Titanium calcium aluminate-zirconium oxide-aluminum oxide multiphase refractory material for heat insulation lining of industrial high-temperature furnace and preparation process of titanium calcium aluminate-zirconium oxide-aluminum oxide multiphase refractory material

Abstract

The invention relates to a titanium calcium aluminate-zirconium oxide-corundum complex-phase refractory material with low heat conductivity, high fire resistance and excellent thermal shock resistance and a preparation process thereof, which are suitable for heat insulation liners of industrial high-temperature equipment and are widely applied to industrial high-temperature furnaces such as ceramic kilns, glass melting furnaces, garbage incinerators, petrochemical heating furnaces and metallurgical heat treatment furnaces. Main raw materials of the material comprise polyacrylonitrile fibers, titanium calcium aluminate micro powder, corundum aggregate, alumina micro powder, zirconia micro powder and the like, and through a specific preparation process, the prepared refractory material has the heat conductivity coefficient of 0.52-1.4 W / (m.K) at 1100 DEG C, the breaking strength of 6-16 MPa and the normal-temperature compressive strength of 30-65 MPa, and has excellent heat insulation performance and mechanical strength.

Description

Technical Field

[0001] This invention relates to the field of inorganic non-metallic refractory materials, specifically a calcium aluminate titanate-zirconia-corundum multiphase refractory material with low thermal conductivity, high refractory resistance and excellent thermal shock resistance, and its preparation process. It is suitable for the heat insulation lining of industrial high-temperature equipment and is widely used in industrial high-temperature furnaces such as ceramic kilns, glass melting furnaces, waste incinerators, petrochemical heating furnaces and metallurgical heat treatment furnaces. Background Technology

[0002] In modern industrial production, efficient energy utilization and equipment lifespan are crucial technical requirements. The lining materials of high-temperature furnaces not only need to meet the requirements of mechanical strength and structural stability under high-temperature environments, but also need excellent thermal insulation properties to minimize heat loss. However, traditional refractory materials such as dense alumina and high-alumina refractory bricks, while possessing high compressive strength, have high thermal conductivity (>3 W / (m·K)) and poor thermal insulation; lightweight refractory bricks and ceramic fibers lack sufficient mechanical strength to meet the long-term service requirements of industrial high-temperature furnaces. Calcium aluminate is a byproduct of the smelting of titanium-iron alloys. Studies have found that calcium aluminate is a raw material with low thermal conductivity and a low coefficient of thermal expansion, and it is generally used in lightweight insulating refractory materials. Some literature provides lightweight application schemes related to calcium aluminate raw materials, such as patent technology CN108558417A, "A calcium aluminate insulating refractory material and its preparation method," which first removes TiO2 from the calcium aluminate raw material to improve the high-temperature stability of the material, and then uses physical foaming to prepare a lightweight insulating material through pore formation. However, the Ti removal process is relatively complex, requiring the introduction of protective gas during high-temperature firing, resulting in high actual production costs and the emission of a large amount of carbon dioxide, which is not conducive to energy conservation and emission reduction. Patent technology CN107963898A, "Mullite-bonded calcium aluminate hollow sphere insulating refractory material and its preparation method," adds calcium aluminate hollow spheres to a mullite matrix to prepare a lightweight insulating material, but the thermal conductivity of the material is 0.4–0.9 W·m. -1 ·K -1(1000℃) Its thermal insulation performance is not significantly superior to existing lightweight insulation materials. Furthermore, in environments exceeding 1200℃, the large difference in expansion coefficients between the hollow calcium aluminate spheres and the mullite matrix leads to structural cracking and damage to the refractory material. Patent CN 107986805A, "A Lightweight Thermal Insulating Refractory Material Based on Calcium Aluminate and Its Preparation Method," utilizes in-situ decomposition of calcium carbonate and oxidation of flake graphite in the raw materials to create pores, resulting in a lightweight thermal insulating refractory material with low bulk density and thermal conductivity. However, due to the chemical foaming method, the refractory material surface has numerous open pores. Alkaline atmospheres or corrosive substances in the operating environment can penetrate the material through these pores, causing the decomposition of calcium aluminate and a decrease in thermal insulation performance. Currently, there are still many problems regarding the rational use of this raw material. Data indicates that the yield of this byproduct is quite large, with the alloy-to-slag ratio generally reaching approximately 1:1. With the increasing demand for ferro-titanium alloys, the amount of byproducts generated is also increasing. If the waste residue is not treated in a timely manner, it will cause environmental pollution, and its accumulation will occupy a large amount of land, which is a waste of resources. Summary of the Invention

[0003] This invention addresses the problems of high thermal conductivity, insufficient strength, and poor chemical stability in existing industrial high-temperature furnace insulation lining materials. It provides a calcium aluminate-zirconia-corundum multiphase refractory material and its preparation process, exhibiting low thermal conductivity, high strength, high thermal stability, and resistance to chemical corrosion. This material is suitable for insulation linings in various industrial high-temperature furnaces, including insulation zones in ceramic kilns, back lining zones in glass melting furnaces, high-temperature insulation layers in waste incinerators, kiln linings in petrochemical heating furnaces, and insulation materials for metallurgical heat treatment furnaces.

[0004] To achieve the above technical effects, the technical solution of the present invention is: a calcium aluminate-zirconia-alumina multiphase refractory material for heat insulation lining of industrial high-temperature furnaces, which requires the pre-preparation of a heat insulation encapsulation. The main raw materials of the heat insulation encapsulation are as follows: 45-65wt% polyacrylonitrile fiber, 0.8-2wt% polysorbate, 35-55wt% calcium aluminate micro powder, 10-30wt% aluminum sol, and 1-3wt% triethanolamine.

[0005] A multiphase refractory material of calcium aluminate titanate-zirconia-alumina for use as an insulation lining in industrial high-temperature furnaces. Main raw materials: 40-60wt% corundum aggregate, 10-40wt% calcium aluminate titanate aggregate, 0.5-2wt% TiO2, 5-30wt% alumina micro powder, 3-10wt% silica micro powder, 1-6wt% zirconia micro powder, plus 1-4wt% starch, 10-25wt% aluminum dihydrogen phosphate solution, and 10-30wt% insulation coating.

[0006] The corundum aggregate has an Al2O3 content of ≥96%, and the aggregate particle sizes are as follows: 1-3mm accounts for 5-20% of the total corundum aggregate, 2-3mm accounts for 50-80% of the total corundum aggregate, and 2-3mm accounts for 20-30% of the total corundum aggregate.

[0007] The alumina micro powder has an Al2O3 content of ≥96% and a particle size of ≤0.025mm.

[0008] The polyacrylonitrile fibers have a length of 5-8 mm and a diameter of 0.1 mm-0.18 mm.

[0009] The particle size of the calcium aluminate aggregate is in the range of 1.0mm-2.5mm, and the particle size of the calcium aluminate micro powder is ≤0.025mm.

[0010] The aluminum sol has a solute content of ≥35%.

[0011] The aluminum dihydrogen phosphate solution contains aluminum ions (Al). 3+ ) and phosphate (H2PO) 4- The molar ratio is 1:2.

[0012] The preparation process of this technology is as follows: The preparation process of the thermal insulation coating is as follows: Polyacrylonitrile fiber and polysorbate are added to an aluminum sol solution and mixed with rapid vibration stirring for 20-30 minutes. The mixture is then allowed to stand for 1-3 hours, followed by rapid vibration stirring for another 10 minutes. During this process, calcium aluminate aggregate, silica powder, triethanolamine, and alumina powder are added sequentially to form a preliminary coating layer with a thickness of 0.5-1.1 mm. The silica powder should be added first, followed by the alumina powder. Then, the mixture is stirred slowly for 20-40 minutes (at a speed of 100-150 rpm). The mixed fiber slurry product is then placed in a drying kiln and dried at 120℃ for 6 hours using a two-stage drying method: first, drying at 60℃-80℃ for 2 hours, then increasing to 120℃ for 4 hours. After drying, remove the moisture and feed the dried encapsulated intermediate into a vibrating screen for sieving. The recommended particle size range is 5mm-15mm. If the proportion of powder in the sieved particles is high, they can be added back into the aluminum sol system for reuse. Place the collected insulating encapsulated material into a crucible and place it in a high-temperature furnace. Set the firing temperature to 1100℃-1300℃, increase the temperature at a rate of 5℃ / min to the target temperature, and hold for 1 hour to form the insulating encapsulated material. Finally, cool it to room temperature for use.

[0013] Preparation of the material blank: Select corundum aggregate, aluminum dihydrogen phosphate solution, heat-insulating inclusion, and calcium aluminate titanate aggregate according to the specified ratio, pour them into a mixing device and stir rapidly for 15-40 minutes to form an aggregate inclusion. Place the formed aggregate inclusion in a drying oven at 50℃ for 1-2 hours, then at 110℃ for 2 hours. After drying, mix the aggregate inclusion with alumina micro powder, zirconium oxide, silica fume, TiO2, and starch for 10-20 minutes. During the mixing process, starch acts as a pore-forming agent, with a preferred dosage of 2%-3%. Pour the uniformly mixed slurry into a mold, remove air bubbles from the slurry by vibration, and compact it into shape. It is recommended to control the vibration amplitude at 15Hz. Place the blank in a drying kiln and dry it at 110℃ for 3 hours. After drying, send the blank to a tunnel kiln for high-temperature firing at 1450℃ and maintain the temperature for 3 hours. The heating rate needs to be appropriately controlled according to the size of the green body. The initial heating rate is set at 4℃ / min (from room temperature to 800℃), and the heating rate is 6℃ / min from 800℃ to the sintering temperature. After firing, the green body is naturally cooled to room temperature to complete the preparation.

[0014] By adopting the above technical solution, the present invention has the following advantages compared with the prior art: 1. Multi-dimensional thermal insulation structure design: Due to the inclusions of mullite and calcium aluminate in the material, the thermal conductivity of mullite ranges from 2.5 to 3.0 W / (m·K) at 1000℃, while that of calcium aluminate ranges from 1.5 to 2.0 W / m·K. The low thermal conductivity of these two materials and the hollow structure of the inclusions endow them with excellent thermal insulation capabilities. Incorporating the prepared inclusions into the material matrix effectively increases the amount of internal thermal resistance. Furthermore, the addition of starch as a pore-forming agent results in a greater number of pores in the material matrix, increasing the heat transfer path through the matrix. The inclusions (three-dimensional thermal resistance) combined with the pores in the material matrix (two-dimensional thermal resistance) effectively improve the total internal thermal resistance of the material. The thermal conductivity of the material at 1100℃ can be controlled between 0.52 and 1.4 W / (m·K).

[0015] 2. Regarding the design of the composite structure particle encapsulation, currently, the more outstanding the thermal insulation performance of an insulation material, the lower its mechanical strength usually is. This is because, in pursuit of higher thermal insulation performance, the addition of large-particle dense aggregates is reduced or avoided, as aggregates act as "thermal bridges" and are the main pathway for heat conduction; dense aggregates can reduce the heat transfer pathways. In this invention, although large-particle aggregates are added inside the material, the surface of the particles is covered by small-particle calcium aluminate aggregates and thermal insulation encapsulation. The thickness of the coverage depends on the total amount of calcium aluminate aggregates and thermal insulation encapsulation added and the stirring time, generally ranging from 1.8 to 3.5 mm. Due to the addition of the encapsulation, the speed at which heat passes through the aggregates is effectively hindered, thus improving the overall thermal insulation capacity of the material. At the same time, due to the addition of large-sized aggregates, the overall mechanical properties of the material are significantly improved compared to ordinary lightweight thermal insulation materials. The material's room temperature compressive strength can reach 30-65 MPa, its high-temperature flexural strength at 1100℃ can reach 6-16 MPa, and its thermal shock resistance is 25-35 cycles.

[0016] 3. Specific Particle Size and Composition Matching: The corundum aggregate, calcium aluminate titanate aggregate, zirconia micro powder, and alumina micro powder are finely graded in terms of proportion and particle size, balancing density and thermal shock stability. Starch, acting as a pore-forming agent, increases the material's porosity after high-temperature firing, achieving a porous thermal insulation effect. Optimized High-Temperature Firing Process: A firing temperature of 1450℃ is adopted, with segmented control of the heating rate. This helps promote the formation of mullite, calcium aluminate titanate, and other phases and improves sintering density during the high-temperature stage, achieving a comprehensive improvement in the material's strength, high-temperature resistance, and thermal insulation.

[0017] 4. Through the above innovations, this invention significantly improves the low thermal conductivity, high strength, corrosion resistance, and thermal stability of high-temperature furnace insulation lining materials. It is suitable for insulation linings of various industrial high-temperature furnaces such as ceramic kilns, glass melting furnaces, waste incinerators, petrochemical heating furnaces, and metallurgical heat treatment furnaces. This material can be made into prefabricated parts of various sizes and shapes according to specific kiln requirements, which is convenient for installation. In addition, this invention effectively solves the problem of using calcium titanate raw materials. Detailed Implementation

[0019] Example 1 To achieve the above technical effects, the technical solution of the present invention is as follows: A calcium aluminate-zirconia-alumina multiphase refractory material for heat insulation lining of industrial high-temperature furnaces requires the pre-preparation of a heat insulation encapsulation. The main raw materials of the heat insulation encapsulation are as follows: 50wt% polyacrylonitrile fiber, 1.1wt% polysorbate, 35wt% calcium aluminate aggregate, 15wt% aluminum sol, and 1.4wt% triethanolamine.

[0020] The main raw materials of a calcium aluminate-zirconia-alumina multiphase refractory material for thermal insulation lining of industrial high-temperature furnaces are: 30wt% corundum aggregate, 30wt% calcium aluminate aggregate, 0.8wt% TiO2, 12wt% alumina micro powder, 10wt% silica micro powder, 2wt% zirconia micro powder, 1wt% starch, 13wt% aluminum dihydrogen phosphate solution, and 5wt% thermal insulation coating.

[0021] The corundum aggregate has an Al2O3 content of ≥96%, and the aggregate particle sizes are as follows: 1-3mm accounts for 20% of the total corundum aggregate, 2-3mm accounts for 50% of the total corundum aggregate, and 0-1mm accounts for 30% of the total corundum aggregate.

[0022] Preparation of the material blank: Corundum aggregate, aluminum dihydrogen phosphate solution, heat-insulating inclusions, and calcium aluminate titanate aggregate are selected according to a specific ratio and poured into a mixing device for rapid stirring for 20 minutes to form aggregate inclusions. The formed aggregate inclusions are then placed in a drying oven at 50℃ for 1.5 hours, followed by drying at 110℃ for 2 hours. The dried aggregate inclusions are then mixed with alumina micropowder, zirconium oxide, silica fume, TiO2, and starch for 20 minutes. During stirring, starch acts as a pore-forming agent, with a preferred dosage of 2%. The uniformly mixed slurry is poured into a mold, and air bubbles are removed by vibration and compacted into shape. The vibration amplitude is recommended to be controlled at 15Hz. The blank is then placed in a drying kiln and dried at 110℃ for 3 hours. The dried blank is then sent to a tunnel kiln for high-temperature firing at 1450℃ for 3 hours. The heating rate needs to be appropriately controlled according to the size of the green body. The initial heating rate is set at 4℃ / min (from room temperature to 800℃), and the heating rate is 6℃ / min from 800℃ to the sintering temperature. After sintering, the green body is allowed to cool naturally to room temperature to complete the preparation. The prepared material has a thermal conductivity of 1.79 W / (m·K) at 1100℃, a compressive strength of 62 MPa at room temperature, a flexural strength of 18 MPa at 1100℃, and withstands 6 thermal shock cycles. Example 2

[0023] To achieve the above technical effects, the technical solution of the present invention is as follows: A calcium aluminate-zirconia-alumina multiphase refractory material for heat insulation lining of industrial high-temperature furnaces requires the pre-preparation of a heat insulation encapsulation. The main raw materials of the heat insulation encapsulation are as follows: 40wt% polyacrylonitrile fiber, 1.1wt% polysorbate, 45wt% calcium aluminate aggregate, 15wt% aluminum sol, and 1.4wt% triethanolamine.

[0024] The main raw materials of a calcium aluminate-zirconia-alumina multiphase refractory material for thermal insulation lining of industrial high-temperature furnaces are: 40wt% corundum aggregate, 10wt% calcium aluminate aggregate, 0.8wt% TiO2, 10wt% alumina micro powder, 13wt% silica micro powder, 5wt% zirconia micro powder, 3wt% starch, 10wt% aluminum dihydrogen phosphate solution, and 10wt% thermal insulation coating.

[0025] The corundum aggregate has an Al2O3 content of ≥96%, and the aggregate particle sizes are as follows: 1-3mm accounts for 20% of the total corundum aggregate, 2-3mm accounts for 50% of the total corundum aggregate, and 0-1mm accounts for 30% of the total corundum aggregate.

[0026] Preparation of the material blank: Corundum aggregate, aluminum dihydrogen phosphate solution, heat-insulating inclusions, and calcium aluminate titanate aggregate are selected according to a specific ratio and poured into a mixing device for rapid stirring for 20 minutes to form aggregate inclusions. The formed aggregate inclusions are then placed in a drying oven at 50℃ for 1.5 hours, followed by drying at 110℃ for 2 hours. The dried aggregate inclusions are then mixed with alumina micropowder, zirconium oxide, silica fume, TiO2, and starch for 20 minutes. During stirring, starch acts as a pore-forming agent, with a preferred dosage of 2%. The uniformly mixed slurry is poured into a mold, and air bubbles are removed by vibration and compacted into shape. The vibration amplitude is recommended to be controlled at 15Hz. The blank is then placed in a drying kiln and dried at 110℃ for 3 hours. The dried blank is then sent to a tunnel kiln for high-temperature firing at 1450℃ for 3 hours. The heating rate needs to be appropriately controlled according to the size of the green body. The initial heating rate is set at 4℃ / min (from room temperature to 800℃), and the heating rate is 6℃ / min from 800℃ to the sintering temperature. After sintering, the green body is allowed to cool naturally to room temperature to complete the preparation. The prepared material has a thermal conductivity of 1.15 W / (m·K) at 1100℃, a compressive strength of 50 MPa at room temperature, a flexural strength of 14.7 MPa at 1100℃, and a thermal shock resistance of 22 cycles. Example 3

[0027] To achieve the above technical effects, the technical solution of the present invention is as follows: A calcium aluminate-zirconia-alumina multiphase refractory material for heat insulation lining of industrial high-temperature furnaces requires the pre-preparation of a heat insulation encapsulation. The main raw materials of the heat insulation encapsulation are as follows: 50wt% polyacrylonitrile fiber, 1.1wt% polysorbate, 35wt% calcium aluminate aggregate, 15wt% aluminum sol, and 1.4wt% triethanolamine.

[0028] The main raw materials of a calcium aluminate-zirconia-alumina multiphase refractory material for thermal insulation lining of industrial high-temperature furnaces are: 30wt% corundum aggregate, 20wt% calcium aluminate aggregate, 0.8wt% TiO2, 10wt% alumina micro powder, 13wt% silica micro powder, 2wt% zirconia micro powder, 3wt% starch, 10wt% aluminum dihydrogen phosphate solution, and 15wt% thermal insulation coating.

[0029] The corundum aggregate has an Al2O3 content of ≥96%, and the aggregate particle sizes are as follows: 1-3mm accounts for 20% of the total corundum aggregate, 2-3mm accounts for 50% of the total corundum aggregate, and 0-1mm accounts for 30% of the total corundum aggregate.

[0030] Preparation of the material blank: Corundum aggregate, aluminum dihydrogen phosphate solution, heat-insulating inclusions, and calcium aluminate titanate aggregate are selected according to a specific ratio and poured into a mixing device for rapid stirring for 20 minutes to form aggregate inclusions. The formed aggregate inclusions are then placed in a drying oven at 50℃ for 1.5 hours, followed by drying at 110℃ for 2 hours. The dried aggregate inclusions are then mixed with alumina micropowder, zirconium oxide, silica fume, TiO2, and starch for 20 minutes. During stirring, starch acts as a pore-forming agent, with a preferred dosage of 2%. The uniformly mixed slurry is poured into a mold, and air bubbles are removed by vibration and compacted into shape. The vibration amplitude is recommended to be controlled at 15Hz. The blank is then placed in a drying kiln and dried at 110℃ for 3 hours. The dried blank is then sent to a tunnel kiln for high-temperature firing at 1450℃ for 3 hours. The heating rate needs to be appropriately controlled according to the size of the green body. The initial heating rate is set at 4℃ / min (from room temperature to 800℃), and the heating rate is 6℃ / min from 800℃ to the sintering temperature. After sintering, the material is allowed to cool naturally to room temperature to complete the green body preparation. The prepared material has a thermal conductivity of 1.05 W / (m·K) at 1100℃, a compressive strength of 45 MPa at room temperature, a flexural strength of 11.4 MPa at 1100℃, and a thermal shock resistance of 25 cycles. Example 4

[0031] To achieve the above technical effects, the technical solution of the present invention is as follows: A calcium aluminate-zirconia-alumina multiphase refractory material for heat insulation lining of industrial high-temperature furnaces requires the pre-preparation of a heat insulation encapsulation. The main raw materials of the heat insulation encapsulation are as follows: 45wt% polyacrylonitrile fiber, 1.1wt% polysorbate, 40wt% calcium aluminate aggregate, 15wt% aluminum sol, and 1.4wt% triethanolamine.

[0032] The main raw materials of a calcium aluminate-zirconia-alumina multiphase refractory material for thermal insulation lining of industrial high-temperature furnaces are: 30wt% corundum aggregate, 20wt% calcium aluminate aggregate, 0.8wt% TiO2, 10wt% alumina micro powder, 10wt% silica micro powder, 2wt% zirconia micro powder, 3wt% starch, 10wt% aluminum dihydrogen phosphate solution, and 18wt% thermal insulation coating.

[0033] The corundum aggregate has an Al2O3 content of ≥96%, and the aggregate particle sizes are as follows: 1-3mm accounts for 20% of the total corundum aggregate, 2-3mm accounts for 50% of the total corundum aggregate, and 0-1mm accounts for 30% of the total corundum aggregate.

[0034] Preparation of the material blank: Corundum aggregate, aluminum dihydrogen phosphate solution, heat-insulating inclusions, and calcium aluminate titanate aggregate are selected according to a specific ratio and poured into a mixing device for rapid stirring for 20 minutes to form aggregate inclusions. The formed aggregate inclusions are then placed in a drying oven at 50℃ for 1.5 hours, followed by drying at 110℃ for 2 hours. The dried aggregate inclusions are then mixed with alumina micropowder, zirconium oxide, silica fume, TiO2, and starch for 20 minutes. During stirring, starch acts as a pore-forming agent, with a preferred dosage of 2%. The uniformly mixed slurry is poured into a mold, and air bubbles are removed by vibration and compacted into shape. The vibration amplitude is recommended to be controlled at 15Hz. The blank is then placed in a drying kiln and dried at 110℃ for 3 hours. The dried blank is then sent to a tunnel kiln for high-temperature firing at 1450℃ for 3 hours. The heating rate needs to be appropriately controlled according to the size of the green body. The initial heating rate is set at 4℃ / min (from room temperature to 800℃), and the heating rate is 6℃ / min from 800℃ to the sintering temperature. After sintering, the green body is allowed to cool naturally to room temperature to complete the preparation. The prepared material has a thermal conductivity of 0.92 W / (m·K) at 1100℃, a compressive strength of 36 MPa at room temperature, a flexural strength of 9.3 MPa at 1100℃, and a thermal shock resistance of 27 cycles. Example 5

[0035] To achieve the above technical effects, the technical solution of the present invention is as follows: A calcium aluminate-zirconia-alumina multiphase refractory material for heat insulation lining of industrial high-temperature furnaces requires the pre-preparation of a heat insulation encapsulation. The main raw materials of the heat insulation encapsulation are as follows: 50wt% polyacrylonitrile fiber, 1.1wt% polysorbate, 35wt% calcium aluminate aggregate, 15wt% aluminum sol, and 1.4wt% triethanolamine.

[0036] The main raw materials of a calcium aluminate-zirconia-alumina multiphase refractory material for thermal insulation lining of industrial high-temperature furnaces are: 20wt% corundum aggregate, 20wt% calcium aluminate aggregate, 0.8wt% TiO2, 10wt% alumina micro powder, 13wt% silica micro powder, 2wt% zirconia micro powder, 3wt% starch, 10wt% aluminum dihydrogen phosphate solution, and 20wt% thermal insulation coating.

[0037] The corundum aggregate has an Al2O3 content of ≥96%, and the aggregate particle sizes are as follows: 1-3mm accounts for 20% of the total corundum aggregate, 2-3mm accounts for 50% of the total corundum aggregate, and 0-1mm accounts for 30% of the total corundum aggregate.

[0038] Preparation of the material blank: Corundum aggregate, aluminum dihydrogen phosphate solution, heat-insulating inclusions, and calcium aluminate titanate aggregate are selected according to a specific ratio and poured into a mixing device for rapid stirring for 20 minutes to form aggregate inclusions. The formed aggregate inclusions are then placed in a drying oven at 50℃ for 1.5 hours, followed by drying at 110℃ for 2 hours. The dried aggregate inclusions are then mixed with alumina micropowder, zirconium oxide, silica fume, TiO2, and starch for 20 minutes. During stirring, starch acts as a pore-forming agent, with a preferred dosage of 2%. The uniformly mixed slurry is poured into a mold, and air bubbles are removed by vibration and compacted into shape. The vibration amplitude is recommended to be controlled at 15Hz. The blank is then placed in a drying kiln and dried at 110℃ for 3 hours. The dried blank is then sent to a tunnel kiln for high-temperature firing at 1450℃ for 3 hours. The heating rate needs to be appropriately controlled according to the size of the green body. The initial heating rate is set at 4℃ / min (from room temperature to 800℃), and the heating rate is 6℃ / min from 800℃ to the sintering temperature. After sintering, the green body is allowed to cool naturally to room temperature to complete the preparation. The prepared material has a thermal conductivity of 0.81 W / (m·K) at 1100℃, a compressive strength of 34 MPa at room temperature, a flexural strength of 8.2 MPa at 1100℃, and a thermal shock resistance of 32 cycles. Example 6

[0039] To achieve the above technical effects, the technical solution of the present invention is as follows: A calcium aluminate-zirconia-alumina multiphase refractory material for heat insulation lining of industrial high-temperature furnaces requires the pre-preparation of a heat insulation encapsulation. The main raw materials of the heat insulation encapsulation are as follows: 50wt% polyacrylonitrile fiber, 1.1wt% polysorbate, 35wt% calcium aluminate aggregate, 15wt% aluminum sol, and 1.4wt% triethanolamine.

[0040] The main raw materials of a calcium aluminate-zirconia-alumina multiphase refractory material for thermal insulation lining of industrial high-temperature furnaces are: 30wt% corundum aggregate, 10wt% calcium aluminate aggregate, 0.8wt% TiO2, 10wt% alumina micro powder, 13wt% silica micro powder, 2wt% zirconia micro powder, 3wt% starch, 10wt% aluminum dihydrogen phosphate solution, and 25wt% thermal insulation coating.

[0041] The corundum aggregate has an Al2O3 content of ≥96%, and the aggregate particle sizes are as follows: 1-3mm accounts for 20% of the total corundum aggregate, 2-3mm accounts for 50% of the total corundum aggregate, and 0-1mm accounts for 30% of the total corundum aggregate.

[0042] Preparation of the material blank: Corundum aggregate, aluminum dihydrogen phosphate solution, heat-insulating inclusions, and calcium aluminate titanate aggregate are selected according to a specific ratio and poured into a mixing device for rapid stirring for 20 minutes to form aggregate inclusions. The formed aggregate inclusions are then placed in a drying oven at 50℃ for 1.5 hours, followed by drying at 110℃ for 2 hours. The dried aggregate inclusions are then mixed with alumina micropowder, zirconium oxide, silica fume, TiO2, and starch for 20 minutes. During stirring, starch acts as a pore-forming agent, with a preferred dosage of 2%. The uniformly mixed slurry is poured into a mold, and air bubbles are removed by vibration and compacted into shape. The vibration amplitude is recommended to be controlled at 15Hz. The blank is then placed in a drying kiln and dried at 110℃ for 3 hours. The dried blank is then sent to a tunnel kiln for high-temperature firing at 1450℃ for 3 hours. The heating rate needs to be appropriately controlled according to the size of the green body. The initial heating rate is set at 4℃ / min (from room temperature to 800℃), and the heating rate is 6℃ / min from 800℃ to the sintering temperature. After sintering, the green body is allowed to cool naturally to room temperature to complete the preparation. The prepared material has a thermal conductivity of 0.69 W / (m·K) at 1100℃, a compressive strength of 26 MPa at room temperature, a flexural strength of 7.1 MPa at 1100℃, and a thermal shock resistance of 36 cycles.

[0043] The samples in Examples 1-6 were compared with ordinary mullite lightweight thermal insulation blocks. Thermal conductivity at 1100℃ and compressive strength at room temperature were tested on the above samples. The test results are as follows:

[0044] As can be seen from the comparison in the table, in Examples 1-6 using this method, the thermal insulation coefficient of the material gradually decreases as the amount of thermal insulation wrapping increases, and the compressive strength of the samples at room temperature decreases with the increase of lightweight aggregate. However, compared with ordinary mullite castable, the average thermal conductivity of the samples in Examples 2-4 at 1100℃ is much lower than that of ordinary lightweight mullite samples.

Claims

1. A calcium aluminate-zirconia-corundum multiphase refractory material for use in the heat insulation lining of industrial high-temperature furnaces, characterized in that, The main raw materials of the material include: 40-60wt% corundum aggregate; 10-40wt% calcium titan-aluminate aggregate; 0.5-2wt% TiO2; 5-30wt% alumina micropowder; 3-10wt% silicon micropowder; 1-6wt% zirconia micropowder; 1-4wt% starch; 10-25wt% aluminum dihydrogen phosphate solution; 10-30wt% thermal insulation wrapper.

2. A refractory material according to claim 1, characterised in that The Al2O3 content of the corundum aggregate is ≥96%, and the particle size distribution is: 1-3mm accounts for 5-20% of the total amount of corundum aggregate, 2-3mm accounts for 50-80% of the total amount of corundum aggregate, and >3mm accounts for 20-30% of the total amount of corundum aggregate.

3. A refractory material according to claim 1, characterised in that The particle size of the calcium titan-aluminate aggregate is 1.0mm-2.5mm, and the micropowder particle size is ≤0.025mm.

4. A process for the production of the refractory material according to claim 1, characterized in that, The method comprises the following steps: Preparation of thermal insulation wrapper: polyacrylonitrile fiber and polysorbate are added to the aluminum sol solution, and after rapid stirring, calcium titan-aluminate aggregate, silicon micropowder, triethanolamine, and alumina micropowder are added to form a coating layer; the aggregate wrapper is mixed with other raw materials to prepare a material blank; the blank is dried and high-temperature fired to obtain the final refractory material. The process according to claim 4, characterized in that The high-temperature firing temperature is 1450℃, and the holding time is 3 hours.

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