CA6-based medium volume density refractory material, manufacturing method and use thereof

Abstract

The present invention discloses a CA6-based medium volume density insulating refractory material, its manufacturing method and its use. In the CA6-based medium volume density insulating refractory material of the present invention, the phase of the insulating refractory material includes CA6 and one or more phases selected from C2M2A14, CM2A8, magnesia alumina spinel and corundum, and the refractory material has high purity, good high temperature stability, uniform texture, stable performance, low thermal conductivity, and good resistance to molten metal corrosion and slag corrosion.

Description

Technical Field

[0001] This application relates to the technical field of refractories, and in particular, to CA6 series medium bulk density refractories, their manufacturing methods, and their uses.

Background Art

[0002] For a molten steel refining ladle, the integrity, safety, prevention of steel leakage, and certain heat preservation properties of the ladle lining refractory are very important, and the permanent lining refractory plays a very important role among them.

[0003] Currently, the ladle lining is usually designed with a three-layer structure of a working lining, a permanent lining, and a heat insulation lining. Since the working lining comes into contact with high-temperature melt, it requires good high-temperature performance and excellent resistance to molten steel and slag erosion. The permanent lining must have both safety and heat insulation effects. It not only needs to withstand the high temperature and erosion of molten slag and molten steel when the working lining is lost and meet the first condition of safety, but also needs to prevent or weaken the external transmission of heat, lower the temperature transmitted to the heat insulation lining, and realize the heat insulation function.

[0004] In the current permanent lining of ladles, existing applicable materials are generally medium-heavy high-alumina castables, or aluminum-magnesium castables, or ordinary low-cement high-alumina castables, or high-alumina castables with partial addition of mullite lightweight aggregates, etc. Since lightweight aggregates are inferior in slag erosion resistance, there are relatively few ladles that use lightweight mullite as the permanent lining aggregate from the perspective of safety.

[0005] Most of the construction of the permanent lining is carried out on-site. After constructing the heat insulation lining in the ladle, a core mold is fixed in the ladle. After adding water to the castable on-site and stirring, it is poured in and vibrated, so that the castable is filled between the core mold and the heat insulation lining by flowing, and a strong whole is formed by the hydration of hydration components such as cement.

[0006] Castables are aggregates of aggregates and fine powders. The aggregates are granular materials with a particle size exceeding 0.088 mm, and the fine powders are powder materials with a particle size less than 0.088 mm. The sintering activity of the granular materials is very weak and basically does not sinter, but the sintering activity of the fine powders is relatively high, and the integrity of the castables is mainly brought about by the sintering of the fine powders. In addition to the main raw material powder, the fine powders contain components with a hydration bonding effect such as aluminate cement and MgO, components that enhance fluidity such as silica fine powder and activated alumina fine powder, additives that promote sintering, and dispersants that promote dispersibility. Therefore, compared with the aggregates, the matrix part is the weakest part in the high-temperature performance of the castables, but due to the manufacturing concept and performance requirements of refractory castables, it is difficult to change this.

[0007] The low-cement high-alumina castables currently used for permanent linings are generally manufactured using bauxite, pure aluminate cement, and silica fine powder as raw materials, and the bulk density is generally 2.95 - 3.15 g / cm 3 ³. Bauxite is generally secondary or tertiary bauxite, with high impurity components, a high content of liquid phase formed at high temperatures, and relatively large high-temperature deformation of the material. Therefore, during the use of this material, the process of densification of the microstructure occurs, resulting in an increase in the thermal conductivity of the material and an increase in heat dissipation. At the same time, due to the large amount of liquid phase of the material at high temperatures, the corrosion resistance to molten steel and slag erosion is weak. When the working lining is eroded and disappears, it is difficult for the above material alone to withstand the erosion of molten steel, and steel leakage is likely to occur. In addition, the structure of this type of material loosens and the strength decreases when used repeatedly.

[0008] Aluminum-magnesium castables are generally manufactured using bauxite, magnesia powder, silicon fine powder, etc. as raw materials, and the bulk density is generally 3.0 - 3.15 g / cm 3It is so. All raw materials used in this material are natural raw materials, with many impurity components, a high liquid phase content formed at high temperatures, and relatively large high-temperature deformation of the material. Therefore, even during the use of this material, a process of densification of the microstructure occurs. As a result, the thermal conductivity of the material increases and heat dissipation becomes greater. At the same time, due to the large amount of liquid phase of the material at high temperatures, the corrosion resistance to molten steel and slag erosion is weak. When the working lining is eroded and disappears, it is difficult for the above material alone to withstand the erosion of molten steel, and steel leakage is likely to occur.

[0009] Such existing application materials and technologies have been used for decades, but they cannot meet the requirements of safety, energy conservation, and heat preservation, and there has been no significant improvement. This is mainly because the raw materials have not changed, which is due to the characteristics of the raw materials. The microstructure of bauxite is mainly composed of rod-shaped and columnar corundum and mullite, and the liquid phase fills the gaps between the corundum and mullite crystals. This structure not only causes deformation and densification of the microstructure but also brings higher thermal conductivity due to the interconnected columnar crystals, which is the most important defect of the currently applied materials.

[0010] Compared with the microstructure of bauxite, the structure of calcium hexaaluminate is more suitable as a raw material for permanent lining. Therefore, in addition to the existing application technology materials, the materials used for permanent lining also include those described in some published patents, such as CA6-containing materials.

[0011] The chemical composition of calcium hexaaluminate (CaO·6Al2O3, abbreviated as CA6) is CaO and Al2O3, the melting point is 1875°C, and the theoretical density is 3.79 g / cm 3and has excellent fire resistance. The crystal structure of calcium hexaaluminate is a magnetoplumbite structure in which lamellar structures are stacked in the C-axis direction. Since the thermal conductivity in the C-axis direction is low and the thermal conductivity is also reduced due to the gaps between the lamellar structures, the thermal conductivity of the raw material calcium hexaaluminate is very low. CMA (a unified abbreviation of CaO·2MgO·8Al2O3 and 2CaO·2MgO·14Al2O3) is based on the C-axis stacking of the CA6 and MgO·Al2O3 structures. Its structure is similar to that of CA6, is easy to form a lamellar structure, and has a low thermal conductivity. Considering that the structures and properties of CMA and CA6 are similar, only CA6 will be used instead in the following description.

[0012] While this lamellar structure reduces the heat transfer performance, it makes it difficult to sinter the calcium hexaaluminate material. Currently, the bulk density of the calcium hexaaluminate material prepared in the laboratory is generally 2.20 - 2.70 g / cm 3 and it is difficult to apply in the high-temperature region. Exactly due to this lamellar structure, the sinterability is very poor, which is the main reason why it is difficult to prepare CA6-based raw materials with a bulk density exceeding 3.0 g / cm 3 In addition, in the manufacturing process of calcium hexaaluminate refractories, the volume expansion effect accompanying the reaction between components also affects the sintering and densification processes of the calcium hexaaluminate material.

[0013] Currently, in order to achieve the densification of calcium hexaaluminate, additives such as SiO2 and TiO2 are often used. At high temperatures, a liquid phase appears, promoting its densification and sintering. For example, Chen Zhaoyou et al. described the physical and chemical properties of Bonite (the trade name of calcium hexaaluminate) in "Calcium Hexaaluminate Materials and Their Applications in Aluminum Industrial Furnaces" (Non-Patent Document 1), and mentioned that the SiO2 content in its chemical composition is 0.9%. Also, "Method for Preparing Dense Calcium Hexaaluminate Refractory Clinker" (Patent Document 1) and "Dense Calcium Hexaaluminate Refractory Clinker and Method for Preparing the Same" (Patent Document 2) each use TiO2 and MnO as sintering aids. However, in this method, densification cannot be achieved by controlling the stacking of atoms in the mirror layer. It only utilizes the liquid phase to reduce the distance between particles. Since the liquid phase fills the space between the crystal particles of calcium hexaaluminate to conduct heat, although the density of calcium hexaaluminate can be improved by this method, the structure of calcium hexaaluminate cannot be controlled, and the thermal conductivity is high.

[0014] The CA6 materials disclosed in previous patent applications can be broadly classified into three categories. (1) CA6-based materials with a bulk density of less than 2.0 g / cm 3 Although CA6-based materials with a bulk density of less than 2.0 g / cm have low thermal conductivity and good heat insulation performance, they are not suitable for the permanent lining of ladles that need to withstand erosion by slag and molten steel; (2) Materials based on composite materials of CA6 and other components increase strength through the formation of a second phase, but the overall density of the material is low, making it difficult to use in permanent linings, etc.; (3) The bulk density of high-purity CA6 materials (Al2O3 + CaO content of 97.0% or more) prepared without introducing sintering-promoting additives is almost 2.5 g / cm 3It is less than that and has extremely low strength, so it cannot meet the usage requirements; (4) mainly based on CA6, sintering densification is realized by adding a sintering aid. Due to the lamellar structure of CA6 itself, CA6 materials are difficult to sinter, and sintering densification is basically promoted by adding SiO2, TiO2, etc.; (5) Most of the CA6 materials add a large amount (more than 20%) of corundum or activated alumina fine powder, and the strength of the composite material is realized by sintering the corundum or activated alumina fine powder.

[0015] Regarding the ladle permanent lining material, the problems and defects existing in the existing industrialization technologies or existing patent technologies are as follows. (1) Inferior resistance to steel slag erosion Castables based on natural bauxite have a high impurity content and a large amount of high-temperature liquid phase, so it is difficult to withstand the erosion of molten steel and slag. Therefore, when the working lining disappears, it is difficult to ensure safety with the current permanent lining materials and technologies. Although the concept of a safety lining is given to the permanent lining, it is difficult to meet its requirements. (2) Due to shrinkage and densification at high temperatures, the microstructure of the material changes, and the thermal conductivity of the material further increases. Bauxite-based permanent lining castables have all-natural bauxite raw materials, many impurities, and a high amount of liquid phase at high temperatures. Furthermore, this type of castable is a system based on improving fluidity with silicon fine powder. When the addition amount of silicon fine powder is large, the amount of liquid phase at high temperatures will double. In this way, when the castable is used at high temperatures, a certain degree of shrinkage and densification process occurs. As it is used, the material becomes more dense and the thermal conductivity further increases. (3) High thermal conductivity of the material As for the current medium-heavy high-alumina castables, whether they are ordinary high-alumina castables, aluminomagnesium castables, or low-cement high-alumina castables, their aggregates and fine powders are mostly sintered bauxite. Although medium-heavy mullite castables use mullite lightweight raw materials as part of the aggregates, the fine powders are still sintered bauxite. They have high density and high thermal conductivity, and the bulk density of these materials is mostly above 2.6 g / cm 3 and may reach 3.15 g / cm 3 . Since these medium-heavy materials have a very high density, it is impossible to significantly reduce their thermal conductivity. (4) Due to the shrinkage of the material, the refractory of the working lining expands outward, the extrusion force between bricks weakens, the integrity decreases, and steel leakage is likely to occur. Castables based on natural raw material bauxite have a high impurity content and a large amount of high-temperature liquid phase. Due to the sintering shrinkage during long-term use, the supporting force on the outer periphery of the working lining becomes weak. Due to the expansion outward, cracks and brick breakage occur in the working lining, and steel leakage accidents are likely to occur. (5) CA6-based materials rely on additives to achieve sintering, have a large amount of liquid phase, poor high-temperature performance, and high thermal conductivity. Since the unique lamellar structure of CA6 makes sintering difficult, most of the existing CA6-based refractories that can be used as the permanent lining of the ladle rely on additives to generate a liquid phase to promote sintering. This method can promote the sintering of CA6, but when the liquid phase increases, the high-temperature performance decreases, and the liquid phase fills between the crystal grains to form a heat transfer bridge, resulting in a significant increase in thermal conductivity. (6) The difficulty in sintering CA6-based materials is compensated by introducing more corundum phases, resulting in a significant increase in thermal conductivity. To improve the sinterability and corrosion resistance of CA6 materials, usually, a lot of activated alumina fine powders, corundum powders, etc. are added according to existing published patents. This improves the sinterability and integrity, but the thermal conductivity also doubles, and the heat insulation performance decreases. (7) High-purity CA6 material has relatively low bulk density and strength, making it difficult to apply as a permanent lining material. Since the CA6 material is difficult to sinter, the density of high-purity CA6 products after firing is generally 2.0 - 2.5 g / cm 3 , with a non-uniform microstructure and very low strength. This makes it impossible to be used as the permanent lining material for the ladle under high pressure. (8) The high-temperature shrinkage of the material is large, and reticulated cracks and large cracks frequently occur, seriously affecting the safety of ladle steelmaking. If the material has a large amount of high-temperature liquid phase and significant creep in the microstructure, the material will shrink and its volume will decrease, resulting in frequent occurrence of reticulated cracks and large cracks in the permanent lining material. Such cracks are very dangerous and a major concern for steel plants. If the working lining is damaged by melting or molten steel penetrates between the working linings, molten steel is likely to flow out from the cracks in the permanent lining, causing a serious steel leakage accident.

Prior Art Documents

Patent Documents

[0016]

Patent Document 1

Patent Document 2

Non-Patent Documents

[0017]

Non-Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0018] Therefore, neither the existing materials currently used in steel mills nor the disclosed patented technologies can truly achieve safety and heat preservation. There are many high-temperature liquid phases, and deformation and densification processes occur under the action of the liquid phase. As a result, the thermal conductivity continues to increase during use, and at the same time, there are many liquid phases, the corrosion resistance to molten steel and slag erosion deteriorates, and it becomes difficult to withstand slag erosion when the working lining material is lost, making it difficult to play a role in protection and safety. Due to high purity, non-dense sintering, and non-uniform structure, it is difficult to resist the expansion pressure of the working lining of the ladle. As a result, the permanent lining material is compressed, the working lining material expands outward as a whole, and the integrity decreases, leading to accidents such as steel leakage.

[0019] The difficulty in solving the above problems and defects is as follows. (1) It is difficult to change its weaknesses by the manufacturing method of castables. Especially for unshaped refractory castables, they can be used directly without firing. The strength at normal temperature and low temperature is generated by the hydration bond of cement. After the crystal water and bound water disappear at 800 - 900 °C, the strength is mainly maintained by the dense stacking of the material itself and the addition of silicon fine powder. When the temperature rises again, the strength is maintained by the addition of silicon fine powder and other low melting point phases. At the same time, refractories are aggregates of aggregates and fine powders. Since the surface of aggregate particles is relatively inert to sintering and reactions, it is difficult to sinter, and the strength of refractories is mainly brought about by the sintering of matrix fine powders. Therefore, the matrix fine powders of refractories are required to be finer and have a larger specific surface area. On the other hand, most of the foreign components necessary for promoting sintering are added to the matrix fine powders, which makes the composition distribution of refractories non-uniform. The matrix fine powders originally have inferior high-temperature performance compared to aggregates, and the addition of sintering aids further reduces the high-temperature performance. In some application fields, sintering aids are necessary. Especially in the case of castables such as the permanent lining of a ladle, they are directly applied without high-temperature sintering, and sintering can only be achieved at high temperatures during use, so many sintering aids are required. This is determined by the development concept of refractories and is difficult to improve. Using high-purity raw materials as the main raw materials makes the prepared materials difficult to sinter and unable to be integrated. In addition, in order to ensure fluidity and workability, additives such as water reducers and micro powders need to be added to the castable. Also, since the raw materials are basically natural raw materials, it is difficult to change the weaknesses of permanent lining materials such as aluminum-magnesium castables and high-alumina castables. (2) Currently, there are many high-temperature liquid phases in the permanent lining castable, and the microstructure becomes denser during use. Natural raw materials have a high impurity content and a large amount of liquid phase at high temperatures. Refractories based on these natural raw materials have large deformations under high-temperature use, unstable microstructures, and may become denser and increase in thermal conductivity. This is something that cannot be changed for refractories based on natural raw materials. (3) The amount of high-temperature liquid phase is large, and the corrosion resistance, resistance to molten steel and slag erosion are low. Different from fired refractories, castables need to use matrix fine powders to satisfy workability, sinterability, and forming strength. Therefore, additives such as aids to promote sintering, water reducers and surfactants to enhance fluidity, and hydration raw materials to form normal-temperature strength and medium-temperature strength are added to the matrix fine powders. As a result, the matrix composition of castables is very complex, and the high-temperature performance will inevitably decrease significantly, but this cannot be changed. (4) The castables based on high-purity raw material CA6 in existing patents also have problems such as aluminum-magnesium castables and high-alumina castables. When compared with bauxite-based castables, the performance of CA6 is much superior to that of bauxite, but the high-temperature performance is still inferior in the following aspects: 1. CA6 castables need to form their own strength even at medium and high temperatures. To meet the integrity as a permanent lining, medium and low-temperature sintering is also necessary, which requires the introduction of components that can sinter into a liquid phase at low temperatures; 2. Additives such as fine powder, water reducer, and fine powder to promote fluidity are also required for CA6 castables; 3. Since sintering is promoted at low temperatures and a large amount of liquid phase is generated at high temperatures, a series of problems occur, such as a decrease in slag erosion resistance at high temperatures, densification of the structure, and an increase in thermal conductivity. (5) In the CA6 castables of existing patent applications, in order to avoid deterioration of the tissue structure and excessive high-temperature liquid phase, there is no choice but to add alumina, corundum, etc., and as a result, the thermal conductivity increases. Depending on the manufacturing method and characteristics of the castable, the substrate becomes a weak point, and this weak point leads to a decrease in the performance of the entire castable. Therefore, to reduce the deficiencies of CA6-based castables, there is no choice but to introduce a large amount of activated alumina fine powder and corundum powder to enhance the high-temperature performance of the substrate and strengthen its structural stability, but this also brings a series of problems such as an increase in thermal conductivity.

[0020] In the case of castables, it is necessary to realize on the substrate characteristics such as good fluidity of the substrate, appropriate hardening, easy sintering, less liquid phase at high temperatures, high corrosion resistance, and no performance deterioration. These are always contradictory and difficult to reconcile, and it is still difficult to solve even now.

[0021] The significance of solving the above problems and drawbacks is as follows. It can achieve the purification of the permanent lining material, enhance the slag erosion resistance and molten steel erosion resistance of the permanent lining material, ensure the safety of the steelmaking ladle, and prevent major accidents such as steel leakage. It can enhance the structural stability and high-temperature integrity of the material, endow the permanent lining material with a low and relatively stable thermal conductivity, prevent heat transfer to the outside, reduce the heating temperature of the molten steel, lower the tapping temperature and carbon-oxygen deposition of the converter, reduce the consumption of refractory materials, reduce the amount of alloy, and bring significant economic benefits and socioeconomic benefits.

Means for Solving the Problem

[0022] In order to solve the above problems, the present invention provides a CA6-based medium bulk density refractory material, a manufacturing method thereof, and its use.

[0023] The present invention mixes fine powder or granular material with fine powder and adopts a hot press sintering method to manufacture a CA6-based medium bulk density refractory material. The obtained refractory material has high purity, good high-temperature stability, uniform structure and stable performance.

[0024] The specific technical solution of the present invention is as follows. 1. A CA6-based medium bulk density insulating refractory material, wherein the phase of the insulating refractory material includes CA6 and one or more phases selected from C2M2A14, CM2A8, magnesia alumina spinel, and corundum. 2. The insulating refractory material according to item 1, wherein the total content of CA6, C2M2A14, CM2A8, magnesia alumina spinel, and corundum is 90% or more, preferably 94.8 - 99.5% by mass percentage in the insulating refractory material. 3. As the mass percentage in the phase of the insulating refractory material, the CA6 phase is 26.7 - 100%, preferably 31.5 - 99.5%, more preferably 38.7 - 99.5%, the C2M2A14 phase is 0 - 72%, preferably 0 - 60%, the CM2A8 phase is 0 - 72%, preferably 0 - 59.5%, The magnesia alumina spinel phase is 0 to 10%, 0 to 4.60%, preferably 0, The cordierite phase is 0 to 30%, preferably 0 to 18%, more preferably 0 to 16.5%, the heat-insulating refractory according to item 1 or 2. 3. As the mass percentage in the phase of the heat-insulating refractory, the CA6 phase is 26.7 to 100%, preferably 29.0 to 100%, preferably 31.5 to 100%, preferably 31.5 to 99.5%, more preferably 38.7 to 99.5%, The C2M2A14 phase is 0 to 72%, preferably 0 to 60%, The CM2A8 phase is 0 to 72%, preferably 0 to 60%, more preferably 0 to 59.5%, The magnesia alumina spinel phase is 0 to 10%, 0 to 8.0%, 0 to 4.60%, 0 to 4.0%, preferably 0, The cordierite phase is 0 to 30%, preferably 0 to 18%, more preferably 0 to 16.5%, still more preferably 0 to 15%, most preferably 0 to 12%, the heat-insulating refractory according to item 1 or 2. 4. The chemical composition of the heat-insulating refractory includes Al2O3, CaO, and MgO. As the mass percentage in the heat-insulating refractory, the Al2O3 is 86.65 to 94.10%, preferably 87.60 to 94.10%, 86.65 to 92.80%, more preferably 88.07 to 94.10%, 87.50 to 92.60%, The CaO is 5.80 to 8.40%, preferably 6.10 to 8.40%, 6.89 to 8.40%, The MgO is 0 to 6.05%, preferably 0 to 5.53%, 0 to 5.43%, 0 to 5.04%, the heat-insulating refractory according to any one of items 1 to 3. 5. The bulk density of the heat-insulating refractory is 2.40 to 2.90 g / cm 3 and preferably 2.40 to 2.82 g / cm 3 The heat-insulating refractory according to any one of items 1 to 4. 6. The heat-insulating refractory according to any one of items 1 to 5, wherein the phase of the matrix portion of the heat-insulating refractory includes CA6 and one or more phases selected from corundum, magnesia alumina spinel, C2M2A14, and CM2A8. 7. As the mass percentage occupied by the phase of the matrix portion of the heat-insulating refractory, the CA6 phase is 67.4 to 100%, preferably 72.5 to 100%, 78.2 to 100%, 78.8 to 100%, the corundum phase is 0 to 30%, preferably 0 to 20%, 0 to 25%, the magnesia alumina spinel phase is 0 to 10%, 0 to 8.0%, 0 to 6.7%, 0 to 5.22%, preferably 0, the C2M2A14 phase is 0 to 30%, preferably 0 to 25%, 0 to 20%, 0 to 18.8%, the CM2A8 phase is 0 to 30%, preferably 0 to 25%, 0 to 20%, 0 to 18.8%, for the heat-insulating refractory according to item 6. 8. The chemical composition of the matrix portion of the heat-insulating refractory includes Al2O3, CaO, and MgO. As the mass percentage occupied by the matrix portion of the heat-insulating refractory, the Al2O3 is 89.03 to 94.10%, preferably 89.03 to 93.65%, 90.30 to 93.20%, 89.03 to 93.28%, the CaO is 5.80 to 8.40%, preferably 6.25 to 8.40%, 6.60 to 8.40%, the MgO is 0 to 2.52%, preferably 0 to 2.10%, 0 to 1.68%, for the heat-insulating refractory according to item 6 or 7. 9. The heat-insulating refractory is manufactured by a method including the steps of mixing granular materials and fine powders to obtain a mixed material, and hot pressing and sintering the mixed material to obtain the heat-insulating refractory. The heat-insulating refractory according to any one of items 1 to 8, which is manufactured by the method including the above steps. 10. The fine powder is one or more selected from CaO-containing fine powder, Al2O3-containing fine powder, and MgO-containing fine powder. Preferably, the CaO-containing fine powder is one or more selected from quicklime, limestone, calcium hydroxide, CaO·Al2O3, CaO·2Al2O3, 12CaO·7Al2O3, CA6, C2M2A14, and CM2A8, Preferably, the Al2O3-containing fine powder is one or more fine powders selected from active α-Al2O3 fine powder, γ-Al2O3 fine powder, ρ-Al2O3 fine powder, aluminum hydroxide fine powder, industrial alumina fine powder, white corundum fine powder, off-white corundum fine powder, dense corundum fine powder, sintered corundum fine powder, and tabular corundum fine powder, Preferably, the MgO-containing fine powder is one or more fine powders selected from magnesite, light burned magnesia, brucite, magnesium hydroxide, magnesium chloride, high-purity magnesia, and fused magnesia, the heat-insulating refractory according to item 9. 11. The heat-insulating refractory according to item 9 or 10, wherein the granular material is one or more selected from CA6, C2M2A14, and CM2A8, preferably CA6. 12. The heat-insulating refractory according to any one of items 9 to 11, wherein the mass ratio of the granular material to the fine powder is 0 to 60:40 to 100. 13. The hot press sintering is to put the mixed material into a mold of a high-temperature device for hot press sintering, or to mold the mixed material at room temperature and then put it into a mold of a high-temperature device for hot press sintering, or to mold the mixed material at room temperature, calcine it temporarily at a low temperature, and then perform hot press sintering. The heat-insulating refractory according to any one of items 9 to 12. 14. The temperature of the hot press sintering is 1550 to 1750 °C, preferably, the hot press strength is 0.5 to 10 MPa. The heat-insulating refractory according to any one of items 9 to 13. 15. A step of mixing a granular material and a fine powder to obtain a mixed material, and hot press sintering the mixed material to obtain a heat-insulating refractory The manufacturing method of a heat-insulating refractory including. 16. The fine powder is one or more selected from CaO-containing fine powder, Al2O3-containing fine powder, and MgO-containing fine powder, Preferably, the CaO-containing fine powder is one or more selected from quicklime, limestone, calcium hydroxide, CaO·Al2O3, CaO·2Al2O3, 12CaO·7Al2O3, CA6, C2M2A14, and CM2A8, Preferably, the Al2O3-containing fine powder is one or more fine powders selected from activated α-Al2O3 fine powder, γ-Al2O3 fine powder, ρ-Al2O3 fine powder, aluminum hydroxide fine powder, industrial alumina fine powder, white corundum fine powder, off-white corundum fine powder, sintered corundum fine powder, and tabular corundum fine powder, The manufacturing method according to item 15, wherein preferably, the MgO-containing fine powder is one or more fine powders selected from magnesite, light-burned magnesia, brucite, magnesium hydroxide, magnesium chloride, high-purity magnesia, and fused magnesia. 17. The manufacturing method according to item 15 or 16, wherein the granular material is one or more selected from CA6, C2M2A14, and CM2A8, and preferably CA6. 18. The manufacturing method according to any one of items 15 to 17, wherein the mass ratio of the granular material to the fine powder is 0 to 60:40 to 100. 19. The hot press sintering is to put the mixed material into a mold of a high-temperature device for hot press sintering, or to form the mixed material at room temperature and then put it into a mold of a high-temperature device for hot press sintering, or to form the mixed material at room temperature, calcine it temporarily at a low temperature, and then perform hot press sintering. The manufacturing method according to any one of items 15 to 18. 20. The temperature of the hot press sintering is 1550 to 1750 °C, and preferably, the hot press strength is 0.5 to 10 MPa. The manufacturing method according to any one of items 15 to 19. 21. The permanent lining of a ladle for molten steel refining, including the heat-insulating refractory according to any one of items 1 to 14, or the heat-insulating refractory manufactured by the manufacturing method according to any one of items 15 to 20. 22. A heat-insulating lining or working lining for a ladle for molten aluminum, comprising the heat-insulating refractory material according to any one of Items 1 to 14, or the heat-insulating refractory material produced by the production method according to any one of Items 15 to 20.

Advantages of the Invention

[0025] The present invention realizes good sintering of high-purity CA6-based materials, high material strength, good heat-insulating performance and strength performance, and good resistance to slag and molten steel erosion, and is very suitable for permanent linings of ladles, working linings such as molten aluminum, heat-insulating linings, and refractory linings of some industrial kilns. It has excellent heat insulation, heat preservation, and safety, and brings significant economic and social benefits. Specific effects will be described in detail as follows. (1) The material of the present invention has high purity and does not contaminate the smelting material. Compared with the corresponding ladle permanent lining material and molten aluminum ladle material, etc., the material of the present invention has high purity, good high-temperature stability, and the total content of Al2O3 + CaO + MgO is 96.5% or more. Although the material of the present invention has high purity, no impurities will be mixed into the solution during the process of smelting steel, aluminum alloys, and other alloys, and it will not affect the purity and performance of alloys, etc. (2) The microstructure of the material is stable and the performance is stable. As a high-purity raw material system, it is relatively difficult to sinter the material. Therefore, in current refractories, promoting sintering by introducing additives, chemical synthesis reactions, or generating low-melting-point liquid phases is fundamental. As a result, the material structure becomes non-uniform. Some regions are high-purity systems with higher melting points and good crystallization, and some regions are liquid-phase regions with complex components, lower melting points, and lower high-temperature properties. This non-uniformity of the structure leads to creep, slip at high temperatures, deterioration of material properties, and increases in thermal conductivity and other properties. However, since the material of the present invention does not generate a low-melting-point liquid phase to promote sintering, there is no low-melting-point liquid phase, no creep or slip of the fine structure, and the performance is stable. Also, different from conventional materials, there is no performance degradation of the material at various usage stages. (3) Good molten metal erosion resistance and slag erosion resistance The material system is a high-purity system, and since the structure of the material does not promote sintering based on a low-melting-point liquid phase, the material structure is uniform and has no weakness in terms of resistance to slag erosion. Therefore, the material of the present invention has very good overall erosion resistance to molten metal and slag, and can guarantee the safety characteristics of the permanent lining. (4) Low thermal conductivity Due to the lamellar structure of CA6, the thermal conductivity of the CA6-based material is low. This is important for the permanent lining that requires heat insulation.

Brief Description of the Drawings

[0026]

Figure 1

Figure 2

Figure 3

Modes for Carrying Out the Invention

[0027] The present invention will be described in detail below. Although specific embodiments of the present invention are shown, it should be understood that the present invention can be embodied in various forms and should not be limited to the embodiments described herein. Rather, these embodiments are provided to more fully understand the present invention and to fully convey the scope of the present invention to those skilled in the art.

[0028] It should be noted that in this specification and the claims, specific terms are used to refer to specific components. Those skilled in the art will understand that different terms may be used to refer to the same component. In this specification and the claims, the difference in function of the components rather than the difference in nouns is used as the criterion for distinguishing components. For example, "containing" or "including" mentioned throughout the specification and the claims is an open term and should be interpreted as "including but not limited to". The following description in this specification is a preferred embodiment for implementing the present invention, but these descriptions are for the purpose of the general principles of this specification and do not limit the scope of the present invention. The protection scope of the present invention should be determined by the appended claims.

[0029] The present invention provides a CA6-based medium bulk density insulating refractory, and the phases of the insulating refractory include CA6 and one or more phases selected from C2M2A14, CM2A8, magnesia alumina spinel, and corundum.

[0030] The phase of a substance is a phase having specific physical and chemical properties in the substance.

[0031] Here, C2M2A14 refers to 2CaO·2MgO·14Al2O3.

[0032] CM2A8 refers to CaO·2MgO·8Al2O3.

[0033] The phases of the heat-insulating refractory material are measured by XRD. For example, after grinding the material to be measured to 325 mesh or less, it is scanned by an X-ray diffractometer. By analyzing the diffraction data and comparing it with the standard PDF (Powder Diffraction File) card, the relevant phases are obtained, and by fitting the entire spectrum of the diffraction data, the content of the relevant phases is obtained.

[0034] In a preferred specific embodiment of the present invention, as the mass percentage in the heat-insulating refractory material, the total content of CA6, C2M2A14, CM2A8, corundum, and magnesia alumina spinel is 90% or more, preferably 94.8 to 99.5%.

[0035] For example, as the mass percentage in the heat-insulating refractory material, the total content of CA6, C2M2A14, CM2A8, magnesia alumina spinel, and corundum may be 90%, 91%, 92%, 93%, 94%, 95%, 96%, 96.2%, 96.55%, 96.6%, 96.8%, 97.1%, 97.5%, 97.7%, 97.8%, 97.9%, 98%, 98.05%, 98.95%, 99.15%, 100%, or any range therebetween.

[0036] In a preferred specific embodiment of the present invention, as the mass percentage in the phases of the heat-insulating refractory material, the CA6 phase is 26.7 to 100%, preferably 29.0 to 100%, preferably 31.5 to 100%, preferably 31.5 to 99.5%, more preferably 38.7 to 99.5%, the C2M2A14 phase is 0 to 72%, preferably 0 to 60%, the CM2A8 phase is 0 to 72%, preferably 0 to 60%, more preferably 0 to 59.5%, the magnesia alumina spinel phase is 0 to 10%, 0 to 8.0%, 0 to 4.60%, 0 to 4.0%, preferably 0. The cordierite phase is 0 to 30%, preferably 0 to 18%, more preferably 0 to 16.5%, still more preferably 0 to 15%, and most preferably 0 to 12%.

[0037] For example, as the mass percentage in the heat-insulating refractory material, the CA6 phase may be 26.7%, 28%, 30%, 35%, 40%, 45%, 50%, 55%, 60%, 65%, 70%, 75%, 80%, 85%, 90%, 95%, 97.8%, 99.5%, 100%, or any range therebetween.

[0038] The C2M2A14 phase may be 0, 5%, 10%, 15%, 20%, 24.5%, 25%, 30%, 35%, 35.2%, 40%, 45%, 50%, 55%, 60%, 65%, 70%, 71%, 72%, or any range therebetween.

[0039] The CM2A8 phase may be 0, 5%, 10%, 15%, 20%, 24%, 25%, 30%, 35%, 40%, 45%, 50%, 55%, 60%, 65%, 70%, 71%, 72%, or any range therebetween.

[0040] The cordierite phase may be 0, 5%, 10%, 12%, 15%, 18%, 20%, 25%, 30%, or any range therebetween.

[0041] The magnesia alumina spinel may be 0, 1%, 2%, 3%, 4%, 4.60%, 5%, 6%, 7%, 8%, 9%, 10%, or any range therebetween.

[0042] In a preferred specific embodiment of the present invention, the chemical composition of the heat-insulating refractory material includes Al2O3, CaO, and MgO, and as the mass percentage in the heat-insulating refractory material, the Al2O3 is 86.65 to 94.10%, preferably 87.60 to 94.10%, 86.65 to 92.80%, more preferably 88.07 to 94.10%, 87.50 to 92.60%, The CaO is 5.80 - 8.40%, preferably 6.10 - 8.40%, 6.89 - 8.40%, the MgO is 0 - 6.05%, preferably 0 - 5.53%, 0 - 5.43%, 0 - 5.04%.

[0043] As the mass percentage in the heat-insulating refractory material, the Al2O3 may be, for example, 86.65%, 87.60%, 88%, 89%, 90%, 91%, 92%, 93%, 94%, 94.10%, or any range therebetween. the CaO may be 5.80%, 6.0%, 7.0%, 8.0%, 8.40%, or any range therebetween. the MgO may be 0, 1.0%, 2.0%, 3.0%, 4.0%, 5.0%, 5.60%, 6.05%, or any range therebetween.

[0044] The chemical composition of the heat-insulating refractory material is measured by fluorescence analysis, i.e., XRF, in accordance with GB / T21114-2007.

[0045] In a preferred specific embodiment of the present invention, the bulk density of the heat-insulating refractory material is 2.40 - 2.90 g / cm 3 and preferably 2.40 - 2.82 g / cm 3 .

[0046] For example, the bulk density of the heat-insulating refractory material may be 2.40 g / cm 3 , 2.50 g / cm 3 , 2.55 g / cm 3 , 2.60 g / cm 3 , 2.70 g / cm 3 , 2.80 g / cm 3 , 2.90 g / cm 3 , or any range therebetween.

[0047] The bulk density of the heat-insulating refractory material is measured in accordance with GB / T2997-2000.

[0048] In a preferred specific embodiment of the present invention, the phases of the matrix portion of the heat-insulating refractory material include CA6 and one or more phases selected from corundum, magnesia alumina spinel, C2M2A14, and CM2A8.

[0049] Here, the matrix portion of the heat-insulating refractory material refers to the portion that does not contain the particles of the heat-insulating refractory material.

[0050] The phases of the matrix portion of the heat-insulating refractory material are measured by microdiffraction using XRD.

[0051] As an operation method, for example, a method of selecting seven different samples and cutting out seven samples from them can be considered. Microdiffraction is performed on each sample, and full-spectrum fitting is executed on the spectrum to determine the content of each phase. Excluding two data with large deviations, the average value of the phase contents of the remaining five samples is obtained, and this is taken as the phase content of the matrix of the heat-insulating refractory material. To ensure accurate analysis and small deviations, it is necessary to maximize the selected matrix region during sample preparation and scanning.

[0052] In a preferred specific embodiment of the present invention, as the mass percentage of the CA6 phase in the phases of the matrix portion of the heat-insulating refractory material, it is 67.4 to 100%, preferably 72.5 to 100%, 78.2 to 100%, 78.8 to 100%, the corundum phase is 0 to 30%, preferably 0 to 20%, 0 to 25%, the magnesia alumina spinel phase is 0 to 10%, 0 to 8.0%, 0 to 6.7%, 0 to 5.22%, preferably 0, the C2M2A14 phase is 0 to 30%, preferably 0 to 25%, 0 to 20%, 0 to 18.8%, the CM2A8 phase is 0 to 30%, preferably 0 to 25%, 0 to 20%, 0 to 18.8%.

[0053] For example, as the mass percentage of the CA6 phase in the phase of the matrix part of the heat-insulating refractory material, it may be 67.4%, 70%, 75%, 80%, 85%, 90%, 95%, 98.5%, 100%, or any range therebetween. The corundum phase may be 0, 5%, 10%, 15%, 20%, 25%, 30%, or any range therebetween. The magnesia alumina spinel phase may be 0, 1%, 2%, 3%, 4%, 4.85%, 5.22%, 6%, 7%, 8%, 9%, 10%, or any range therebetween. The C2M2A14 phase may be 0, 5%, 10%, 15%, 20%, 25%, 30%, or any range therebetween. The CM2A8 phase may be 0, 5%, 10%, 15%, 20%, 25%, 28.4%, 30%, or any range therebetween.

[0054] In a preferred specific embodiment of the present invention, the chemical composition of the matrix of the heat-insulating refractory material includes Al2O3, CaO, and MgO. As the mass percentage in the matrix part of the heat-insulating refractory material, the Al2O3 is 89.03 - 94.10%, preferably 89.03 - 93.65%, 90.30 - 93.20%, 89.03 - 93.28%. The CaO is 5.80 - 8.40%, preferably 6.25 - 8.40%, 6.60 - 8.40%. The MgO is 0 - 2.52%, preferably 0 - 2.10%, 0 - 1.68%.

[0055] For example, as the mass percentage in the matrix portion of the heat-insulating refractory material, the Al2O3 may be 89.03%, 90.55%, 91.00%, 91.10%, 91.20%, 91.30%, 91.40%, 91.50%, 91.60%, 91.70%, 91.80%, 91.90%, 92.00%, 92.10%, 92.20%, 92.30%, 92.40%, 92.50%, 92.60%, 92.70%, 92.80%, 92.90%, 93.00%, 93.10%, 93.20%, 93.30%, 93.40%, 93.50%, 93.60%, 93.70%, 93.80%, 93.90%, 94.00%, 94.10%, or any range therebetween; The CaO may be 5.80%, 5.85%, 5.90%, 6.00%, 6.10%, 6.20%, 6.30%, 6.40%, 6.50%, 6.60%, 6.70%, 6.80%, 6.90%, 7.00%, 7.10%, 7.20, 7.30%, 7.40%, 7.50%, 7.60%, 7.70%, 7.80%, 7.90%, 8.00%, 8.10%, 8.20%, 8.30%, 8.40%, or any range therebetween; The MgO may be 0, 1.00%, 1.10%, 1.20%, 1.30%, 1.40%, 1.48%, 1.50%, 1.60%, 1.70%, 1.80%, 1.90%, 2.00%, 2.10%, 2.20%, 2.30%, 2.52%, or any range therebetween.

[0056] The chemical composition of the matrix of the heat-insulating refractory material is measured by performing elemental analysis of the matrix portion of the sample, i.e., EDS analysis, under an electron microscope.

[0057] Preferably, this method includes the following steps. Select 10 different samples, cut out 12 or more samples from them, and polish the surfaces. Place each polished sample under an electron microscope, select the substrate part, select a rectangular area of a size suitable for element collection, convert the element content into oxides, and calculate the chemical composition content. Exclude two data with large deviations, and obtain the average values of the contents of Al2O3, CaO, and MgO of the 10 samples, which will be the chemical composition of the heat-insulating refractory. To ensure an accurate chemical composition with a small deviation, it is necessary to maximize the rectangular area selected when collecting elements.

[0058] In a preferred specific embodiment of the present invention, the heat-insulating refractory is manufactured by a method including the steps of mixing granular materials and fine powders to obtain a mixed material, and hot pressing and sintering the mixed material to obtain a refractory.

[0059] The granular materials refer to the parts that cannot be sieved by a 180-mesh square-hole sieve (Xinxiang Zhongtuo Machinery Equipment Co., Ltd.), that is, the parts above 180 mesh. The particle size of the granular materials is 180 mesh to 8 mm.

[0060] The fine powders refer to the parts that pass through a 180-mesh square-hole sieve, that is, the parts below the 180-mesh square-hole sieve, and their particle size is 180 mesh or less.

[0061] The hot pressing and sintering refers to a method of achieving the sintering of materials under the combined action of the applied pressure and temperature.

[0062] In a preferred specific embodiment of the present invention, the fine powders are one or more selected from CaO-containing fine powders, Al2O3-containing fine powders, and MgO-containing fine powders, Preferably, the CaO-containing fine powders are one or more selected from quicklime, limestone, calcium hydroxide, CaO·Al2O3, CaO·2Al2O3 (CA2), 12CaO·7Al2O3 (C12A7), CA6, C2M2A14, and CM2A8,​ Preferably, the Al2O3-containing fine powder is one or more fine powders selected from activated α-Al2O3 powder, γ-Al2O3 powder, ρ-Al2O3 powder, aluminum hydroxide, industrial alumina, white corundum powder, off-white corundum powder, dense corundum powder, sintered corundum powder, and tabular corundum powder, Preferably, the MgO-containing fine powder is one or more fine powders selected from magnesite, light burned magnesia, brucite, magnesium hydroxide, magnesium chloride, high-purity magnesia, and fused magnesia.

[0063] Here, the CaO-containing fine powder means a fine powder containing a CaO component in its chemical composition, or a fine powder containing CaO and Al2O3, or a fine powder containing CaO, MgO, and Al2O3.

[0064] The Al2O3-containing fine powder means an alumina-based fine powder whose chemical composition is mainly Al2O3.

[0065] The MgO-containing fine powder refers to a fine powder whose chemical composition is mainly MgO or Mg(OH)2.

[0066] The quicklime, also called burnt lime, is mainly composed of calcium oxide. Usually, natural rock mainly composed of calcium carbonate is calcined at high temperature to be decomposed into carbon dioxide and calcium oxide (chemical formula: CaO, that is, quicklime, also known as marble) for production.

[0067] The activated α-Al2O3 powder refers to a highly active alumina powder mainly composed of α-Al2O3 obtained by treating industrial alumina or aluminum hydroxide as raw materials at 1250 to 1450 °C.

[0068] The γ-Al2O3 powder is an alumina powder with a large specific surface area and good adsorbability obtained by high-temperature treatment using aluminum hydroxide as a raw material.

[0069] ρ-Al2O3 powder is alumina powder with a certain degree of hydration bonding property, which is obtained by rapid high-temperature treatment at 600-900 °C using aluminum hydroxide as the raw material.

[0070] Industrial alumina is an alumina-based raw material obtained by firing aluminum hydroxide as the raw material at 900-1250 °C.

[0071] White fused alumina powder is an alumina raw material with an aluminum oxide (Al2O3) content of 97.5% or more, which is manufactured by electric melting using industrial alumina as the raw material, contains trace components such as iron oxide and silicon oxide, and is white.

[0072] Sub-white fused alumina powder is manufactured using bauxite as the raw material. Since its chemical composition and physical properties are similar to those of white fused alumina, it is called sub-white fused alumina. This product is an ideal high-grade refractory and abrasive material that combines the hardness of white fused alumina and the toughness of brown fused alumina.

[0073] Sintered fused alumina powder refers to refractory clinker obtained by pulverizing alumina into pellets or green bodies and sintering at a high temperature of 1750-1900 °C. It has a high bulk density, a low porosity, and excellent thermal shock resistance and slag erosion resistance at high temperatures.

[0074] Tabular fused alumina powder has a coarse and well-developed α-Al2O3 crystal structure, an Al2O3 content of 97% or more, a tabular crystal structure, small pores, and many closed pores.

[0075] Light-burned magnesia is a magnesia-based raw material with high activity and a periclase phase, which is obtained by firing magnesite (the main component is magnesium carbonate) as the raw material at 800-1000 °C.

[0076] Brucite is a raw material with Mg(OH)2 as the main component.

[0077] High-purity magnesia is a sintered magnesia raw material with a MgO content of 96.5% or more, which is made from light-burned magnesia as a raw material, briquetted, and fired at high temperature.

[0078] Fused magnesia is a dense magnesia raw material with a MgO content of 96.5% or more, which is produced by arc melting using light-burned magnesia or magnesite as a raw material.

[0079] In a preferred specific embodiment of the present invention, when one or more CaO-containing fine powders among quicklime, limestone, calcium hydroxide, CaO·Al2O3, CaO·2Al2O3, 12CaO·7Al2O3 (these CaO-containing fine powders alone cannot form phases such as CA6 or CMA) are used as the raw material of the CaO component source in the substrate and the phases and chemical composition of the product substrate cannot be satisfied, the fine powders also include Al2O3-containing fine powders or Al2O3 fine powders and MgO-containing fine powders, and the specific situation is determined by the phases and chemical composition of the product. When using MgO-containing fine powders (these MgO-containing fine powders alone cannot form phases such as CA6 or CMA) and these MgO-containing fine powders alone cannot satisfy the phases and chemical composition of the product substrate, the fine powders also include Al2O3-containing fine powders or Al2O3 fine powders and CaO-containing fine powders, and the specific situation is determined by the phases and chemical composition of the product. When using Al2O3-containing fine powders and these Al2O3-containing fine powders alone cannot satisfy the phases and chemical composition of the product substrate, the fine powders also include CaO-containing fine powders or MgO-containing fine powders, or both CaO-containing fine powders and MgO-containing fine powders, and the specific situation is determined by the phases and chemical composition of the product.

[0080] In a preferred specific embodiment of the present invention, the granular material is one or more selected from CA6, C2M2A14, and CM2A8, preferably CA6.

[0081] In a preferred specific embodiment of the present invention, the mass ratio of the granular material to the fine powder is 0 to 60:40 to 100.

[0082] For example, the mass ratio of the granular material to the fine powder (i.e., the granular material / the fine powder) may be 0, 1 / 99, 2 / 98, 3 / 97, 4 / 96, 5 / 95, 6 / 94, 7 / 93, 8 / 92, 9 / 91, 10 / 90, 11 / 89, 12 / 88, 13 / 87, 14 / 86, 15 / 85, 16 / 84, 17 / 83, 18 / 82, 19 / 81, 20 / 80, 21 / 79, 22 / 78, 23 / 77, 24 / 76, 25 / 75, 26 / 74, 27 / 73, 28 / 72, 29 / 71, 30 / 70, 31 / 69, 32 / 68, 33 / 67, 34 / 66, 35 / 65, 36 / 64, 37 / 63, 38 / 62, 39 / 61, 40 / 60, 41 / 59, 42 / 58, 43 / 57, 44 / 56, 45 / 55, 46 / 54, 47 / 53, 48 / 52, 49 / 51, 50 / 50, 51 / 49, 52 / 48, 53 / 47, 54 / 46, 55 / 45, 56 / 44, 57 / 43, 58 / 42, 59 / 41, 60 / 40, or any range therebetween.

[0083] In a preferred specific embodiment of the present invention, the hot press sintering is to put the mixed material into a mold of a high-temperature device for hot press sintering, or to form the mixed material at room temperature and then put it into a mold of a high-temperature device for hot press sintering, or to form the mixed material at room temperature, pre-sinter it at a low temperature, and then perform hot press sintering.

[0084] For example, putting the mixed material into a mold of a high-temperature device and hot-press sintering means putting the mixed material into a mold of a high-temperature device, heating it, and then applying pressure and sintering it when the temperature reaches the maximum temperature; or putting the mixed material into a mold of a high-temperature device, heating it to a certain temperature, applying pressure, and then gradually increasing the temperature and increasing the pressure until the maximum temperature and pressure reach their maximum value, thereby completing hot-press sintering of the material; or putting the mixed material into a mold of a high-temperature device, gradually increasing the pressure applied to the mixed material while increasing the temperature until the temperature and pressure reach their maximum value, thereby completing hot-press sintering of the material.

[0085] The mixed material is molded at room temperature and then placed in a mold of a high-temperature device for hot-press sintering, which means that the mixed material is pressed at room temperature to form a body, or prefabricated at room temperature to form a body, dried, and then hot-press sintered. The hot-press sintering method is the same as above.

[0086] The mixed material is molded at room temperature, pre-sintered at a low temperature, and then hot-press sintered. This means that the mixed material is press-molded or prefabricated at a low temperature, pre-sintered at 1350 to 1500°C, and then placed in a mold of a high-temperature device for hot-press sintering.

[0087] The high-temperature device is a high-temperature device commonly used in this field, for example, a hot press furnace.

[0088] In a preferred specific embodiment of the present invention, the hot press sintering temperature is 1550 to 1750°C, and preferably the hot press strength is 0.5 to 10 MPa. For example, the temperature may be 1550°C, 1600°C, 1650°C, 1700°C, 1750°C, or any range therebetween.

[0089] The hot press strength may be, for example, 0.5 MPa, 1 MPa, 1.5 MPa, 2 MPa, 2.5 MPa, 3 MPa, 3.5 MPa, 4 MPa, 4.5 MPa, 5 MPa, 5.5 MPa, 6 MPa, 6.5 MPa, 7 MPa, 7.5 MPa, 8 MPa, 8.5 MPa, 9 MPa, 9.5 MPa, 10 MPa, or any range therebetween.

[0090] The present invention includes the steps of mixing a granular material with a fine powder to obtain a mixed material, and hot-pressing and sintering the mixed material to obtain a refractory material. The present invention provides a method for manufacturing an insulating fireproof material, comprising:

[0091] In a preferred specific embodiment of the present invention, the mass ratio of the granular material to the fine powder is 0-60:40-100.

[0092] In a preferred specific embodiment of the present invention, the hot-press sintering is performed by placing the mixed material in a mold of a high-temperature device and hot-press sintering it, or by molding the mixed material at room temperature and then placing it in a mold of a high-temperature device and hot-press sintering it, or by molding the mixed material at room temperature and pre-sintering it at a low temperature and then hot-press sintering it.

[0093] In a preferred specific embodiment of the present invention, the temperature is 1550 to 1750° C., and preferably the hot press strength is 0.5 to 10 MPa.

[0094] The CA6-based medium volume density insulating refractory material obtained by the present invention achieves good sintering of high-purity CA6-based materials, high material strength, a uniform microstructure, relatively uniform insulation and strength performance, and good resistance to slag and molten steel corrosion. It is therefore highly suitable for permanent linings of ladles, working linings and insulating linings for molten aluminum, and refractory linings for some industrial kilns, with excellent insulation, heat retention, and safety properties, bringing significant economic and social benefits.

[0095] The present invention provides a permanent lining for a ladle for refining molten steel, comprising the above-mentioned insulating refractory material or an insulating refractory material manufactured by the above-mentioned manufacturing method.

[0096] The present invention provides an insulating lining or working lining for a ladle for molten aluminum, which comprises the above-mentioned insulating refractory material or an insulating refractory material manufactured by the above-mentioned manufacturing method. [Example]

[0097] The present invention generally and / or specifically describes the materials and test methods used in the tests. In the following examples, unless otherwise specified, % stands for weight % (i.e., weight percentage). Unless the manufacturer of the raw materials or equipment used is specified, they are all commercially available conventional raw material products. Here, Table 1 shows the quality of the raw materials used in the examples.

[0098] [Table 1]

[0099] Example 1 (1) 500 g of CA6 granular material (maximum particle size 5 mm) and 500 g of CA6 fine powder were uniformly mixed to obtain a mixed material. (2) The mixed material was placed in a mold of a high-temperature device and directly hot-pressed and sintered. When the temperature reached a maximum of 1630°C, a pressure of 5 MPa was applied at this temperature to obtain a medium volume density refractory material. The phases of the resulting refractory material were analyzed by XRD. Specifically, the material to be measured was crushed to 325 mesh or less and then scanned using an X-ray diffractometer (Bruker: D8 ADVANCE). The diffraction data was analyzed and compared with a standard PDF card to obtain the relevant phases, and the content of the relevant phases was then obtained by full spectrum fitting of the diffraction data. As a result, the obtained phase was mainly CA6, and the content of the CA6 phase, as a mass percentage of the phases of the refractory material, was 99.5%. The chemical composition of the refractory material was analyzed by fluorescence analysis, i.e., XRF, in accordance with GB / T21114-2007. As the mass percentage in the refractory material, its chemical composition contained 91.04% of Al2O3 and 8.40% of CaO. The phase analysis of the matrix part in the refractory material was measured by micro diffraction using XRD. That is, 12 different refractory materials were selected, and 12 samples were cut out from them. From each sample, a matrix region with relatively uniform color and structure was selected for micro diffraction, and full-spectrum fitting was performed on the diffraction pattern to determine the content of each phase. Excluding the two data with large deviations, the average value of the phase contents of the remaining 10 samples was obtained and taken as the phase content of the matrix of the refractory material. The phase of the matrix part of the refractory material mainly contained CA6. As the mass percentage in the phase of the matrix part of the refractory material, the content of the CA6 phase was 99.2%. The chemical composition of the matrix part of the refractory material was measured by the EDS method. That is, 12 different refractory materials were selected, 12 samples were cut out from them, and the surfaces were polished. Each polished sample was placed under an electron microscope, and a region with a relatively uniform tissue structure in the matrix part was selected. A rectangular collection region of a size suitable for element collection was selected within this region to collect elements. The collected element contents were converted to oxides to calculate the chemical composition content. Excluding the two data with large deviations, the average values of the contents of Al2O3, CaO, and MgO in 10 samples were obtained and taken as the chemical composition of the matrix of the refractory material. As the mass percentage in the matrix part of the refractory material, the obtained chemical composition of the matrix part of the refractory material contained 91.20% of Al2O3 and 8.40% of CaO. When the CA6 series medium bulk density refractory material was measured in accordance with GB / T2997-2000, the obtained bulk density was 2.54 g / cm 3 It was. As a result of measurement according to the standard YB / T 4130-2005, the thermal conductivity of the refractory material obtained in Example 1 at 350 °C was 0.61 w / m·k. The manufactured material was produced in a crucible. Steelmaking slag was put into the crucible, heated up to 1500 °C, held for 3 hours, and then the cooled sample was cut along the center. When the thickness eroded by the steel slag of the sample was measured, it was 3.12 mm.

[0100] Example 2 (1) 400 g of CA6 granular material (maximum particle size is 3 mm), 280 g of CA6 fine powder, 188 g of γ-Al2O3 powder, 122 g of plate-shaped corundum powder, and 23 g of Ca(OH)2 fine powder were uniformly mixed to obtain a mixed material. (2) The above mixed material was press-molded at room temperature, lightly calcined at 1500 °C, then put into a mold of a high-temperature device. When the temperature rose to 1550 °C, pressure was gradually applied. When the maximum temperature rose to 1720 °C and the maximum hot press strength reached 1 MPa, a medium bulk density refractory was obtained. When the phase was analyzed in the same method as in Example 1, the phase of the medium bulk density refractory contained CA6 and corundum. As the mass percentage in the phase of the refractory, the content of the CA6 phase was 86.50%, and the content of the corundum phase was 12%. When the chemical composition was analyzed in the same method as in Example 1, as the mass percentage in the refractory, the chemical composition of the obtained medium bulk density refractory contained 92.60% of Al2O3 and 6.72% of CaO. When the phase of the substrate part was analyzed in the same method as in Example 1, the phase of the substrate part of the refractory contained CA6 and corundum. As the mass percentage in the phase of the substrate part of the refractory, the content of the CA6 phase was 78.8%, and the content of the corundum phase was 20%. When the chemical composition of the substrate part was analyzed in the same method as in Example 1, as the mass percentage in the substrate part of the refractory, the chemical composition of the substrate of the refractory contained 93.28% of Al2O3 and 6.60% of CaO. When the bulk density was analyzed in the same method as in Example 1, the bulk density of the medium bulk density refractory was 2.55 g / cm 3 It was. When analyzed in the same method as in Example 1, the thermal conductivity of the obtained refractory at 350 °C was 1.02 w / m.k. When measured in the same manner as in Example 1, the erosion thickness of the refractory material was 2.87 mm.

[0101] Example 3 (1) 500 g of CA6 granular material (maximum particle size: 3 mm), 400 g of CA6 fine powder, and 100 g of C2M2A14 powder were uniformly mixed to obtain a mixed material. (2) The mixed material was placed in a mold of a high-temperature device and directly hot-pressed and sintered. When the temperature reached a maximum of 1630°C, a pressure of 3 MPa was applied to obtain a medium-density refractory material. The phases were analyzed in the same manner as in Example 1. The phases of the medium volume density refractory material included CA6 and C2M2A14, and the content of the CA6 phase was 89.12% and the content of the C2M2A14 phase was 9.4%, in terms of mass percentages of the phases of the refractory material. The chemical composition was analyzed in the same manner as in Example 1, and the chemical composition of the obtained medium volume density refractory material was found to contain, as mass percentages of the refractory material, 91.03% Al2O3, 0.43% MgO, and 8.02% CaO. The phase of the matrix portion was analyzed using the same method as in Example 1. The phase of the matrix portion of the refractory material contained CA6 and C2M2A14, and the content of the CA6 phase was 78.2% and the content of the C2M2A14 phase was 18.8%, in terms of mass percentage, of the phase of the matrix portion of the refractory material. The chemical composition of the substrate portion was analyzed in the same manner as in Example 1, and the chemical composition of the substrate of the refractory material was found to contain 90.8% Al2O3, 0.8% MgO, and 8.0% CaO, as mass percentages of the substrate portion of the refractory material. When the volume density was analyzed in the same manner as in Example 1, the volume density of the medium volume density refractory material was 2.55 g / cm 3 It was. When analyzed in the same manner as in Example 1, the thermal conductivity of the resulting refractory material at 350°C was 0.95 w / mk. When measured in the same manner as in Example 1, the erosion thickness of the refractory material was 3.66 mm.

[0102] Example 4 (1) 500 g of CA6 granular material (maximum particle diameter 3 mm), 400 g of CA6 fine powder, 85.8 g of industrial alumina powder, 8.6 g of high-purity magnesia powder, and 7.8 g of calcium hydroxide powder were uniformly mixed to obtain a mixed material. (2) The mixed material was placed in a mold of a high-temperature device and directly hot-pressed and sintered. When the temperature reached a maximum of 1650°C, a pressure of 8 MPa was applied at this temperature to obtain a medium volume density refractory material. The phases were analyzed in the same manner as in Example 1. The phases of the medium volume density refractory material included CA6 and CM2A8, and the content of the CA6 phase was 89.04% and the content of the CM2A8 phase was 9.4%, in terms of mass percentages of the phases of the refractory material. The chemical composition was analyzed in the same manner as in Example 1, and the chemical composition of the obtained medium volume density refractory material was found to contain, as mass percentages of the refractory material, 90.34% Al2O3, 0.78% MgO, and 7.86% CaO. The phase of the matrix portion was analyzed using the same method as in Example 1. The phase of the matrix portion of the refractory material contained CA6 and CM2A8, and the content of the CA6 phase was 78.2% and the content of the CM2A8 phase was 18.8%, in terms of mass percentage, of the phase of the matrix portion of the refractory material. The chemical composition of the matrix portion was analyzed in the same manner as in Example 1, and the chemical composition of the matrix of the refractory material was found to contain 90.3% Al2O3, 1.68% MgO, and 7.81% CaO, as mass percentages of the matrix portion of the refractory material. When the volume density was analyzed in the same manner as in Example 1, the volume density of the medium volume density refractory material was 2.53 g / cm 3 It was. When analyzed in the same manner as in Example 1, the thermal conductivity of the resulting refractory material at 350°C was 0.96 w / mk. When measured in the same manner as in Example 1, the erosion thickness of the refractory material was 3.70 mm.

[0103] Example 5 (1) 200 g of CA6 granular material (maximum particle size: 3 mm), 200 g of C2M2A14 aggregate (maximum particle size: 3 mm), 540 g of CA6 fine powder, 4.3 g of quicklime powder, 3.05 g of fused magnesia, and 54 g of white corundum fine powder were uniformly stirred to obtain a mixed material. (2) After press-molding the mixed material, it was placed in a mold of a high-temperature device and hot press-sintered. While increasing the temperature from room temperature, pressure was gradually applied. The temperature rose to a maximum of 1710 °C, and the maximum hot press strength reached 2 MPa, obtaining a medium bulk density refractory material. When the phase was analyzed in the same manner as in Example 1, the phase of the medium bulk density refractory material contained CA6 and C2M2A14. As the mass percentage in the phase of the refractory material, the content of the CA6 phase was 71.30%, and the content of the C2M2A14 phase was 23.5%. When the chemical composition was analyzed in the same manner as in Example 1, as the mass percentage in the refractory material, the chemical composition of the obtained medium bulk density refractory material contained 88.67% of Al2O3, 1.03% of MgO, and 7.64% of CaO. When the phase of the matrix part was analyzed in the same manner as in Example 1, the phase of the matrix part of the refractory material contained CA6 and C2M2A14. As the mass percentage in the phase of the matrix part of the refractory material, the content of the CA6 phase was 87.2%, and the content of the C2M2A14 phase was 8.3%. When the chemical composition of the matrix part was analyzed in the same manner as in Example 1, as the mass percentage in the matrix part of the refractory material, the chemical composition of the matrix of the refractory material contained 89.03% of Al2O3, 0.35% of MgO, and 7.95% of CaO. When the bulk density was analyzed in the same manner as in Example 1, the bulk density of the medium bulk density refractory material was 2.55 g / cm 3 It was. When analyzed in the same manner as in Example 1, the thermal conductivity of the obtained refractory material at 350 °C was 0.84 w / m·K. When measured in the same manner as in Example 1, the erosion thickness of the refractory material was 3.46 mm.

[0104] Example 6 (1) 600 g of CM2A8 granular material (maximum particle size: 3 mm), 220 g of CA6 fine powder, 176 g of dense corundum fine powder, and 15.63 g of CaCO3 fine powder were uniformly mixed to obtain a mixed material. (2) The mixed material was placed into a mold of a high-temperature device and directly hot-pressed and sintered. When the maximum temperature rose to 1700 °C, a pressure with a hot-press strength of 4.5 MPa was applied at this temperature to obtain a medium bulk density refractory. When the phase was analyzed in the same method as in Example 1, the phases of the medium bulk density refractory included CA6, corundum, and CM2A8. As the mass percentage in the phases of the refractory, the content of the CA6 phase was 31.5%, the content of the corundum phase was 7.78%, and the content of the CM2A8 phase was 58.4%. When the chemical composition was analyzed in the same method as in Example 1, as the mass percentage in the refractory, the chemical composition of the obtained medium bulk density refractory included 87.92% of Al2O3, 4.82% of MgO, and 6.10% of CaO. When the phase of the matrix part was analyzed in the same method as in Example 1, the phases of the matrix part of the refractory included CA6 and corundum. As the mass percentage in the phases of the matrix part of the refractory, the content of the CA6 phase was 78.8%, and the content of the corundum phase was 20%. When the chemical composition of the matrix part was analyzed in the same method as in Example 1, as the mass percentage in the matrix part of the refractory, the chemical composition of the matrix of the refractory included 93.28% of Al2O3 and 6.60% of CaO. When the bulk density was analyzed in the same method as in Example 1, the bulk density of the medium bulk density refractory was 2.55 g / cm 3 It was. When analyzed in the same method as in Example 1, the thermal conductivity of the obtained refractory at 350 °C was 1.32 w / m·k. When measured in the same method as in Example 1, the erosion thickness of the refractory was 3.72 mm.

[0105] Example 7 (1) 835 g of CA6 fine powder, 60 g of plate-like corundum fine powder, and 110 g of ρ-Al2O3 fine powder were uniformly mixed to obtain a mixed material. (2) Water was added to the mixed material to form a preform, which was then dried. The mixture was then placed in a mold in a high-temperature device and heated. When the temperature reached a maximum of 1650°C, a pressure of 6 MPa was applied at this temperature to obtain a CA6-based medium volume density refractory material. The phases were analyzed in the same manner as in Example 1. The phases of the medium volume density refractory material contained CA6 and corundum, and the content of the CA6 phase, as a mass percentage of the phases of the refractory material, was 82.0% and the content of the corundum phase was 16.5%. The chemical composition was analyzed in the same manner as in Example 1, and the chemical composition of the obtained medium volume density refractory material was found to contain 91.6% Al2O3 and 6.92% CaO as mass percentages in the refractory material. The phase of the matrix portion was analyzed in the same manner as in Example 1. The phase of the matrix portion of the refractory material contained CA6 and corundum, and the content of the CA6 phase was 82.0% and the content of the corundum phase was 16.5%, in terms of mass percentage, of the phase of the matrix portion of the refractory material. The chemical composition of the substrate portion was analyzed using the same method as in Example 1, and the chemical composition of the substrate of the refractory material was found to contain 91.6% Al2O3 and 6.92% CaO as mass percentages of the substrate portion of the refractory material. When the volume density was analyzed in the same manner as in Example 1, the volume density of the medium volume density refractory material was 2.52 g / cm 3 It was. When analyzed in the same manner as in Example 1, the thermal conductivity of the resulting refractory material at 350°C was 0.9 w / mk. When measured in the same manner as in Example 1, the erosion thickness of the refractory material was 4.48 mm.

[0106] Example 8 (1) 800 g of CA6 fine powder, 100 g of plate-like corundum fine powder, and 105 g of ρ-Al2O3 fine powder were uniformly mixed to obtain a mixed material. (2) Water was added to the mixed material for pre - forming. After drying, it was put into the mold of a high - temperature device and heated. When the temperature rose to a maximum of 1600 °C, a pressure with a hot - press strength of 8 MPa was applied at this temperature to obtain a CA6 - based medium - bulk - density refractory material. When the phase was analyzed in the same way as in Example 1, the phases of the medium - bulk - density refractory material included CA6 and corundum. As the mass percentage in the phases of the refractory material, the content of the CA6 phase was 78.6%, and the content of the corundum phase was 20%. When the chemical composition was analyzed in the same way as in Example 1, as the mass percentage in the refractory material, the chemical composition of the obtained medium - bulk - density refractory material included 92.4% of Al2O3 and 6.52% of CaO. When the phase of the matrix part was analyzed in the same way as in Example 1, the phases of the matrix part of the refractory material included CA6 and corundum. As the mass percentage in the phases of the matrix part of the refractory material, the content of the CA6 phase was 78.6%, and the content of the corundum phase was 20%. When the chemical composition of the matrix part was analyzed in the same way as in Example 1, as the mass percentage in the matrix part of the refractory material, the chemical composition of the matrix of the refractory material included 92.4% of Al2O3 and 6.52% of CaO. When the bulk density was analyzed in the same way as in Example 1, the bulk density of the medium - bulk - density refractory material was 2.52 g / cm 3 . When analyzed in the same way as in Example 1, the thermal conductivity of the obtained refractory material at 350 °C was 0.92 w / m·k. When measured in the same way as in Example 1, the erosion thickness of the refractory material was 4.34 mm.

[0107] [[ID=ID=19]] Example 9 (1) 600 g of C2M2A14 granular material (maximum particle size is 5 mm), 85.7 g of CA6 fine powder, 308 g of aluminum hydroxide fine powder, 18.8 g of CaO fine powder, and 100 g of CM2A8 fine powder were uniformly mixed to obtain a mixed material. (2) Press-mold the mixed material at room temperature, perform light calcination treatment at 1450 °C, then put it into the mold of the high-temperature device and hot press sinter. When the temperature rises to a maximum of 1600 °C, apply a pressure at which the hot press strength is 3.8 MPa at this temperature to obtain a medium bulk density refractory material. When the phase was analyzed by the same method as in Example 1, the phases of the medium bulk density refractory material included CA6, C2M2A14, and CM2A8. As the mass percentage in the phases of the refractory material, the content of the CA6 phase was 29.0%, the content of the C2M2A14 phase was 60%, and the content of the CM2A8 phase was 8.41%. When the chemical composition was analyzed by the same method as in Example 1, as the mass percentage in the refractory material, the chemical composition of the obtained medium bulk density refractory material included 87.7% of Al2O3, 3.74% of MgO, and 6.68% of CaO. When the phase of the substrate part was analyzed by the same method as in Example 1, the phases of the substrate part of the refractory material included CA6 and CM2A8. As the mass percentage in the phases of the substrate part of the refractory material, the content of the CA6 phase was 72.5%, and the content of the CM2A8 phase was 25.0%. When the chemical composition of the substrate part was analyzed by the same method as in Example 1, as the mass percentage in the substrate part of the refractory material, the chemical composition of the substrate of the refractory material included 89.03% of Al2O3, 2.10% of MgO, and 7.02% of CaO. When the bulk density was analyzed by the same method as in Example 1, the bulk density of the medium bulk density refractory material was 2.55 g / cm 3 It was. When analyzed by the same method as in Example 1, the thermal conductivity of the obtained refractory material at 350 °C was 1.42 w / m.k. When measured by the same method as in Example 1, the erosion thickness of the refractory material was 4.21 mm.

[0108] Example 10 (1) 600 g of CM2A8 aggregate (maximum particle size is 5 mm), 200 g of CA6 fine powder, 100 g of C2M2A14 powder, 95 g of industrial alumina powder, and 8.7 g of CaO powder were uniformly stirred to obtain a mixed material. (2) Put the above-mentioned mixed material into the mold of the high-temperature device and directly hot press and sinter it. When the temperature rises to a maximum of 1690 °C, apply a pressure with a hot press strength of 3.4 MPa at this temperature to obtain a medium bulk density refractory material. When the phases were analyzed in the same manner as in Example 1, the phases of the medium bulk density refractory material included CA6, C2M2A14, and CM2A8. As the mass percentage in the phases of the refractory material, the content of the CA6 phase was 29%, the content of the C2M2A14 phase was 9.07%, and the content of the CM2A8 phase was 60%. When the chemical composition was analyzed in the same manner as in Example 1, as the mass percentage in the refractory material, the chemical composition of the obtained medium bulk density refractory material included 86.65% of Al2O3, 5.53% of MgO, and 6.22% of CaO. When the phases of the matrix part were analyzed in the same manner as in Example 1, the phases of the matrix part of the refractory material included CA6 and C2M2A14. As the mass percentage in the phases of the matrix part of the refractory material, the content of the CA6 phase was 72.5%, and the content of the C2M2A14 phase was 25.0%. When the chemical composition of the matrix part was analyzed in the same manner as in Example 1, as the mass percentage in the matrix part of the refractory material, the chemical composition of the matrix of the refractory material included 89.06% of Al2O3, 1.20% of MgO, and 7.64% of CaO. When the bulk density was analyzed in the same manner as in Example 1, the bulk density of the medium bulk density refractory material was 2.55 g / cm 3 . When analyzed in the same manner as in Example 1, the thermal conductivity of the obtained refractory material at 350 °C was 1.48 w / m.k. When measured in the same manner as in Example 1, the erosion thickness of the refractory material was 4.28 mm.

[0109] Example 11 (1) 600 g of CM2A8 granular material (maximum particle size is 3 mm), 200 g of CA6 fine powder, 280.2 g of aluminum hydroxide fine powder, and 22.2 g of calcium hydroxide fine powder were uniformly mixed to obtain a mixed material. (2) After press-forming the mixed material at room temperature, it was placed in a mold of a high-temperature device, and pressure was gradually applied while the temperature was raised from room temperature. The temperature rose to a maximum of 1700 °C, and the maximum hot press strength reached 2 MPa, obtaining a medium bulk density refractory material. When the phase was analyzed in the same manner as in Example 1, the phases of the medium bulk density refractory material included CA6 and CM2A8. As the mass percentage in the phases of the refractory material, the content of the CA6 phase was 38.7%, and the content of the CM2A8 phase was 59.5%. When the chemical composition was analyzed in the same manner as in Example 1, as the mass percentage in the refractory material, the chemical composition of the obtained medium bulk density refractory material included 88.07% of Al2O3, 5.04% of MgO, and 6.89% of CaO. When the phase of the matrix part was analyzed in the same manner as in Example 1, the phase of the matrix part of the refractory material included CA6. As the mass percentage in the phase of the matrix part of the refractory material, the content of the CA6 phase was 98.7%. When the chemical composition of the matrix part was analyzed in the same manner as in Example 1, as the mass percentage in the matrix part of the refractory material, the chemical composition of the matrix of the refractory material included 90.5% of Al2O3 and 8.40% of CaO. When the bulk density was analyzed in the same manner as in Example 1, the bulk density of the medium bulk density refractory material was 2.65 g / cm 3 . When analyzed in the same manner as in Example 1, the thermal conductivity of the obtained refractory material at 350 °C was 1.12 w / m·k. When measured in the same manner as in Example 1, the erosion thickness of the refractory material was 3.67 mm.

[0110] Example 12 (1) 600 g of C2M2A14 granular material (maximum particle size: 3 mm) and 400 g of CA6 fine powder were uniformly mixed to obtain a mixed material. (2) The mixed material was placed in a mold of a high-temperature device and hot press sintered. When the temperature rose to 1400 °C, pressure was gradually applied. The temperature rose to a maximum of 1720 °C, and the maximum hot press strength reached 10 MPa, obtaining a medium bulk density refractory material. The phases were analyzed in the same manner as in Example 1. The phases of the medium volume density refractory material included CA6 and C2M2A14, and the content of the CA6 phase was 38.7% and the content of the C2M2A14 phase was 60%, in terms of mass percentages of the phases of the refractory material. The chemical composition was analyzed in the same manner as in Example 1, and the chemical composition of the obtained medium volume density refractory material was found to contain, as mass percentages of the refractory material, 89.32% Al2O3, 2.74% MgO, and 7.41% CaO. When the phase of the substrate portion was analyzed using the same method as in Example 1, it was found that the phase of the substrate portion of the refractory material contained CA6, and the content of the CA6 phase in terms of mass percentage in the phase of the substrate portion of the refractory material was 100%. The chemical composition of the substrate portion was analyzed using the same method as in Example 1, and the chemical composition of the substrate of the refractory material was found to contain 90.8% Al2O3 and 8.40% CaO as mass percentages of the substrate portion of the refractory material. When the volume density was analyzed in the same manner as in Example 1, the volume density of the medium volume density refractory material was 2.82 g / cm 3 It was. When analyzed in the same manner as in Example 1, the thermal conductivity of the resulting refractory material at 350°C was found to be 1.55 w / mk. When measured in the same manner as in Example 1, the erosion thickness of the refractory material was 3.08 mm.

[0111] Example 13 (1) 600 g of CA6 fine powder, 247.8 g of plate-like corundum fine powder, 155 g of ρ-Al2O3 fine powder, and 8.7 g of CaO fine powder were uniformly mixed to obtain a mixed material. (2) Water was added to the mixed material to form a preform, which was then dried. The mixture was then placed in a mold in a high-temperature device and heated to a maximum temperature of 1550°C. At this temperature, a pressure of 10 MPa was applied to obtain a medium-volume density refractory material. The phases were analyzed in the same manner as in Example 1. The phases of the medium volume density refractory material contained CA6 and corundum, and the content of the CA6 phase, as a mass percentage of the phases of the refractory material, was 67.4%, and the content of the corundum phase was 30%. When the chemical composition was analyzed in the same manner as in Example 1, as the mass percentage in the refractory, the chemical composition of the obtained medium bulk density refractory contained 94.10% of Al2O3 and 5.80% of CaO. When the phase of the substrate portion was analyzed in the same manner as in Example 1, the phase of the substrate portion of the refractory contained CA6 and corundum. As the mass percentage in the phase of the substrate portion of the refractory, the content of the CA6 phase was 67.4% and the content of the corundum phase was 30%. When the chemical composition of the substrate portion was analyzed in the same manner as in Example 1, as the mass percentage in the substrate portion of the refractory, the chemical composition of the substrate of the refractory contained 94.10% of Al2O3 and 5.80% of CaO. When the bulk density was analyzed in the same manner as in Example 1, the bulk density of the medium bulk density refractory was 2.55 g / cm 3 It was. When analyzed in the same manner as in Example 1, the thermal conductivity of the obtained refractory at 350 °C was 1.02 w / m·K. When measured in the same manner as in Example 1, the erosion thickness of the refractory was 4.55 mm.

[0112] Example 14 (1) 600 g of CM2A8 granular material (maximum particle size: 3 mm), 320 g of CA6 fine powder, and 80 g of CM2A8 fine powder were uniformly mixed to obtain a mixed material. (2) The mixed material was press-molded at room temperature and then placed in a mold of a high-temperature device for hot press sintering. When the temperature rose to a maximum of 1670 °C, pressure was applied at this temperature to obtain a hot press strength of 0.5 MPa, and a medium bulk density refractory was obtained. When the phase was analyzed in the same manner as in Example 1, the phase of the medium bulk density refractory contained CA6 and CM2A8. As the mass percentage in the phase of the refractory, the content of the CA6 phase was 31.5% and the content of the CM2A8 phase was 67.1%. The chemical composition was analyzed in the same manner as in Example 1, and the chemical composition of the obtained medium volume density refractory material was found to contain, as mass percentages of the refractory material, 87.60% Al2O3, 5.62% MgO, and 6.43% CaO. The phase of the matrix portion was analyzed using the same method as in Example 1. The phase of the matrix portion of the refractory material contained CA6 and CM2A8, and the content of the CA6 phase was 78.2% and the content of the CM2A8 phase was 19.2%, in terms of mass percentage, of the phase of the matrix portion of the refractory material. The chemical composition of the matrix portion was analyzed in the same manner as in Example 1, and the chemical composition of the matrix of the refractory material was found to contain 90.30% Al2O3, 1.68% MgO, and 7.82% CaO, as mass percentages of the matrix portion of the refractory material. When the volume density was analyzed in the same manner as in Example 1, the volume density of the medium volume density refractory material was 2.63 g / cm 3 It was. When analyzed in the same manner as in Example 1, the thermal conductivity of the resulting refractory material at 350°C was found to be 1.29 w / mk. When measured in the same manner as in Example 1, the erosion thickness of the refractory material was 4.06 mm.

[0113] Example 15 (1) 947.4 g of CA6 fine powder, 15 g of electrofused magnesia fine powder, and 38 g of activated α-Al2O3 fine powder were uniformly mixed to obtain a mixed material. (2) The mixed material was press-molded at room temperature and lightly baked at 1350°C. Then, it was placed in a mold of a high-temperature device. When the temperature rose to 1500°C, pressure was applied. The maximum temperature was 1580°C, and the maximum hot press strength was 5 MPa, resulting in a medium volume density refractory material. The phases were analyzed in the same manner as in Example 1. The phases of the medium volume density refractory material included CA6 and C2M2A14, and the content of the CA6 phase was 67.4% and the content of the C2M2A14 phase was 30%, in terms of mass percentages of the phases of the refractory material. When the chemical composition was analyzed in the same manner as in Example 1, as the mass percentage in the refractory, the chemical composition of the obtained medium bulk density refractory contained 89.32% of Al2O3, 1.38% of MgO, and 7.81% of CaO. When the bulk density was analyzed in the same manner as in Example 1, the bulk density of the medium bulk density refractory was 2.48 g / cm 3 . When analyzed in the same manner as in Example 1, the thermal conductivity of the obtained refractory at 350 °C was 1.00 w / m·k. When measured in the same manner as in Example 1, the erosion thickness of the refractory was 5.60 mm.

[0114] Example 16 (1) 600 g of CM2A8 granular material (maximum particle size: 8 mm), 80 g of CA6 fine powder, 281 g of aluminum hydroxide fine powder, 17.5 g of lime fine powder, and 120 g of CM2A8 fine powder were uniformly mixed to obtain a mixed material. (2) The mixed material was press-molded at room temperature, lightly calcined at 1400 °C, then placed in a mold of a high-temperature device and hot press sintered. When the temperature rose to 1500 °C, pressure was applied, and the pressure was gradually increased as the temperature rose. When the temperature rose to a maximum temperature of 1750 °C, the maximum hot press strength became 0.5 MPa, and a medium bulk density refractory was obtained. When the phase was analyzed in the same manner as in Example 1, the phase of the medium bulk density refractory contained CA6 and CM2A8. As the mass percentage in the phase of the refractory, the content of the CA6 phase was 26.7%, and the content of the CM2A8 phase was 72%. When the chemical composition was analyzed in the same manner as in Example 1, as the mass percentage in the refractory, the chemical composition of the obtained medium bulk density refractory contained 86.65% of Al2O3, 6.05% of MgO, and 6.22% of CaO. When the phase of the matrix part was analyzed in the same manner as in Example 1, the phase of the matrix part of the refractory contained CA6 and CM2A8. As the mass percentage in the phase of the matrix part of the refractory, the content of the CA6 phase was 68%, and the content of the corundum phase was 30%. The chemical composition of the matrix portion was analyzed in the same manner as in Example 1, and the chemical composition of the matrix of the refractory material was found to contain 89.03% Al2O3, 2.52% MgO, and 7.60% CaO, as mass percentages of the matrix portion of the refractory material. When the volume density was analyzed in the same manner as in Example 1, the volume density of the medium volume density refractory material was 2.90 g / cm 3 It was. When analyzed in the same manner as in Example 1, the thermal conductivity of the resulting refractory material at 350°C was found to be 1.71 w / mk. When measured in the same manner as in Example 1, the erosion thickness of the refractory material was 2.94 mm.

[0115] Example 17 (1) 100 g of C2M2A14 granular material (maximum particle diameter 1 mm), 630 g of CA6 fine powder, 18.7 g of quicklime fine powder, 13.4 g of high-purity magnesia powder, 180 g of white corundum fine powder, and 58 g of activated α-Al2O3 powder were uniformly mixed to obtain a mixed material. (2) The mixed material was press-molded at room temperature, lightly baked at 1450°C, and then placed in a mold in a high-temperature device for hot-press sintering. When the temperature rose to 1500°C, pressure was applied. When the temperature rose to a maximum of 1620°C, the maximum hot-press strength reached 8 MPa, and a medium-volume density refractory material was obtained. The phases were analyzed in the same manner as in Example 1. The phases of the medium volume density refractory material were found to include CA6, C2M2A14, and MgO·Al2O3, and the mass percentages of the phases of the refractory material were as follows: the CA6 phase content was 84.2%, the C2M2A14 phase content was 9.28%, and the MgO·Al2O3 phase content was 4.60%. The chemical composition was analyzed in the same manner as in Example 1, and the chemical composition of the obtained medium volume density refractory material was found to contain, as mass percentages of the refractory material, 89.14% Al2O3, 1.71% MgO, and 7.65% CaO. When the phase of the substrate portion was analyzed in the same manner as in Example 1, the phase of the substrate portion of the refractory contained CA6 and MgO·Al2O3. As the mass percentage in the phase of the substrate portion of the refractory, the content of the CA6 phase was 93.5%, and the content of the MgO·Al2O3 phase was 5.22%. When the chemical composition of the substrate portion was analyzed in the same manner as in Example 1, as the mass percentage in the substrate portion of the refractory, the chemical composition of the substrate of the refractory contained 90.07% of Al2O3, 1.32% of MgO, and 7.67% of CaO. When the bulk density was analyzed in the same manner as in Example 1, the bulk density of the medium bulk density refractory was 2.57 g / cm 3 It was as follows. When analyzed in the same manner as in Example 1, the thermal conductivity of the obtained refractory at 350 °C was 1.15 w / m·k. When measured in the same manner as in Example 1, the erosion thickness of the refractory was 5.04 mm.

[0116] Example 18 (1) 700 g of CA6 fine powder, 150 g of tabular corundum fine powder, and 155 g of ρ-Al2O3 fine powder were uniformly mixed to obtain a mixed material. (2) Water was added to the mixed material for preforming. After drying, it was put into a mold of a high-temperature device and heated. When the temperature rose to a maximum temperature of 1550 °C, a pressure with a hot press strength of 10 MPa was applied at this temperature to obtain a CA6-based medium bulk density refractory. When the phase was analyzed in the same manner as in Example 1, the phase of the medium bulk density refractory contained CA6 and corundum. As the mass percentage in the phase of the refractory, the content of the CA6 phase was 66.4%, and the content of the corundum phase was 30%. When the chemical composition was analyzed in the same manner as in Example 1, as the mass percentage in the refractory, the chemical composition of the obtained medium bulk density refractory contained 94.10% of Al2O3 and 5.80% of CaO. When the bulk density was analyzed in the same manner as in Example 1, the bulk density of the medium bulk density refractory was 2.52 g / cm 3 It was as follows. When analyzed by the same method as in Example 1, the thermal conductivity of the obtained refractory material at 350 °C was 1.02 w / m·K. When measured by the same method as in Example 1, the erosion thickness of the refractory material was 4.55 mm.

[0117] Example 19 (1) 600 g of C2M2A14 granular material (maximum particle size is 10 mm), 280 g of CA6 fine powder, and 120 g of C2M2A14 fine powder were uniformly mixed to obtain a mixed material. (2) The mixed material was put into a mold of a high-temperature device and hot-pressed and sintered. While heating up from room temperature, pressure was gradually applied. The temperature rose to a maximum of 1610 °C, and the maximum hot-press strength became 6 MPa, obtaining a medium bulk density refractory material. When the phase was analyzed by the same method as in Example 1, the phase of the medium bulk density refractory material included CA6 and C2M2A14. As the mass percentage in the phase of the refractory material, the content of the CA6 phase was 26.7%, and the content of the C2M2A14 phase was 72%. When the chemical composition was analyzed by the same method as in Example 1, as the mass percentage in the refractory material, the chemical composition of the obtained medium bulk density refractory material included 88.87% of Al2O3, 3.36% of MgO, and 7.16% of CaO. When the phase of the substrate part was analyzed by the same method as in Example 1, the phase of the substrate part of the refractory material included CA6 and C2M2A14. As the mass percentage in the phase of the substrate part of the refractory material, the content of the CA6 phase was 68.1%, and the content of the C2M2A14 phase was 30%. When the chemical composition of the substrate part was analyzed by the same method as in Example 1, as the mass percentage in the substrate part of the refractory material, the chemical composition of the substrate of the refractory material included 90.46% of Al2O3, 1.31% of MgO, and 7.82% of CaO. When the bulk density was analyzed by the same method as in Example 1, the bulk density of the medium bulk density refractory material was 2.60 g / cm 3 It was. When analyzed by the same method as in Example 1, the thermal conductivity of the obtained refractory material at 350 °C was 1.21 w / m·K. When measured by the same method as in Example 1, the erosion thickness of the refractory material was 4.9 mm.

[0118] Example 20 (1) 400 g of CA6 granular material (maximum particle size: 3 mm), 280 g of CA6 fine powder, 184 g of γ-Al2O3 powder, 120 g of tabular corundum powder, and 22.2 g of Ca(OH)2 fine powder were uniformly mixed to obtain a mixed material. (2) The mixed material was press-molded at room temperature and lightly calcined at 1500 °C. Then, it was placed in a mold of a high-temperature device. When the temperature rose to 1550 °C, pressure was gradually applied. When the maximum temperature rose to 1750 °C and the maximum hot press strength reached 6 MPa, a medium bulk density refractory material was obtained. When the phases were analyzed by the same method as in Example 1, the phases of the medium bulk density refractory material included CA6 and corundum. As the mass percentage in the phases of the refractory material, the content of the CA6 phase was 85.50%, and the content of the corundum phase was 11.8%. When the chemical composition was analyzed by the same method as in Example 1, as the mass percentage in the refractory material, the chemical composition of the obtained medium bulk density refractory material included 92.03% of Al2O3 and 7.18% of CaO. When the phases of the substrate part were analyzed by the same method as in Example 1, the phases of the substrate part of the refractory material included CA6 and corundum. As the mass percentage in the phases of the substrate part of the refractory material, the content of the CA6 phase was 77.2%, and the content of the corundum phase was 20%. When the chemical composition of the substrate part was analyzed by the same method as in Example 1, as the mass percentage in the substrate part of the refractory material, the chemical composition of the substrate of the refractory material included 93.2% of Al2O3 and 6.61% of CaO. When the bulk density was analyzed by the same method as in Example 1, the bulk density of the medium bulk density refractory material was 2.90 g / cm 3 It was. When analyzed by the same method as in Example 1, the thermal conductivity of the obtained refractory material at 350 °C was 1.67 w / m·K. When measured by the same method as in Example 1, the erosion thickness of the refractory material was 2.73 mm.

[0119] Example 21 (1) 100 g of C2M2A14 granular material (maximum particle size: 1 mm), 324 g of CA6 fine powder, 53 g of quicklime fine powder, 28.5 g of high-purity magnesia powder, 400 g of white corundum fine powder, and 108 g of active α-Al2O3 powder were uniformly mixed to obtain a mixed material. (2) The mixed material was press-molded at room temperature, lightly calcined at 1450 °C, then placed in a mold of a high-temperature device and hot-pressed and sintered. When the temperature rose to 1500 °C, pressure was applied. When the temperature rose to a maximum temperature of 1550 °C, the maximum hot-press strength reached 1 MPa, and a medium bulk density refractory was obtained. When the phase was analyzed in the same manner as in Example 1, the phases of the medium bulk density refractory included CA6, C2M2A14, and MgO·Al2O3. As the mass percentage in the phases of the refractory, the content of the CA6 phase was 70.7%, the content of the C2M2A14 phase was 9.28%, and the content of the MgO·Al2O3 phase was 10.0%. When the chemical composition was analyzed in the same manner as in Example 1, as the mass percentage in the refractory, the chemical composition of the obtained medium bulk density refractory included 88.5% of Al2O3, 3.02% of MgO, and 7.21% of CaO. When the phase of the substrate part was analyzed in the same manner as in Example 1, the phases of the substrate part of the refractory included CA6 and MgO·Al2O3. As the mass percentage in the phases of the substrate part of the refractory, the content of the CA6 phase was 78.6%, and the content of the MgO·Al2O3 phase was 11.2%. When the chemical composition of the substrate part was analyzed in the same manner as in Example 1, as the mass percentage in the substrate part of the refractory, the chemical composition of the substrate of the refractory included 89.3% of Al2O3, 2.95% of MgO, and 7.20% of CaO. When the bulk density was analyzed in the same manner as in Example 1, the bulk density of the medium bulk density refractory was 2.85 g / cm 3 . When analyzed in the same manner as in Example 1, the thermal conductivity of the obtained refractory at 350 °C was 1.96 w / m·k. When measured by the same method as in Example 1, the erosion thickness of the refractory was 4.83 mm.

[0120] Example 22 (1) 600 g of C2M2A14 granular material (maximum particle size 3 mm), 220 g of CA6 fine powder, 165.8 g of industrial alumina powder, 6.9 g of high-purity magnesia powder, and 18 g of calcium hydroxide powder were uniformly mixed to obtain a mixed material. (2) The mixed material was press-molded at room temperature, lightly calcined at 1450 °C, then placed in a mold of a high-temperature device and hot press-sintered. While raising the temperature from room temperature, pressure was gradually applied, and the temperature rose to a maximum of 1730 °C, with a maximum hot press strength of 1.5 MPa, to obtain a medium bulk density refractory. When the phases were analyzed by the same method as in Example 1, the phases of the medium bulk density refractory included CA6, C2M2A14, and CM2A8. As the mass percentage in the phases of the refractory, the content of the CA6 phase was 31.5%, the content of the C2M2A14 phase was 60%, and the content of the CM2A8 phase was 7.48%. When the chemical composition was analyzed by the same method as in Example 1, as the mass percentage in the refractory, the chemical composition of the obtained medium bulk density refractory included 88.08% of Al2O3, 3.41% of MgO, and 7.15% of CaO. When the phases of the matrix part were analyzed by the same method as in Example 1, the phases of the matrix part of the refractory included CA6 and CM2A8. As the mass percentage in the phases of the matrix part of the refractory, the content of the CA6 phase was 78.8%, and the content of the CM2A8 phase was 20%. When the chemical composition of the matrix part was analyzed by the same method as in Example 1, as the mass percentage in the matrix part of the refractory, the chemical composition of the matrix of the refractory included 89.03% of Al2O3, 1.68% of MgO, and 7.74% of CaO. When the bulk density was analyzed by the same method as in Example 1, the bulk density of the medium bulk density refractory was 2.55 g / cm 3 It was. When analyzed by the same method as in Example 1, the thermal conductivity of the obtained refractory at 350 °C was 1.23 w / m.k. When measured in the same manner as in Example 1, the erosion thickness of the refractory material was 3.82 mm.

[0121] Example 23 (1) 600 g of CM2A8 granular material (maximum particle size: 3 mm), 220 g of CA6 fine powder, 80 g of C2M2A14 fine powder, 94 g of activated alumina fine powder, and 8.75 g of CaO fine powder were uniformly mixed to obtain a mixed material. (2) The mixed material was press-molded at room temperature, then placed in a mold in a high-temperature device and hot-pressed and sintered. When the temperature rose to a maximum of 1740°C, pressure was applied at this temperature, and the hot-press strength reached 0.5 MPa, yielding a medium-volume density refractory material. The phases were analyzed in the same manner as in Example 1. The phases of the medium volume density refractory material included CA6, C2M2A14, and CM2A8, and the content of the CA6 phase, C2M2A14 phase, and CM2A8 phase, as mass percentages of the phases of the refractory material, was 31.5%, 8%, and 60%, respectively. The chemical composition was analyzed in the same manner as in Example 1, and the chemical composition of the obtained medium volume density refractory material was found to contain, as mass percentages of the refractory material, 87.50% Al2O3, 5.43% MgO, and 6.08% CaO. The phase of the matrix portion was analyzed using the same method as in Example 1. The phase of the matrix portion of the refractory material contained CA6 and C2M2A14, and the content of the CA6 phase was 78.8% and the content of the C2M2A14 phase was 20%, in terms of mass percentage, of the phase of the matrix portion of the refractory material. The chemical composition of the matrix portion was analyzed in the same manner as in Example 1, and the chemical composition of the matrix of the refractory material was found to contain 90.60% Al2O3, 0.98% MgO, and 7.76% CaO, as mass percentages of the matrix portion of the refractory material. When the volume density was analyzed in the same manner as in Example 1, the volume density of the medium volume density refractory material was 2.55 g / cm 3 It was. When analyzed in the same manner as in Example 1, the thermal conductivity of the resulting refractory material at 350°C was found to be 1.30 w / mk. When measured in the same manner as in Example 1, the erosion thickness of the refractory material was 3.84 mm.

[0122] Example 24 (1) 400 g of CA6 aggregate (maximum particle size 3 mm), 450 g of CA6 fine powder, 238.40 g of industrial alumina fine powder, 11.8 g of electrofused magnesia fine powder, and 8.7 g of CaO powder were uniformly mixed to obtain a mixed material. (2) The mixed material was press-molded at room temperature, then placed in a mold in a high-temperature device and hot-pressed and sintered. When the temperature rose to a maximum of 1570°C, pressure was applied at this temperature, and the hot-press strength reached 8 MPa, yielding a medium-volume density refractory material. The phases were analyzed in the same manner as in Example 1. The phases of the medium volume density refractory material included CA6, corundum, and MgAl2O4, and the mass percentages of the phases of the refractory material were as follows: the CA6 phase content was 82.8%, the corundum phase content was 9.72%, and the MgAl2O4 phase content was 4.0%. The chemical composition was analyzed in the same manner as in Example 1, and the chemical composition of the obtained medium volume density refractory material was found to contain, as mass percentages of the refractory material, 89.31% Al2O3, 1.14% MgO, and 6.92% CaO. The phases of the matrix portion were analyzed in the same manner as in Example 1. The phases of the matrix portion of the refractory material included CA6, corundum, and MgAl2O4, and the content of the CA6 phase, the corundum phase, and the MgAl2O4 phase, as mass percentages of the phases of the matrix portion of the refractory material, were 73.8%, 16.3%, and 6.7%, respectively. The chemical composition of the matrix portion was analyzed in the same manner as in Example 1, and the chemical composition of the matrix of the refractory material was found to contain 90.28% Al2O3, 1.91% MgO, and 6.25% CaO, as mass percentages of the matrix portion of the refractory material. When the volume density was analyzed in the same manner as in Example 1, the volume density of the medium volume density refractory material was 2.55 g / cm 3 It was. When analyzed in the same manner as in Example 1, the thermal conductivity of the resulting refractory material at 350°C was found to be 1.34 w / mk. When measured in the same manner as in Example 1, the erosion thickness of the refractory material was 3.86 mm.

[0123] Example 25 (1) 400 g of CA6 granular material (maximum particle size 3 mm), 80 g of 12CaO·7Al2O3 fine powder, 384 g of activated α-Al2O3 fine powder, and 154 g of white corundum powder were uniformly mixed to obtain a mixed material. (2) The mixed material was press-molded at room temperature and lightly baked at 1480°C. Then, it was placed in a mold of a high-temperature device. When the temperature rose to 1600°C, pressure was gradually applied until the maximum temperature reached 1670°C. The maximum hot-press strength was 5.5 MPa, and a medium-volume density refractory material was obtained. The phases were analyzed in the same manner as in Example 1. The phases of the medium volume density refractory material contained CA6 and corundum, and the content of the CA6 phase was 82.7% and the content of the corundum phase was 15%, in terms of mass percentages in the phases of the refractory material. The chemical composition was analyzed in the same manner as in Example 1, and the chemical composition of the obtained medium volume density refractory material was found to contain 92.80% Al2O3 and 6.52% CaO as mass percentages in the refractory material. The phase of the matrix portion was analyzed in the same manner as in Example 1. The phase of the matrix portion of the refractory material contained CA6 and corundum, and the content of the CA6 phase was 72.5% and the content of the corundum phase was 25%, in terms of mass percentage, of the phase of the matrix portion of the refractory material. The chemical composition of the substrate portion was analyzed in the same manner as in Example 1, and the chemical composition of the substrate of the refractory material was found to contain 93.65% Al2O3 and 6.25% CaO as mass percentages of the substrate portion of the refractory material. When the volume density was analyzed in the same manner as in Example 1, the volume density of the medium volume density refractory material was 2.55 g / cm 3 It was. When analyzed in the same manner as in Example 1, the thermal conductivity of the resulting refractory material at 350°C was 1.37 w / mk. When measured in the same manner as in Example 1, the erosion thickness of the refractory was 3.74 mm.

[0124] Example 26 (1) 600 g of CM2A8 granular material (maximum particle size: 3 mm), 200 g of CA6 fine powder, 144.5 g of plate-shaped corundum fine powder, 52.5 g of ρ-Al2O3 fine powder, and 8.7 g of CaO fine powder were uniformly mixed to obtain a mixed material. (2) After the mixed material was press-molded at room temperature, it was placed in a mold of a high-temperature device and hot press sintered. When the temperature rose to a maximum of 1680 °C, pressure was applied at this temperature to obtain a medium bulk density refractory with a hot press strength of 4.8 MPa. When the phase was analyzed in the same manner as in Example 1, the phases of the medium bulk density refractory included CA6, corundum, and CM2A8. As the mass percentage in the phases of the refractory, the content of the CA6 phase was 29.0%, the content of the corundum phase was 9.15%, and the content of the CM2A8 phase was 57.5%. When the chemical composition was analyzed in the same manner as in Example 1, as the mass percentage in the refractory, the chemical composition of the obtained medium bulk density refractory included 88.91% of Al2O3, 4.92% of MgO, and 5.80% of CaO. When the phase of the substrate part was analyzed in the same manner as in Example 1, the phases of the substrate part of the refractory included CA6 and corundum. As the mass percentage in the phases of the substrate part of the refractory, the content of the CA6 phase was 73.1%, and the content of the corundum phase was 25.0%. When the chemical composition of the substrate part was analyzed in the same manner as in Example 1, as the mass percentage in the substrate part of the refractory, the chemical composition of the substrate of the refractory included 93.65% of Al2O3 and 6.25% of CaO. When the bulk density was analyzed in the same manner as in Example 1, the bulk density of the medium bulk density refractory was 2.55 g / cm 3 It was. When analyzed in the same manner as in Example 1, the thermal conductivity of the obtained refractory at 350 °C was 1.53 w / m·K. When measured by the same method as in Example 1, the erosion thickness of the refractory was 3.98 mm.

[0125] Example 27 (1) 100 g of CA6 aggregate (maximum particle size is 1 mm), 630 g of CA6 fine powder, 92 g of sintered corundum powder (97.8), 162 g of γ-Al2O3 fine powder, and 42 g of limestone fine powder were uniformly mixed to obtain a mixed material. (2) After the mixed material was press-molded at room temperature, it was placed in a mold of a high-temperature device. When the temperature rose to 1450 °C, pressure was gradually applied. When the temperature rose to a maximum temperature of 1580 °C and the maximum hot press strength became 7 MPa, a medium bulk density refractory was obtained. When the phases were analyzed by the same method as in Example 1, the phase of the medium bulk density refractory contained CA6. As the mass percentage in the phase of the refractory, the content of the CA6 phase was 100%. When the chemical composition was analyzed by the same method as in Example 1, as the mass percentage in the refractory, the chemical composition of the obtained medium bulk density refractory contained 91.2% of Al2O3 and 8.40% of CaO. When the phases of the substrate part were analyzed by the same method as in Example 1, the phase of the substrate part of the refractory contained CA6. As the mass percentage in the phase of the substrate part of the refractory, the content of the CA6 phase was 100%. When the chemical composition of the substrate part was analyzed by the same method as in Example 1, as the mass percentage in the substrate part of the refractory, the chemical composition of the substrate of the refractory contained 91.1% of Al2O3 and 8.40% of CaO. When the bulk density was analyzed by the same method as in Example 1, the bulk density of the medium bulk density refractory was 2.55 g / cm 3 It was. When analyzed by the same method as in Example 1, the thermal conductivity of the obtained refractory at 350 °C was 0.56 w / m·k. When measured by the same method as in Example 1, the erosion thickness of the refractory was 4.66 mm.

[0126] Example 28 (1) 940 g of activated alumina fine powder, 24.4 g of light-burned magnesia powder, and 80.9 g of Ca(OH) were uniformly mixed to obtain a mixed material. (2) The mixed material was press-molded at room temperature, lightly baked at 1350°C, and then placed in a mold in a high-temperature device for hot-press sintering. When the temperature rose to a maximum of 1560°C, a pressure of 9 MPa was applied at this temperature to obtain a medium-volume density refractory material. The phases were analyzed in the same manner as in Example 1. The phases of the medium volume density refractory material included CA6, corundum, and MgAl2O4, and the mass percentages of the phases of the refractory material were as follows: the CA6 phase content was 61.7%, the corundum phase content was 20.3%, and the MgAl2O4 phase content was 8%. The chemical composition was analyzed in the same manner as in Example 1, and the chemical composition of the obtained medium volume density refractory material was found to contain, as mass percentages of the refractory material, 90.04% Al2O3, 2.25% MgO, and 5.80% CaO. When the volume density was analyzed in the same manner as in Example 1, the volume density of the medium volume density refractory material was 2.55 g / cm 3 It was. When analyzed in the same manner as in Example 1, the thermal conductivity of the resulting refractory material at 350°C was 0.95 w / mk. When measured in the same manner as in Example 1, the erosion thickness of the refractory material was 4.72 mm.

[0127] Example 29 (1) 500 g of CA6 granular material (maximum particle size: 5 mm) and 500 g of CA6 fine powder were uniformly mixed to obtain a mixed material. (2) The mixed material was placed in a mold of a high-temperature device and hot-pressed and sintered. When the temperature reached 1620°C, pressure was applied, and the maximum hot-press strength reached 3 MPa, resulting in a medium-volume density refractory material. The phases were analyzed in the same manner as in Example 1, and it was found that the phase of the medium volume density refractory material contained CA6, and the content of the CA6 phase in terms of mass percentage of the phase of the refractory material was 99.5%. When the chemical composition was analyzed in the same manner as in Example 1, as the mass percentage in the refractory, the chemical composition of the obtained medium bulk density refractory contained 91.51% of Al2O3 and 8.40% of CaO. When the phase of the substrate portion was analyzed in the same manner as in Example 1, the phase of the substrate portion of the refractory contained CA6, and as the mass percentage in the phase of the substrate portion of the refractory, the content of the CA6 phase was 100%. When the chemical composition of the substrate portion was analyzed in the same manner as in Example 1, as the mass percentage in the substrate portion of the refractory, the chemical composition of the substrate of the refractory contained 91.52% of Al2O3 and 8.40% of CaO. When the bulk density was analyzed in the same manner as in Example 1, the bulk density of the medium bulk density refractory was 2.40 g / cm 3 It was. When analyzed in the same manner as in Example 1, the thermal conductivity of the obtained refractory at 350 °C was 0.46 w / m·K. When measured in the same manner as in Example 1, the erosion thickness of the refractory was 3.95 mm.

[0128] Example 30 (1) 500 g of CA6 granular material (maximum particle size: 5 mm) and 500 g of CA6 fine powder were uniformly mixed to obtain a mixed material. (2) The mixed material was put into a mold of a high-temperature device and hot-pressed and sintered. When the temperature rose to 1500 °C, pressure was applied, and the pressure was gradually increased as the temperature rose. When the temperature rose to a maximum temperature of 1700 °C, the maximum hot-press strength reached 4 MPa, and a medium bulk density refractory was obtained. When the phase was analyzed in the same manner as in Example 1, the phase of the medium bulk density refractory contained CA6, and as the mass percentage in the phase of the refractory, the content of the CA6 phase was 100%. When the chemical composition was analyzed in the same manner as in Example 1, as the mass percentage in the refractory, the chemical composition of the obtained medium bulk density refractory contained 91.51% of Al2O3 and 8.39% of CaO. When the phase of the substrate portion was analyzed using the same method as in Example 1, it was found that the phase of the substrate portion of the refractory material contained CA6, and the content of the CA6 phase in terms of mass percentage in the phase of the substrate portion of the refractory material was 100%. The chemical composition of the substrate portion was analyzed using the same method as in Example 1, and the chemical composition of the substrate of the refractory material was found to contain 91.54% Al2O3 and 8.39% CaO as mass percentages of the substrate portion of the refractory material. When the volume density was analyzed in the same manner as in Example 1, the volume density of the medium volume density refractory material was 2.82 g / cm 3 It was. When analyzed in the same manner as in Example 1, the thermal conductivity of the resulting refractory material at 350°C was found to be 1.75 w / mk. When measured in the same manner as in Example 1, the erosion thickness of the refractory material was 2.41 mm.

[0129] Example 31 (1) 500 g of CA6 granular material (maximum particle size: 5 mm) and 500 g of CA6 fine powder were uniformly mixed to obtain a mixed material. (2) The mixed material was placed in a mold in a high-temperature device and hot-pressed for sintering. When the temperature reached 1500°C, pressure was applied, and the pressure was gradually increased as the temperature increased. When the temperature reached a maximum of 1750°C, the maximum hot-press strength was 2.5 MPa, and a medium-volume density refractory material was obtained. The phases were analyzed in the same manner as in Example 1, and it was found that the phase of the medium volume density refractory material contained CA6, and the content of the CA6 phase in terms of mass percentage of the phase of the refractory material was 99.5%. The chemical composition was analyzed in the same manner as in Example 1, and the chemical composition of the obtained medium volume density refractory material was found to contain 91.51% Al2O3 and 8.39% CaO as mass percentages in the refractory material. The phase of the matrix portion was analyzed using the same method as in Example 1. It was found that the phase of the matrix portion of the refractory material contained CA6 and corundum, and the content of the CA6 phase in terms of mass percentage in the phase of the matrix portion of the refractory material was 99.5%. The chemical composition of the substrate portion was analyzed using the same method as in Example 1, and the chemical composition of the substrate of the refractory material was found to contain 91.51% Al2O3 and 8.40% CaO as mass percentages of the substrate portion of the refractory material. When the volume density was analyzed in the same manner as in Example 1, the volume density of the medium volume density refractory material was 2.90 g / cm 3 It was. When analyzed in the same manner as in Example 1, the thermal conductivity of the resulting refractory material at 350°C was found to be 1.87 w / mk. When measured in the same manner as in Example 1, the erosion thickness of the refractory material was 1.85 mm.

[0130] Example 32 (1) 430 g of CA6 fine powder, 29 g of electrofused magnesia powder, 41.3 g of quicklime powder, and 518.5 g of white corundum fine powder were uniformly mixed to obtain a mixed material. (2) The mixed material was press-molded at room temperature, lightly baked at 1450°C, and then placed in a mold in a high-temperature device for hot-press sintering. When the temperature rose to 1500°C, pressure was gradually applied until the temperature reached a maximum of 1550°C, at which point the maximum hot-press strength reached 1 MPa, resulting in a medium-volume density refractory material. The phases were analyzed in the same manner as in Example 1. The phases of the medium volume density refractory material contained CA6 and MgO·Al2O3, and the content of the CA6 phase was 86.7% and the content of the MgO·Al2O3 phase was 10.0%, in terms of mass percentages of the phases of the refractory material. The chemical composition was analyzed in the same manner as in Example 1, and the chemical composition of the obtained medium volume density refractory material was found to contain, as mass percentages of the refractory material, 95.72% Al2O3, 2.81% MgO, and 7.36% CaO. When the volume density was analyzed in the same manner as in Example 1, the volume density of the medium volume density refractory material was 2.85 g / cm 3 It was. When analyzed in the same manner as in Example 1, the thermal conductivity of the resulting refractory material at 350°C was found to be 1.57 w / mk. When measured by the same method as in Example 1, the erosion thickness of the refractory material was 4.78 mm.

[0131] Comparative Example 1 The difference between Comparative Example 1 and Example 1 is that in Comparative Example 1, a conventional manufacturing method, that is, the method of Example 1 of Chinese Patent Application CN107500747A, was adopted to obtain the refractory material. When analyzed by the same method as in Example 1, the chemical composition of the obtained refractory material included Al2O3 and CaO. As the mass percentage in the refractory material, Al2O3 was 92.03% and CaO was 7.12%. When analyzed by the same method as in Example 1, the phases of the obtained refractory material were mainly CA6, corundum, CA2, and CA. As the mass percentage in the phases of the refractory material, CA6 was 68.75%, corundum was 24.16%, CA2 was 2.32%, and CA was 2.51%. When analyzed by the same method as in Example 1, the bulk density of the obtained refractory material was 3.02 g / cm 3 It was. When analyzed by the same method as in Example 1, the thermal conductivity of the obtained refractory material at 350 °C was 2.27 w / m.k. When measured by the same method as in Example 1, the erosion thickness of the refractory material was 11 mm.

[0132]

Table 2-1

[0133]

Table 2-2

[0134]

Table 2-3

[0135]

Table 2-4

[0136] [Table 3]

[0137] Experimental Example 1 The refractory obtained in Example 1 was compared with the CA6 castable material obtained in Comparative Example 1. Here, the treatment method is as follows. The CA6 refractory obtained in Example 1 and the CA6 castable material obtained in Comparative Example 1 were placed in a high-temperature furnace and heated to 1550 °C, followed by heat preservation treatment for 3 hours. The appearance after the treatment is shown in Fig. 1. As shown in Fig. 1, the sintering shrinkage of the two samples is very small and the surface is very clean. Figs. 2 and 3 are schematic diagrams showing the states of the samples of Example 1 and Comparative Example 1 after being eroded by steelmaking slag at 1500 °C for 3 hours. Here, the steps of erosion resistance to steelmaking slag at 1500 °C for 3 hours are as follows. A crucible was made using the refractory, steelmaking slag was put into the crucible, heated to 1500 °C, heat-preserved for 3 hours, and then cooled. The cooled sample was cut along the center, and the erosion thickness and corrosion of the slag were measured. As shown in Figs. 2 and 3, in the CA6 castable sample of Comparative Example 1, the steelmaking slag has penetrated deeply, and the steelmaking slag has penetrated through the sample crucible to the outer surface of the crucible. This indicates that the slag erosion resistance and penetration resistance of the castable are low. If this sample is used for the permanent lining of the ladle, when the working lining disappears, steel will leak from the ladle or the ladle will turn red. In contrast, although the bulk density of Example 1 was only 2.55 g / cm 3 it had excellent molten slag penetration resistance and erosion resistance. This indicates that the molten slag penetration resistance of Example 1 is very good.

[0138] The above is only a preferred embodiment of the present invention, and is not intended to limit the present invention to other forms, and those skilled in the art can use the technical content disclosed above to change or modify the above into equivalent embodiments with equivalent changes. However, without departing from the content of the technical solution of the present invention, any simple modifications, equivalent changes and modifications made to the above embodiments according to the technical essence of the present invention still fall within the protection scope of the technical solution of the present invention.

Claims

1. A volume density insulating refractory material in the CA6 system, wherein the phases of the insulating refractory material include CA6 and one or more phases selected from C2M2A14, CM2A8, magnesia alumina spinel, and corundum, As a mass percentage in the insulating refractory material, the total content of CA6, C2M2A14, CM2A8, magnesia alumina spinel, and corundum is 90% or more, As a mass percentage in the phases of the insulating refractory material, the CA6 phase is 26.7 to 100%, The C2M2A14 phase is 0 to 60%, The CM2A8 phase is 0 to 60%, The magnesia alumina spinel phase is 0 to 10%, and The corundum phase is 0 to 12%, The phases of the matrix portion of the insulating refractory material include CA6 and one or more phases selected from corundum, magnesia alumina spinel, C2M2A14, and CM2A8, As a mass percentage in the phases of the matrix portion of the insulating refractory material, the CA6 phase is 67.4 to 100%, The corundum phase is 0 to 30%, The magnesia alumina spinel phase is 0 to 10%, The C2M2A14 phase is 0 to 30%, and The CM2A8 phase is 0 to 30%, The volume density of the insulating refractory material is 2.40 to 2.90 g / cm3, Insulating refractory material.

2. As a mass percentage in the insulating refractory material, the total content of CA6, C2M2A14, CM2A8, magnesia alumina spinel, and corundum is 94.8 to 100%, the insulating refractory material according to Claim 1.

3. As a mass percentage in the phases of the insulating refractory material, the CA6 phase is 31.5 to 100%, The CM2A8 phase is 0 to 59.5%, The magnesia alumina spinel phase is 0, the insulating refractory material according to Claim 1.

4. The chemical composition of the heat-insulating refractory material contains Al ２ O ３ , CaO, and optional MgO. As the mass percentage in the heat-insulating refractory material, the Al ２ O ３ is 86.65 to 94.10%, The CaO is 5.80 to 8.40%, The MgO is 0 to 6.05%, the insulating refractory material according to Claim 1.

5. The chemical composition of the insulating refractory material includes Al2O3, CaO, and optional MgO. As a mass percentage in the insulating refractory material, the Al2O3 is 87.50 to 92.60%, The CaO is 6.10 to 8.40%, The MgO is 0 to 5.43%, the insulating refractory material according to Claim 1.

6. The bulk density of the heat-insulating refractory material is 2.40 to 2.82 g / cm ３ The heat-insulating refractory material according to claim 1, wherein the heat-insulating refractory material has the bulk density.

7. As a mass percentage in the phases of the matrix portion of the insulating refractory material, the CA6 phase is 78.2 to 100%, The corundum phase is 0 to 20%, the magnesia alumina spinel phase is 0, the C2M2A14 phase is 0 to 20%, the CM2A8 phase is 0 to 20%, the heat-insulating refractory according to claim 1.

8. The chemical composition of the matrix portion of the heat-insulating refractory material contains Al ２ O ３ , CaO, and optional MgO. As a mass percentage in the matrix portion of the heat-insulating refractory material, the Al ２ O ３ is 89.03 to 94.10%, and wherein the CaO is 5.80 to 8.40%, the MgO is 0 to 2.52%, the heat-insulating refractory according to claim 1.

9. The chemical composition of the matrix part of the heat-insulating refractory contains Al 2 O 3, CaO, and optional MgO, and as a mass percentage in the matrix part of the heat-insulating refractory, the Al 2 O 3 is 89.03 to 93.28%, the CaO is 6.60 to 8.40%, the MgO is 0 to 1.68%, the heat-insulating refractory according to claim 1.

10. A step of mixing any granular material and fine powder to obtain a mixed material, and hot press sintering the mixed material to obtain a refractory is included, the manufacturing method of the heat-insulating refractory according to claim 1.

11. The fine powder is one or more selected from CaO-containing fine powder, Al ２ O ３ -containing fine powder, and MgO-containing fine powder. The manufacturing method according to claim 10.

12. The mass ratio of the granular material to the fine powder is 0 to 60:40 to 100, the manufacturing method according to claim 10.

13. The hot press sintering is to put the mixed material into a mold of a high-temperature device for hot press sintering, or to mold the mixed material at room temperature and then put it into a mold of a high-temperature device for hot press sintering, or to mold the mixed material at room temperature, calcine it temporarily at a low temperature, and then perform hot press sintering, the manufacturing method according to claim 10.

14. The permanent lining of the ladle for molten steel refining including the heat-insulating refractory according to claim 1.

15. The heat-insulating lining or working lining of the ladle for molten aluminum including the heat-insulating refractory according to claim 1.

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