Medium bulk density refractory based on ca6, method of making and use thereof

Abstract

The application discloses a medium volume density heat-insulating refractory material based on CA6, a preparation method of the medium volume density heat-insulating refractory material and application of the medium volume density heat-insulating refractory material. The medium volume density heat-insulating refractory material based on CA6 has a phase including CA6 and one or more than two phases selected from C2M2A14, CM2A8, magnesium-aluminum spinel and corundum. The heat-insulating refractory material has high purity, good high-temperature stability, uniform tissue structure, stable performance, low thermal conductivity and good corrosion resistance to metal melt and molten slag.

Description

Technical Field

[0001] This invention relates to the field of refractory materials technology, and in particular to a medium bulk density refractory material based on CA6, its preparation method and its application. Background Technology

[0002] For steel refining ladles, the integrity, safety, leak-proof properties, and thermal insulation performance of the refractory lining are crucial, and permanent refractory lining plays a very important role in this process.

[0003] Currently, ladle linings typically employ a three-layer structure: a working lining, a permanent lining, and an insulating lining. The working lining, in contact with the high-temperature molten metal, requires excellent high-temperature performance and good resistance to erosion from molten steel and slag. The permanent lining must provide both safety and thermal insulation. It must be able to resist the high temperatures and erosion from molten slag and steel in the absence of the working lining, meeting the primary safety requirement. Simultaneously, it must prevent or reduce heat transfer, lowering the temperature borne by the insulating lining to achieve its thermal insulation function.

[0004] The current permanent lining materials for steel ladles are generally medium-heavy high-alumina castables, or aluminum-magnesium castables, or ordinary low-cement high-alumina castables, or high-alumina castables with added mullite lightweight aggregates, etc.

[0005] The construction of the permanent lining is carried out on site. After the insulation lining is built in the steel ladle, the core mold is fixed inside the steel ladle. The refractory is mixed with water on site and then poured and vibrated. The refractory fills the space between the core mold and the insulation lining by means of flow, and then forms a whole with the help of the hydration of cement and other hydrating components, thus forming strength.

[0006] Castable refractory is an aggregate of aggregates and fine powders. Aggregates are granular materials with a particle size greater than 0.088 mm, while fine powders are powders with a particle size less than 0.088 mm. Granular materials have very weak sintering activity and basically do not sinter, while fine powders have relatively high sintering activity. The overall integrity of castable refractory mainly comes from the sintering effect of the fine powders. In addition to the main raw material powders, the fine powders also contain components with hydration bonding effects such as aluminate cement and MgO, components that enhance fluidity such as silica fume and activated alumina fume, as well as additives that promote sintering and dispersants that promote dispersion. Therefore, compared to aggregates, the matrix is ​​the weakest link in the high-temperature performance of castable refractory, but it is difficult to change. This is determined by the preparation concept and performance requirements of refractory castables.

[0007] Currently, low-cement, high-alumina castables used in permanent linings are generally prepared from raw materials such as bauxite, pure aluminate cement, and silica fume, with a bulk density typically ranging from 2.95 to 3.15 g / cm³. 3Bauxite is generally grade II or III, with high impurity content and a high content of liquid phase formed at high temperatures. It also undergoes significant high-temperature deformation, resulting in a densification process during use, leading to high thermal conductivity and substantial heat dissipation. Furthermore, due to the large amount of liquid phase at high temperatures, it has weak resistance to erosion by molten steel and slag. Once the working lining is completely corroded, this material alone is insufficient to resist molten steel corrosion, easily leading to steel leakage. Additionally, after repeated use, the structure of this type of material becomes porous, and its strength decreases.

[0008] Aluminum-magnesium castables are generally prepared from raw materials such as bauxite, magnesia powder, and silica fume, with a bulk density typically ranging from 3.0 to 3.15 g / cm³. 3 The raw materials used in this material are all natural, with a high impurity content and a high liquid phase content at high temperatures. Furthermore, the material undergoes significant high-temperature deformation, resulting in a densification process during use, leading to high thermal conductivity and substantial heat dissipation. Additionally, due to the large liquid phase content at high temperatures, its resistance to molten steel and slag corrosion is weak. Once the working lining is completely corroded, this material alone is insufficient to resist molten steel corrosion, easily leading to steel leakage.

[0009] Existing materials and technologies like these have been used for decades, yet they have failed to adequately meet the requirements for safety, energy efficiency, and thermal insulation, and have not seen significant improvements. This is primarily due to the unchanged raw materials and their inherent characteristics. The microstructure of bauxite mainly consists of rod-shaped and columnar corundum and mullite, with a liquid phase filling the interstices between the corundum and mullite crystals. This structure not only leads to structural deformation and densification but also results in high thermal conductivity due to the interconnected columnar crystals, which is the most significant drawback of current application materials. Summary of the Invention

[0010] Compared to the microstructure of bauxite, the structure of calcium hexaaluminate is more suitable as a raw material for permanent lining materials. Therefore, in addition to currently available application technologies, there are also some publicly disclosed patents for materials used in permanent linings, such as materials containing CA6.

[0011] Calcium hexaaluminate (CaO·6Al2O3, abbreviated CA6) has the chemical composition of CaO and Al2O3, a melting point of 1875℃, and a theoretical density of 3.79 g / cm³. 3It has good refractory properties. Calcium hexaaluminate has a magnetolite crystal structure, consisting of stacked lamellar structures along the C-axis. Its thermal conductivity along the C-axis is low, and the gaps between the lamellar structures also contribute to its low thermal conductivity. Therefore, calcium hexaaluminate raw materials have very low thermal conductivity. CMA (a unified abbreviation for CaO·2MgO·8Al2O3 and 2CaO·2MgO·14Al2O3) is based on the C-axis stacking of CA6 and MgO·Al2O3 structures. Its structure is similar to CA6, also tending to form a layered structure, and its thermal conductivity is also low. Given the similarity in structure and properties between CMA and CA6, CA6 will be used as a substitute in the following description.

[0012] This layered structure results in poor heat transfer performance and also makes it difficult to sinter calcium hexaaluminate materials. Currently, the bulk density of calcium hexaaluminate materials prepared in the laboratory is generally between 2.20 and 2.70 g / cm³. 3 This makes it difficult to apply in high-temperature applications. Due to its layered structure, it has poor sinterability, which is why it is currently difficult to prepare materials with a bulk density greater than 3.0 g / cm³. 3 The main reason is the use of CA6-based raw materials. Additionally, the volume expansion effect accompanying the reactions between the components during the preparation of calcium hexaaluminate refractory materials also affects the sintering and densification process of the calcium hexaaluminate materials.

[0013] Currently, to achieve densification of calcium hexaaluminate, most methods involve adding additives such as SiO2 and TiO2, which induce a liquid phase at high temperatures, promoting densification and sintering. For example, Chen Zhaoyou et al. discussed the physicochemical properties of Bonate (trade name for calcium hexaaluminate) in their work on calcium hexaaluminate materials and its application in aluminum industrial furnaces (Chen Zhaoyou et al., Calcium hexaaluminate materials and its application in aluminum industrial furnaces [J]. Refractory Materials, 2011, 45(2): 122-125.), in which the chemical composition SiO2 was 0.9%. For example, "A method for preparing dense calcium hexaaluminate refractory clinker" (CN110171980A) and "A method for preparing dense calcium hexaaluminate refractory clinker" (CN105585314A) use TiO2 and MnO as sintering agents, respectively. However, this method cannot achieve densification by controlling the stacking of mirror layer atoms. Instead, it only uses the liquid phase to bring the grains closer together. The liquid phase fills the spaces between the calcium hexaaluminate crystal grains and transfers heat. Therefore, although this method can improve the density of calcium hexaaluminate, the structure of calcium hexaaluminate is uncontrollable and has a high thermal conductivity.

[0014] The CA6 materials disclosed in current patent applications can be roughly classified into three categories: (1) those with a bulk density of less than 2.0 g / cm³. 3(1) CA6 materials, although having low thermal conductivity and good heat preservation performance, are not suitable for permanent linings of steel ladles that need to resist erosion by molten slag and steel. (2) Materials based on CA6 and other components enhance strength through the formation of a second phase, but the overall density of the materials is low, making them difficult to use for permanent linings. (3) High-purity CA6 materials (Al2O3+CaO and ≥97.0% in content) prepared without introducing sintering-promoting additives generally have a bulk density of less than 2.5 g / cm³. 3 (4) Based on CA6, sintering densification is achieved by adding sintering aids. Because of the lamellar structure of CA6 itself, CA6 material is difficult to sinter. Basically, SiO2, TiO2, etc. are added to promote sintering densification. (5) CA6 material is mostly achieved by adding more (≥20%) corundum or active alumina micro powder, and the strength of the composite material is achieved by sintering corundum or active alumina micro powder.

[0015] The problems and shortcomings of existing industrialization technologies or existing patented technologies are as follows:

[0016] (1) Poor resistance to steel slag corrosion

[0017] The high impurity content and large amount of high-temperature liquid phase in castables made from natural bauxite make them difficult to resist the erosion of molten steel and slag. Therefore, in the event of the working lining disappearing, current permanent lining materials and technologies are difficult to ensure safety. Although the concept of a safety lining is given to permanent linings, it is difficult to meet the requirements.

[0018] (2) Shrinkage and densification at high temperatures lead to changes in the microstructure of the material and further increase its thermal conductivity.

[0019] Permanent lining castables based on bauxite use natural bauxite raw materials, which contain a lot of impurities and have a high liquid phase content at high temperatures. At the same time, these castables are based on a system that improves fluidity with silica powder. The amount of silica powder added is relatively large, and the liquid phase content at high temperatures will increase several times. As a result, when the castable is used at high temperatures, it will undergo a certain degree of shrinkage and densification process. The material becomes more densified with application, and the thermal conductivity increases further.

[0020] (3) The material has high thermal conductivity

[0021] Currently, most medium-heavy high-alumina castables, whether ordinary high-alumina castables, alumina-magnesia castables, or low-cement high-alumina castables, primarily use sintered bauxite as aggregate and fine powder. While medium-heavy mullite castables use mullite as a lightweight raw material for some of the aggregate, the fine powder is still sintered bauxite. Bauxite has a high density and thermal conductivity, and the bulk density of these materials is generally around 2.6 g / cm³. 3Above, even as high as 3.15 g / cm³ 3 These medium-heavy materials have a very high density, and their thermal conductivity cannot be reduced significantly.

[0022] (4) Material shrinkage causes the working lining refractory material to expand outward, weakens the compressive force between bricks, reduces the integrity, and easily leads to steel leakage.

[0023] Castables made from natural bauxite have high impurity content and a large amount of high-temperature liquid phase. When used for a long time, they undergo sintering shrinkage, which weakens the supporting force on the outer perimeter of the working lining. The working lining expands outward, causing cracks or broken bricks, which can easily lead to steel leakage accidents.

[0024] (5) CA6 series materials rely on additives to achieve sintering, with a large liquid phase content, reduced high-temperature performance, and high thermal conductivity.

[0025] Given that CA6's unique lamellar structure makes it difficult to sinter, most existing CA6-based refractories suitable for permanent ladle linings rely on additives to generate a liquid phase and promote sintering. While this method can promote CA6 sintering, the increased liquid phase leads to a decrease in its high-temperature performance. The liquid phase fills the spaces between grains, acting as a bridge for heat transfer and resulting in a significant increase in thermal conductivity.

[0026] (6) By introducing more corundum phases, the difficulty of sintering CA6 material is compensated, resulting in a significant increase in thermal conductivity.

[0027] To improve the sintering and corrosion resistance of CA6 materials, existing patents typically add a large amount of active alumina micro powder, corundum powder, etc. While this can improve sintering and integrity, it will also increase the thermal conductivity several times over and reduce the thermal insulation performance.

[0028] (7) High-purity CA6 materials have relatively low bulk density and strength, making them difficult to use as permanent lining materials.

[0029] Due to the difficulty in sintering CA6 material, the density of high-purity CA6 products after sintering is generally between 2.0 and 2.5 g / cm3, and the microstructure is uneven and the strength is very low, which is not feasible for permanent lining materials of steel ladles that bear high pressure.

[0030] (8) The material shrinks greatly at high temperatures, often resulting in network cracks and large cracks, which seriously affect the safety of ladle smelting.

[0031] When a material has a high concentration of liquid phase at high temperatures and exhibits significant creep in its microstructure, it shrinks and reduces in volume, leading to frequent network cracks and large cracks in the permanent lining material. These cracks are extremely dangerous and are a major concern for steel mills. When the working lining is corroded or molten steel seeps between the working linings, it can easily leak through cracks in the permanent lining, causing a major steel leak accident.

[0032] Therefore, neither the existing materials used in steel mills nor the publicly available patented technologies can truly achieve safety and heat preservation. Either there is a high amount of high-temperature liquid phase, which undergoes deformation and densification under the action of the liquid phase, resulting in a continuous increase in thermal conductivity during use. At the same time, the high amount of liquid phase makes it less resistant to the erosion of molten steel and slag, making it difficult to resist the erosion of slag when the working lining material is lost, and thus failing to play a protective and safe role. Or the purity is high, the sintering is not dense and the structure is uneven, making it difficult to resist the expansion pressure of the ladle working lining. This leads to the compression of the permanent lining material, the overall expansion of the working lining material outward, and a decrease in overall integrity, resulting in accidents such as steel leakage.

[0033] The difficulty in solving the above problems and defects is as follows:

[0034] (1) The preparation method of castable refractory determines that its weaknesses are difficult to change.

[0035] Especially as an amorphous refractory castable, it can be used directly without firing. Its strength at room temperature and low temperature comes from the hydration and bonding of cement. When the crystal water and binding water disappear at 800-900℃, the strength is mainly maintained by the close packing of the material itself and the addition of silica fume, etc. When the temperature rises further, the strength is maintained by the addition of silica fume and other low melting point phases.

[0036] Meanwhile, refractories are aggregates of aggregates and fine powders. Because the surface of aggregate particles is relatively passive in sintering and reaction, they are difficult to sinter. The strength of refractories mainly comes from the sintering of the matrix fine powder. Therefore, the matrix fine powder of refractories requires both small fineness and a large specific surface area. At the same time, many external components that need to promote sintering are also added to the matrix fine powder, leading to uneven composition distribution in the refractories. The high-temperature performance of the matrix fine powder is already somewhat worse than that of aggregates, and this is further weakened by the addition of sintering aids. For some applications, sintering aids are essential, especially for castables like permanent ladle linings, which are applied directly without high-temperature sintering and can only achieve sintering through the high temperatures of the service process. This necessitates a large amount of sintering aids, a requirement determined by the design philosophy of refractory materials and difficult to improve. Furthermore, materials prepared primarily from high-purity raw materials are difficult to sinter and cannot form a unified whole.

[0037] In addition, to ensure fluidity and construction performance, castables also need to be mixed with additives such as water-reducing agents and micro powders; moreover, the raw materials are basically all natural raw materials, so the weaknesses of permanent lining materials such as aluminum-magnesium castables and high-alumina castables are difficult to change.

[0038] (2) Currently, most permanent lining castables are high-temperature liquid phases, and their microstructure becomes further densified during use.

[0039] Natural raw materials have high impurity content and a large liquid phase at high temperatures. Refractory materials based on these natural raw materials undergo large deformation and have unstable microstructures under high-temperature service, exhibiting densification and increased thermal conductivity. This is something that refractory materials based on natural raw materials cannot change.

[0040] (3) The high temperature liquid phase has a large amount of liquid phase, and its resistance to corrosion and resistance to molten steel and slag is low.

[0041] Unlike sintered refractories, castables must rely on fine matrix powder to achieve workability, sintering, and strength. Therefore, sintering aids, water-reducing agents and surfactants that enhance fluidity, and hydration raw materials that form room temperature and medium temperature strength are all added to the fine matrix powder. This results in a very complex matrix composition for castables, which inevitably leads to a significant reduction in high-temperature performance, which is unavoidable.

[0042] (4) Existing patents also have problems with aluminum-magnesium castables and high-alumina castables.

[0043] Compared to bauxite-based castables, although CA6 performs much better, its high-temperature performance is still relatively poor due to the following factors: ① CA6 castables also need to develop strength at medium to high temperatures to ensure their integrity as a permanent lining, and they also require medium to low-temperature sintering, which necessitates the introduction of components that can be sintered into a liquid phase at low temperatures; ② CA6 castables also require the addition of micro-powders, water-reducing agents, and flow-promoting micro-powders; ③ Sintering is promoted at low temperatures, while a large amount of liquid phase is formed at high temperatures, resulting in a series of problems such as decreased resistance to slag erosion at high temperatures, densification of the microstructure, and increased thermal conductivity.

[0044] (5) In order to avoid the deterioration of the microstructure and the excessive amount of high-temperature liquid phase in the CA6 castable in the existing patent applications, only alumina, corundum, etc. can be added, which increases the thermal conductivity.

[0045] The preparation method and characteristics of castables determine that the matrix is ​​the weak point, which will lead to a decline in the overall performance of the castable. Therefore, in order to reduce the shortcomings of CA6-based castables, the only way is to introduce a large amount of activated alumina micro powder and corundum powder to enhance the high-temperature performance of the matrix and strengthen its structural stability. However, this also brings a series of problems such as increased thermal conductivity.

[0046] For castables, good matrix fluidity, suitable hardening, easy sintering, low high-temperature liquid phase, high erosion resistance, and no performance reduction are all factors that need to be addressed in the matrix. This has always been a difficult contradiction to reconcile and remains difficult to resolve to this day.

[0047] The significance of solving the above problems and defects is as follows: it can purify the permanent lining material, enhance its resistance to slag and molten steel corrosion, ensure the safety of the smelting ladle, and prevent major accidents such as steel leakage; it can enhance the structural stability and high-temperature integrity of the material, give the permanent lining material a lower and more stable thermal conductivity, prevent heat from being transferred outward, reduce the heating temperature of molten steel, reduce the tapping temperature and carbon-oxygen product of the converter, reduce the consumption of refractory materials, and reduce the amount of alloys used. The economic and socio-economic benefits are very significant.

[0048] To address the aforementioned problems, this invention provides a medium-density refractory material based on CA6, its preparation method, and its applications.

[0049] This invention uses fine powder or granular material mixed with fine powder, and then uses hot pressing sintering to prepare a medium bulk density refractory material based on CA6. The resulting refractory material has high purity, good high temperature stability, uniform microstructure, and stable performance.

[0050] The specific technical solution of this invention is as follows:

[0051] 1. A medium-density thermal insulation refractory material based on CA6, wherein the phases of the thermal insulation refractory material include CA6 and one or more phases selected from C2M2A14, CM2A8, magnesium aluminum spinel and corundum.

[0052] 2. The heat-insulating refractory material according to item 1, wherein, based on the mass percentage of CA6, C2M2A14, CM2A8, magnesium aluminum spinel and corundum in the heat-insulating refractory material, the total content is ≥90%, preferably 94.8-99.5%.

[0053] 3. The heat-insulating refractory material according to item 1 or 2, wherein, based on the mass percentage of the phase in the heat-insulating refractory material, the CA6 phase is 26.7-100%, preferably 31.5-99.5%, and more preferably 38.7-99.5%;

[0054] The C2M2A14 phase content is 0-72%, preferably 0-60%;

[0055] The CM2A8 phase content is 0-72%, preferably 0-59.5%;

[0056] The magnesium aluminum spinel phase is 0-10%, 0-4.60%, preferably 0%, and...

[0057] The corundum phase comprises 0-30%, preferably 0-18%, and more preferably 0-16.5%.

[0058] 4. The heat-insulating refractory material according to any one of items 1-3, wherein the chemical composition of the heat-insulating refractory material includes Al2O3, CaO and MgO, and the Al2O3 is 86.65-94.10% by mass percentage in the heat-insulating refractory material, preferably 87.60-94.10%, more preferably 88.07-94.10%;

[0059] The CaO content is 5.80-8.40%, preferably 6.89-8.40%; and

[0060] The MgO content is 0-6.05%, preferably 0-5.04%.

[0061] 5. The heat-insulating refractory material according to any one of items 1-4, wherein the bulk density of the heat-insulating refractory material is 2.40-2.90 g / cm³. 3 The preferred value is 2.40-2.82 g / cm³. 3 .

[0062] 6. The heat-insulating refractory material according to any one of items 1-5, wherein the matrix portion of the heat-insulating refractory material comprises CA6 and one or more phases selected from corundum, magnesium aluminum spinel, C2M2A14 and CM2A8.

[0063] 7. The heat-insulating refractory material according to item 6, wherein, based on the mass percentage of the phase in the matrix portion of the heat-insulating refractory material, the CA6 phase is 67.4-100%, preferably 78.2-100%;

[0064] The corundum phase comprises 0-30%, preferably 0-20%;

[0065] The magnesium aluminum spinel phase is 0-10% or 0-5.22%, preferably 0%.

[0066] The C2M2A14 phase comprises 0-30%, preferably 0-18.8%; and

[0067] The CM2A8 phase content is 0-30%, preferably 0-18.8%.

[0068] 8. The heat-insulating refractory material according to item 6 or 7, wherein the chemical composition of the matrix portion of the heat-insulating refractory material includes Al2O3, CaO and MgO, and the Al2O3 is 89.03-94.10% by mass percentage, preferably 90.30-93.20% in the matrix portion of the heat-insulating refractory material;

[0069] The CaO content is 5.80-8.40%, preferably 6.60-8.40%; and

[0070] The MgO content is 0-2.52%, preferably 0-1.68%.

[0071] 9. The heat-insulating and refractory material according to any one of claims 1-8, wherein the heat-insulating and refractory material is prepared by a method comprising the steps of:

[0072] The mixture is obtained by mixing granular material and fine powder, and then hot-pressing and sintering the mixture.

[0073] 10. The heat-insulating and refractory material according to item 9, wherein the fine powder is selected from one or more of the following: fine powder containing CaO, fine powder containing Al2O3, and fine powder containing MgO;

[0074] Preferably, the CaO-containing fine powder is selected from one or more of quicklime, limestone, calcium hydroxide, CaO·Al2O3, CaO·2Al2O3, 12CaO·7Al2O3, CA6, C2M2A14 and CM2A8;

[0075] Preferably, the fine powder containing Al2O3 is selected from one or more of the following: active α-Al2O3 powder, γ-Al2O3 powder, ρ-Al2O3 powder, aluminum hydroxide, industrial alumina, white corundum powder, sub-white corundum powder, dense corundum powder, sintered corundum powder, and tabular corundum powder.

[0076] Preferably, the MgO-containing fine powder is selected from one or more of magnesite, lightly calcined magnesia, brucite, magnesium hydroxide, magnesium chloride, high-purity magnesia, and fused magnesia.

[0077] 11. The heat-insulating and refractory material according to item 9 or 10, wherein the granular material is selected from one or more of CA6, C2M2A14 and CM2A8, preferably CA6.

[0078] 12. The heat-insulating refractory material according to any one of items 9-11, wherein the mass ratio of the granules to the fine powder is 0-60:40-100.

[0079] 13. The heat-insulating refractory material according to any one of items 9-12, wherein the hot pressing sintering involves placing the mixture into a mold of a high-temperature device for hot pressing sintering, or forming the mixture at room temperature and then placing it into a mold of a high-temperature device for hot pressing sintering, or forming the mixture at room temperature and pre-sintering at low temperature before hot pressing sintering.

[0080] 14. The heat-insulating refractory material according to any one of items 9-13, wherein the hot-pressing sintering temperature is 1550-1750°C, preferably, the hot-pressing strength is 0.5-10 MPa.

[0081] 15. A method for preparing a heat-insulating and refractory material, comprising the following steps:

[0082] The mixture is obtained by mixing granular material and fine powder, and then hot-pressing and sintering the mixture.

[0083] 16. The preparation method according to item 15, wherein the fine powder is selected from one or more of the following: fine powder containing CaO, fine powder containing Al2O3, and fine powder containing MgO;

[0084] Preferably, the CaO-containing fine powder is selected from one or more of quicklime, limestone, calcium hydroxide, CaO·Al2O3, CaO·2Al2O3, 12CaO·7Al2O3, CA6, C2M2A14 and CM2A8;

[0085] Preferably, the fine powder containing Al2O3 is selected from one or more of the following: active α-Al2O3 powder, γ-Al2O3 powder, ρ-Al2O3 powder, aluminum hydroxide, industrial alumina, white corundum powder, sub-white corundum powder, sintered corundum powder, and tabular corundum powder.

[0086] Preferably, the MgO-containing fine powder is selected from one or more of magnesite, lightly calcined magnesia, brucite, magnesium hydroxide, magnesium chloride, high-purity magnesia, and fused magnesia.

[0087] 17. The preparation method according to item 15 or 16, wherein the granules are selected from one or more of CA6, C2M2A14 and CM2A8, preferably CA6.

[0088] 18. The preparation method according to any one of items 15-17, wherein the mass ratio of the granules to the fine powder is 0-60:40-100.

[0089] 19. The preparation method according to any one of items 15-18, wherein the hot pressing sintering involves placing the mixture into a mold of a high-temperature device for hot pressing sintering, or forming the mixture at room temperature and then placing it into a mold of a high-temperature device for hot pressing sintering, or forming the mixture at room temperature and pre-sintering at low temperature followed by hot sintering.

[0090] 20. The preparation method according to any one of items 15-19, wherein the hot pressing sintering temperature is 1550-1750°C, preferably, the hot pressing strength is 0.5-10 MPa.

[0091] 21. A permanent lining for a steel ladle in iron and steel smelting, comprising the heat-insulating refractory material as described in any one of items 1-14 or the heat-insulating refractory material prepared by any one of items 15-20.

[0092] 22. A heat-insulating lining or working lining for molten aluminum ladle, comprising the heat-insulating refractory material as described in any one of items 1-14 or the heat-insulating refractory material prepared by the preparation method as described in any one of items 15-20.

[0093] The effects of the invention

[0094] This invention achieves good sintering of high-purity CA6 system materials, resulting in high material strength. The material exhibits a uniform microstructure, consistent thermal insulation and strength properties, and good resistance to slag and molten steel corrosion. It is highly suitable for permanent linings of steel ladles, working linings and insulation linings for molten aluminum, and refractory linings for some industrial kilns. It offers excellent thermal insulation, heat preservation, and safety, resulting in significant economic and social benefits. Detailed effects are described below:

[0095] (1) The materials of this invention have high purity and do not pollute the smelting materials.

[0096] Compared with the present invention, materials such as permanent lining materials for steel ladles and liquid aluminum ladles have higher purity and better high-temperature stability, with a total Al2O3+CaO+MgO content of ≥96.5%.

[0097] Although the material of this invention has high purity, it will not introduce impurities into the solution during the smelting of steel, aluminum alloys or other alloys, and will not affect the purity and performance of the alloys.

[0098] (2) The material has a uniform microstructure and stable performance.

[0099] As a high-purity raw material system, sintering the material is quite difficult. Therefore, in current refractory materials, sintering is primarily promoted by introducing additives, through chemical reactions, or by generating a low-melting-point liquid phase. This results in a non-uniform material structure: some regions are high-purity systems with high melting points and good crystallinity, while others are liquid phase regions with complex compositions and lower melting points and high-temperature performance. This structural non-uniformity leads to creep and slip at high temperatures, decreased material properties, and increased thermal conductivity.

[0100] The material of this invention does not rely on the formation of a low-melting-point liquid phase to promote sintering; therefore, it does not contain a low-melting-point liquid phase, and there is no creep or slip in the microstructure. The material structure is uniform, and its performance is stable. Furthermore, it does not exhibit performance degradation at different stages of service, a characteristic not found in traditional materials.

[0101] (3) Good resistance to corrosion from molten metals and slag.

[0102] Because the material system is a high-purity system and the material structure is not based on sintering promoted by a low-melting-point liquid phase, the material structure is uniform and there are no weak points that resist slag erosion. Therefore, the material of this invention has excellent overall resistance to erosion by molten metal and slag, which can ensure the safety characteristics of the permanent lining.

[0103] (4) Low thermal conductivity

[0104] Due to the layered structure of CA6, CA6-based materials have low thermal conductivity. This is important for permanent linings that require thermal insulation properties. Attached Figure Description

[0105] Figure 1 This is a schematic diagram of the heat-insulating and refractory material obtained in Example 1 of the present invention and the CA6 castable obtained in Comparative Example 1 after being treated at 1500℃.

[0106] Figure 2 This is a schematic cross-sectional view of the heat-insulating and refractory material described in Embodiment 1 of the present invention after being eroded by slag at 1500℃;

[0107] Figure 3 This is a schematic cross-sectional view of the CA6 material obtained in Comparative Example 1 after slag erosion at 1500℃. Detailed Implementation

[0108] The present invention will now be described in detail. While specific embodiments of the invention have been shown, it should be understood that the invention can be implemented in various forms and should not be limited to the embodiments set forth herein. Rather, these embodiments are provided to enable a more thorough understanding of the invention and to fully convey the scope of the invention to those skilled in the art.

[0109] It should be noted that certain terms are used in the specification and claims to refer to specific components. Those skilled in the art will understand that different terms may be used to refer to the same component. This specification and claims do not distinguish components based on differences in terminology, but rather on differences in function. The terms "comprising" or "including" used throughout the specification and claims are open-ended and should be interpreted as "comprising but not limited to." The following descriptions are preferred embodiments for carrying out the invention; however, these descriptions are for the purpose of understanding the general principles of the specification and are not intended to limit the scope of the invention. The scope of protection of this invention is determined by the appended claims.

[0110] The present invention provides a medium bulk density thermal insulation refractory material based on CA6, wherein the phases of the thermal insulation refractory material include CA6 and one or more phases selected from C2M2A14, CM2A8, magnesium aluminum spinel and corundum.

[0111] A phase is a phase in a substance that possesses specific physicochemical properties.

[0112] C2M2A14 refers to 2CaO·2MgO·14Al2O3.

[0113] CM2A8 refers to CaO·2MgO·8Al2O3.

[0114] The phase composition of the heat-insulating refractory material is determined by XRD, for example, by grinding the material to below 325 mesh and then scanning it with an X-ray diffractometer. By analyzing the diffraction data and matching it with a standard PDF card, the relevant phases are obtained, and then the content of the relevant phases is obtained by fitting the full spectrum of the diffraction data.

[0115] In a preferred embodiment of the present invention, the total content of CA6, C2M2A14, CM2A8, corundum and magnesium aluminum spinel is ≥90%, preferably 94.8-99.5%, based on the mass percentage of the heat-insulating refractory material.

[0116] For example, the total content of CA6, C2M2A14, CM2A8, magnesium aluminum spinel and corundum, as a percentage by mass in the heat-insulating refractory material, can 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 thereof.

[0117] In a preferred embodiment of the present invention, the CA6 phase, based on the mass percentage of the phase in the heat-insulating refractory material, is 26.7-100%, preferably 31.5-99.5%, and more preferably 38.7-99.5%.

[0118] The C2M2A14 phase content is 0-72%, preferably 0-60%;

[0119] The CM2A8 phase content is 0-72%, preferably 0-59.5%;

[0120] The magnesium aluminum spinel phase is 0-10%, 0-4.60%, preferably 0%; and

[0121] The corundum phase comprises 0-30%, preferably 0-18%, and more preferably 0-16.5%.

[0122] For example, the CA6 phase can be any range from 26.7%, 28%, 30%, 35%, 40%, 45%, 50%, 55%, 60%, 65%, 70%, 75%, 80%, 85%, 90%, 95%, 97.8%, 99.5%, 100%, or any other range thereof, based on the mass percentage of the phase in the insulating refractory material.

[0123] The C2M2A14 phase can 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 thereof.

[0124] The CM2A8 phase can be 0%, 5%, 10%, 15%, 20%, 24%, 25%, 30%, 35%, 40%, 45%, 50%, 55%, 60%, 65%, 70%, 71%, 72%, or any range thereof.

[0125] The corundum phase can be 0%, 5%, 10%, 12%, 15%, 18%, 20%, 25%, 30%, or any range thereof.

[0126] Magnesium aluminum spinel can be 0%, 1%, 2%, 3%, 4%, 4.60%, 5%, 6%, 7%, 8%, 9%, 10%, or any range thereof.

[0127] In a preferred embodiment of the present invention, the chemical composition of the heat-insulating and refractory material includes Al2O3, CaO and MgO, and the Al2O3 content in the heat-insulating and refractory material is 86.65-94.10% by mass, preferably 87.6-94.10%, and more preferably 88.07-94.10%.

[0128] The CaO content is 5.80-8.40%, preferably 6.89-8.40%, and the MgO content is 0-6.05%, preferably 0-5.04%.

[0129] The Al2O3, by mass percentage in the heat-insulating refractory material, can be, for example, 86.65%, 87.60%, 88%, 89%, 90%, 91%, 92%, 93%, 94%, 94.10%, or any range thereof;

[0130] The CaO content can be 5.80%, 6.0%, 7.0%, 8.0%, 8.40%, or any range thereof.

[0131] The MgO content can be 0, 1.0%, 2.0%, 3.0%, 4.0%, 5.0%, 5.60%, 6.0%, or any range thereof.

[0132] The chemical composition of the heat-insulating and refractory material was determined by fluorescence XRF analysis in accordance with GB / T21114-2007.

[0133] In a preferred embodiment of the present invention, the bulk density of the heat-insulating refractory material is 2.40-2.90 g / cm³. 3 The preferred value is 2.40-2.82 g / cm³. 3 .

[0134] For example, the bulk density of the heat-insulating and refractory material can be 2.40 g / cm³. 3 2.50g / cm 3 2.55g / cm 3 2.60g / cm 3 2.70 g / cm 3 2.80g / cm 3 2.90g / cm 3 or any range thereof.

[0135] The bulk density of the heat-insulating and refractory material was determined according to GB / T2997-2000.

[0136] In a preferred embodiment of the present invention, the phase of the heat-insulating and refractory material matrix includes CA6 and one or more phases selected from corundum, magnesium aluminum spinel, C2M2A14 and CM2A8.

[0137] The matrix portion of the heat-insulating refractory material refers to the portion of the heat-insulating refractory material that does not include granular materials.

[0138] The phase composition of the thermal insulation and refractory material matrix was determined by micro-area diffraction using XRD.

[0139] For example, the procedure can involve selecting seven different samples and cutting out seven specimens from them. Each specimen undergoes micro-area diffraction, and the spectra are then fitted to the full spectrum to determine the content of each phase. Two data points with significant deviations are removed, and the average of the phase contents of the remaining five specimens is taken as the phase content of the thermal insulation and refractory material matrix. To ensure accurate analysis and minimize deviations, the selected matrix area should be maximized during sample preparation and scanning.

[0140] In a preferred embodiment of the present invention, the CA6 phase comprises 67.4-100% by mass percentage of the phase in the thermal insulation and refractory matrix portion, preferably 78.2-100%.

[0141] The corundum phase comprises 0-30%, preferably 0-20%;

[0142] The magnesium aluminum spinel phase is 0-10% or 0-5.22%, preferably 0%.

[0143] The C2M2A14 phase comprises 0-30%, preferably 0-18.8%; and

[0144] The CM2A8 phase content is 0-30%, preferably 0-18.8%.

[0145] For example, the CA6 phase can be any range from 67.4%, 70%, 75%, 80%, 85%, 90%, 95%, 98.5%, 100% or more, based on the mass percentage of the phase in the matrix portion of the thermal insulation refractory material.

[0146] The corundum phase can be 0%, 5%, 10%, 15%, 20%, 25%, 30%, or any range thereof;

[0147] The magnesium aluminum spinel phase can be 0%, 1%, 2%, 3%, 4%, 4.85%, 5.22%, 6%, 7%, 8%, 9%, 10%, or any range thereof;

[0148] The C2M2A14 phase can be 0%, 5%, 10%, 15%, 20%, 25%, 30%, or any range thereof;

[0149] The CM2A8 phase can be 0%, 5%, 10%, 15%, 20%, 25%, 28.4%, 30%, or any range thereof.

[0150] In a preferred embodiment of the present invention, the chemical composition of the heat-insulating refractory material matrix includes Al2O3, CaO and MgO, and the Al2O3 is 89.03-94.10% by mass percentage in the heat-insulating refractory material matrix portion, preferably 90.3-93.2%.

[0151] The CaO content is 5.80-8.40%, preferably 6.60-8.4%, and

[0152] The MgO content is 0-2.52%, preferably 0-1.68%.

[0153] For example, based on the mass percentage of the matrix portion of the heat-insulating refractory material, the Al2O3 can 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%, etc. 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 thereof;

[0154] The CaO can 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 thereof.

[0155] The MgO can 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 thereof.

[0156] The chemical composition of the thermal insulation and refractory material matrix was determined by elemental analysis of the matrix portion of the sample under an electron microscope, i.e., EDS analysis.

[0157] Preferably, the method includes the following steps: selecting 10 different samples, and cutting out at least 12 specimens from them, and surface-cutting them. Each cut specimen is placed under an electron microscope, the matrix portion is selected, and a rectangular area of ​​appropriate size is chosen for elemental analysis; the elemental content is converted into oxides, and the chemical composition is calculated, i.e., converted to Al2O3, CaO, and MgO content. Two data points with large deviations are removed, and the average of the Al2O3, CaO, and MgO contents of the 10 specimens is taken as the chemical composition of the thermal insulation and refractory material matrix. To ensure accurate chemical composition and small deviation, the selected rectangular area should be maximized during elemental analysis.

[0158] In a preferred embodiment of the present invention, the heat-insulating and refractory material is prepared by a method comprising the following steps:

[0159] The mixture is obtained by mixing granular material and fine powder, and then hot-pressing and sintering the mixture.

[0160] The granular material refers to the portion that cannot be screened through a 180-mesh square hole sieve (Xinxiang Zhongtuo Machinery Equipment Co., Ltd.), that is, the portion located on the 180-mesh square hole sieve, and the particle size of the granular material is 180 mesh - 8mm.

[0161] The fine powder refers to the portion that passes through a 180-mesh square-hole sieve, that is, the portion located below the 180-mesh square-hole sieve, with a particle size of ≤180 mesh.

[0162] Hot pressing sintering refers to a method of sintering materials under the combined action of pressure and temperature.

[0163] In a preferred embodiment of the present invention, the fine powder is selected from one or more of the following: fine powder containing CaO, fine powder containing Al2O3, and fine powder containing MgO.

[0164] Preferably, the CaO-containing fine powder is selected from one or more of quicklime, limestone, calcium hydroxide, CaO·Al2O3, CaO·2Al2O3 (CA2), 12CaO·7Al2O3 (C12A7), CA6, C2M2A14 and CM2A8;

[0165] Preferably, the fine powder containing Al2O3 is selected from one or more of the following: active α-Al2O3 powder, γ-Al2O3 powder, ρ-Al2O3 powder, aluminum hydroxide, industrial alumina, white corundum powder, sub-white corundum powder, dense corundum powder, sintered corundum powder, and tabular corundum powder.

[0166] Preferably, the MgO-containing fine powder is selected from one or more of magnesite, light-burned magnesia, brucite, magnesium hydroxide, magnesium chloride, high-purity magnesia, and fused magnesia.

[0167] Among them, fine powder containing CaO refers to fine powder whose chemical composition includes CaO, or fine powder containing CaO and Al2O3, or fine powder containing CaO, MgO and Al2O3.

[0168] Fine powder containing Al2O3 refers to alumina-based fine powder whose main chemical component is Al2O3.

[0169] Fine powder containing MgO refers to fine powder whose main chemical component is MgO.

[0170] Quicklime, also known as calcined lime, is mainly composed of calcium oxide. It is usually produced by calcining natural rocks, whose main component is calcium carbonate, at high temperatures, which decomposes them into carbon dioxide and calcium oxide (chemical formula: CaO, i.e., quicklime, also known as marble).

[0171] Activated α-Al2O3 powder is an alumina powder with high activity, mainly composed of α-Al2O3, obtained by treating industrial alumina or aluminum hydroxide as raw materials at 1250-1450℃.

[0172] γ-Al2O3 powder is an alumina powder with a high specific surface area and good adsorption properties, obtained by treating aluminum hydroxide as raw material at 140-150℃.

[0173] ρ-Al2O3 powder is an alumina powder with certain hydration bonding properties obtained by rapidly processing aluminum hydroxide at high temperatures of 600-900℃.

[0174] Industrial alumina is a mineral whose main component is α-Al2O3. It is prepared by calcining aluminum hydroxide at 900-1250℃.

[0175] White corundum powder is an alumina raw material with an aluminum oxide (Al2O3) content of over 97.5% prepared by electro-melting of industrial alumina. It also contains small amounts of iron oxide, silicon oxide, and other components, and is white in color.

[0176] Sub-white fused alumina powder is produced from bauxite. Because its chemical composition and physical properties are similar to those of white fused alumina, it is called sub-white fused alumina. This product possesses the hardness of white fused alumina while also having the toughness of brown fused alumina, making it an ideal high-grade refractory and abrasive material.

[0177] Sintered corundum powder refers to refractory clinker made from alumina as raw material, which is ground into pellets or blanks and sintered at a high temperature of 1750-1900℃. It has high bulk density, low porosity, and excellent thermal shock resistance and slag erosion resistance at high temperatures.

[0178] The tabular corundum powder has a coarse-grained, well-developed α-Al2O3 crystal structure with an Al2O3 content of over 97%. It has a plate-like crystal structure with small pores and a large number of closed pores.

[0179] Lightly calcined magnesia is a magnesia-based raw material with high activity and periclase phase, prepared by calcining magnesite (mainly composed of magnesium carbonate) at 800-1000℃.

[0180] Brussels crystal is a raw material with Mg(OH)2 as its main component.

[0181] High-purity magnesia is a sintered magnesia raw material with an MgO content of ≥96.5%, which is produced by pressing lightly calcined magnesia into balls and calcining at high temperature.

[0182] Fused magnesia is a dense magnesia raw material with an MgO content of ≥96.5% prepared by electric arc melting of lightly calcined magnesia or magnesite as raw materials.

[0183] In a preferred embodiment of the present invention, when using one or more of the following CaO-containing fine powders (which cannot form CA6 or CMA phases by relying solely on these CaO-containing fine powders) as the source of CaO in the matrix and failing to meet the phase and chemical composition requirements of the product matrix, the fine powder may further include Al2O3-containing fine powder or Al2O3-containing fine powder and MgO-containing fine powder, depending on the phase and chemical composition of the product.

[0184] When using fine powder containing MgO (which alone cannot form phases such as CA6 or CMA), if the phase and chemical composition of the product matrix cannot be satisfied by relying solely on the fine powder containing MgO, the fine powder may also include fine powder containing Al2O3 or fine powder containing Al2O3 and fine powder containing CaO, depending on the phase and chemical composition of the product.

[0185] When using fine powder containing Al2O3, if using these fine powders containing Al2O3 alone cannot meet the phase and chemical composition requirements of the product matrix, the fine powder may also include fine powder containing CaO or fine powder containing MgO, or fine powder containing both CaO and MgO, depending on the phase and chemical composition of the product.

[0186] In a preferred embodiment of the present invention, the granular material is selected from one or more of CA6, C2M2A14 and CM2A8, preferably CA6.

[0187] In a preferred embodiment of the present invention, the mass ratio of the granules to the fine powder is 0-60:40-100.

[0188] For example, the mass ratio of the granules to the fine powder (i.e., the granules / fine powder) can 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 thereof.

[0189] In a preferred embodiment of the present invention, the hot pressing sintering involves placing the mixture into a mold of a high-temperature device for hot pressing sintering, or forming the mixture at room temperature and then placing it into a mold of a high-temperature device for hot pressing sintering, or forming the mixture at room temperature and pre-sintering at low temperature before hot pressing sintering.

[0190] For example, hot pressing sintering of the mixture in a mold of a high-temperature device refers to placing the mixed material in the mold of the high-temperature device and heating it. When the temperature reaches the maximum temperature, pressure is applied to achieve sintering; or placing the mixture in the mold of the high-temperature device and heating it to a certain temperature while applying pressure, then gradually increasing the temperature and simultaneously increasing the applied pressure until the temperature reaches the maximum temperature and the pressure reaches the maximum value, thus completing the hot pressing sintering of the material; or placing the mixture in the mold of the high-temperature device and gradually increasing the pressure applied to the mixture while heating it until the temperature reaches the maximum temperature and the pressure reaches the maximum value, thus completing the hot pressing sintering of the material.

[0191] The process of hot pressing and sintering the mixture after it has been formed at room temperature refers to pressing the mixture into a blank at room temperature or pre-forming it into a blank at room temperature, drying it, and then hot pressing and sintering it. The hot pressing and sintering method is the same as above.

[0192] The process of forming the mixture at room temperature and pre-sintering at low temperature followed by hot pressing and sintering refers to the process of forming or pre-forming the mixture at low temperature and pre-sintering it at 1350-1500℃ before placing it into a mold in a high-temperature device for hot pressing and sintering.

[0193] The high-temperature device is a commonly used high-temperature device in this field, such as a hot press furnace.

[0194] In a preferred embodiment of the present invention, the hot pressing sintering temperature is 1550-1750℃, and preferably, the hot pressing strength is 0.5-10MPa. For example, the temperature can be 1550℃, 1600℃, 1650℃, 1700℃, 1750℃ or any range therebetween.

[0195] The hot-pressing strength can be, for example, 0.5MPa, 1MPa, 1.5MPa, 2MPa, 2.5MPa, 3MPa, 3.5MPa, 4MPa, 4.5MPa, 5MPa, 5.5MPa, 6MPa, 6.5MPa, 7MPa, 7.5MPa, 8MPa, 8.5MPa, 9MPa, 9.5MPa, 10MPa or any range thereof.

[0196] This invention provides a method for preparing a heat-insulating and refractory material, comprising the following steps:

[0197] The mixture is obtained by mixing granular material and fine powder, and then hot-pressing and sintering the mixture.

[0198] In a preferred embodiment of the present invention, the mass ratio of the granular material to the fine powder is 0-60:40-100.

[0199] In a preferred embodiment of the present invention, the hot pressing sintering involves placing the mixture into a mold of a high-temperature device for hot pressing sintering, or forming the mixture at room temperature and then placing it into a mold of a high-temperature device for hot pressing sintering, or forming the mixture at room temperature and pre-sintering at low temperature before hot sintering.

[0200] In a preferred embodiment of the present invention, the temperature is 1550-1750℃, and preferably, the hot-pressing strength is 0.5-10MPa.

[0201] The thermal insulation refractory material based on CA6 with medium bulk density obtained by this invention achieves good sintering of high-purity CA6 system materials, resulting in high material strength. The material has a uniform microstructure, relatively uniform thermal insulation and strength properties, and good resistance to erosion by molten slag and steel. It is very suitable for permanent linings of steel ladles, working linings and thermal insulation linings of aluminum liquid, and refractory material linings of some industrial kilns. It has good thermal insulation, heat preservation and safety, and significant economic and social benefits.

[0202] The present invention provides a permanent lining for steel ladles in steel smelting, comprising the heat-insulating refractory material described above or the heat-insulating refractory material prepared by the preparation method described above.

[0203] The present invention provides a heat-insulating lining or working lining for molten aluminum ladle, comprising the heat-insulating refractory material described above or the heat-insulating refractory material prepared by the preparation method described above.

[0204] Example

[0205] This invention provides a general and / or specific description of the materials and test methods used in the experiments. In the following examples, unless otherwise specified, % represents wt%, i.e., weight percentage. Raw materials or instruments whose manufacturers are not specified are all commercially available conventional raw material products. Table 1 shows the quality of the raw materials used in the examples.

[0206] Table 1 shows the quality of raw materials used in the examples.

[0207]

[0208]

[0209] Example 1

[0210] (1) Mix 500g of CA6 granules (maximum particle size 5mm) and 500g of CA6 fine powder evenly to obtain a mixture.

[0211] (2) The mixture is placed in a mold of a high-temperature device for direct hot pressing and sintering. When the temperature rises to the maximum temperature of 1630°C, a pressure of 5MPa is applied at this temperature to obtain a medium-density refractory material.

[0212] The phase analysis of the refractory material was performed using XRD analysis. The material was ground to below 325 mesh and then scanned using an X-ray diffractometer (Bruker: D8 ADVANCE). By analyzing the diffraction data and matching it with a standard PDF card, the relevant phases were obtained. The content of these phases was then determined by fitting the full spectrum of the diffraction data, revealing that the main phase was CA6. Based on the mass percentage of the phases in the refractory material, the content of the CA6 phase was 99.5%.

[0213] The chemical composition of the refractory material was analyzed by fluorescence XRF analysis in accordance with GB / T21114-2007. The chemical composition, based on the mass percentage of the refractory material, contains 91.04% Al2O3 and 8.40% CaO.

[0214] The phase analysis of the matrix portion of the refractory material was performed using XRD micro-area diffraction. Twelve different refractory materials were selected, and twelve samples were cut from each. Within each sample, a matrix region with relatively uniform color and microstructure was selected for micro-area diffraction, and the diffraction patterns were fully fitted to determine the content of each phase. Two data points with significant deviations were removed, and the average of the phase contents of the remaining ten samples was taken as the phase content of the refractory material matrix. The matrix portion of the refractory material was found to primarily contain CA6, with the CA6 phase accounting for 99.2% of the matrix portion by mass.

[0215] The chemical composition of the matrix portion of the refractory material was determined using the EDS method. Twelve different refractory materials were selected, and twelve samples were cut and polished. Each polished sample was placed under an electron microscope, and a region with a relatively uniform microstructure was selected within the matrix. A rectangular sampling area of ​​appropriate size was then chosen within this region for elemental analysis. The collected elemental contents were converted into oxides, and the chemical composition was calculated, specifically the contents of Al₂O₃, CaO, and MgO. Two data points with significant deviations were discarded, and the average value of the Al₂O₃, CaO, and MgO contents from the ten samples was taken as the chemical composition of the refractory material matrix. Based on the mass percentage of the matrix portion, the chemical composition of the refractory material matrix consisted of 91.20% Al₂O₃ and 8.40% CaO.

[0216] The medium bulk density refractory material based on CA6 was tested according to GB / T2997-2000, and the measured bulk density was 2.54 g / cm³. 3 .

[0217] According to the national standard GB / T 5990-2006, the thermal conductivity of the refractory material obtained in Example 1 at 350℃ is 1.36 W / mK.

[0218] The prepared material was made into a crucible, steel slag was placed in the crucible, the temperature was raised to 1500℃ and held for 3 hours, and then the cooled sample was cut open along the middle. The depth of steel slag erosion on the sample was measured to be 2.41 mm.

[0219] Example 2

[0220] (1) Mix 450g of CA6 granules (maximum particle size 3mm), 440g of CA6 fine powder, and 110g of tabular corundum powder evenly to obtain a mixture.

[0221] (2) The mixture is placed in the mold of the high-temperature device and hot-pressed and sintered directly. When the temperature rises to the maximum temperature of 1580℃, a pressure of 3MPa is applied at this temperature to obtain a medium-density refractory material.

[0222] Phase analysis was performed using the same method as in Example 1. The phases of the medium bulk density refractory material included CA6 and corundum. The content of the CA6 phase was 86.5% and the content of the corundum phase was 11% by mass percentage of the phases in the refractory material.

[0223] Chemical composition analysis was performed using the same method as in Example 1. The chemical composition of the obtained medium bulk density refractory material, based on the mass percentage of the refractory material, included 91.3% Al2O3 and 7.28% CaO.

[0224] The phase analysis of the matrix portion was performed using the same method as in Example 1. The phases of the matrix portion of the refractory material include CA6 and corundum. The content of the CA6 phase is 77.2% and the content of the corundum phase is 20% by mass percentage of the phases in the matrix portion of the refractory material.

[0225] The chemical composition of the matrix portion was analyzed using the same method as in Example 1. The chemical composition of the matrix portion of the refractory material, as a percentage by mass of the matrix portion, comprises 93.2% Al2O3 and 6.60% CaO.

[0226] The bulk density was analyzed using the same method as in Example 1, and the bulk density of the medium-density refractory material was 2.41 g / cm³. 3 .

[0227] The analysis was performed using the same method as in Example 1, and the obtained refractory material had a thermal conductivity of 1.33 W / mK at 350°C.

[0228] The erosion depth of the refractory material was measured using the same method as in Example 1, and the result was 2.61 mm.

[0229] Example 3

[0230] (1) Mix 500g of CA6 granules (maximum particle size 3mm), 400g of CA6 fine powder, and 100g of C2M2A14 powder evenly to obtain a mixture.

[0231] (2) The mixture is placed in the mold of the high-temperature device and hot-pressed and sintered directly. When the temperature rises to the maximum temperature of 1630°C, a pressure of 3MPa is applied at this temperature to obtain a medium-density refractory material.

[0232] Phase analysis was performed using the same method as in Example 1. The phases of the medium bulk density refractory material included CA6 and C2M2A14. The content of the CA6 phase was 89.12% and the content of the C2M2A14 phase was 9.4% by mass percentage of the phases in the refractory material.

[0233] Chemical composition analysis was performed using the same method as in Example 1. The chemical composition of the obtained medium bulk density refractory material, based on the mass percentage of the refractory material, included 91.03% Al2O3, 0.43% MgO, and 8.02% CaO.

[0234] The phase analysis of the matrix portion was performed using the same method as in Example 1. The phases of the matrix portion of the refractory material include CA6 and C2M2A14, wherein, based on the mass percentage of the phases in the matrix portion of the refractory material, the content of the CA6 phase is 78.2% and the content of the C2M2A14 phase is 18.8%.

[0235] The chemical composition of the matrix portion was analyzed using the same method as in Example 1. The chemical composition of the matrix portion of the refractory material, expressed as a percentage by mass, includes 90.8% Al2O3, 0.8% MgO, and 8.0% CaO.

[0236] The bulk density was analyzed using the same method as in Example 1, and the bulk density of the medium-density refractory material was 2.55 g / cm³. 3 .

[0237] The analysis was performed using the same method as in Example 1, and the obtained refractory material had a thermal conductivity of 1.38 W / mK at 350°C.

[0238] The erosion depth of the refractory material was measured using the same method as in Example 1, and the result was 2.52 mm.

[0239] Example 4

[0240] (1) Mix 500g of CA6 granules (maximum particle size 3mm), 400g of CA6 fine powder, 85.8g of industrial alumina powder, 8.6g of high-purity magnesia powder and 7.8g of calcium hydroxide powder evenly to obtain a mixture.

[0241] (2) The mixture is placed in the mold of the high-temperature device and hot-pressed and sintered directly. When the temperature rises to the maximum temperature of 1650°C, a hot-pressing pressure of 8MPa is applied at this temperature to obtain a medium-density refractory material.

[0242] Phase analysis was performed using the same method as in Example 1. The phases of the medium bulk density refractory material included CA6 and CM2A8. The content of the CA6 phase was 89.04% and the content of the CM2A8 phase was 9.4% by mass percentage of the phases in the refractory material.

[0243] Chemical composition analysis was performed using the same method as in Example 1. The chemical composition of the obtained medium bulk density refractory material, based on the mass percentage of the refractory material, included 90.34% Al2O3, 0.78% MgO, and 7.86% CaO.

[0244] The phase analysis of the matrix portion was performed using the same method as in Example 1. The phases of the matrix portion of the refractory material include CA6 and CM2A8, wherein, based on the mass percentage of the phases in the matrix portion of the refractory material, the content of the CA6 phase is 78.2% and the content of the CM2A8 phase is 18.8%.

[0245] The chemical composition of the matrix portion was analyzed using the same method as in Example 1. The chemical composition of the matrix portion of the refractory material, expressed as a percentage by mass, comprises 90.30% Al2O3, 1.68% MgO, and 7.81% CaO.

[0246] The bulk density was analyzed using the same method as in Example 1, and the bulk density of the medium-density refractory material was 2.53 g / cm³. 3 .

[0247] The analysis was performed using the same method as in Example 1, and the obtained refractory material had a thermal conductivity of 1.40 W / mK at 350°C.

[0248] The erosion depth of the refractory material was measured using the same method as in Example 1, and the result was 2.64 mm.

[0249] Example 5

[0250] (1) Mix 450g of CA6 granules (maximum particle size 3mm), 40g of CA6 fine powder, 69g of 12CaO·7Al2O3 fine powder, 331g of active α-Al2O3 micro powder, and 110g of white corundum powder evenly to obtain a mixture.

[0251] (2) The mixture is placed in a mold of a high-temperature device for direct hot pressing and sintering. Pressure is applied when the temperature rises to 1350°C and gradually increased as the temperature rises. The maximum temperature reaches 1750°C and the maximum hot pressing strength is 0.5 MPa, thus producing a medium-density refractory material.

[0252] Phase analysis was performed using the same method as in Example 1. The phases of the medium bulk density refractory material included CA6 and corundum. The content of the CA6 phase was 84.1% and the content of the corundum phase was 10.7% by mass percentage of the phases in the refractory material.

[0253] Chemical composition analysis was performed using the same method as in Example 1. The chemical composition of the obtained medium bulk density refractory material, based on the mass percentage of the refractory material, included 92.01% Al2O3 and 7.21% CaO.

[0254] The phase analysis of the matrix portion was performed using the same method as in Example 1. The phases of the matrix portion of the refractory material include CA6 and corundum. The content of the CA6 phase is 73.9% and the content of the corundum phase is 19.5% by mass percentage of the phases in the matrix portion of the refractory material.

[0255] The chemical composition of the matrix portion was analyzed using the same method as in Example 1. The chemical composition of the matrix portion of the refractory material, as a percentage by mass of the matrix portion, comprises 93.20% Al2O3 and 6.61% CaO.

[0256] The bulk density was analyzed using the same method as in Example 1, and the bulk density of the medium-density refractory material was 2.61 g / cm³. 3 .

[0257] The analysis was performed using the same method as in Example 1, and the obtained refractory material had a thermal conductivity of 1.58 W / mK at 350°C.

[0258] The erosion depth of the refractory material was measured using the same method as in Example 1, and the result was 2.40 mm.

[0259] Example 6

[0260] (1) Mix 400g of CA6 granules (maximum particle size 3mm), 280g of CA6 fine powder, 184g of γ-Al2O3 powder, 120g of tabular corundum powder, and 22.2g of Ca(OH)2 fine powder evenly to obtain a mixture.

[0261] (2) The mixture is pressed at room temperature and lightly calcined at 1500°C before being placed in a mold of a high-temperature device. Pressure is gradually applied starting from 1550°C, with the highest temperature reaching 1720°C and the maximum hot-pressing strength being 1MPa, to obtain a medium-density refractory material.

[0262] Phase analysis was performed using the same method as in Example 1. The phases of the medium bulk density refractory material included CA6 and corundum. The content of the CA6 phase was 85.5% and the content of the corundum phase was 11.8% by mass percentage of the phases in the refractory material.

[0263] Chemical composition analysis was performed using the same method as in Example 1. The chemical composition of the obtained medium bulk density refractory material, based on the mass percentage of the refractory material, included 92.03% Al2O3 and 7.18% CaO.

[0264] The phase analysis of the matrix portion was performed using the same method as in Example 1. The phases of the matrix portion of the refractory material include CA6 and corundum. The content of the CA6 phase is 77.2% and the content of the corundum phase is 20% by mass percentage of the phases in the matrix portion of the refractory material.

[0265] The chemical composition of the matrix portion was analyzed using the same method as in Example 1. The chemical composition of the matrix portion of the refractory material, as a percentage by mass of the matrix portion, comprises 93.2% Al2O3 and 6.61% CaO.

[0266] The bulk density was analyzed using the same method as in Example 1, and the bulk density of the medium-density refractory material was 2.60 g / cm³. 3 .

[0267] The analysis was performed using the same method as in Example 1, and the obtained refractory material had a thermal conductivity of 1.56 W / mK at 350°C.

[0268] The erosion depth of the refractory material was measured using the same method as in Example 1, and the result was 2.43 mm.

[0269] Example 7

[0270] (1) Mix 835g of CA6 fine powder, 60g of tabular corundum fine powder and 110g of ρ-Al2O3 fine powder evenly to obtain a mixture.

[0271] (2) The mixture is pre-formed with water and dried, and then placed in a mold of a high-temperature device for heating. The temperature is raised to a maximum of 1650°C. At this temperature, a hot-pressing pressure of 6 MPa is applied to obtain a medium-density refractory material based on CA6.

[0272] Phase analysis was performed using the same method as in Example 1. The phases of the medium bulk density refractory material included CA6 and corundum. The content of the CA6 phase was 82.0% and the content of the corundum phase was 16.5% by mass percentage of the phases in the refractory material.

[0273] Chemical composition analysis was performed using the same method as in Example 1. The chemical composition of the obtained medium bulk density refractory material, based on the mass percentage of the refractory material, included 91.6% Al2O3 and 6.92% CaO.

[0274] The phase analysis of the matrix portion was performed using the same method as in Example 1. The phases of the matrix portion of the refractory material include CA6 and corundum. The content of the CA6 phase is 82.0% and the content of the corundum phase is 16.5% by mass percentage of the phases in the matrix portion of the refractory material.

[0275] The chemical composition of the matrix portion was analyzed using the same method as in Example 1. The chemical composition of the matrix portion of the refractory material, as a percentage by mass, includes 91.6% Al2O3 and 6.92% CaO.

[0276] The bulk density was analyzed using the same method as in Example 1, and the bulk density of the medium-density refractory material was 2.52 g / cm³. 3 .

[0277] The analysis was performed using the same method as in Example 1, and the obtained refractory material had a thermal conductivity of 1.31 W / mK at 350°C.

[0278] The erosion depth of the refractory material was measured using the same method as in Example 1, and the result was 3.20 mm.

[0279] Example 8

[0280] (1) Mix 800g of CA6 fine powder, 100g of tabular corundum fine powder and 105g of ρ-Al2O3 fine powder evenly to obtain a mixture.

[0281] (2) The mixture is pre-formed with water and dried, and then placed in a mold of a high-temperature device for heating. The temperature is raised to a maximum of 1600°C. At this temperature, a hot-pressing pressure of 8 MPa is applied to obtain a medium-density refractory material based on CA6.

[0282] Phase analysis was performed using the same method as in Example 1. The phases of the medium bulk density refractory material included CA6 and corundum. The content of the CA6 phase was 78.6% and the content of the corundum phase was 20% by mass percentage of the phases in the refractory material.

[0283] Chemical composition analysis was performed using the same method as in Example 1. The chemical composition of the obtained medium bulk density refractory material, based on the mass percentage of the refractory material, included 92.4% Al2O3 and 6.52% CaO.

[0284] The phase analysis of the matrix portion was performed using the same method as in Example 1. The phases of the matrix portion of the refractory material include CA6 and corundum. The content of the CA6 phase is 78.6% and the content of the corundum phase is 20% by mass percentage of the phases in the matrix portion of the refractory material.

[0285] The chemical composition of the matrix portion was analyzed using the same method as in Example 1. The chemical composition of the matrix portion of the refractory material, as a percentage by mass of the matrix portion, comprises 92.4% Al2O3 and 6.52% CaO.

[0286] The bulk density was analyzed using the same method as in Example 1, and the bulk density of the medium-density refractory material was 2.52 g / cm³. 3 .

[0287] The analysis was performed using the same method as in Example 1, and the obtained refractory material had a thermal conductivity of 1.34 W / mK at 350°C.

[0288] The erosion depth of the refractory material was measured using the same method as in Example 1, and the result was 3.10 mm.

[0289] Example 9

[0290] (1) Mix 700g of CA6 fine powder, 100g of sintered corundum powder, 174.8g of γ-Al2O3 fine powder and 45g of limestone fine powder evenly.

[0291] (2) The mixture is pressed at room temperature and then placed in the mold of a high-temperature device. Pressure is gradually applied starting from the temperature of 1450°C, with the maximum temperature reaching 1600°C and the maximum hot-pressing strength being 1MPa, to obtain a medium-density refractory material.

[0292] Phase analysis was performed using the same method as in Example 1. The phases of the medium bulk density refractory material included CA6, and the content of the CA6 phase was 97.5% by mass percentage of the phases in the refractory material.

[0293] Chemical composition analysis was performed using the same method as in Example 1. The chemical composition of the obtained medium bulk density refractory material, based on the mass percentage of the refractory material, included 90.1% Al2O3 and 8.40% CaO.

[0294] The phase analysis of the matrix portion was performed using the same method as in Example 1. The phase of the matrix portion of the refractory material includes CA6, wherein the content of the CA6 phase is 97.5% by mass percentage of the phase in the matrix portion of the refractory material.

[0295] The chemical composition of the matrix portion was analyzed using the same method as in Example 1. The chemical composition of the matrix portion of the refractory material, as a percentage by mass of the matrix portion, comprises 90.1% Al2O3 and 8.40% CaO.

[0296] The bulk density was analyzed using the same method as in Example 1, and the bulk density of the medium-density refractory material was 2.40 g / cm³. 3 .

[0297] The analysis was performed using the same method as in Example 1, and the obtained refractory material had a thermal conductivity of 1.31 W / mK at 350°C.

[0298] The erosion depth of the refractory material was measured using the same method as in Example 1, and the result was 3.30 mm.

[0299] Example 10

[0300] (1) Mix 200g of CA6 granules (maximum particle size 3mm), 200g of C2M2A14 aggregate (maximum particle size 3mm), 540g of CA6 fine powder, 4.3g of quicklime powder, 3.0g of fused magnesium oxide, and 52.9g of white corundum fine powder evenly to obtain a mixture.

[0301] (2) The mixture is pressed and shaped and then placed in a mold of a high-temperature device for hot pressing and sintering. When the maximum temperature rises to 1550°C, a pressure of 4MPa is applied at this temperature to obtain a medium-density refractory material.

[0302] Phase analysis was performed using the same method as in Example 1. The phases of the medium bulk density refractory material included CA6 and C2M2A14. Based on the mass percentage of the phases in the refractory material, the content of the CA6 phase was 71.3% and the content of the C2M2A14 phase was 23.5%.

[0303] Chemical composition analysis was performed using the same method as in Example 1. The chemical composition of the obtained medium bulk density refractory material, based on the mass percentage of the refractory material, included 90.04% Al2O3, 1.22% MgO, and 7.56% CaO.

[0304] The phase analysis of the matrix portion was performed using the same method as in Example 1. The phases of the matrix portion of the refractory material include CA6 and C2M2A14, wherein, based on the mass percentage of the phases in the matrix portion of the refractory material, the content of the CA6 phase is 88.6% and the content of the C2M2A14 phase is 9.74%.

[0305] The chemical composition of the matrix portion was analyzed using the same method as in Example 1. The chemical composition of the matrix portion of the refractory material, as a percentage by mass of the matrix portion, comprises 90.37% Al2O3, 0.42% MgO, and 8.18% CaO.

[0306] The bulk density was analyzed using the same method as in Example 1, and the bulk density of the medium-density refractory material was 2.43 g / cm³. 3 .

[0307] The analysis was performed using the same method as in Example 1, and the obtained refractory material had a thermal conductivity of 1.42 W / mK at 350°C.

[0308] The erosion depth of the refractory material was measured using the same method as in Example 1, and the result was 2.67 mm.

[0309] Example 11

[0310] (1) Mix 600g of CM2A8 granules (maximum particle size 3mm), 200g of CA6 fine powder, 280.2g of aluminum hydroxide fine powder, and 22.2g of calcium hydroxide fine powder evenly to obtain a mixture;

[0311] (2) The mixture is pressed into shape at room temperature and then placed in the mold of a high-temperature device. Pressure is gradually applied from room temperature. When the maximum temperature reaches 1700℃, the maximum hot-pressing strength is 2MPa, and a medium-density refractory material is obtained.

[0312] Phase analysis was performed using the same method as in Example 1. The phases of the medium bulk density refractory material included CA6 and CM2A8. The content of the CA6 phase was 38.7% and the content of the CM2A8 phase was 59.5% by mass percentage of the phases in the refractory material.

[0313] Chemical composition analysis was performed using the same method as in Example 1. The chemical composition of the obtained medium bulk density refractory material, based on the mass percentage of the refractory material, included 88.07% Al2O3, 5.04% MgO, and 6.89% CaO.

[0314] The phase analysis of the matrix portion was performed using the same method as in Example 1. The phase of the matrix portion of the refractory material includes CA6, wherein the content of the CA6 phase is 98.7% by mass percentage of the phase in the matrix portion of the refractory material.

[0315] The chemical composition of the matrix portion was analyzed using the same method as in Example 1. The chemical composition of the matrix portion of the refractory material, expressed as a percentage by mass, comprises 90.5% Al2O3 and 8.40% CaO.

[0316] The bulk density was analyzed using the same method as in Example 1, and the bulk density of the medium-density refractory material was 2.65 g / cm³. 3 .

[0317] The analysis was performed using the same method as in Example 1, and the obtained refractory material had a thermal conductivity of 1.62 W / mK at 350°C.

[0318] The erosion depth of the refractory material was measured using the same method as in Example 1, and the result was 2.62 mm.

[0319] Example 12

[0320] (1) Mix 600g of C2M2A14 granules (maximum particle size 3mm) and 400g of CA6 fine powder evenly to obtain a mixture.

[0321] (2) The mixture is placed in a mold of a high-temperature device for hot pressing and sintering. When the temperature rises to 1400°C, pressure is gradually applied. When the temperature rises to 1720°C, the maximum hot pressing strength is 10 MPa, and a medium bulk density refractory material is obtained.

[0322] Phase analysis was performed using the same method as in Example 1. The phases of the medium bulk density refractory material included CA6 and C2M2A14. The content of the CA6 phase was 38.7% and the content of the C2M2A14 phase was 60% by mass percentage of the phases in the refractory material.

[0323] Chemical composition analysis was performed using the same method as in Example 1. The chemical composition of the obtained medium bulk density refractory material, based on the mass percentage of the refractory material, included 89.32% Al2O3, 2.74% MgO, and 7.41% CaO.

[0324] The phase analysis of the matrix portion was performed using the same method as in Example 1. The phase of the matrix portion of the refractory material includes CA6, wherein the content of the CA6 phase is 100% based on the mass percentage of the phase in the matrix portion of the refractory material.

[0325] The chemical composition of the matrix portion was analyzed using the same method as in Example 1. The chemical composition of the matrix portion of the refractory material, as a percentage by mass of the matrix portion, comprises 90.8% Al2O3 and 8.40% CaO.

[0326] The bulk density was analyzed using the same method as in Example 1, and the bulk density of the medium-density refractory material was 2.82 g / cm³. 3 .

[0327] The analysis was performed using the same method as in Example 1, and the obtained refractory material had a thermal conductivity of 2.25 W / mK at 350°C.

[0328] The erosion depth of the refractory material was measured using the same method as in Example 1, and the result was 2.2 mm.

[0329] Example 13

[0330] (1) Mix 600g of CM2A8 granules (maximum particle size 3mm), 320g of CA6 fine powder, and 80g of dense corundum fine powder evenly to obtain a mixture.

[0331] (2) The mixture is placed in a mold of a high-temperature device and hot-pressed and sintered directly. When the temperature rises to a maximum of 1700°C, a pressure of 5MPa is applied at this temperature to obtain a medium-density refractory material.

[0332] Phase analysis was performed using the same method as in Example 1. The phases of the medium bulk density refractory material included CA6, CM2A8, and corundum. Based on the mass percentage of the phases in the refractory material, the content of the CA6 phase was 31.5%, the content of the CM2A8 phase was 58.3%, and the content of the corundum phase was 7.4%.

[0333] Chemical composition analysis was performed using the same method as in Example 1. The chemical composition of the obtained medium bulk density refractory material, based on the mass percentage of the refractory material, included 88.41% Al2O3, 5.04% MgO, and 7.43% CaO.

[0334] The phase analysis of the matrix portion was performed using the same method as in Example 1. The phases of the matrix portion of the refractory material include CA6 and corundum, wherein, based on the mass percentage of the phases in the matrix portion of the refractory material, the content of the CA6 phase is 78.2% and the content of the corundum phase is 18.6%.

[0335] The chemical composition of the matrix portion was analyzed using the same method as in Example 1. The chemical composition of the matrix portion of the refractory material, as a percentage by mass of the matrix portion, comprises 93.2% Al2O3 and 6.60% CaO.

[0336] The bulk density was analyzed using the same method as in Example 1, and the bulk density of the medium-density refractory material was 2.72 g / cm³. 3 .

[0337] The analysis was performed using the same method as in Example 1, and the obtained refractory material had a thermal conductivity of 2.13 W / mK at 350°C.

[0338] The erosion depth of the refractory material was measured using the same method as in Example 1, and the result was 2.52 mm.

[0339] Example 14

[0340] (1) Mix 600g of CM2A8 granules (maximum particle size 3mm), 320g of CA6 fine powder, and 80g of CM2A8 fine powder evenly to obtain a mixture.

[0341] (2) The mixture is pressed into shape at room temperature and then placed in a mold of a high-temperature device for hot pressing and sintering. When the temperature rises to a maximum of 1670°C, pressure is applied at this temperature and the hot pressing strength is 0.5 MPa, thus obtaining a medium bulk density refractory material.

[0342] Phase analysis was performed using the same method as in Example 1. The phases of the medium bulk density refractory material included CA6 and CM2A8. The content of the CA6 phase was 31.5% and the content of the CM2A8 phase was 67.1% by mass percentage of the phases in the refractory material.

[0343] Chemical composition analysis was performed using the same method as in Example 1. The chemical composition of the obtained medium bulk density refractory material, based on the mass percentage of the refractory material, included 87.60% Al2O3, 5.62% MgO, and 6.43% CaO.

[0344] The phase analysis of the matrix portion was performed using the same method as in Example 1. The phases of the matrix portion of the refractory material include CA6 and CM2A8, wherein, based on the mass percentage of the phases in the matrix portion of the refractory material, the content of the CA6 phase is 78.2% and the content of the CM2A8 phase is 19.2%.

[0345] The chemical composition of the matrix portion was analyzed using the same method as in Example 1. The chemical composition of the matrix portion of the refractory material, as a percentage by mass of the matrix portion, comprises 90.30% Al2O3, 1.68% MgO, and 7.82% CaO.

[0346] The bulk density was analyzed using the same method as in Example 1, and the bulk density of the medium-density refractory material was 2.63 g / cm³. 3 .

[0347] The analysis was performed using the same method as in Example 1, and the obtained refractory material had a thermal conductivity of 1.87 W / mK at 350°C.

[0348] The erosion depth of the refractory material was measured using the same method as in Example 1, and the result was 2.9 mm.

[0349] Example 15

[0350] (1) Mix 947.4g of CA6 fine powder, 15g of fused magnesia fine powder and 38g of active α-Al2O3 fine powder evenly to obtain a mixture.

[0351] (2) The mixture is pressed into shape at room temperature and lightly calcined at 1350°C before being placed in the mold of a high-temperature device. Pressure is applied starting from the temperature of 1500°C, with the temperature reaching a maximum of 1580°C and the maximum hot-pressing strength being 5MPa, to obtain a medium-density refractory material.

[0352] Phase analysis was performed using the same method as in Example 1. The phases of the medium bulk density refractory material included CA6 and C2M2A14. The content of the CA6 phase was 67.4% and the content of the C2M2A14 phase was 30% by mass percentage of the phases in the refractory material.

[0353] Chemical composition analysis was performed using the same method as in Example 1. The chemical composition of the obtained medium bulk density refractory material, based on the mass percentage of the refractory material, included 89.32% Al2O3, 1.38% MgO, and 7.81% CaO.

[0354] The bulk density was analyzed using the same method as in Example 1, and the bulk density of the medium-density refractory material was 2.48 g / cm³. 3 .

[0355] The phase analysis of the matrix portion was performed using the same method as in Example 1. The phase of the matrix portion of the refractory material includes CA6, wherein the content of the CA6 phase is 98.5% by mass percentage of the phase in the matrix portion of the refractory material.

[0356] The chemical composition of the matrix portion was analyzed using the same method as in Example 1. The chemical composition of the matrix portion of the refractory material, expressed as a percentage by mass, includes 89.32% Al2O3, 1.38% MgO, and 7.81% CaO.

[0357] The analysis was performed using the same method as in Example 1, and the obtained refractory material had a thermal conductivity of 1.46 W / mK at 350°C.

[0358] The erosion depth of the refractory material was measured using the same method as in Example 1, and the result was 4.0 mm.

[0359] Example 16

[0360] (1) Mix 600g of CM2A8 granules (maximum particle size 8mm), 80g of CA6 fine powder, 281g of aluminum hydroxide fine powder, 17.5g of lime fine powder and 120g of CM2A8 fine powder evenly to obtain a mixture.

[0361] (2) The mixture is pressed into shape at room temperature and lightly sintered at 1400°C, and then placed in a mold of a high-temperature device for hot pressing and sintering. When the temperature rises to 1500°C, pressure is applied and gradually increased as the temperature rises. When the temperature reaches a maximum of 1750°C, the maximum hot pressing strength is 0.5 MPa, thus obtaining a medium bulk density refractory material.

[0362] Phase analysis was performed using the same method as in Example 1. The phases of the medium bulk density refractory material included CA6 and CM2A8. The content of the CA6 phase was 26.7% and the content of the CM2A8 phase was 72% by mass percentage of the phases in the refractory material.

[0363] Chemical composition analysis was performed using the same method as in Example 1. The chemical composition of the obtained medium bulk density refractory material, based on the mass percentage of the refractory material, included 86.65% Al2O3, 6.05% MgO, and 6.22% CaO.

[0364] The phase analysis of the matrix portion was performed using the same method as in Example 1. The phases of the matrix portion of the refractory material include CA6 and CM2A8, wherein, based on the mass percentage of the phases in the matrix portion of the refractory material, the content of the CA6 phase is 68% and the content of the corundum phase is 30%.

[0365] The chemical composition of the matrix portion was analyzed using the same method as in Example 1. The chemical composition of the matrix portion of the refractory material, expressed as a percentage by mass, includes 89.03% Al2O3, 2.52% MgO, and 7.60% CaO.

[0366] The bulk density was analyzed using the same method as in Example 1, and the bulk density of the medium-density refractory material was 2.90 g / cm³. 3 .

[0367] The analysis was performed using the same method as in Example 1, and the obtained refractory material had a thermal conductivity of 2.48 W / mK at 350°C.

[0368] The erosion depth of the refractory material was measured using the same method as in Example 1, and the result was 2.10 mm.

[0369] Example 17

[0370] (1) Mix 100g of C2M2A14 granules (maximum particle size 1mm), 630g of CA6 fine powder, 18.7g of quicklime fine powder, 13.4g of high-purity magnesia powder, 180g of white corundum fine powder and 58g of active α-Al2O3 powder evenly to obtain a mixture.

[0371] (2) The mixture is pressed into shape at room temperature and lightly sintered at 1450°C, and then placed into the mold of a high-temperature device for hot pressing and sintering. When the temperature rises to 1500°C, pressure is gradually applied. The temperature rises to a maximum of 1620°C, and the maximum hot pressing strength is 8MPa, thus obtaining a medium bulk density refractory material.

[0372] Phase analysis was performed using the same method as in Example 1. The phases of the medium bulk density refractory material included CA6, C2M2A14, and MgO·Al2O3. Based on the mass percentage of the phases in the refractory material, the content of the CA6 phase was 84.2%, the content of the C2M2A14 phase was 9.28%, and the content of the MgO·Al2O3 phase was 4.60%.

[0373] Chemical composition analysis was performed using the same method as in Example 1. The chemical composition of the obtained medium bulk density refractory material, based on the mass percentage of the refractory material, included 89.14% Al2O3, 1.71% MgO, and 7.65% CaO.

[0374] The phase analysis of the matrix portion was performed using the same method as in Example 1. The phases of the matrix portion of the refractory material include CA6 and MgO·Al2O3, wherein, based on the mass percentage of the phases in the matrix portion of the refractory material, the content of the CA6 phase is 93.5% and the content of the MgO·Al2O3 phase is 5.22%.

[0375] The chemical composition of the matrix portion was analyzed using the same method as in Example 1. The chemical composition of the matrix portion of the refractory material, as a percentage by mass of the matrix portion, comprises 90.07% Al2O3, 1.32% MgO, and 7.67% CaO.

[0376] The bulk density was analyzed using the same method as in Example 1, and the bulk density of the medium-density refractory material was 2.57 g / cm³. 3 .

[0377] The analysis was performed using the same method as in Example 1, and the obtained refractory material had a thermal conductivity of 1.67 W / mK at 350°C.

[0378] The erosion depth of the refractory material was measured using the same method as in Example 1, and the result was 3.6 mm.

[0379] Example 18

[0380] (1) Mix 700g of CA6 fine powder, 150g of tabular corundum fine powder and 155g of ρ-Al2O3 fine powder evenly to obtain a mixture.

[0381] (2) The mixture is pre-formed with water and dried, and then placed in a mold of a high-temperature device for heating. The temperature is raised to a maximum of 1550°C. At this temperature, a hot-pressing pressure of 10 MPa is applied to obtain a medium-density refractory material based on CA6.

[0382] Phase analysis was performed using the same method as in Example 1. The phases of the medium bulk density refractory material included CA6 and corundum. The content of the CA6 phase was 66.4% and the content of the corundum phase was 30% by mass percentage of the phases in the refractory material.

[0383] Chemical composition analysis was performed using the same method as in Example 1. The chemical composition of the obtained medium bulk density refractory material, based on the mass percentage of the refractory material, included 94.10% Al2O3 and 5.80% CaO.

[0384] The phase analysis of the matrix portion was performed using the same method as in Example 1. The phases of the matrix portion of the refractory material include CA6 and corundum. The content of the CA6 phase is 66.4% and the content of the corundum phase is 30% by mass percentage of the phases in the matrix portion of the refractory material.

[0385] The chemical composition of the matrix portion was analyzed using the same method as in Example 1. The chemical composition of the matrix portion of the refractory material, as a percentage by mass of the matrix portion, comprises 94.10% Al2O3 and 5.80% CaO.

[0386] The bulk density was analyzed using the same method as in Example 1, and the bulk density of the medium-density refractory material was 2.52 g / cm³. 3 .

[0387] The analysis was performed using the same method as in Example 1, and the obtained refractory material had a thermal conductivity of 1.48 W / mK at 350°C.

[0388] The erosion depth of the refractory material was measured using the same method as in Example 1, and the result was 3.10 mm.

[0389] Example 19

[0390] (1) Mix 600g of C2M2A14 granules (maximum particle size 10mm), 280g of CA6 fine powder, and 120g of C2M2A14 fine powder evenly to obtain a mixture.

[0391] (2) The mixture is placed in a mold of a high-temperature device for hot pressing and sintering. Pressure is gradually applied starting from room temperature. The temperature rises to a maximum of 1610℃ and the maximum hot pressing strength is 6MPa, thus producing a medium-density refractory material.

[0392] Phase analysis was performed using the same method as in Example 1. The phases of the medium bulk density refractory material included CA6 and C2M2A14. The content of the CA6 phase was 26.7% and the content of the C2M2A14 phase was 72% by mass percentage of the phases in the refractory material.

[0393] Chemical composition analysis was performed using the same method as in Example 1. The chemical composition of the obtained medium bulk density refractory material, based on the mass percentage of the refractory material, included 88.87% Al2O3, 3.36% MgO, and 7.16% CaO.

[0394] The phase analysis of the matrix portion was performed using the same method as in Example 1. The phases of the matrix portion of the refractory material include CA6 and C2M2A14, wherein, based on the mass percentage of the phases in the matrix portion of the refractory material, the content of the CA6 phase is 68.1% and the content of the C2M2A14 phase is 30%.

[0395] The chemical composition of the matrix portion was analyzed using the same method as in Example 1. The chemical composition of the matrix portion of the refractory material, expressed as a percentage by mass, comprises 90.46% Al2O3, 1.31% MgO, and 7.82% CaO.

[0396] The bulk density was analyzed using the same method as in Example 1, and the bulk density of the medium-density refractory material was 2.60 g / cm³. 3 .

[0397] The analysis was performed using the same method as in Example 1, and the obtained refractory material had a thermal conductivity of 1.75 W / mK at 350°C.

[0398] The erosion depth of the refractory material was measured using the same method as in Example 1, and the result was 3.5 mm.

[0399] Example 20

[0400] (1) Mix 400g of CA6 granules (maximum particle size 3mm), 280g of CA6 fine powder, 184g of γ-Al2O3 powder, 120g of tabular corundum powder, and 22.2g of Ca(OH)2 fine powder evenly to obtain a mixture.

[0401] (2) The mixture is pressed and calcined at room temperature and then placed in the mold of a high-temperature device. Pressure is gradually applied starting from the temperature of 1550°C, with the maximum temperature reaching 1750°C and the maximum hot-pressing strength being 6MPa, to obtain a medium-density refractory material.

[0402] Phase analysis was performed using the same method as in Example 1. The phases of the medium bulk density refractory material included CA6 and corundum. The content of the CA6 phase was 85.5% and the content of the corundum phase was 11.8% by mass percentage of the phases in the refractory material.

[0403] Chemical composition analysis was performed using the same method as in Example 1. The chemical composition of the obtained medium bulk density refractory material, based on the mass percentage of the refractory material, included 92.03% Al2O3 and 7.18% CaO.

[0404] The phase analysis of the matrix portion was performed using the same method as in Example 1. The phases of the matrix portion of the refractory material include CA6 and corundum. The content of the CA6 phase is 77.2% and the content of the corundum phase is 20% by mass percentage of the phases in the matrix portion of the refractory material.

[0405] The chemical composition of the matrix portion was analyzed using the same method as in Example 1. The chemical composition of the matrix portion of the refractory material, as a percentage by mass of the matrix portion, comprises 93.2% Al2O3 and 6.61% CaO.

[0406] The bulk density was analyzed using the same method as in Example 1, and the bulk density of the medium-density refractory material was 2.90 g / cm³. 3 .

[0407] The analysis was performed using the same method as in Example 1, and the obtained refractory material had a thermal conductivity of 2.42 W / mK at 350°C.

[0408] The erosion depth of the refractory material was measured using the same method as in Example 1, and the result was 1.95 mm.

[0409] Example 21

[0410] (1) Mix 100g of C2M2A14 granules (maximum particle size 1mm), 324g of CA6 fine powder, 53g of quicklime fine powder, 28.5g of high-purity magnesia powder, 400g of white corundum fine powder and 108g of active α-Al2O3 powder evenly to obtain a mixture.

[0411] (2) The mixture is pressed into shape at room temperature and lightly sintered at 1450°C, and then placed into the mold of a high-temperature device for hot pressing and sintering. When the temperature rises to 1500°C, pressure is gradually applied. The temperature rises to a maximum of 1550°C, and the maximum hot pressing strength is 1MPa, thus obtaining a medium bulk density refractory material.

[0412] Phase analysis was performed using the same method as in Example 1. The phases of the medium bulk density refractory material included CA6, C2M2A14, and MgO·Al2O3. Based on the mass percentage of the phases in the refractory material, 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%.

[0413] Chemical composition analysis was performed using the same method as in Example 1. The chemical composition of the obtained medium bulk density refractory material, based on the mass percentage of the refractory material, included 88.5% Al2O3, 3.02% MgO, and 7.21% CaO.

[0414] The phase analysis of the matrix portion was performed using the same method as in Example 1. The phases of the matrix portion of the refractory material include CA6 and MgO·Al2O3, wherein, based on the mass percentage of the phases in the matrix portion of the refractory material, the content of the CA6 phase is 78.6% and the content of the MgO·Al2O3 phase is 11.2%.

[0415] The chemical composition of the matrix portion was analyzed using the same method as in Example 1. The chemical composition of the matrix portion of the refractory material, as a percentage by mass of the matrix portion, includes 89.3% Al2O3, 2.95% MgO, and 7.20% CaO.

[0416] The bulk density was analyzed using the same method as in Example 1, and the bulk density of the medium-density refractory material was 2.85 g / cm³. 3 .

[0417] The analysis was performed using the same method as in Example 1, and the obtained refractory material had a thermal conductivity of 2.54 W / mK at 350°C.

[0418] The erosion depth of the refractory material was measured using the same method as in Example 1, and the result was 3.45 mm.

[0419] Comparative Example 1

[0420] The difference between Comparative Example 1 and Example 1 is that Comparative Example 1 uses a conventional preparation method, namely, the method of Example 1 in Chinese Patent Application CN107500747A to obtain the refractory material.

[0421] The chemical composition of the obtained refractory material was analyzed using the same method as in Example 1. The chemical composition of the refractory material included Al2O3 and CaO, with Al2O3 accounting for 92.03% and CaO accounting for 7.12% by mass percentage in the refractory material.

[0422] The analysis was performed using the same method as in Example 1. The main phases of the obtained refractory material were CA6, corundum, CA2, and CA. The mass percentages of the phases in the refractory material were 68.75% for CA6, 24.16% for corundum, 2.32% for CA2, and 2.51% for CA.

[0423] The analysis was performed using the same method as in Example 1, and the resulting refractory material had a bulk density of 3.02 g / cm³. 3 .

[0424] The same method as in Example 1 was used for analysis, and the obtained refractory material had a thermal conductivity of 2.88 W / mK at 350°C.

[0425] The erosion depth of the refractory material was measured to be 8 mm using the same method as in Example 1.

[0426] Table 2. Raw materials used in the examples and comparative examples, and the composition of the resulting refractory materials.

[0427]

[0428]

[0429] Table 3 shows the thermal conductivity and erosion depth of the refractory materials obtained in the examples and comparative examples at 350°C.

[0430]

[0431]

[0432] Experimental Example 1

[0433] The refractory material obtained in Example 1 was compared with the CA6 castable prepared in Comparative Example 1.

[0434] The treatment method is as follows: The CA6 refractory material obtained in Example 1-1 and the mullite casting are placed in a high-temperature furnace and heated to 1550℃, and then held for 3 hours. The morphology after treatment is as follows. Figure 1 As shown.

[0435] from Figure 1 It can be seen that the surface of the CA6 sample after sintering is very clean, with no cracks and virtually no sintering shrinkage. In contrast, the mullite castable sample showed network cracks on its surface after sintering, indicating that it exhibited sintering shrinkage. These micro-cracks may develop into larger cracks after repeated thermal cycles, even leading to sample fracture. This fully demonstrates that the high-temperature stability of the sample obtained by this invention is excellent.

[0436] Figure 2 , Figure 3 These are schematic diagrams illustrating the resistance of the samples from Example 1 and Comparative Example 1 to steel slag erosion after being subjected to 1500℃ for 3 hours. The steps for resisting steel slag erosion after 1500℃ for 3 hours are as follows: A crucible is made of refractory material, steel slag is placed inside the crucible, the temperature is raised to 1500℃, and held at that temperature for 3 hours before cooling. The cooled sample is then cut open along the middle to observe the erosion depth and corrosion condition of the molten slag.

[0437] from Figure 2 and Figure 3 As can be seen, in Comparative Example 1, the slag in the CA6 castable sample had penetrated very deeply, reaching the outside of the crucible. This indicates that the castable's resistance to slag erosion is very poor. If this sample were used as a permanent ladle lining, its resistance would decrease significantly when the working lining disappears, leading to ladle leakage or red-hot ladle. In contrast, Example 1 exhibits excellent resistance to slag penetration and erosion, despite its bulk density of only 2.54 g / cm³. 3 This demonstrates that the structure of Example 1 is uniform, has excellent resistance to slag penetration, and thus has good erosion resistance, with no weak points.

[0438] The above description is merely a preferred embodiment of the present invention and is not intended to limit the invention in any other way. Any person skilled in the art may make changes or modifications to the above-disclosed technical content to create equivalent embodiments. However, any simple modifications, equivalent changes, and modifications made to the above embodiments based on the technical essence of the present invention without departing from the scope of the present invention shall still fall within the protection scope of the present invention.

Claims

1. A medium bulk density thermal insulation refractory material based on CA6, wherein the phases of the thermal insulation refractory material include CA6 and one or more phases selected from C2M2A14, CM2A8, magnesium aluminum spinel and corundum; The total content of CA6, C2M2A14, CM2A8, magnesium aluminum spinel and corundum in the thermal insulation and refractory materials is ≥90% by mass percentage. The proportion of CA6 phase is 26.7-100%; The C2M2A14 phase content is 0-72%; The phase composition of CM2A8 is 0-72%; The magnesium aluminum spinel phase is 0-10%; The corundum phase content is 0-11.8%; The matrix portion of the heat-insulating and refractory material includes CA6 and one or more phases selected from corundum, magnesium aluminum spinel, C2M2A14 and CM2A8. The CA6 phase comprises 67.4-100% by mass percentage in the matrix portion of the thermal insulation and refractory material. The corundum phase comprises 0-30%; The magnesium aluminum spinel phase is 0-10%; The C2M2A14 phase content is 0-30%; and The phase composition of CM2A8 is 0-30%; The bulk density of the heat-insulating refractory material is 2.40-2.90 g / cm³. 3 .

2. The heat-insulating and refractory material according to claim 1, wherein, The total content of CA6, C2M2A14, CM2A8, magnesium aluminum spinel and corundum is 94.8-99.5% by mass percentage in the heat-insulating refractory material.

3. The heat-insulating and refractory material according to claim 1, wherein, Based on the mass percentage of the phases in thermal insulation and refractory materials, the CA6 phase comprises 31.5%-99.5%; The C2M2A14 phase content is 0-60%; The CM2A8 phase composition is 0-59.5%; and The magnesium aluminum spinel phase is 0-4.60%.

4. The heat-insulating and refractory material according to claim 1, wherein, Based on the mass percentage of the phases in thermal insulation and refractory materials, the CA6 phase comprises 38.7%-99.5%; as well as The magnesium aluminum spinel phase is 0.

5. The heat-insulating and refractory material according to claim 1, wherein, The chemical composition of the heat-insulating refractory material includes Al2O3, CaO, and MgO, and the Al2O3 accounts for 86.65-94.10% of the total mass of the heat-insulating refractory material. The CaO content is 5.80-8.40%; and The MgO content is 0-6.05%.

6. The heat-insulating and refractory material according to claim 5, wherein, The Al2O3 constitutes 87.60-94.10% of the total mass of the heat-insulating and refractory material. The CaO content is 6.89-8.40%; and The MgO content is 0-5.04%.

7. The heat-insulating and refractory material according to claim 5, wherein, The Al2O3 constitutes 88.07-94.10% of the total mass of the heat-insulating and refractory material.

8. The heat-insulating and refractory material according to claim 1, wherein, The bulk density of the heat-insulating refractory material is 2.40-2.82 g / cm³. 3 .

9. The heat-insulating and refractory material according to claim 1, wherein, The CA6 phase comprises 78.2-100% by mass percentage in the matrix portion of the thermal insulation and refractory material. The corundum phase is 0-20%; The magnesium aluminum spinel phase comprises 0-5.22%; The C2M2A14 phase composition is 0-18.8%; and The phase composition of CM2A8 is 0-18.8%.

10. The heat-insulating and refractory material according to claim 1, wherein, The percentage by mass of the phase in the matrix portion of the heat-insulating and refractory material is 0, wherein the magnesium aluminum spinel phase is 0.

11. The heat-insulating and refractory material according to claim 1, wherein, The chemical composition of the thermal insulation and refractory material matrix includes Al2O3, CaO, and MgO, and the Al2O3 accounts for 89.03-94.10% of the matrix by mass. The CaO content is 5.80-8.40%; and The MgO content is 0-2.52%.

12. The heat-insulating and refractory material according to claim 11, wherein, The Al2O3 comprises 90.30-93.20% by mass percentage of the matrix portion of the heat-insulating and refractory material. The CaO content is 6.60-8.40%; and The MgO content is 0-1.68%.

13. The heat-insulating and refractory material according to any one of claims 1-12, wherein, The heat-insulating and refractory material is prepared by a method comprising the following steps: The mixture is obtained by mixing granular material and fine powder, and then hot-pressing and sintering the mixture.

14. The heat-insulating and refractory material according to claim 13, wherein, The fine powder is selected from one or more of the following: fine powder containing CaO, fine powder containing Al2O3, and fine powder containing MgO.

15. The heat-insulating and refractory material according to claim 14, wherein, The CaO-containing fine powder is selected from one or more of quicklime, limestone, calcium hydroxide, CaO·Al2O3, CaO·2Al2O3, 12CaO·7Al2O3, CA6, C2M2A14 and CM2A8.

16. The heat-insulating and refractory material according to claim 14, wherein, The Al2O3-containing fine powder is selected from one or more of the following: active α-Al2O3 powder, γ-Al2O3 powder, ρ-Al2O3 powder, aluminum hydroxide, industrial alumina, white corundum powder, sub-white corundum powder, dense corundum powder, sintered corundum powder, and tabular corundum powder.

17. The heat-insulating and refractory material according to claim 14, wherein, The MgO-containing fine powder is selected from one or more of magnesite, light-burned magnesia, brucite, magnesium hydroxide, magnesium chloride, high-purity magnesia, and fused magnesia.

18. The heat-insulating and refractory material according to claim 13, wherein, The granular material is selected from one or more of CA6, C2M2A14 and CM2A8.

19. The heat-insulating and refractory material according to claim 13, wherein, The granular material is CA6.

20. The heat-insulating and refractory material according to claim 13, wherein, The mass ratio of the granular material to the fine powder is 35-60:40-65.

21. The heat-insulating and refractory material according to claim 13, wherein, The hot pressing sintering involves placing the mixture into a mold of a high-temperature device for hot pressing sintering, or forming the mixture at room temperature and then placing it into a mold of a high-temperature device for hot pressing sintering, or forming the mixture at room temperature and pre-sintering at low temperature before hot pressing sintering.

22. The heat-insulating and refractory material according to claim 13, wherein, The hot pressing sintering temperature is 1550-1750℃.

23. The heat-insulating and refractory material according to claim 13, wherein, The hot-pressing strength is 0.5-10 MPa.

24. A method for preparing a heat-insulating and refractory material, comprising the following steps: The mixture is obtained by mixing granular material and fine powder, and then hot-pressing and sintering the mixture. The phases of the heat-insulating and refractory material include CA6 and one or more phases selected from C2M2A14, CM2A8, magnesium aluminum spinel and corundum. The total content of CA6, C2M2A14, CM2A8, magnesium aluminum spinel and corundum in the thermal insulation and refractory materials is ≥90% by mass percentage. The proportion of CA6 phase is 26.7-100%; The C2M2A14 phase content is 0-72%; The phase composition of CM2A8 is 0-72%; The magnesium aluminum spinel phase is 0-10%; The corundum phase content is 0-11.8%; The matrix portion of the heat-insulating and refractory material includes CA6 and one or more phases selected from corundum, magnesium aluminum spinel, C2M2A14 and CM2A8. The CA6 phase comprises 67.4-100% by mass percentage in the matrix portion of the thermal insulation and refractory material. The corundum phase comprises 0-30%; The magnesium aluminum spinel phase is 0-10%; The C2M2A14 phase content is 0-30%; and The phase composition of CM2A8 is 0-30%; The bulk density of the heat-insulating refractory material is 2.40-2.90 g / cm³. 3 .

25. The preparation method according to claim 24, wherein, The fine powder is selected from one or more of the following: fine powder containing CaO, fine powder containing Al2O3, and fine powder containing MgO.

26. The preparation method according to claim 25, wherein, The CaO-containing fine powder is selected from one or more of quicklime, limestone, calcium hydroxide, CaO·Al2O3, CaO·2Al2O3, 12CaO·7Al2O3, CA6, C2M2A14 and CM2A8.

27. The preparation method according to claim 25, wherein, The Al2O3-containing fine powder is selected from one or more of the following: active α-Al2O3 powder, γ-Al2O3 powder, ρ-Al2O3 powder, aluminum hydroxide, industrial alumina, white fused alumina powder, sub-white fused alumina powder, sintered fused alumina powder, and tabular fused alumina powder.

28. The preparation method according to claim 25, wherein, The MgO-containing fine powder is selected from one or more of magnesite, light-burned magnesia, brucite, magnesium hydroxide, magnesium chloride, high-purity magnesia, and fused magnesia.

29. The preparation method according to claim 24, wherein, The granular material is selected from one or more of CA6, C2M2A14 and CM2A8.

30. The preparation method according to claim 24, wherein, The granular material is CA6.

31. The preparation method according to claim 24, wherein, The mass ratio of the granules to the fine powder is 35-60:40-65.

32. The preparation method according to claim 24, wherein, The hot pressing sintering involves placing the mixture into a mold of a high-temperature device for hot pressing sintering, or forming the mixture at room temperature and then placing it into a mold of a high-temperature device for hot pressing sintering, or forming the mixture at room temperature and pre-sintering at low temperature before hot sintering.

33. The preparation method according to any one of claims 24-32, wherein, The hot pressing sintering temperature is 1550-1750℃.

34. The preparation method according to any one of claims 24-32, wherein, The hot-pressing strength is 0.5-10 MPa.

35. A permanent lining for a steel ladle in steel smelting, comprising the heat-insulating refractory material according to any one of claims 1-23 or the heat-insulating refractory material prepared by the preparation method according to any one of claims 24-34.

36. A heat-insulating lining or working lining for molten aluminum ladle, comprising the heat-insulating refractory material according to any one of claims 1-23 or the heat-insulating refractory material prepared by the preparation method according to any one of claims 24-34.

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