix glass and cracks will occur. It is possible to cast a melt-cast refractory with a high yield without having to do so, and even if it is used as a refractory for the part that comes into contact with the molten glass of the glass kiln, it does not show chipping or residual expansion, and has high reliability and high zirconia quality. A molten cast refractory can be provided.

The high-zirconia melt-cast refractory having a small variation in chemical composition can be cast by the method for producing a high-zirconia melt-cast refractory according to the present invention. That is, a small amount of a chemical component contained in a large amount of ZrO ₂ raw material that forms a matrix glass (when desiliconized zircon is used as a ZrO ₂ raw material, a SiO ₂ component of about 2.5 wt% is contained. The mixed raw material having the composition of the matrix glass in which the molten cast refractory is to be included in advance is melted into a glass raw material, and this glass raw material crushed to an appropriate particle size is ZrO ₂ It is obtained by mixing the raw materials and arc melting and casting the mixed raw materials.

In this case, since the easily meltable glass particles are scattered in the mixed raw material, arc melting of the mixed raw material of the refractory material can be carried out quickly in a short time, which is necessary for homogenizing the molten metal batch. The melting time can be remarkably shortened. Thus, it is possible to significantly reduce the deviation of the chemical components due to the scattering or evaporation of the raw material components and the influence of gravity. This method is also effective for casting a high zirconia melt cast refractory having a characteristic matrix glass composition, for example, a low content of alkali components.

Further, since the melting of the mixed raw materials can be completed in a short time, the consumption of electric power and the corrosion of the lining material of the arc electric furnace by the molten metal are small, and the movement of the chemical components in the molten metal due to gravity can be reduced. It is possible to significantly reduce the variation in the chemical composition of the matrix glass in one melt-cast refractory, and to significantly reduce the variation in the chemical composition of the melt-cast refractory inside, especially in the melt-cast refractory, especially for each melt batch. be able to.

In a high-zirconia melt-cast refractory containing 80 wt% or more of ZrO ₂ , since the amount of matrix glass contained in the refractory is relatively small, even if a step of melting the matrix glass is added, The time required for melting the raw material of the high-zirconia melt-cast refractory can be shortened, and the sufficient demerit can be obtained, and the labor is not so increased.

Excellent corrosion resistance and low foamability when the high zirconia melt-cast refractory is used in contact with molten glass are brought about by the high content of ZrO ₂ component of 80% by weight or more. However, Zr in refractory
If the O ₂ component exceeds 95% by weight, the amount of the matrix glass in the refractory becomes small and it becomes difficult to absorb the expansion and contraction of the volume of the ZrO ₂ crystal due to the crystal transformation of the ZrO ₂ crystal, and In addition to difficult casting, residual expansion tends to accumulate when using refractories, and cracks are likely to occur.

The high zirconia melt cast refractory used for the wall surface of the glass kiln that comes into contact with the molten glass has a rectangular parallelepiped shape in most cases, and the shortest ridge length, that is, the thickness of the refractory is In order to impart durability to the glass kiln, it is usually set to 200 mm or more. Further, the larger the thickness of the molten cast refractory, the greater the variation of the internal chemical components, difficult to cast so that cracks do not occur, in the method of producing a high zirconia melt cast refractory of the present invention. According to this, even a large-sized melt-cast refractory having a large wall thickness can be cast with a small variation in chemical composition, and a high-zirconia melt-cast refractory without cracks can be cast with high yield.

Since the surface of the melt-cast refractory has a high solidification rate during casting, the crystal structure is different from that of the inside, and the refractory whose surface is scraped off is used for the portion of the glass kiln that comes into contact with the molten glass. In many cases, since it is hard and difficult to break, the refractory sample to be analyzed was taken from a position 20 mm or more away from the cast surface. In the present invention, the analytical samples are collected from five points in the refractory material that are separated from each other by 70 mm or more. For each sample, 0.4 wt% or more, or 0.
Chemical analysis is carried out for all components containing 15% by weight or more. Quantitative determination of chemical components can be performed by fluorescent X-ray analysis as well as ordinary wet analysis and spectroscopic analysis.

The average analytical values M _i of the content of chemical components i contained in the refractory is the average analytical values X _ij for samples j taken at five locations, the average chemical components i The deviation V _i of the chemical component i based on the analytical value M _i is V _i =
Given by | (X _ij −M _i ) / M _i | × 100 (%),
In the high zirconia melt cast refractory of the present invention, the maximum value of this deviation V _imax is all chemical components (provided that the melt cast refractory contains less than 0.4% by weight, or less than 0.15% by weight). 8% or less,
It is more preferably at most 6% and the maximum value V of the deviation of the chemical component i of the high zirconia melt cast refractory of the present invention V
_{The imax} is remarkably small, about 1/5 or less as compared with the case of the conventional high zirconia melt cast refractory.

0.4 in the high zirconia melt cast refractory
The chemical components contained by weight% or more are ZrO ₂ , SiO
₂ and Al ₂ O ₃ , Na ₂ O, K ₂ O, P ₂ O
₅ , B ₂ O _3, etc., for example, a melt-cast refractory material is
ZrO ₂ 80-95 wt%, SiO ₂ 3.5-15
% By weight, 0.8 to 4.5% by weight of Al ₂ O ₃ , Na ₂ O
0 to 1.5% by weight, K ₂ O 0 to 1.0% by weight, P ₂
It is preferable that O ₅ contains 0 to 0.75% by weight, B ₂ O ₃ contains 0 to 0.75% by weight, and a small amount of unavoidable impurities.

[0029] In the method of producing a high zirconia fused cast refractory of the present invention, the ZrO ₂ component in the matrix glass of the final product refractories are included, the ZrO ₂ component in the glass melting advance You may add it,
If the ZrO ₂ component is added, the glass viscosity becomes large and melting becomes difficult. Therefore, it is preferable to use the glass composition excluding the ZrO ₂ component. In addition, ZrO ₂ raw materials containing SiO ₂ components, such as desiliconized zircon,
When the O ₂ raw material is used as the main raw material of the high zirconia fused cast refractory material, it is preferable to reduce the SiO ₂ component in the glass to be melted in advance by this amount.

In the preferred method for producing a high-zirconia molten cast refractory material of the present invention, a mixed raw material having a chemical composition of matrix glass in advance is arc-melted in, for example, an arc electric furnace, or is melted in a crucible to form a molten glass. Is poured into cold water and crushed simultaneously with cooling (water granulation),
Even a composition that is easily crystallized and hardly becomes glass can be easily vitrified and can be crushed simultaneously. In many cases, this glass raw material has a particle size of approximately 10 mm or less, and can be used as it is as a raw material simply by water granulation and drying.

The high zirconia melt cast refractory cast by the method of the present invention contains 80 to 95 wt% ZrO _2.
In addition to being a refractory consisting mainly of ZrO ₂ crystals, the chemical composition of the refractory is controlled within a narrow range determined, and the deviation of the internal chemical composition is small.
Since the matrix glass having appropriate viscosity around 0 ° C is evenly present in the refractory, the expansion and contraction of the ZrO ₂ crystal near 1100 ° C is absorbed, and the strain accumulation is effectively relaxed. To be done.

Therefore, a high-zirconia molten cast refractory without cracks can be cast with high yield, and at the same time, chipping phenomenon when the refractory is used, cumulative tendency of residual expansion when subjected to temperature cycle, and occurrence of cracks. The refractory is stable even when it is used in a glass kiln, and thus the life of the glass kiln is stable, and a refractory that hardly produces bubbles and gravel in the glass product is obtained, and the yield of the glass product is also improved. become.

[0033]

EXAMPLES The present invention will be specifically described below with reference to examples, but the present invention is not limited to these examples.

Example 1 SiO which is a chemical component of the matrix glass of a high zirconia melt cast refractory containing 93.5% by weight of ZrO _2.
With respect to ₂ , Al ₂ O ₃ and Na ₂ O components, powders of high-purity silica sand, low-soda alumina and sodium carbonate were respectively weighed to obtain a predetermined target composition (SiO contained in the ZrO ₂ raw material).
Mix until ₂ components are subtracted) and mix about 50
0 kg of a mixed raw material for matrix glass was obtained.

This mixed raw material was mixed with a graphite electrode 500
It was charged into a single-phase alternating-current arc electric furnace of kVA and arc-melted.

Molten glass was poured into a water granulation box filled with water, rapidly cooled, water granulated, taken out of the water granulation box and sufficiently dried. The particle size thus obtained is 0.5 to 10 m
A target of high zirconia fused cast refractory is obtained by mixing desiliconized zircon (most of which contains about 5% by weight of SiO ₂ component with ZrO ₂₎ having the same particle size into a glass raw material of about m. As a mixed raw material having a composition, this mixed raw material was charged into a 500 kVA single-phase AC arc electric furnace equipped with a graphite electrode, and was subjected to arc melting at a temperature of 2200 to 2400 ° C.

The time required for melting this mixed raw material is about 35.
It was a minute. Then, the obtained molten metal was embedded in a powder of Bayer alumina (heat insulating material) and the inner dimension was 300 mm.
It was poured into a graphite mold of × 400 mm × 1000 mm and allowed to cool until the cast product reached a temperature near room temperature.

An analytical sample weighing about 10 g was taken from the high-zirconia melt-cast refractory taken out of the mold as follows. That is, the vertices of a molten cast refractory having a rectangular parallelepiped shape are represented by A, B, C, D, E, F, G and H in FIG. 1, and E, F, G and H are the bottom surfaces during casting, A (0,0,1), E (0,0,0), I (1
/ 2,0,1 / 2), J (1 / 2,1 / 2,0), K
Five points of (1/2, 1/2, 1/2) were set as the sampling points of the analysis sample. However, all of these analytical samples were taken from a portion excluding a portion within 20 mm from the surface of the refractory during casting.

The analytical samples collected at these five points were crushed in a zirconia mortar, boric acid and sodium carbonate were added to the crushed sample, and the samples were melted and dissolved in warm water to adjust the content of each chemical component to ICP (induction). Quantification was performed using a combined plasma) emission spectroscopy analyzer. For the quantitative analysis of Na ₂ O, a ground sample was separately dissolved with hydrofluoric acid and sulfuric acid and analyzed by atomic absorption spectrometry.

Further, in order to evaluate the heat cycle resistance of the cast refractory, a test piece having a size of 40 mm × 40 mm × 30 mm was cut from the vicinity of the five locations shown in FIG. After putting these in an electric furnace and raising the temperature from room temperature to 800 ° C at 300 ° C / h,
Temperature rise from ℃ to 1250 ℃ over 1 hour, 1250 ℃
The temperature was lowered to 800 ° C. over 1 hour, and the temperature rising / falling cycle between 800 ° C. and 1250 ° C. in which the temperature was kept at 800 ° C. for 1 hour was repeated.

This temperature increase / decrease between 800 ° C. and 1250 ° C. was set as one temperature cycle, this cycle was repeated for 40 cycles, and then cooled to room temperature. Those with a cumulative amount of 3% or less were judged to have good heat cycle resistance. The results are summarized in Table 1.

[0042]

[Table 1]

Comparative Example 1 Desiliconized zircon, which is a zirconia raw material, and raw material powders of high-purity silica sand, low soda alumina, sodium carbonate, etc. were blended to prepare a mixed raw material having the same amount and chemical composition as in Example 1, which was described above. Charged into a single-phase AC arc electric furnace of 2200-2400
It melted completely at a temperature of ° C. The time required for this melting was about 60 minutes.

This molten metal was similarly embedded in a Bayer alumina powder, and the internal dimensions were 300 mm × 400 mm.
It was poured into a graphite mold of × 1000 mm and allowed to cool to a temperature near room temperature. Table 2 shows the results of chemical analysis by the same method as in Example 1 and the test results of heat cycle resistance.

[0045]

[Table 2]

Example 2 In the same manner as in Example 1, first, the glass raw material was melted, and the granular glass raw material was mixed with the ZrO ₂ raw material to obtain 8 parts of ZrO ₂ .
The dimensions including 8.5% by weight are 400 mm x 300 mm x 30
A 0 mm high zirconia melt cast refractory was cast. The time required for melting the mixed raw material was about 30 minutes. Chemical analysis and heat cycle resistance test were conducted in the same manner as in Example 1, and the results are summarized in Table 3.

[0047]

[Table 3]

Comparative Example 2 By the same method as in Comparative Example 1, a high zirconia melt cast refractory containing 85.5% by weight of ZrO ₂ was cast to obtain a refractory having dimensions of 400 mm × 300 mm × 300 mm.
The time required for melting the mixed raw material was about 45 minutes. Further, a chemical analysis and a heat cycle resistance test were conducted in the same manner as in Example 1, and the results are summarized in Table 4.

[0049]

[Table 4]

From the above test results, the high-zirconia molten cast refractory of the present invention has a very small deviation in the chemical composition inside the cast refractory and between the lots of the cast refractory and the unevenness of the structure, and is a crack-free cast. Is obtained with good yield, and even when used in a glass kiln, the cumulative tendency of residual expansion is slight, cracks do not occur, excellent durability of the glass kiln can be secured, and it is caused by cracks in the refractory It can be seen that it is a high-quality and highly reliable refractory which does not release gravel into the molten glass and does not contaminate the molten glass.

More recently, large-sized melt-cast refractory materials are often used, and according to the method for producing a high-zirconia melt-cast refractory material of the present invention, large-scale melt-cast refractory materials, which have been difficult in the past, can be obtained. Can be cast with good yield. Further, as for the high-zirconia melt-casting refractory having a high electric resistivity used in an electric melting furnace for glass and containing almost no alkali component, a stable quality product can be cast with a good yield by the manufacturing method of the present invention.

[0052]

EFFECTS OF THE INVENTION The high-zirconia melt-cast refractory of the present invention is stable because it has very little unevenness in the chemical composition and structure between each cast refractory lot and inside the cast refractory as compared with the conventional manufacturing method. It has high quality and reliability, not only durability but also no tendency of chipping such as partial chipping of refractory material at the time of temperature rise, and remarkably excellent thermal cycle resistance. Therefore, when this refractory is used in a glass kiln, the durability and reliability of the glass kiln are significantly improved.

Further, in recent glass kilns, large-sized melt-cast refractories are often used for furnace construction, so that large-scale melt-cast refractories, which are considered difficult to cast, can be cast with high yield. The method for producing a high-zirconia melt-cast refractory material of the present invention is very useful.

Further, as for the high-zirconia melt-cast refractory having a large electric resistivity used in the electric melting furnace for glass, a high-quality one having less unevenness in chemical composition and structure can be cast by the manufacturing method of the present invention. Therefore, a molten cast refractory having a high electric resistivity can be obtained with a good yield, and current can be efficiently passed through the molten glass without leaking current to the refractory side, so that the glass can be energy-efficiently electrically fused.

The high zirconia melt cast refractory material of the present invention comprises:
It is used for wall surfaces of ordinary glass kilns where erosion is particularly severe, and kilns that melt glass with a high melting point, glass substrates for electronics that require high quality, glass substrates for displays, and other fine glass products are manufactured. It can be used for the wall surface of a glass kiln that comes into contact with molten glass, and if it includes effects such as greatly improving the quality and yield of these glass products, its industrial application effect is great.

[Brief description of drawings]

FIG. 1 is a perspective view of coordinates for explaining an example of a position at which an analytical sample is taken from a high-zirconia molten cast refractory material of the present invention.

[Explanation of symbols]

A, B, C, D, E, F, G, H: Coordinates of vertices of rectangular parallelepiped refractories I, J, K: Coordinates of sampling points of analysis sample

Claims (7)

[Claims] 1. ZrO ₂ is contained in an amount of 80 to 95% by weight, and 200
a melt-cast refractory having a wall thickness of not less than mm, which is 0.4% by weight or more of the analytical value of each chemical component contained in the samples taken from five locations 70 mm or more apart from each other of the refractory. A high zirconia melt cast refractory material having a maximum deviation from the average analysis value of 8% or less of the average analysis value. 2. ZrO ₂ is contained in an amount of 80 to 95% by weight, and 200
a melt-cast refractory having a wall thickness of mm or more, which is 0.15 wt% or more of the analytical value of each chemical component contained in the samples taken out from 5 points 70 mm or more apart from each other of the refractory. A high zirconia melt cast refractory material having a maximum deviation from the average analysis value of 8% or less of the average analysis value. 3. The high zirconia melt cast refractory material according to claim 1, wherein the maximum value of the deviation is 6% or less of the average analysis value for each chemical component. 4. The refractory material according to claim 1, wherein the chemical component other than ZrO ₂ contained in the refractory is mainly S.
iO ₂ and Al ₂ O ₃ , and Na ₂ O, K ₂ O, P
A high zirconia melt-cast refractory material containing 0.2 wt% or more of one or more selected from ₂ O ₅ and B ₂ O _{3 in} total. 5. A mixed raw material of a glass raw material having a chemical composition of a matrix glass which constitutes a molten cast refractory and a ZrO ₂ raw material is melted in an arc electric furnace and cast into a mold. 1. A method for producing a high zirconia melt cast refractory material. 6. A mixed raw material having a chemical composition of a matrix glass, which constitutes a substantially molten cast refractory, in which the compounding amounts of chemical components forming a small amount of matrix glass contained in the ZrO ₂ raw material are adjusted, Glass, and a mixture of crushed glass and a ZrO ₂ raw material added thereto is arc-melted and cast to produce a high-zirconia fused cast refractory. 7. The method for producing a high-zirconia fused cast refractory material according to claim 6, wherein the molten glass is put into water, and the glass is crushed simultaneously with cooling and solidification.