Title of invention: Brick for blast furnace hearth, blast furnace hearth using the same, and method for manufacturing brick for blast furnace hearth
Technical field
[0001]
　The present invention relates to a blast furnace hearth brick used in a blast furnace hearth part (referring to a hearth part including a side wall and a furnace bottom below a tuyere in a blast furnace; the same shall apply hereinafter) and a brick used for the same. The present invention relates to a method for manufacturing a blast furnace hearth part and a brick for a blast furnace hearth part.
Background art
[0002]
　The blast furnace hearth mainly uses carbonaceous bricks with aggregates of graphite or alumina bricks with aggregates of alumina, but these blast furnace furnaces are one of the factors governing the furnace life. The wear of floor bricks can be mentioned.
[0003]
　For example, as the lining material (lining material) for the blast furnace hearth, carbonaceous bricks (blocks) are the mainstream, but for bricks with many carbon components, carbon melts into the hot metal when used in the blast furnace hearth. Easy to take out and poor hot metal resistance. Therefore, the cooling of the lining material from the outside of the furnace is strengthened to form a hot metal viscous layer on the working surface of the brick, and this hot metal viscous layer prevents carbon from leaching from the carbon brick into the hot metal. The sex is secured. However, such cooling from outside the furnace results in a large energy loss.
[0004]
　Therefore, alumina bricks mainly composed of alumina that hardly dissolves into hot metal have been used in recent years. In particular, sialon bonded alumina bricks containing β'-sialon represented by the chemical formula Si 6-Z Al Z O Z N 8-Z in the matrix portion contain almost no carbon, so they have excellent hot metal resistance and are also suitable for use in blast furnaces. Excellent corrosion resistance (slag resistance) against slag generated in
[0005]
　For example, Patent Document 1, the matrix portion (bound substrate) (chemical formula: Si of β'- sialon Z value 6-Z Al Z O Z N 8-Z refers to a Z value in.) Of 0.5 to Sialon bonded alumina bricks containing 12 to 45% by weight of 4 β′-sialon are disclosed. However, in the sialon bond alumina brick of Patent Document 1, since the Si in β′-sialon contained in the matrix portion gradually melts into the hot metal, the wear of the brick proceeds and the hot metal resistance is not sufficient.
[0006]
　Accordingly, an aluminum compound bonded brick having an aluminum compound as a connective structure has been developed as a brick not containing Si in the matrix portion.
[0007]
　For example, in Patent Document 2, the brick structure is composed of a crystalline phase and an amorphous phase. The crystalline phase is 80 to 98% by mass of corundum, and 1 to 18% by mass of aluminum nitride crystals and / or aluminum oxycarbide crystals. %, An amorphous phase is 0.5 to 10% by mass, and an aluminum compound-bonded brick for a blast furnace hearth having an Si content of 3% by mass or less is disclosed. Further, it is disclosed that a refractory having a connective structure of aluminum nitride or aluminum oxycarbide (mainly Al 2 OC or Al 4 O 4 C) is excellent in hot metal resistance.
[0008]
　However, since the aluminum compound bonded brick for the blast furnace hearth of Patent Document 2 contains aluminum nitride or aluminum oxycarbide, the moisture during the cutting of the brick, the moisture in the mortar during construction, or during storage There is a problem inferior in hydration resistance that these are easily hydrated by moisture in the air. Moreover, the slag resistance was still insufficient.
[0009]
　On the other hand, Example 3 of Patent Document 3 discloses an aluminum compound bonded brick containing AlON as corundum, aluminum nitride, and aluminum oxynitride. And, as a method for producing this brick, it is disclosed that a molded body of a composition composed of aluminum powder and refractory raw material powder is put into a sealable container and fired in a state in which the container is filled with silicon nitride particles. Yes. At this time, since oxygen derived from the air coexists in the firing atmosphere, aluminum oxynitride is also generated in addition to aluminum nitride. That is, it is disclosed that aluminum oxynitride is simultaneously generated and precipitated in addition to aluminum nitride through a gas phase reaction in accordance with the nitrogen partial pressure and oxygen partial pressure in the firing atmosphere.
[0010]
　In the aluminum compound-bonded brick obtained by the manufacturing method of Patent Document 3, aluminum oxynitride is generated by oxidation of aluminum nitride as a by-product of aluminum nitride, and aluminum oxynitride is preferentially generated. It is difficult and the amount of production is small. The brick of Example 3 has an X-ray diffraction peak intensity of AlN of 800 versus AlON of 200, and the ratio of AlON is low. For this reason, although the hot metal resistance and the slag resistance have been improved, further improvements are desired. In addition, aluminum nitride is easily hydrated, and when its content is high, there is a problem of hydration resistance described above.
[0011]
　In other words, after the blast furnace was newly built, it has been used for 15-20 years recently, and the blast furnace hearth cannot be repaired. Improvement of slag resistance and hot metal resistance is desired.
Prior art documents
Patent Literature
[0012]
Patent Document 1: Japanese Patent Publication No. Hei 6-502140 (Patent No. 3212600)
Patent Document 2: International Publication No. 2009/72652
Patent Document 3: Patent No. 4245122
Summary of the Invention
Problems to be solved by the invention
[0013]
　The problem to be solved by the present invention is to provide a brick for a blast furnace hearth with excellent hydration resistance and improved hot metal resistance and slag resistance, and further to improve the life of the blast furnace hearth. .
Means for solving the problem
[0014]
　The present inventor considers that the structure of the matrix part has a great influence on the hot metal resistance and the slag resistance in a brick having an aluminum compound for the blast furnace hearth as a connective structure, and pays attention to the improvement of the matrix part. Various experiments were conducted. As a result, it was found that the oxynitride of aluminum as the matrix structure is much more excellent in slag resistance and hot metal resistance than aluminum nitride and aluminum oxycarbide, and also in hydration resistance.
[0015]
　That is, the gist of the present invention is as follows.
(1) It
　contains 47 to 92% by mass of corundum and 7 to 50% by mass of oxynitride of aluminum, the total amount thereof is 84% ​​by mass or more, and
　the content of carbonaceous raw material is 10% by mass Or less (not including 0), the content of aluminum nitride is 3% by mass or less (including 0), and the total content of AlN polymorphic sialon, β′-sialon, and silicon nitride is 3% by mass or less (0 And a
　brick for a blast furnace hearth part containing 7% by mass or more of the aluminum oxynitride in the matrix part.
(2) It
　contains 47 to 92% by mass of corundum and 7 to 50% by mass of oxynitride of aluminum, and the total amount thereof is 94% by mass or more
　and contains no carbonaceous raw material. the content of 3 mass% or less (including 0), AlN polymorph sialon, beta .'- sialon, and the content of silicon nitride is 3% by mass or less in total (including 0),
　further to the matrix portion A brick for a blast furnace hearth containing 7 mass% or more of the aluminum oxynitride.
(3)
　A blast furnace hearth part lined with the brick for a blast furnace hearth part according to (1) or (2).
(4)
　A: Mass ratio (A / B) of calcined alumina having an average particle diameter of 10 μm or less and / or an alumina precursor having an average particle diameter of 10 μm or less to metallic aluminum having a particle diameter of 0.1 mm or less is 0.4 to 7 .6 is a refractory raw material composition containing 6 to 38% by mass of a mixture and 62 to 94% by mass of an alumina raw material excluding calcined alumina. A method for producing a brick for a blast furnace hearth, which is fired at 1300 to 1800 ° C.
(5)
　50 to 87% by mass of alumina material excluding calcined alumina, 5 to 30% by mass of calcined alumina having an average particle size of 10 μm or less, and 7% of aluminum oxynitride having a particle size of 0.1 mm or less A method for producing a brick for a blast furnace hearth, comprising adding a binder to a refractory raw material composition containing ˜50% by mass, kneading and molding, followed by firing at 1300 to 1600 ° C. in a nitrogen atmosphere.
(6) The
　method for producing a brick for a blast furnace hearth according to (4) or (5), wherein the refractory raw material composition contains 1 to 10% by mass of scaly graphite having a particle size of 0.2 mm or less.
[0016]
　Details of the present invention will be described below.
[0017]
　The structure of the blast furnace hearth brick of the present invention (hereinafter also simply referred to as “the brick of the present invention”) includes an aggregate part composed of aggregates, and a matrix part that is a connective structure that connects the aggregates together. Consists of. And as shown in FIG. 1, an aggregate is a particle | grain exceeding 0.1 mm, and a matrix part is a part of the structure | tissue where the particle | grains below 0.1 mm which exist between aggregates and an aggregate are continuous.
[0018]
　In the brick of the present invention, the matrix part is mainly composed of only aluminum oxynitride or aluminum oxynitride and corundum, and the aggregate part is mainly composed of only corundum or corundum and aluminum oxynitride. Yes. Here, “aluminum oxynitride” is a range from AlON / x = 0.22 to 2Hδ / x = 6 in the Si 3 N 4 —AlN—Al 2 O 3 —SiO 2 system composition diagram of FIG. Refers to the composition contained in That is, in the present invention, these are called aluminum oxynitrides. AlON / x is Al (8 + X) / 3 O (4-X) N X , and 2Hδ / x is Si (6-X) Al (16 + X) O X N (24-X) . In the present invention, the AlON solid solution means a composition included in the range of AlON / x = 0.22 to AlON / x = 0.57 in FIG.
[0019]
　Since the oxynitride of aluminum has higher slag resistance than corundum, the slag resistance is increased by being present in the matrix portion where the slag is more easily penetrated than the aggregate portion. Specifically, in the brick of the present invention, aluminum oxynitride is contained in the matrix part in an amount of 7% by mass or more. When it is less than 7% by mass, the slag resistance is insufficient. Aluminum oxynitride is not adversely affected even if it is contained in the aggregate part, and can be contained in the aggregate part up to about 15% by mass.
[0020]
　In the brick of the present invention, the total content of aluminum oxynitride is 7 to 50% by mass. If it is less than 7% by mass, the slag resistance is insufficient, and if it exceeds 50% by mass, the hot metal resistance is insufficient.
[0021]
　Corundum is mainly contained in the aggregate part because it has excellent hot metal resistance, but a part of the corundum may be contained in the matrix part without any problem. When the corundum is less than 47% by mass, the hot metal resistance becomes insufficient, and when it exceeds 92% by mass, the oxynitride of aluminum becomes relatively insufficient, so that the slag resistance becomes insufficient.
[0022]
　Furthermore, in the brick of the present invention, the total amount of corundum and aluminum oxynitride is 84% ​​by mass or more when containing carbonaceous raw materials such as scaly graphite, calcined anthracite, coke, and pitch, In the case where no carbonaceous raw material is contained in order to improve the hot metal resistance, the content can be 94% by mass or more. When the total amount of corundum and aluminum oxynitride is less than 84% by mass, the corrosion resistance (slag resistance) required for practical use cannot be obtained. Components other than corundum and aluminum oxynitride include an amorphous phase mainly composed of Al 2 O 3 that cannot be quantitatively measured by X-ray measurement . Furthermore, a small amount of aluminum nitride or AlN polymorphic sialon can be included to assist slag resistance or as a by-product during production.
[0023]
　In the brick of the present invention, aluminum nitride is effective for increasing the slag resistance, but it is better not to contain it because the hydration resistance is lowered. However, if it is 3% by mass or less, the adverse effect of hydration resistance can be minimized.
[0024]
　In the brick of the present invention, AlN polymorphic sialon, β′-sialon, and silicon nitride are preferably not contained because they are easily dissolved in the molten iron, but are acceptable if the total amount is 3% by mass or less. The AlN polymorphic sialon is a Si—Al—O—N solid solution, and in the Ramsdell notation, the 2Hδ type, 27R type, 21R type, 12H type, 15R type and 8H type are listed in ascending order of Si content. There are six types.
[0025]
　In the brick of the present invention, when priority is given to hot metal resistance such as when lining to a part that does not come into contact with slag even in the blast furnace hearth, carbonaceous raw materials such as scaly graphite, calcined anthracite, coke, and pitch are in the hot metal. It is better not to contain it because it dissolves easily. On the other hand, when priority is given to slag resistance, such as when lining the part in contact with the slag, carbonaceous raw materials such as scaly graphite, calcined anthracite, coke, pitch, etc. are 10 masses for the purpose of improving slag resistance. % Or less. In particular, by containing 1 to 10% by mass of scaly graphite having a particle size of 0.2 mm or less, the slag resistance can be improved without causing a decrease in the hot metal resistance. The “part not in contact with the slag” is specifically the part below the tap hole in the blast furnace hearth, and the “part in contact with the slag” is specifically the part in the blast furnace hearth. It is an upper part including a fistula.
[0026]
　The brick of the present invention as described above can significantly extend the durability of the blast furnace by lining the blast furnace hearth.
[0027]
　Next, the manufacturing method of the brick of this invention is demonstrated.
　There are two methods of manufacturing the brick of the present invention. That is, a first production method in which alumina and aluminum nitride produced by nitriding metal aluminum react to produce aluminum oxynitride, and a second production using aluminum oxynitride as a raw material from the beginning Is the method.
[0028]
　In the manufacturing method disclosed in Patent Document 3, aluminum oxynitride is obtained by a gas phase reaction by heat-treating metallic aluminum in a mixed atmosphere containing nitrogen and oxygen. Therefore, the crystal form of the obtained aluminum oxynitride has a feather shape, a needle shape, or a whisker shape, and it is difficult to obtain an aluminum oxynitride having a dense structure. In contrast, in the first production method of the present invention, an aluminum oxynitride having a dense structure is obtained by heat-treating active calcined alumina or a mixture of an alumina precursor and metallic aluminum in a nitrogen atmosphere. Can do.
[0029]
　That is, the calcined alumina used for the refractory raw material composition in the first production method of the present invention reacts with aluminum nitride formed by nitriding metal aluminum to produce aluminum oxynitride, and the particle size The smaller the is, the higher the activity is and the higher the rate of formation of aluminum oxynitride. Therefore, in the first production method of the present invention, the average particle size of the calcined alumina is 10 μm or less. If the average particle size of the calcined alumina exceeds 10 μm, the reactivity with aluminum nitride is lowered, so the proportion of aluminum oxynitride formed is low, and conversely the proportion of aluminum nitride is high, so the hydration resistance is high. It will be insufficient. Like the calcined alumina having an average particle size of 10 μm or less, an alumina precursor having an average particle size of 10 μm or less can be used alone or in combination with the calcined alumina having an average particle size of 10 μm or less. Here, the “average particle diameter” means the particle diameter when the relationship between the particle diameter measured by a laser diffraction / scattering particle size distribution meter and the mass ratio is plotted on a graph and the mass integrated ratio reaches 50%.
[0030]
　Moreover, in order to make activity high like the above-mentioned, the particle size of the metal aluminum used for a refractory raw material compound shall be 0.1 mm or less. Here, “particle size” refers to a sieve mesh, and a particle size of 0.1 mm or less refers to a material that has passed through a sieve mesh of 0.1 mm.
[0031]
　In the first production method, the present inventor found that Al 4 O 6 / Al 4 N 4 is 18/82 to 80/20 from the Si 3 N 4 —AlN—Al 2 O 3 —SiO 2 system composition diagram of FIG. In this range, the production ratio of aluminum oxynitride was considered to be high. And these ratios are raw materials used in the refractory raw material composition, that is, A: calcined alumina having an average particle size of 10 μm or less and / or calcined alumina precursor having an average particle size of 10 μm or less, and B: particle size of 0.1 mm or less. The mass ratio A / B was 0.4 to 7.6 in terms of metal aluminum. When the mass ratio A / B is less than 0.4, the amount of metallic aluminum becomes excessive, so that the amount of free aluminum nitride in the brick becomes too large, resulting in a problem of hydration resistance, and when the amount of metallic aluminum added is large. Is difficult to obtain a sufficient density during molding. On the other hand, if the mass ratio A / B exceeds 7.6, the proportion of aluminum oxynitride becomes small and the slag resistance becomes insufficient.
[0032]
　In the first production method, A in the refractory raw material composition: A: calcined alumina having an average particle size of 10 μm or less and / or alumina precursor having an average particle size of 10 μm or less, and B: metallic aluminum having a particle size of 0.1 mm or less. If the total amount (mixture amount) is less than 6% by mass, the oxynitride of aluminum in the matrix part will be insufficient and the slag resistance will be insufficient, and if it exceeds 38% by mass, the matrix part will be too much and the hot metal resistance will be increased. Is insufficient.
[0033]
　The alumina raw material excluding the calcined alumina is used for constituting the aggregate part and matrix part of the brick. Specifically, it is used in the range of 62 to 94% by mass in the first production method.
[0034]
　Next, the second manufacturing method will be described.
　The second manufacturing method uses a sintered bond (bonding) in which the matrix portion contains aluminum oxynitride by using calcined alumina having an average particle size of 10 μm or less and aluminum oxynitride having a particle size of 0.1 mm or less. Therefore, the structure is excellent in hydration resistance and has improved hot metal resistance and slag resistance. Furthermore, by using aluminum oxynitride as a raw material, a brick in which aluminum oxynitride is uniformly contained from the surface layer to the central portion can be produced even with a thick large brick having a thickness of 200 mm to 300 mm.
[0035]
　The aluminum oxynitride used for the refractory raw material composition in the second production method has a particle diameter of 0.1 mm or less in order to be present in the matrix portion.
　In addition, since the aluminum oxynitride used in the refractory raw material composition in the second production method does not change during firing, the ratio of the brick after firing and the ratio in the refractory raw material composition are almost the same. Use the necessary amount of bricks. More specifically, the ratio in the refractory raw material mixture is 7 to 50% by mass. If the amount is less than 7% by mass, the obtained brick has insufficient slag resistance, and if it exceeds 50% by mass, the hot metal resistance becomes insufficient.
[0036]
　In the second production method, calcined alumina having an average particle size of 10 μm or less is used in an amount of 5 to 30% by mass in order to form the matrix portion. If it is less than 5% by mass, the connective structure of the matrix portion is not developed, so that the brick has low strength. If it exceeds 30% by mass, the slag resistance becomes insufficient.
　The alumina raw material excluding the calcined alumina is used for constituting the aggregate part and matrix part of the brick. Specifically, it is used in the range of 50 to 87% by mass or less.
[0037]
　In the first and second production methods, carbonaceous raw materials such as scaly graphite, calcined anthracite, coke, and pitch can be used at 10% by mass or less for the purpose of improving slag resistance. In particular, when scaly graphite having a particle size of 0.2 mm or less is used in the range of 1 to 10% by mass, the slag resistance can be improved without causing a decrease in hot metal resistance.
[0038]
　On the other hand, in the first production method, when metal silicon powder is contained in the refractory raw material composition, AlN polymorphic sialon is more preferentially produced than aluminum oxynitride or aluminum nitride, and hot metal resistance is insufficient. Become. Further, in the second manufacturing method, silicon nitride is generated and the hot metal resistance is still insufficient. Therefore, in the production method of the present invention, it is preferable to use a refractory raw material composition containing no metal silicon, but it is acceptable if it is 2% by mass or less.
[0039]
　Further, a small amount of SiO in the alumina material or carbonaceous material excluding the calcined alumina used in refractory raw material formulation in the first and second production method 2 SiO are contained, in these raw materials 2 Since the Si component derived from is melted into the hot metal, the hot metal resistance is lowered. For this reason, it is best that there is no Si component in the refractory raw material composition, but it is preferable to keep it to 3% by mass or less, preferably 1% by mass or less. If it is this range, since the bad influence which has on slag resistance and hot metal resistance is small, it can also be used.
[0040]
　Further, in the first and second production methods, in addition to the above-mentioned raw materials, mullite, silicon nitride , silicon carbide, titanium oxide, chromium oxide, etc. are 7% by mass or less as an aggregate having a particle size exceeding 0.1 mm and When the Si component in the refractory raw material composition is 3% by mass or less, preferably 1% by mass or less, it can be used because there is little adverse effect on the slag resistance and hot metal resistance.
[0041]
　The brick for the blast furnace hearth of the present invention is obtained by adding a binder to the refractory raw material composition as described above, kneading and molding, followed by 1300 ° C. to 1800 ° C. in the first production method in a nitrogen atmosphere. In this production method, it is obtained by firing at 1300 ° C. to 1600 ° C. Note that the aluminum nitride contained in the brick after firing may become excessive if the firing temperature is too low. In this case, the reaction between aluminum nitride and alumina is promoted by increasing the firing temperature, so that unreacted nitride Aluminum can be reduced or eliminated.
　In the first production method, if the firing temperature is lower than 1300 ° C., the formation of aluminum oxynitride is insufficient, the effect of improving the hot metal resistance and slag resistance cannot be obtained, and the water resistance is also inferior. Become. The upper limit of the firing temperature is 1800 ° C., and if this temperature is exceeded, the oxynitride grain growth of aluminum proceeds excessively, resulting in a decrease in brick density or mechanical strength. The result is an unfavorable brick.
　In the second production method, if the firing temperature is lower than 1300 ° C., the calcined alumina is not sufficiently sintered, and the effect of improving the hot metal resistance and slag resistance cannot be obtained. The upper limit of the firing temperature is 1600 ° C., and if this temperature is exceeded, sintering of the calcined alumina proceeds excessively and grain growth occurs, thereby impairing the denseness. Furthermore, since aluminum oxynitride also causes grain growth and partial decomposition, high corrosion resistance is impaired as a result.
Effect of the invention
[0042]
　Since the brick of the present invention is excellent in hydration resistance, hot metal resistance, and slag resistance, the life of the blast furnace hearth can be improved.
Brief Description of Drawings
[0043]
FIG. 1 is an example of a structure photograph of a brick for a blast furnace hearth according to the present invention.
FIG. 2 is a composition diagram of Si 3 N 4 —AlN—Al 2 O 3 —SiO 2 system.
BEST MODE FOR CARRYING OUT THE INVENTION
[0044]
　The calcined alumina having an average particle size of 10 μm or less used for the refractory raw material composition in the present invention is a highly specific alumina having a high specific surface area, and is sometimes referred to as easily sinterable alumina, but is generally commercially available. You can use what you have. An alumina precursor having an average particle size of 10 μm or less is an aluminum compound that generates aluminum oxide when heated in a nitrogen atmosphere, such as pseudoboehmide type aluminum hydroxide, γ alumina, aluminum alkoxide, and the like. .
[0045]
　Moreover, as an alumina raw material except calcination alumina, 1 or more types can be used among electrofused alumina, a sintered alumina, bauxite, and a banquet, for example. However, since the hot metal resistance is improved as the content of SiO 2 is smaller, an alumina material having a content of SiO 2 of 1% by mass or less, more preferably 0.5% by mass or less is preferably used. In addition, the Al 2 O 3 purity is preferably 90% by mass or more, more preferably 98% by mass or more from the viewpoint of hot metal resistance.
[0046]
　In the present invention, the metallic aluminum having a particle size of 0.1 mm or less used for the refractory raw material composition can be used without any problem as long as it is usually in the form of powder used for the refractory. Powdered aluminum is commercially available in atomized powder and flake powder due to the difference in its production method. Either one can be used in the present invention.
[0047]
　In the present invention, as the carbonaceous raw material for further improving the slag resistance, scaly graphite, calcined anthracite, coke, pitch and the like can be used alone or in combination. Here, the carbonaceous raw material does not include an organic binder such as a phenol resin or tar used as a binder.
[0048]
　As the scaly graphite, those generally used as raw materials for refractories can be used, and those having a particle size of 0.2 mm or less are used. As described above, “particle size” means a sieve mesh, and a particle size of 0.2 mm or less means a material that has passed through a 0.2 mm mesh. A pulverized product can also be used.
[0049]
　As the oxynitride of aluminum having a particle size of 0.1 mm or less used for the refractory raw material composition in the present invention, in the Si 3 N 4 —AlN—Al 2 O 3 —SiO 2 system composition diagram (FIG. 2), One having a composition within the range of AlON / x = 0.22 to 2Hδ / x = 6, specifically, having a crystal phase such as AlON solid solution, 3Al 2 O 3 .AlN , Al 2 O 3 .AlN And a mixture thereof can be used without any problem. Further, the ratio of these crystal phases is preferably 95% by mass or more and the Si component content is preferably 1% by mass or less.
　The aluminum oxynitride may be one produced by a known production method. For example, an AlON solid solution composition and Al 2 O 3 synthesized by a nitriding reaction between metallic aluminum and calcined alumina or an alumina precursor. · AlN phase, 2Al 2 O 3 can be used which consist · AlN phase.
[0050]
　When the brick for a blast furnace hearth of the present invention is used (lining) for a blast furnace hearth, it can be used in combination with a conventional carbon brick or entirely replaced. Specifically, it can be applied to the side wall or the bottom of the furnace below the tuyere.
Example
[0051]
　In each case, the bricks were added to the refractory raw material blends shown in Tables 1 and 2 with an appropriate amount of a resol-type phenol resin as a binder and kneaded, and an oil press produced a JIS regular brick-shaped compact. 250 After heat treatment at ° C., it was obtained by firing at 1400 ° C. in a nitrogen stream.
[0052]
　Fused alumina used in the refractory raw material formulation Al 2 O 3 is 98 mass% or more, SiO 2 but is less 0.5 wt%, calcined alumina Al 2 O 3 is 98 mass% or more, SiO 2 Is 0.5% by mass or less, scaly graphite is natural scaly graphite having C of 95% by mass or more, and metal aluminum is a flake type having a particle size of 74 μm or less. AlN was a commercial product with a purity of 98% or more, and AlN polymorph sialon was used as 27R type synthesized in advance by a reactive sintering method. The aluminum oxynitride used was an AlON solid solution composition synthesized by nitriding reaction between metallic aluminum and calcined alumina and an Al 2 O 3 .AlN phase. The purity of each mineral composition was 95%, and the content of Si component was less than 1% by mass.
[0053]
　The resulting brick was analyzed for mineral composition, measured for apparent porosity and compressive strength, and evaluated for slag resistance, hot metal resistance and hydration resistance. The apparent porosity was measured according to JIS-R2205, and the compressive strength was measured according to JIS-R2206. Mineral species were quantified using X-ray diffraction and chemical analysis. Although the total amount was not 100% by mass in the mineral composition, the balance was an amorphous phase mainly composed of Al 2 O 3 that could not be quantitatively measured by X-ray .
[0054]
　For slag resistance and hot metal resistance, blast furnace slag and pig iron were induction-heated and melted and adjusted to 1600 ° C, and the test brick with a square bar shape of 20 x 20 x 180 mm was eroded for 5 h to reduce the erosion thickness. It was measured and evaluated by an erosion damage index with the erosion thickness of the brick of Comparative Example 5 being 100. Specifically, the hot metal resistance was measured by the erosion thickness of the hot metal immersion part, and the slag resistance was measured by measuring the erosion thickness of the maximum wear part of the slag-hot metal boundary part. It was evaluated with. The smaller the erosion damage index, the better the hot metal resistance and slag resistance.
[0055]
　Regarding hydration resistance, a 10 × 10 × 10 mm sample was cut out from a JIS standard test brick, immersed in 200 ml of room temperature water, the pH was measured, and the amount of ammonia gas generated from the pH after 24 hours was calculated. Then, the ammonia gas amount of Comparative Example 4 was set as 100 and displayed as an index. The smaller the index, the better the hydration resistance.
[0056]
[table 1]

[0057]
[Table 2]

[0058]
　Example 1 is a solid solution of AlON as an aluminum oxynitride, Example 2 is Al 2 O 3 .AlN as an aluminum oxynitride, and Example 3 is 2Hδ / x = 6 as an aluminum oxynitride. It is contained in a 15% by mass matrix part and is excellent in slag resistance, hot metal resistance, and hydration resistance. In Example 4, the total amount of AlON solid solution and Al 2 O 3 .AlN as aluminum oxynitride was 15% by mass. In Example 5, Al 2 O 3 .AlN and 2Hδ / x = 6 is contained in a total of 15% by mass in the matrix portion, and is excellent in slag resistance, hot metal resistance, and hydration resistance.
[0059]
　Further, Example 6 is an example including aluminum oxynitride in a 7 mass% matrix portion, and Example 7 is an example including aluminum oxynitride in a 50 mass% matrix portion. Is also excellent in slag resistance, hot metal resistance, and hydration resistance.
[0060]
　On the other hand, in Comparative Example 1, the oxynitride of aluminum is 4% by mass, which is lower than the lower limit value of the present invention, and the slag resistance is greatly reduced. Further, in Comparative Example 2, the aluminum oxynitride is 60% by mass, which exceeds the upper limit of the present invention, and the hot metal resistance is lowered.
[0061]
　Example 8 is an example containing 3% by mass of AlN polymorphic sialon, but is excellent in slag resistance, hot metal resistance, and hydration resistance. On the other hand, Comparative Example 3 was an example containing 4% by mass of AlN polymorphic sialon, which resulted in poor hydration resistance.
[0062]
　Examples 9 and 10 contain 2% by mass and 3% by mass of aluminum nitride, respectively, but are excellent in slag resistance, hot metal resistance, and hydration resistance. On the other hand, Comparative Example 4 contained 4% by mass of aluminum nitride, resulting in poor hydration resistance. In addition, Example 9, Example 10, and Comparative Example 4 were manufactured by firing at a lower temperature than other Examples and Comparative Examples in order to leave unreacted aluminum nitride.　
[0063]
　Example 11 contains scaly graphite and exhibits good slag resistance.
[0064]
　In Comparative Example 5, A: mass ratio A / B of A: alumina having an average particle diameter of 10 μm or less and / or an alumina precursor having an average particle diameter of 10 μm or less and B: metallic aluminum having a particle diameter of 0.1 mm or less is 0.25. And lower than the lower limit value of the present invention, and 5% by mass of aluminum nitride is contained, so that the hydration resistance is lowered.
[0065]
　In Comparative Example 6, the mass ratio A / B is 10 which exceeds the upper limit of the present invention, and the slag resistance is reduced.
[0066]
　Example 12 is an example in which γ-alumina having an average particle diameter of 5 μm is used as an alumina precursor, and Example 13 is an example in which aluminum hydroxide having an average particle diameter of 5 μm is used as an alumina precursor. It has slag resistance, hot metal resistance, and hydration resistance equivalent to or better than when used. On the other hand, Comparative Example 7 is an example using calcined alumina having an average particle diameter of 20 μm, and the amount of aluminum oxynitride produced is as small as 5% by mass.
[0067]
　Example 14 is an example in which an AlON solid solution is used as a raw material as an oxynitride of aluminum, and the result is equivalent to or better than that of Example 1 with respect to slag resistance, hot metal resistance, and hydration resistance.
　Example 15 is an example in which Al 2 O 3 .AlN is used as a raw material as an oxynitride of aluminum , and the result is equivalent to or better than that of Example 2 with respect to slag resistance, hot metal resistance, and hydration resistance. ing.
[0068]
　Comparative Example 8 was fired in a container filled with silicon nitride grains and coke grains, and a large amount of aluminum nitride was produced, resulting in reduced hydration resistance. Comparative Example 9 was fired in a container filled with silicon nitride grains and coke grains without using calcined alumina having an average grain size of 10 μm or less, and the production ratio of aluminum nitride relative to the amount of metal aluminum used was Further, the hydration resistance is lowered.
The scope of the claims
[Claim 1]
　It contains 47 to 92% by mass of corundum and 7 to 50% by mass of aluminum oxynitride, the total amount of which is 84% ​​by mass or more, and
　the content of the carbonaceous raw material is 10% by mass or less (0 ), Aluminum nitride content is 3% by mass or less (including 0), AlN polymorphic sialon, β′-sialon, and silicon nitride content is 3% by mass or less (including 0) , and the
　further matrix unit, blast furnace floor bricks containing oxynitride of the aluminum 7% by mass or more.
[Claim 2]
　Contains 47 to 92% by mass of corundum and 7 to 50% by mass of aluminum oxynitride, the total amount of which is 94% by mass or more,
　contains no carbonaceous raw material, and contains aluminum nitride Is 3% by mass or less (including 0), and the total content of AlN polymorphic sialon, β′-sialon, and silicon nitride is 3% by mass or less (including 0), and the
　aluminum is contained in the matrix portion. Brick for blast furnace hearth containing 7% by mass or more of oxynitride.
[Claim 3]
　A blast furnace hearth part lined with a brick for a blast furnace hearth part according to claim 1 or 2.
[Claim 4]
　A: Mass ratio (A / B) of calcined alumina having an average particle diameter of 10 μm or less and / or an alumina precursor having an average particle diameter of 10 μm or less to metallic aluminum having a particle diameter of 0.1 mm or less is 0.4 to 7 .6 is a refractory raw material composition containing 6 to 38% by mass of a mixture and 62 to 94% by mass of an alumina raw material excluding calcined alumina. A method for producing a brick for a blast furnace hearth, which is fired at 1300 to 1800 ° C.
[Claim 5]
　50 to 87% by mass of alumina material excluding calcined alumina, 5 to 30% by mass of calcined alumina having an average particle size of 10 μm or less, and 7 to 50% by mass of oxynitride of aluminum having a particle size of 0.1 mm or less A method for producing a brick for a blast furnace hearth, comprising adding a binder to a refractory raw material composition containing 50%, kneading and molding, followed by firing at 1300 to 1600 ° C. in a nitrogen atmosphere.
[Claim 6]
　The method for producing a brick for a blast furnace hearth according to claim 4 or 5, wherein the refractory raw material composition contains 1 to 10% by mass of scaly graphite having a particle size of 0.2 mm or less.