Shrinkable refractory material, method for manufacturing the same, and refractory lining structure for blast furnace tuyeres

Abstract

To provide a shrinkable refractory having strength that can withstand the load of an upper refractory without being deformed even without using a support material at room temperature, and compressible against the load newly applied by thermal expansion (thermal stress load) in a high-temperature state in operation, and to provide a refractory lining structure of a blast furnace tuyere part.SOLUTION: A compressible refractory contains a refractory material comprising a total of 30-70 mass% of inorganic particles, at least partially containing silicon carbide particles, and a total of 30-70 mass% of alumina-based or silica-based inorganic fibers, and a pasting agent. The compressible refractory is a plate-like molded article having a laminated structure in which inorganic particles 12 are embedded in a void of a mesh-like framework intertwined with inorganic fibers 13, and comprises 30 mass% or more and 65 mass% or less of Al2O3 component, 25 mass% or more and 50 mass% or less of SiC component, and has a room-temperature compressive strength of 0.5 MPa or more.SELECTED DRAWING: Figure 5

Description

Technical Field

[0001] The present invention relates to a shrinkable refractory used for a blast furnace tuyere section, a method for manufacturing the same, and a refractory lining structure of a blast furnace tuyere section including the shrinkable refractory.

Background Art

[0002] Fig. 1 shows a refractory lining structure of a general blast furnace tuyere section (hereinafter, also simply referred to as "tuyere section structure"). The blast furnace tuyere section exists over the entire circumference (360 degrees) in the circumferential direction of the blast furnace, and the number of tuyeres varies depending on the size of the furnace body, but there are 20 to 40 tuyeres. Figs. 1(a), (b), and (c) show a front view, an A-A' sectional view, and a B-B' sectional view of the tuyere section structure, respectively, as viewed from the inside of the furnace. The tuyere section structure is a structure constructed between the upper tuyere refractory or cooling panel 3 and the lower tuyere refractory 4 such that the tuyere refractory 1 covers the tuyere cooling device 2. The tuyere refractory 1 is generally divided into upper and lower stages centered on the tuyere, and is composed of an upper tuyere refractory 1.a and a lower tuyere refractory 1.b.

[0003] During the operation of the blast furnace tuyere section, upward thrust due to the thermal expansion of the lower tuyere refractory 4 occurs, and damage to the cooling panel 3 and leakage of furnace gas due to gaps caused by the upward thrust have been problems. In Patent Document 1, in order to mitigate the upward thrust, as shown in Fig. 1, a design is made in which a shrinkable mortar 5, which is a monolithic refractory, is filled between the tuyere cooling device 2 and the tuyere refractory 1 to absorb the expansion of the lower tuyere refractory 4.

[0004] This shrinkable mortar is also called cushion mortar. Patent Document 1 discloses a monolithic refractory that achieves both slag resistance and shrinkability by blending silicon carbide powder, which has excellent slag resistance, to prevent infiltration of molten slag in the vicinity of the tuyere. The shrinkable mortar is inserted into joints for the purpose of absorbing thermal expansion when the molten metal container receives heat and is constructed.

[0005] In the structure of Patent Document 1, shrinkable mortar 5 is applied only between the tuyere refractory 1 and the tuyere cooling device 2. Therefore, although it can be expected to mitigate the uplift phenomenon between the tuyere refractory 1 and the tuyere cooling device 2, it cannot absorb the expansion at the point where the upper tuyere refractory 1.a and the lower tuyere refractory 1.b are in direct contact. Thus, the structure of Patent Document 1 is not a structure that can absorb the expansion around the entire circumference of the blast furnace tuyere and cannot completely suppress the uplift of the tuyere refractory 1. Therefore, gaps tend to occur, especially at the top of the blast furnace tuyere, and it has been a problem that these gaps must be filled from the outside with press-fitting material or the like to prevent the leakage of furnace gas during the initial operation period after blast furnace renovation work. In addition, in recent blast furnaces, it is common to introduce a cooling plate to the bell-shaped section above the tuyere in order to prevent the disappearance of the bell-shaped refractory. The cooling plate is a water-cooled structure and is fixed to the steel shell. Therefore, in conventional lining structures using cushion mortar, there is a risk of deformation and damage to the cooling plate when the refractory material 4 at the bottom of the tuyeres undergoes thermal expansion. Consequently, a structure is needed that can absorb the thermal expansion of the refractory material throughout the entire blast furnace tuyeres.

[0006] To suppress the upward thrust of the entire blast furnace tuyere, Patent Document 2 proposes a structure in which a shrinkable refractory 9 is installed not only on the contact surface between the tuyere refractory 1 and the tuyere cooling device 2, but also around the entire circumference of the refractory material constituting the blast furnace tuyere, as shown in Figures 2 and 3. Specifically, in Figure 2, the shrinkable refractory 9 is introduced between the lower tuyere refractory 1.b and the lower tuyere refractory 4, and in Figure 3, it is introduced between the upper tuyere refractory 1.a and the lower tuyere refractory 1.b, and the shrinkable refractory 9 is applied around the entire circumference to absorb the thermal expansion of the blast furnace tuyere. Since these shrinkable refractory materials 9 are introduced as mortar made by mixing water and refractory powder, their strength during construction is low. Therefore, to prevent deformation by the load of the refractory material built on top during construction, the refractory material above the shrinkable refractory 9 is supported by a support material 10 during construction. [Prior art documents] [Patent Documents]

[0007] [Patent Document 1] Japanese Patent Publication No. 2007-291415 [Patent Document 2] Japanese Patent Publication No. 2019-167599 [Overview of the Initiative] [Problems that the invention aims to solve]

[0008] Figure 4 shows the structure of a conventional shrinkable refractory. Conventional shrinkable refractories are amorphous refractories, and are made by mixing inorganic particles 12 and inorganic fibers 13 with liquid phase 14 and casting them. As a result, the constructed material contains a large amount of liquid phase 14, as shown in Figure 4(a). In other words, because conventional shrinkable refractories are soft during construction, a support material for the upper refractory is necessary when applying them to structural parts that will bear the load of the upper refractory.

[0009] However, the introduction of support members poses problems in terms of workability because the metal fittings that serve as support members are welded during construction, which increases the construction time. Furthermore, problems include the inability to adequately absorb expansion due to the difference in thermal expansion behavior between the fixed support members and the refractory material, and the fact that if the tuyere refractory material is damaged and the support members come into contact with the molten material, the support members melt, making it impossible to maintain the tuyere structure. For this reason, a refractory material and structure that can be easily constructed independently without the use of support members is desired.

[0010] The object of the present invention is to provide a shrinkable refractory that mitigates problems such as the uplift phenomenon caused by thermal expansion of refractories, which are particularly likely to occur in the early stages of blast furnace operation, and that has sufficient strength to withstand the load of the refractory above without deformation even when constructed at room temperature without the use of support materials, while also being shrinkable in response to the load (thermal stress load) newly added due to thermal expansion under high-temperature conditions during operation, as well as a refractory lining structure for the blast furnace tuyere. [Means for solving the problem]

[0011] The gist of this invention is as follows: (1) A fire-resistant material containing a total of 30-70% by mass of inorganic particles, at least partially containing silicon carbide particles, and a total of 30-70% by mass of alumina-based or silica-based inorganic fibers, and an adhesive, The plate-shaped molded body has a laminated structure in which the inorganic particles are embedded in the voids of a mesh-like framework in which the inorganic fibers are intertwined. The structure has inorganic particles embedded in the voids of a mesh-like framework in which the inorganic fibers are intertwined. It contains 30% to 65% by mass of Al2O3 component and 25% to 50% by mass of SiC component. A collapsible refractory material with a compressive strength of 0.5 MPa or higher at room temperature. (2) The shrinkable refractory material according to (1), wherein the inorganic fiber includes at least one selected from the group consisting of alumina fiber, mullite fiber, zirconia alumina silicate fiber, aluminosilicate fiber, and alkaline earth silicate fiber. (3) A shrinkable refractory material as described in (1) or (2), which does not shrink under no load at 500°C and has a shrinkage rate of 30% or more under a load of 1.0 MPa. (4) A refractory lining structure for a blast furnace tuyere, comprising a tuyere refractory divided into upper and lower sections and a shrinkable refractory as described in (1) or (2), The upper and lower sections of the aforementioned tuyere refractory are not supported by any support material from the iron shell. The refractory lining structure for a blast furnace tuyere is provided, wherein the shrinkable refractory material is positioned between the upper and lower sections of the tuyere refractory material, or at least in the lower part of the tuyere refractory material. (5) A method for producing a shrinkable refractory material as described in (1) or (2), A method for producing a shrinkable refractory, comprising the steps of: dispersing the aforementioned refractory material and an adhesive in a solvent to form a slurry; molding the slurry under pressure or under reduced pressure to form a plate-shaped molded body; and drying the molded body. [Effects of the Invention]

[0012] According to the present invention, even if a refractory is built on top without using a receiving support material during construction, a stable refractory lining structure of the blast furnace tuyere can be maintained without deformation. As a result, it is possible to omit the installation work of the receiving support material, reduce the working time, load, and cost, and eliminate concerns about thermal expansion and melting loss of the receiving support material during operation. Thus, according to the present invention, it is possible to prevent pushing up to the upper structure more simply and at a lower cost compared to the prior art.

Brief Description of the Drawings

[0013] [Figure 1] Shows the lining structure of a general blast furnace tuyere, (a) is a front view seen from the inside of the furnace, (b) is a cross-sectional view taken along A - A’, and (c) is a cross-sectional view taken along B - B’. [Figure 2] Shows the tuyere structure with an expansion absorption section provided using a receiving support material at the lower part of the tuyere refractory, (a) is a front view seen from the inside of the furnace, (b) is a cross-sectional view taken along A - A’, and (c) is a cross-sectional view taken along B - B’. [Figure 3] Shows the tuyere structure with an expansion absorption section provided using a receiving support material between the upper and lower stages of the tuyere refractory, (a) is a front view seen from the inside of the furnace, (b) is a cross-sectional view taken along A - A’, and (c) is a cross-sectional view taken along B - B’. [Figure 4] Schematically shows the structure of a conventional shrinkable refractory, (a) shows the state during construction, (b) shows the state during drying, and (c) shows the state after drying completion. [Figure 5] Schematically shows the structure of a shrinkable refractory which is an embodiment of the present invention, (a) shows the state during molding, (b) shows the state during drying, and (c) shows the state after drying completion. [Figure 6] Shows the tuyere structure with an expansion absorption section provided at the lower part of the tuyere refractory using a shrinkable refractory which is an embodiment of the present invention, (a) is a front view seen from the inside of the furnace, (b) is a cross-sectional view taken along A - A’, and (c) is a cross-sectional view taken along B - B’. [Figure 7] Shows the tuyere structure with an expansion absorption section provided between the upper and lower stages of the tuyere refractory using a shrinkable refractory which is an embodiment of the present invention, (a) is a front view seen from the inside of the furnace, (b) is a cross-sectional view taken along A - A’, and (c) is a cross-sectional view taken along B - B’. [Figure 8] Figure showing the sample shape for the corrosion resistance test.

Mode for Carrying Out the Invention

[0014] In order to realize a strength that can withstand the load of the upper refractory without deformation during construction without using a receiving support material and, on the other hand, a shrinkability with respect to a newly applied load (thermal stress load) due to thermal expansion in the high-temperature state during the operation period, the present inventors considered the shaping of a shrinkable refractory.

[0015] The shrinkable refractory of the present invention (hereinafter referred to as "the present refractory") has a laminated structure in which inorganic particles 12 are present in the voids of a network-like skeleton in which inorganic fibers 13 are intertwined, as shown in FIG. 5, and is a shaped refractory having a structure containing a large number of fine voids in the structure. By forming voids, the voids are crushed when a load is applied, and the shrinkable characteristics are exhibited. On the other hand, since the presence of voids reduces the strength as a refractory, there is a concern that the strength to withstand the load of the upper refractory during construction is insufficient. Therefore, inorganic particles are added to improve the strength of the material. That is, by filling the voids formed by the inorganic fibers with inorganic particles having excellent strength, the strength of the entire shrinkable refractory is improved. In order to achieve both the strength improvement by the inorganic particles and the shrinkability improvement by the inorganic fibers, the present refractory contains 30 to 70% by mass of inorganic fibers and 30 to 70% by mass of inorganic particles as refractory materials.

[0016] Further, the present refractory contains 30% by mass or more and 65% by mass or less of an Al2O3 component and 25% by mass or more and 50% by mass or less of a SiC component as chemical components. That is, the total amount of the Al2O3 component and the SiC component is 60% by mass or more. Since the present refractory is assumed to come into contact with slag, it contains an Al2O3 component and a SiC component in order to achieve both corrosion resistance and fire resistance. The Al2O3 component is effective in improving the refractoriness of refractories; however, if the content is low, the refractoriness decreases and the material becomes more prone to melting. Furthermore, since the Al2O3 component is a major component of typical inorganic fibers, in this invention, it is set to 30% by mass or more in order to have both refractoriness and shrinkability. On the other hand, this refractory material is applied to the tuyeres of blast furnaces and is subject to erosion by slag inside the furnace, so it is necessary to balance this with corrosion resistance. Therefore, in order to introduce a SiC component with excellent corrosion resistance into the refractory structure, the Al2O3 component is set to 65% by mass or less.

[0017] In this refractory, silicon carbide particles are used as at least a portion of the inorganic particles. Alumina particles may also be included. The primary purpose of the silicon carbide particles is to improve corrosion resistance when used in an actual furnace, but they also serve as a filler to increase the density of the shrinkable refractory and improve its strength. To ensure corrosion resistance and material strength, the SiC component is set at 25% by mass or more. On the other hand, since the shrinkability of this refractory is ensured by voids in the structure where inorganic fibers are intertwined, adding too many silicon carbide particles would reduce the proportion of inorganic fibers and decrease the shrinkability of the material, so the SiC component is set at 50% by mass or less.

[0018] This refractory material maintains a certain strength at room temperature while becoming shrinkable in high-temperature environments (e.g., 500°C). The unique characteristic of this refractory material is that, structurally, it contains numerous minute voids at room temperature to high temperatures. These voids collapse under load, undergoing microscopic fracture, which distributes the pressure during compression, thus achieving shrinkability. On the other hand, despite its structure containing numerous such voids, it maintains strength at room temperature and does not deform (shrink) under the load of the overlying refractory material.

[0019] Comparing the structure of this refractory material with that of conventional materials, conventional materials are amorphous refractory materials, and during construction, as shown in Figure 4(a), liquid components 14 with polyhydric alcohol as a solvent are present in the structure of inorganic particles 12 and inorganic fibers 13. Then, during drying, as shown in Figure 4(b), the inorganic particles 12 and inorganic fibers 13 aggregate as the liquid components evaporate. As a result, after drying is complete, coarse voids of about 1 to 10 mm in size are formed, as shown in Figure 4(c). Consequently, insufficient strength and variations in void size tend to occur, leading to variations in shrinkability.

[0020] Therefore, the inventors attempted to achieve a uniform structure by uniformly dispersing inorganic particles and inorganic fibers by adding a sizing agent to a solvent. They also attempted to uniformly laminate inorganic fibers by performing pressurized or vacuum molding with the sizing agent added. Specifically, a slurry is prepared by adding a sizing agent to a refractory material (raw material formulation) containing inorganic particles and inorganic fibers, along with a solvent such as water. At this time, the inorganic particles 12 and inorganic fibers 13 are uniformly dispersed by coating them with the sizing agent. Subsequently, pressurized molding such as vacuum molding or press molding is performed. In these molding processes, applying pressure due to the internal-external pressure difference caused by pressurization or depressurization has the effect of removing solvent and large voids in the structure, and firmly bonding the inorganic particles and inorganic fibers. As a result, a structure is formed in which inorganic fibers 13 intertwined with inorganic particles 12, as shown in Figure 5(a), are uniformly laminated. Furthermore, because the inorganic particles 12 and inorganic fibers 13 are bonded together by the adhesive, aggregation does not occur when the liquid component 14 volatilizes or evaporates, as shown in Figure 5(b). After drying is complete, a uniform void structure can be obtained as shown in Figure 5(c), preventing a decrease in strength.

[0021] A key feature of this refractory material is the use of a binder, rather than the hydraulic or thermosetting binders commonly used in refractories. Examples of hydraulic binders include alumina cement, Portland cement, magnesia cement, and gypsum, which harden through a hydration reaction. Refractories hardened using these hydraulic binders develop strength from room temperature to high temperatures, and therefore cannot achieve adequate shrinkability at high temperatures. Examples of thermosetting binders include epoxy resins, phenolic resins, water glass, phosphoric acid, and phosphates. These thermosetting binders also generally develop strength in high-temperature environments, and therefore cannot achieve adequate shrinkability at high temperatures.

[0022] The adhesive used in this invention also provides strength to shrinkable refractories to give them shape retention. Therefore, this refractory material can be handled as a fixed-shape refractory material in the same way as tuyere refractories during construction. Typical adhesives used in this invention include starches such as dextrin, wheat flour starch, potato starch, sweet potato starch, tapioca starch, rice starch, sago starch, corn starch, and high-amylose corn starch, as well as guar gum, locust bean gum, sanzan gum, karaya gum, agar, sodium alginate, gelatin, carrageenan, gum arabic, mannan, PVA, CMC, and MC, and these can be used individually or in combination of two or more.

[0023] This refractory material ensures strength at room temperature to high temperatures through bonding of refractory materials (inorganic particles and inorganic fibers) with an adhesive and pressurized or vacuum molding (hereinafter also referred to as "compression molding"). To withstand the load from the refractory material above, it is preferable that the compressive strength be at least 0.5 MPa when applied at room temperature. Furthermore, considering the impacts applied during application, it is desirable that it be 5 MPa or more, and even more desirable that it be 10 MPa or more. Compression molding methods include pressurized molding such as CIP, HIP, hydraulic press, and flexion press, as well as vacuum molding, which involves casting in a reduced pressure environment and using the pressure difference with the ambient air to densify the structure, but any method may be used. In addition to combining inorganic fibers and inorganic particles to create composite materials, compression molding allows inorganic particles to densely fill the gaps in the mesh structure of the inorganic fibers, thereby improving strength.

[0024] It is preferable that this refractory material be a standardized refractory material in the form of a plate (board). This allows for easy installation on top of the refractory material at the bottom of the tuyere section without the need for supporting materials, and furthermore, it enables stable installation of refractory material on top of this refractory material. One of the objectives of this refractory material is to absorb the thermal expansion of the refractory material at the lower part of the tuyere over its entire circumference. This makes it possible to apply it to the tuyere around the entire circumference of the blast furnace without using support materials, even in areas where conventional amorphous refractory materials (mortar) would have required support materials.

[0025] Based on the inventors' experience with operating blast furnaces, temperature simulations of the tuyere structure indicated that the region where this refractory is used would reach a maximum temperature of 500°C during operation. Therefore, it is preferable that this refractory has shrinkability characteristics corresponding to the thermal stress load caused by the thermal expansion of the tuyere refractory and other components from room temperature up to 500°C. On the other hand, it is preferable that it does not shrink from room temperature up to 500°C under loads other than thermal stress loads. That is, it is preferable that it does not shrink under no load at 500°C. Furthermore, for shrinkability under thermal stress loads, it is preferable that the shrinkage rate under a load of 1.0 MPa at 500°C is 30% or more. For this reason, the fibers forming the framework of this refractory are preferably alumina-based or silica-based inorganic fibers, and specifically, it is preferable that they include at least one of the following: alumina fibers, mullite fibers, zirconia alumina silicate fibers, aluminosilicate fibers, alkaline earth silicate fibers, etc.

[0026] In the tuyere structure using this refractory material, as shown in Figure 6, neither the upper tuyere refractory material 1.a nor the lower tuyere refractory material 1.a is supported by a support material from the steel shell 7. The refractory material 11 is positioned below the tuyere refractory material 1 as shown in Figure 6, and at least one of the spaces between the upper and lower tuyere refractory materials as shown in Figure 7, and in each case it serves as an expansion absorption space.

[0027] Furthermore, the method for manufacturing this refractory material includes the steps of: dispersing the above-mentioned refractory material and adhesive in a solvent to form a slurry; molding the slurry under pressure or under reduced pressure to form a plate-shaped molded body; and drying the molded body. The amount of adhesive added can be approximately 0.1 to 5% by mass per 100% by mass of the refractory material, applied externally. Typically, water or an organic solvent can be used as the solvent, and the amount added should be adjusted appropriately to produce a slurry suitable for subsequent pressurized or vacuum molding. Furthermore, drying can be carried out in an atmospheric environment at 100-120°C for approximately 12-24 hours. [Examples]

[0028] Table 1 shows the material composition and component composition (chemical composition) of the examples and comparative examples of the present invention, as well as the evaluation results of their durability. Three types of fibers, A to C, were investigated as the fibers to be used. Fiber A was an alumina fiber, and fiber B was an aluminosilicate fiber, with the alumina components of fibers A and B being 70% by mass and 50% by mass, respectively. Fiber C was a vinylon fiber. Two types of inorganic particles, particle D and particle E, were also investigated as the inorganic particles to be used. Particle D was a silicon carbide particle, and particle E was an alumina particle. When a binder was used, it was added in an external amount of 1-2% by mass relative to the total amount of refractory material, i.e., fibers and particles. During the molding process, vacuum molding was performed as a reduced-pressure molding method, and uniaxial press molding at 0.5 MPa was performed as a pressure molding method. Drying was carried out in an atmospheric atmosphere at 110°C for 24 hours to obtain plate-shaped samples.

[0029] The compression strength at room temperature was measured using a 100mm x 100mm pressure surface with a thickness of 40mm, referencing JIS R2206. The shrinkage rate is measured by cutting and filling a bottomed cylindrical crucible with an open top and an inner diameter of φ25 mm, and measuring the height L0 of the sample at this stage. In the examples and comparative examples, L0 = 40 mm. Next, with the sample in the crucible kept uniformly at 500°C, the height L1 of the sample is measured under no load. After that, 1 MPa (approximately 10 kgf / cm²) is applied. 2 A load of ) is gently applied to the sample and held for 20 minutes. The height L2 of the sample is read when the compression of the sample stabilizes. Here, the shrinkage rate under no load at 500°C is calculated as (L0-L1) / L0×100%, and the shrinkage rate at 1 MPa at 500°C is calculated as (L0-L2) / L0×100%. Corrosion resistance (resistance to slag erosion) was evaluated using a rotary erosion tester. The drum lining was made of refractory silicon carbide, and samples with the shape shown in Figure 8 were filled into grooves formed in the lining. Blast furnace slag was charged into the drum, and the drum was rotated while the blast furnace slag was melted with a burner. After that, the erosion dimensions of the maximum erosion part of each sample were measured, and each measured value was divided by the erosion dimension of Example 1 and multiplied by 100 to show the relative value (erosion index). A higher erosion index indicates greater erosion. An erosion index of less than 80 was marked with ◎ (excellent), 80 to 100 with ○ (good), and over 100 with × (poor). Figure 8 shows a detailed view of the samples subjected to the rotary erosion tester. Refractory silicon carbide 17 was cut into a trapezoidal plate shape with a top edge of 65 mm, a bottom edge of 110 mm, and a depth of 65 mm. A groove 10 mm wide and 40 mm deep was made in this silicon carbide refractory 17, and samples from each example were cut to fit the groove and filled in. Then, tests were conducted using these 10 samples.

[0030] [Table 1]

[0031] Examples 1 to 5 of this refractory material, as shown in Table 1, did not shrink even at 500°C and all exhibited excellent corrosion resistance, shrinkability, and compressive strength at room temperature. This is thought to be because the inorganic fibers ensure voids in the structure, while the inorganic particles containing silicon carbide particles maintain material strength. As a result, both compressive strength at room temperature and shrinkability at 500°C are achieved. Furthermore, the use of silicon carbide particles greatly contributes to corrosion resistance. In addition, the addition of adhesives and the implementation of pressurized or vacuum molding treatment strengthens the bond between inorganic fibers and inorganic particles, thereby improving compressive strength at room temperature.

[0032] Comparative Example 1 is a typical composition of conventional shrinkable mortar applied in Patent Documents 1 and 2, and has excellent shrinkability due to its high inorganic fiber content. However, because no binder is added, the inorganic fibers are not uniformly dispersed, and since the mortar construction is dried without molding, it has an uneven structure due to the aggregation of fibers and particles during drying. Therefore, it is unsuitable due to insufficient strength. Comparative Example 2 has a high proportion of silicon carbide particles, resulting in excellent overall material strength and corrosion resistance. However, it is unsuitable due to its low inorganic fiber content, which leads to poor shrinkability. Comparative Example 3 exhibits shrinkability under a load of 500°C, but because it is a vinylon fiber that melts at around 250°C, it shrinks by about 25% even under no load at around 500°C, making it unsuitable. Furthermore, because it is an organic fiber, its corrosion resistance is also poor, making it unsuitable. Comparative Example 4 exhibits excellent shrinkability, but is unsuitable due to insufficient compressive strength at room temperature because it contains few inorganic particles. Comparative Example 5, while exhibiting excellent strength and corrosion resistance at room temperature due to a large amount of inorganic particle addition and pressure molding, is unsuitable due to insufficient inorganic fibers and poor shrinkability. Comparative Examples 6 and 7 are examples in which a hydraulic binder and a thermosetting binder were used, respectively, and are unsuitable due to their poor shrinkability. [Explanation of Symbols]

[0033] 1 Tuyere refractory 1.a Upper tuyere fireproofing 1.b Lower tuyere refractory 2 Tuyere cooling device 3. Refractory material or cooling plate on the upper part of the tuyere. 4 Lower tuyere refractory 5. Shrinkable mortar 6. Stave 7 Ironhide 8. Fireproof material poured into the front of the staves. 9 Shrinkable refractory layer 10 Support material 11 refractories 12 Inorganic particles 13 Inorganic Fibers 14. Liquid components (water, organic solvents) 15 void 16. Adhesive 17. Refractories made from silicon carbide 18 samples

Claims

1. A fire-resistant material containing a total of 30 to 70% by mass of inorganic particles, at least partially containing silicon carbide particles, and a total of 30 to 70% by mass of alumina-based or silica-based inorganic fibers, and an adhesive, The plate-shaped molded body has a laminated structure in which the inorganic particles are embedded in the voids of a mesh-like framework in which the inorganic fibers are intertwined. Al ２ O ３ It contains 30% to 65% by mass of the component and 25% to 50% by mass of the SiC component. A shrinkable refractory material with a compressive strength of 0.5 MPa or higher at room temperature.

2. The shrinkable refractory material according to claim 1, wherein the inorganic fiber includes at least one selected from the group consisting of alumina fiber, mullite fiber, zirconia alumina silicate fiber, aluminosilicate fiber, and alkaline earth silicate fiber.

3. A shrinkable refractory material according to claim 1 or 2, wherein it does not shrink under no load at 500°C and has a shrinkage rate of 30% or more under a load of 1.0 MPa.

4. A refractory lining structure for a blast furnace tuyere, comprising a tuyere refractory divided into upper and lower sections and a shrinkable refractory according to claim 1 or 2, The upper and lower sections of the aforementioned tuyere refractory are not supported by any support material from the iron shell. The refractory lining structure for a blast furnace tuyere is provided, wherein the shrinkable refractory material is positioned between the upper and lower sections of the tuyere refractory material, or at least in the lower part of the tuyere refractory material.

5. A method for producing a shrinkable refractory material according to claim 1 or 2, A method for producing a shrinkable refractory, comprising the steps of: dispersing the aforementioned refractory material and an adhesive in a solvent to form a slurry; molding the slurry under pressure or under reduced pressure to form a plate-shaped molded body; and drying the molded body.

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