JP2941128B2 - Zirconia-containing magnesia-alumina spinel clinker and refractory obtained using the same - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

TECHNICAL FIELD The present invention provides a refractory material having high erosion resistance to slag generated in steel making, steel making, and the like, excellent heat shock resistance, and digestion resistance for enabling refractory construction with water. The present invention relates to a clinker and a refractory obtained using the same.

[0002]

BACKGROUND ART Conventionally, in the steel industry and the steel industry,
In general, basic refractories having excellent slag erosion resistance have been used, and among them, magnesia refractories exhibiting particularly high refractory properties have been suitably used. However, since the magnesia refractory has a large volume change with respect to heat, thermal spalling is likely to occur, and since slag easily penetrates into its crystal grain boundaries, structural spalling is also likely to occur. It has such a drawback.

For this reason, in recent years, instead of such magnesia refractories, alumina (Al ₂ O ₃ ) having a small expansion and contraction rate is added to magnesia (MgO), and this is obtained by firing at a high temperature. Refractories manufactured using magnesia-alumina-based spinel clinker having excellent spalling resistance have come to be used, and accordingly, such refractories have spalling resistance and slag erosion resistance. Various proposals have been made in order to further improve properties such as properties.

For example, JP-A-2-102167, JP-A-3-60460, and JP-A-3-6046
In Publication No. 1 and the like, a magnesia alumina-based spinel clinker composed of MgO, Al ₂ O ₃ and other impurities and having various contents thereof is disclosed.

However, in a refractory obtained using such a magnesia-alumina-based spinel clinker, even if the composition is further densified, CaO exhibiting high basicity cannot be obtained due to its chemical composition. There is naturally a limit in improving the erosion resistance of slag as the main component.

On the other hand, JP-A-63-166750 discloses a magnesia-alumina-based spinel containing zirconia (ZrO ₂ ) as a third component in addition to two main components of MgO and Al ₂ O _3. Clinker,
It has been disclosed. And, in this publication, ZrO
₂ is C, which is a slag component having a large erosion effect on refractories.
Since it has excellent chemical resistance at high temperatures to aO and SiO ₂ , the magnesia-alumina-based spinel clinker disclosed therein, and furthermore, the refractory obtained by using the magnesia-alumina-based spinel clinker, Is shown to be even better.

However, the present inventors have examined the magnesia-alumina-based spinel clinker and found that the clinker contains MgO in a high range of 29.5 to 94.5% by weight. Therefore, the crystal phase contains a large amount of periclase crystals that are easily reactive to water, and therefore, in such a magnesia-alumina-based spinel clinker, the reaction resistance with water is high. Is extremely low in digestion resistance and exhibits Mg as a periclase crystal when exposed to water.
It was clarified that O immediately reacted with water and changed to Mg (OH) ₂ , and as a result, the clinker particles were caused to disintegrate. Although the presence of periclase crystals makes it easier to obtain dense crystals, when such periclase crystals are contained in large amounts, the grain growth of spinel crystals is inhibited and the coefficient of thermal expansion increases. As a result, it has also been found that the thermal shock resistance of the clinker and the refractory obtained by using the clinker is significantly reduced.

For this reason, the magnesia-alumina-based spinel clinker disclosed in the above-mentioned publication is inferior in thermal shock resistance, and is used in large quantities in the steelmaking and steelmaking industries in recent years. Increasingly, by adding water and performing a predetermined molding operation, a refractory product having a desired shape can be obtained. A very big problem, such as none, was inherent.

[0009]

Here, the present invention has been made in view of such circumstances, and a problem to be solved is to ensure excellent slag erosion resistance and to improve thermal shock resistance. Zirconia-containing magnesia-alumina-based spinel clinker, which can be suitably used for water-based refractory construction by further improving digestion resistance.
Another object of the present invention is to provide a refractory obtained by using the same.

[0010]

The present invention provides an Al ₂ O ₃ material, a MgO material and a ZrO ₂ material.
By firing at a temperature of 1700 ° C. to 1950 ° C.
Clinker, ZrO ₂ , MgO and Al ₂
O ₃ , the total content of these three components is 95% by weight or more, the ZrO ₂ content is 0.5 to 20% by weight, and the following formula: 0 <MgO content− (0. 0
7 × ZrO ₂ content) − (Al ₂ O ₃ content / 2.5
3) Magnesium formed of a chemical composition satisfying ≤ 3
Alumina spinel has an average crystal diameter of 10 μm or more.
A zirconia-containing magnesia-alumina-based spinel clinker characterized by containing zirconia crystals in a magnesia-alumina-based spinel crystal phase containing a small amount of periclase crystals.

[0011] Then, in the zirconia-containing magnesia alumina spinel clinker according to the present invention, advantageously, the apparent porosity is such that 20% or less, further to di zirconia crystals, It will be made of tetragonal or cubic.

Further, the present invention provides an Al ₂ O ₃ raw material, M
The mixture of the gO raw material and the ZrO ₂ raw material is
A clinker obtained by firing at a temperature of 50 ° C.,
Mainly composed of ZrO ₂ , MgO and Al ₂ O ₃ , wherein the total content of these three components is 95% by weight or more,
The O ₂ content is 0.5 to 20% by weight, and the following formula:
0 <MgO content− (0.07 × ZrO ₂ content) −
(Al ₂ O ₃ consists of a chemical composition that satisfies the content /2.53)≦3, is generated magnesia alumina spinel 1
A zirconia-containing magnesia-alumina-based spinel clinker containing zirconia crystals in a magnesia-alumina-based spinel crystal phase containing a small amount of periclase crystals , having an average crystal diameter of 0 μm or more, characterized in that it is used as a refractory material. The refractory to be used is also the gist.

[0013]

The zirconia-containing magnesia-alumina-based spinel clinker according to the present invention comprises MgO, Al ₂ O ₃ and ZrO.
Although made of ₂ which, the total content thereof ternary needs to be 95 wt% or more. That is, in other words, in the clinker according to the present invention, impurities,
For example, it is permissible to contain various oxides such as CaO, SiO ₂ , K ₂ O, and Fe ₂ O ₃ , but the content of such impurities is not limited unless the total is 5 wt% or less. No. However, if these impurities are contained in an amount exceeding 5% by weight, the heat resistance of the clinker and the refractory obtained by using the clinker will decrease.

The clinker according to the present invention can ensure high slag erosion resistance by containing ZrO ₂ having high chemical resistance at high temperature to slag as one of its main components. However, such ZrO
₂ will be contained in such an amount as to be 0.5 to 20% by weight. In such a clinker, if the content of ZrO ₂ is less than 0.5% by weight, the effect of improving the slag erosion resistance by adding ZrO ₂ cannot be sufficiently obtained, and the amount of expensive ZrO ₂ exceeds 20% by weight. When it is included, it becomes economically impractical,
Furthermore, due to the high thermal expansion coefficient of ZrO ₂ , such an excessive content of ZrO ₂ increases the thermal expansion coefficient of clinker and refractories obtained therefrom, and consequently their spalling resistance. Will be reduced.

Here, the theoretical chemical composition of the magnesia-alumina spinel is MgO: 28.3% by weight, Al
₂ O ₃ : 71.7% by weight. Therefore, the amount of MgO contained in the theoretical spinel crystal, in other words, the estimated amount of MgO that can produce Al ₂ O ₃ and spinel crystal is (Al ₂
O ₃ and thus represented by a formula: content /2.53).
On the other hand, MgO that can be dissolved in ZrO ₂ crystal is
It is known that the estimated amount can be obtained from the equation (0.07 × ZrO ₂ content). Therefore, based on the total amount of MgO contained in the magnesia-alumina-based spinel clinker, the amount of MgO capable of forming Al ₂ O ₃ and spinel crystals and the amount of Mg that can be dissolved in ZrO ₂ crystals
The amount obtained by subtracting the amount of gO from the remaining amount, that is, the amount obtained by the following formula: MgO content− (0.07 × ZrO ₂ content) − (Al ₂ O ₃ content / 2.53) M that precipitates as periclase crystals in the clinker crystal phase
This is the estimated amount of gO.

In the zirconia-containing magnesia-alumina spinel clinker according to the present invention, Mg
O and Al ₂ O ₃ are 0 <MgO content (% by weight) −
[0.07 × ZrO ₂ content (% by weight)] − [Al ₂ O
₃ content (% by weight) /2.53] ≦ 3. That is, the clinker according to the present invention comprises a periclase crystal (MgO)
Must have a magnesia-alumina-based spinel crystal phase contained in a small amount at a ratio of 3% by weight or less.

Because, as mentioned above, the presence of such a small amount of periclase crystals densifies the structure and enhances the thermal stability of the clinker without impairing the grain growth of the clinker, This is because it advantageously contributes to the improvement of the slag erosion resistance.
Periclase crystals (MgO), which readily react with water and change to Mg (OH) ₂ , contain 3% by weight in the clinker.
If clinker particles are present in excess of water, the surface of the clinker particles will crack when exposed to water, and in extreme cases, the clinker particles may collapse. In addition, such a problem,
In order to avoid this more advantageously, the content of periclase crystals is 1.5% by weight or less, that is, MgO and Al ₂ O _3.
Are contained in an amount satisfying 0 <MgO content− (0.07 × ZrO ₂ content) − (Al ₂ O ₃ content / 2.53) ≦ 1.5. desirable. Further, as described above, since the MgO content in the theoretical chemical composition of the magnesia-alumina-based spinel is 28.3% by weight, the clinker according to the present invention is used for the purpose of controlling the content of periclase crystals. It is preferable that the content of MgO be 29.0% by weight or less.

Therefore, in the zirconia-containing magnesia alumina-based spinel clinker according to the present invention, MgO and Al ₂ O ₃ are contained in an amount satisfying the above formula, and the crystal phase thereof is reduced in a small amount of periclase crystal. By making it a magnesia-alumina-based spinel crystal phase containing, it is possible to effectively improve the thermal shock resistance,
Digestion resistance is remarkably improved, so that water is added,
By performing a predetermined molding operation, it can be used very advantageously as a refractory material for producing an amorphous refractory which can obtain a desired refractory product.

The zirconia-containing magnesia-alumina-based spinel clinker is apparent in further improving the slag erosion resistance of the clinker and the refractory obtained by using the clinker. It is preferable that the particles have a porosity of 20% or less and have a dense structure, and that the average crystal diameter of the magnesia-alumina-based spinel crystal is 10 μm or more, more preferably 20 μm or more. It is desirable.

Furthermore, in such a clinker,
It is preferable that the contained ZrO ₂ is stabilized or partially stabilized by dissolving MgO, and the ZrO ₂ crystal is preferably made of tetragonal or cubic. Thereby, the transformation of the crystal form of ZrO ₂ from a tetragonal system with volume expansion to a monoclinic system due to thermal change is effectively prevented, and the spalling resistance of such clinker and refractory is enhanced. Will be done.

In addition, regarding the clinker according to the present invention, the Japanese Society for the Promotion of Science, 1324th Committee, Analysis Subcommittee, 4. After the digestibility test performed according to “Digestibility test method for magnesia clinker”, the weight increase due to the change from MgO to Mg (OH) ₂ is 1.5% or less as compared with before the test. It is desirable that such a clinker can exhibit better digestion resistance.

Thus, the zirconia-containing magnesia alumina-based spinel clinker having such excellent characteristics can be advantageously produced by the following method.

First, after sintering, ZrO ₂ is 0.5
-20% by weight, and Al ₂ O ₃ and MgO
<MgO content− (0.07 × ZrO ₂ content) − (A
l ₂ O ₃ content / 2.53) ≦ ₃ (weight%)
And an Al ₂ O ₃ raw material, respectively, so that the total content of these three components is 95% by weight or more.
An MgO raw material and a ZrO ₂ raw material are mixed.

The raw materials used therewith are not particularly limited as long as they can give the above-mentioned chemical composition after firing, and are conventionally known as raw materials for clinker or refractories. Can be used. For example, examples of the Al ₂ O ₃ raw material include commercially available alumina clinker, aluminum hydroxide produced by the Bayer method and aluminum oxide obtained by calcining the same, natural bauxite and calcined products thereof, various aluminum salts, and the like. As the MgO raw material, commercially available magnesia clinker, magnesium hydroxide, magnesium oxide obtained by calcining the same, natural magnesite, magnesium oxide obtained by calcining the same, various magnesium salts, and the like can be used. is there. Further, as the ZrO ₂ raw material, zirconium oxide, synthetic zirconia, natural baddelite, various zirconium salts, and the like can be used. When the raw materials are blended, the raw materials are appropriately selected from the raw materials as exemplified above, and one type is used or two or more types are used in combination.

Next, the compound thus obtained is pulverized and mixed. In the subsequent heat treatment, sintering becomes easier and the structure in the sintered body becomes homogeneous. Preferably 15
The blend is ground and mixed until it is less than μm. If the average particle size of the pulverized mixture thus obtained exceeds 50 μm, a problem such as a decrease in bulk density of clinker particles finally obtained will be caused. Further, in this pulverization and mixing, any conventionally known apparatus can be used, and further, either a wet method or a dry method can be adopted.

Next, the pulverized mixture thus obtained is subjected to a granulation operation by a general method corresponding to the pulverization / mixing method to obtain a granulated product. That is, of those pulverized mixtures, the slurry obtained by a wet pulverization / mixing method in a ball mill or the like is dewatered by a filter press or the like, and then granulated into pellets by an extruder or the like. The obtained dry mixture is granulated in a dry manner by a tumbling granulator or the like.

After drying the granules as necessary, the granules are usually dried in a general sintering facility such as a rotary kiln, a tunnel kiln or a shaft kiln in the air.
By performing a heat treatment at a temperature of 1700 to 1950 ° C., a sintered body that is a target zirconia-containing magnesia alumina-based spinel clinker is obtained.
Further, in order to obtain a clinker having excellent spalling resistance and further enhanced erosion resistance to slag, ZrO ₂ is preferably sufficiently reacted with MgO, and its crystal form is changed to MgO. Or a cubic crystal in which magnesia-alumina-based spinel has a mean crystal diameter of 10 μm or more, more preferably 20 μm or more.
The granulated material is heated and sintered until it has a dense structure with an apparent porosity of 20% or less.

[0028]

Thus, the refractory according to the present invention uses the above-mentioned clinker as a refractory material, and is advantageously obtained by the following method.

That is, first, having the features of the present invention,
The zirconia-containing magnesia-alumina-based spinel clinker is subjected to pulverization and sizing operations according to a conventional method, thereby obtaining a refractory material comprising the clinker powder or granules. Then, the refractory material thus obtained is formed into a predetermined shape by a conventionally known method, and further, if necessary, is heated and sintered to obtain a fixed refractory such as a brick.

As another method, various cements, binders and the like are blended with the refractory material comprising the clinker according to the present invention obtained as described above to obtain a powdery or clay-like material. The result is an irregular refractory. In addition,
As is well known, in this amorphous refractory, after adding water, a molding operation such as a stamp molding method or a vibration molding method is performed to obtain a refractory product having a desired shape. Becomes

As described above, the refractory according to the present invention can be advantageously manufactured as a fixed refractory or an amorphous refractory in either shape.
Moreover, as described above, such a refractory is made of a refractory material having both high slag erosion resistance and high thermal shock resistance, and also having high digestion resistance that enables refractory construction by a water system. Things.

Therefore, in the refractory according to the present invention,
As a refractory for steel making and steel making, excellent slag erosion resistance and thermal shock resistance, and extremely good furnace construction workability can be simultaneously exhibited. In addition, such refractories also have high heat resistance,
It can be used for a wide range of applications such as refractories for cement and lime burning kilns in addition to steelmaking.

The refractory material used for obtaining such a refractory according to the present invention is most preferably composed only of the clinker powder or granules according to the present invention. The material may be blended in particle size and used as a blended refractory material. At that time, as a general refractory material, if a refractory material that is less expensive than the clinker according to the present invention or a refractory material having characteristics that cannot be obtained with the clinker is selected and used, it can be obtained only by the clinker according to the present invention. Refractories that are cheaper and have a wider range of properties than refractories are obtained. However, in order to obtain a refractory having high erosion resistance to slag, such a compounded refractory material contains at least 5% by weight or more of the clinker powder or granular material according to the present invention. Is desirable.

Incidentally, examples of the refractory material to be mixed with the clinker according to the present invention in particle size include, for example, an alumina refractory material, a magnesia refractory material, and a spinel refractory material. Specifically, as the alumina refractory material, fired materials of high alumina rocks, calcined or fired bauxites, diaspores,
Sillimanites, synthetic mullite, fused alumina, sintered alumina, activated alumina, aluminum oxide, sand shale, etc. can be used, and magnesia refractory materials include
Seawater magnesia clinker, magnesite ore and its calcined product, molten magnesia, sintered magnesia and the like can be used, and as the spinel-based refractory material, electrofused or sintered spinel clinker can be used.

Further, in the refractory according to the present invention,
In addition to these compounded refractory materials, it is acceptable to include auxiliary materials such as clay, silicon carbide, finely divided silica, graphite, and various binders. In particular, any binder may be used as the auxiliary material as long as it is used in a normal refractory manufacturing process. That is, various amorphous silicas, hydraulic cements such as alumina cement, alkali metal salts such as sodium phosphate and sodium silicate, aluminum phosphates, alkaline earth metal salts such as magnesium sulfate and the like, inorganic binders such as orthophosphoric acid, phenolic resins and the like. Organic binders such as furan resins, tar and pitch-based carbon binders, as well as pulp waste liquor and bitter can be used.

[0037]

Hereinafter, typical examples of the present invention will be described to clarify the present invention more specifically. However, the present invention imposes no restrictions on the description of such examples. It goes without saying that you don't receive anything. In addition, the present invention, in addition to the following examples, in addition to the above specific description, various modifications based on the knowledge of those skilled in the art, unless departing from the spirit of the present invention,
It should be understood that modifications, improvements and the like can be made.

First, Al ₂ O ₃ raw material, MgO raw material, Zr
As the O ₂ raw material, commercially available calcined alumina, magnesium hydroxide, and natural baddelite were used, and they were blended in different amounts so that the theoretical chemical composition after sintering was within the scope of the present invention. I was sorry. And the obtained compound was set to Example 1, Example 2, and Example 3, respectively. For comparison, MgO and Al ₂ O
₃ is a content not satisfying the expression of 0 <MgO content− (0.07 × ZrO ₂ content) − (Al ₂ O ₃ content / 2.53) ≦ ₃ as defined in the present invention. Without using the blended compound and natural buderite, using only a mixture of magnesium hydroxide and calcined alumina in an amount satisfying the above formula,
Comparative Example 1 and Comparative Example 2 were set. Theoretical chemical compositions of Examples 1-3 and Comparative Examples 1-2 after sintering, and their M
gO content− (0.07 × ZrO ₂ content) − (Al ₂
The calculated value of O ₃ content / 2.53), that is, the content of periclase crystals, is shown in Table 1 below.

[0039]

[Table 1]

Next, each of the blends was put into a ball mill, and water was further added. The mixture was pulverized and mixed by a wet method to obtain each slurry. Then, the thus obtained slurry was taken out of a ball mill, dehydrated by a filter press, and then granulated into pellets by an extruder. Next, the obtained granules are dried, and then the granules are subjected to 1
Heat treatment was performed for 30 minutes at a heating temperature of 700 ° C. to 1900 ° C., respectively, to obtain heat-treated particles serving as target clinkers. The physical properties of the heat-treated particles at different heating temperatures, that is, apparent specific gravity, bulk specific gravity, apparent porosity, and water absorption were measured. The results and the constituent minerals of each heat-treated particle are shown in Table 2 below. In addition, these physical characteristics are described in “JIS R220
5-7 Measurement method for apparent porosity, water absorption and specific gravity of refractory brick ". The constituent minerals were determined by identifying each crystal phase using an X-ray diffractometer. Furthermore,
In Table 2 below, Sp represents a spinel crystal, Zr represents a zirconia crystal, and Pe represents a periclase crystal.

[0041]

[Table 2]

As is clear from Tables 1 and 2, in the case of a composition having a chemical composition after sintering within the range specified in the present invention, a predetermined operation is carried out, In the magnesia-alumina-based spinel crystal phase containing a small amount of periclase crystals, a sintered body containing zirconia crystals and having a dense structure with an apparent porosity of 20% or less was obtained.

In order to examine the digestion resistance of the clinker obtained as described above, a digestion resistance test was performed on the heat-treated particles at 1900 ° C. among the heat-treated particles shown in Table 2. Done. At that time, the particle state of each heat-treated particle after the test was observed and evaluated. The results are shown in Table 3 below. This test was conducted by the Japan Society for the Promotion of Science 1324 Committee Analysis Subcommittee. Performed in accordance with the “Magnesia clinker digestibility test method”, and by reacting MgO with water,
The digestion resistance was evaluated based on the rate of weight increase of the sample before and after the reaction, which was caused by the weight increase accompanying the change to Mg (OH) ₂ . In the evaluation of the grain state after the test shown in Table 3, ○ indicates no change, and X indicates that a crack was recognized on the grain surface.

[0044]

[Table 3]

As is apparent from Table 3, 0 <MgO content− (0.07 × Z) defined in the present invention.
rO ₂ content) − (Al ₂ O ₃ content / 2.53) ≦ ₃
The amount of Al ₂ O ₃ and MgO contained in the amount satisfying the above, and the magnesia-alumina-based spinel crystal phase containing a small amount of periclase crystal has a weight increase rate of 0.31 to 0.83. %, The weight gain is very small, and the grain state after the test is also good, indicating that they have excellent properties in digestion resistance. On the other hand, out of the range specified in the present invention, Al ₂ O ₃ and MgO are contained, and in the crystal phase of Comparative Example 1, which contains a large amount of periclase crystals, the weight change rate is low. 4.02%, which is extremely high, and after the test, cracks are observed on the grain surface, resulting in extremely poor digestion resistance as compared with those containing only a small amount of periclase crystals. I have.

Next, among the heat-treated particles shown in Table 2 above, the heat-treated particles at 1900 ° C. in Examples 1 to 3, which are zirconia-containing magnesia-alumina-based spinel clinkers having the characteristics of the present invention, And heat-treated particles at 1900 ° C. in Comparative Example 2, which are magnesia-alumina-based spinel clinker containing no, were pulverized to obtain pulverized materials. Then, using the crushed material and the sintered alumina crushed material as a general refractory material, they were respectively blended at a blending ratio and a particle size distribution as shown in Table 4 below,
Different refractory materials were obtained. Among those refractory materials, those obtained by using Examples 1 to 3 alone were used in Examples 4 to
6, and further, pulverized sintered alumina was added to Examples 1 and 3, respectively, and the obtained blended refractory materials were named Examples 7 and 8, respectively. Moreover, what was obtained by using Comparative Example 2 alone was referred to as Comparative Example 3, and further, pulverized sintered alumina was added to Comparative Example 2, and the obtained compounded refractory material was compared with Comparative Example 4. did.

[0047]

[Table 4]

Subsequently, a predetermined amount of a phenol resin was added as a binder to the thus obtained refractory material, and then each of them was subjected to an Amsler type pressure tester at a pressure of 1 ton / cm ² and 50 mmφ × 50 mmh cylindrical compacts were each produced. After that, the compacts were heated in a gas furnace at a heating temperature of 1900 ° C.
Each of them was subjected to a heat treatment for 30 minutes to obtain a heat-treated body as a refractory. Then, the apparent porosity of each of the refractory heat-treated bodies was measured. The results are shown in Table 5 below. The apparent porosity was measured by the same method as the method for measuring the apparent porosity of the clinker.

[0049]

[Table 5]

Further, in order to clarify the erosion resistance of these refractories to slag, the center of each refractory was cut out to a depth of 20 mm and a diameter of 10 mm, and a hole formed in this way. , A predetermined amount of slag having a chemical composition as shown in Table 6 below was charged, and a heat treatment was performed at 1600 ° C. for 2 hours in that state. Thereafter, the refractory is cut so as to bisect the hole into which the slag is charged, and the reaction state between the refractory and the slag, that is, the state of crack formation due to the erosion of the slag by the refractory and the refractory The average penetration depth of the slag was measured. Table 7 below shows the measurement results and the evaluation results for the reactivity with the slag determined from the measurement results. In addition, in the evaluation results of Table 7, ○ is good,
△ indicates acceptable, × indicates impermissible, and Δ and × indicate that the reactivity with slag is substantially poor.

[0051]

[Table 6]

[0052]

[Table 7]

As is apparent from the results shown in Tables 6 and 7, a magnesia alumina-based spinel clinker containing a predetermined amount of MgO and Al ₂ O ₃ and containing 0.5 to 20% by weight of ZrO ₂ was used as a refractory material. The refractory used as a refractory has an average slag penetration depth of only about ２ as compared with a refractory made of a refractory material containing no ZrO ₂ . That is, thereby, the refractory obtained using the zirconia-containing magnesia-alumina-based spinel clinker having the chemical composition defined in the present invention has superior characteristics in erosion resistance to slag as compared with those not containing ZrO _2. It has been proved to be effective.

[0054]

As is apparent from the above description, in the zirconia-containing magnesia alumina-based spinel clinker according to the present invention, MgO and Al ₂ O ₃ are represented by the following formulas:
0 <MgO content− (0.07 × ZrO ₂ content) −
(Al ₂ O ₃ content / 2.53) ≦ ₃ is satisfied, and since only a small amount of periclase crystal is contained in the magnesia-alumina-based spinel crystal phase, the thermal shock resistance is reduced. It can be efficiently increased, and the clinker particles can be advantageously prevented from collapsing due to the reaction between the periclase crystals and water. Thus, water can be added as a refractory material for obtaining a shaped refractory, of course. Thus, it can be used very advantageously as a refractory material for producing an amorphous refractory, which can obtain a refractory product having a desired shape. Moreover, in the clinker and the refractory, since ZrO ₂ is contained in a predetermined amount, excellent slag erosion resistance is advantageously secured without incurring a rise in cost. It is.

In the refractory according to the present invention,
Since such a characteristic zirconia-containing magnesia-alumina-based spinel clinker is used as a refractory material, as a refractory for steelmaking and steelmaking, excellent slag erosion resistance and thermal shock resistance, and further, Extremely good furnace workability could be exhibited at the same time.

In the clinker according to the present invention, the magnesia alumina spinel has an average crystal diameter of 10%.
By making a fine structure having an apparent porosity of not less than 20 μm in the range of μm or more, the erosion resistance of the refractory obtained using such a clinker to slag can be further improved. Yes, and ZrO ₂ crystals
By being made of tetragonal or cubic,
The spalling resistance can also be advantageously increased.

──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Kimito Nakamoto 4-11, Shiosagusa-cho, Seto-shi, Aichi Prefecture Inside and outside Ceramics Co., Ltd. (72) Eiichi Tanima 11-shiocho-cho, Seto-shi, Aichi 4. Inside and outside Ceramics Co., Ltd. (56) References JP-A-62-216961 (JP, A) JP-A-2-102167 (JP, A) (58) Fields investigated (Int. Cl. ⁶ , DB name) ) C04B 35/42-35/51 C04B 35/10

Claims (4)

(57) [Claims] 1. An Al ₂ O ₃ raw material, a MgO raw material, and a ZrO raw material.
Baking the mixture of the _two raw materials at a temperature of 1700 ° C to 1950 ° C
A clinker obtained by, is mainly composed of ZrO ₂ and MgO and Al ₂ O ₃ Prefecture, they three total content of the component 95 wt% or more, ZrO ₂ content of 0.5
20% by weight, and the following formula: 0 <MgO content−
(0.07 × ZrO ₂ content) − (Al ₂ O ₃ content /
2.53) The mask formed of a chemical composition satisfying ≤ 3
Gnesia alumina based spinel with average crystal of 10μm or more
A zirconia-containing magnesia alumina-based spinel clinker having a diameter and containing zirconia crystals in a magnesia-alumina-based spinel crystal phase containing a small amount of periclase crystals. 2. The method according to claim 1, wherein the apparent porosity is 20% or less.
2. A zirconia-containing magnesia alumina-based spinel clinker according to item 1. Wherein the zirconia crystal, zirconia-containing magnesia alumina spinel clinker according to claim 1 or claim 2 which is tetragonal or cubic. 4. An Al ₂ O ₃ raw material, a MgO raw material and ZrO
Baking the mixture of the _two raw materials at a temperature of 1700 ° C to 1950 ° C
A clinker obtained by, is mainly composed of ZrO ₂ and MgO and Al ₂ O ₃ Prefecture, they three total content of the component 95 wt% or more, ZrO ₂ content of 0.5
20% by weight, and the following formula: 0 <MgO content−
(0.07 × ZrO ₂ content) − (Al ₂ O ₃ content /
2.53) The mask formed of a chemical composition satisfying ≤ 3
Gnesia alumina based spinel with average crystal of 10μm or more
A refractory comprising a zirconia-containing magnesia-alumina-based spinel clinker having a diameter and containing zirconia crystals in a magnesia-alumina-based spinel crystal phase containing a small amount of periclase crystals as a refractory material.