Low-dimensional mullite phase enhanced silicon carbide-aluminate refractory product and preparation method thereof

Abstract

The invention belongs to the technical field of novel refractory materials, and particularly relates to a low-dimensional mullite phase reinforced silicon carbide-aluminate refractory product and a preparation method thereof. The low-dimensional mullite phase enhanced silicon carbide-aluminate refractory product is prepared from the following raw materials in percentage by mass: 50 to 85 percent of aggregate, 6 to 35 percent of matrix, 1 to 10 percent of binding agent, 0.1 to 6 percent of additive and water reducing agent which accounts for 0.1 to 1 percent of the total mass of the raw materials, the binding agent is hydrated alumina (rho-Al2O3), and the additive is at least one of ammonium molybdate, boric oxide, aluminum fluoride, silica powder, tungsten oxide and molybdenum oxide. According to the invention, a hydrated alumina binding agent and an additive have a synergistic effect, and a low-dimensional mullite phase is catalytically generated through staged temperature-controlled sintering in a buried carbon atmosphere. The problems that a silicon carbide-aluminate refractory material is poor in interface bonding property, low in strength, easy to oxidize at high temperature, water-oxygen corrosion, high in heat conductivity and the like are solved.

Description

Technical Field

[0001] The invention belongs to the technical field of new refractory materials, and particularly relates to a low-dimensional mullite phase reinforced silicon carbide-aluminate refractory product and a preparation method thereof. Background Art

[0002] As one of the core equipment in the coal gasification process, water-coal slurry gasifier is widely used in coal clean utilization technology. Refractory materials used in the lining of the gasifier play a vital role in its stable operation and efficient coal gasification process. At present, water-coal slurry gasifiers generally use high-chrome bricks (Cr2O3-Al2O3-ZrO2 materials) as lining materials. This is because high-chrome bricks have excellent high-temperature mechanical properties, slag resistance and wear resistance. However, high-chrome bricks may release hexavalent chromium (Cr2O3-Al2O3-ZrO2) during production, use and disposal. 6+ ), a potent carcinogen with high environmental hazards. Hexavalent chromium not only contaminates soil and water but can also become airborne, endangering the health of workers and surrounding residents.

[0003] Among the many chromium-free materials for coal gasification, silicon carbide-oxide composites are considered one of the most promising chromium-free refractory materials due to their excellent high-temperature performance, good thermal shock resistance, and relatively good slag resistance. However, in the practical application of silicon carbide-oxide composites, several key technical challenges remain to be overcome.

[0004] First, the high thermal conductivity of silicon carbide leads to rapid, non-directional heat transfer through the lining material within the water-coal slurry gasifier. A large amount of heat is conducted through the silicon carbide-based lining to the outer wall, resulting in a decrease in the effective internal energy utilization rate within the furnace. Rapid heat dissipation creates localized low-temperature zones near the furnace wall, while concentrated heat in the center leads to overheating. This non-uniform temperature distribution disrupts the chemical equilibrium of the gasification reaction and reduces the yield and purity of the syngas. Sharp fluctuations in the temperature field can cause periodic thermal stresses within the material, accelerating the initiation and propagation of microcracks and ultimately causing the lining to peel or break.

[0005] Secondly, due to the essential differences in chemical bonding properties and thermal expansion coefficient between silicon carbide materials and oxides such as aluminum oxide, it is difficult to form a ceramic bond between silicon carbide and oxides, resulting in a weak bonding area easily formed at the interface between the two. Under the repeated action of thermal stress or mechanical stress, microcracks are easily initiated and expanded, resulting in the deterioration of the material's structural strength and prone to thermal spalling and fracture at high temperatures.

[0006] Existing patents have proposed various solutions to the interfacial bonding and high-temperature stability challenges of silicon carbide-oxide composites, but these solutions still have certain limitations. For example, patent CN111704466B introduces coated spherical aluminum powder into a matrix, which reacts with atmospheric O2, CO, or N2 to produce highly active Al2O3, Al4C3, or AlN. Another patent, CN107879753B, incorporates one or more antioxidants—fine or micronized Si, Al, C, AlN, B4C, or BN—to produce Si3N4, SiO2, Sialon, and borate products at high temperatures, surpassing the oxidation of silicon carbide. Another patent, CN118993738B, introduces passivated aluminum powder into a matrix, which reacts with atmospheric N2 to produce AlN with various morphologies. However, the non-oxide phase is susceptible to oxidation at high temperatures, leading to failure of the bonding phase, which in turn reduces the strength of the composite and causes thermal spalling and / or fracture of the composite. Furthermore, the problem of non-oxides failing due to water-oxygen corrosion is even more pronounced in the high-temperature, water-oxygen synergistic corrosion environment experienced during the service life of the gasifier. During gasifier operation, the long-term penetration of water vapor and trace amounts of oxygen can cause an interfacial reaction with silicon carbide, generating volatile silanol compounds or low-melting-point silicates. This can cause the material's surface protective layer to continuously peel off, ultimately leading to a loose structure and a sudden drop in strength of the lining, seriously threatening the long-term safe operation of the gasifier.

[0007] Existing methods have failed to achieve the synergistic optimization of composite materials' high strength, high thermal conductivity, and strong resistance to oxidation and water-oxygen corrosion, making it difficult to meet the long-term operation requirements of gasifiers. Therefore, there is an urgent need to develop new composite material systems that combine strong interfacial bonding with synergistic protection against high-temperature oxidation and water-oxygen corrosion. Summary of the Invention

[0008] In view of the problems and shortcomings in the prior art, the present invention aims to provide a low-dimensional mullite phase reinforced silicon carbide-aluminate refractory product and a preparation method thereof.

[0009] In order to achieve the purpose of the present invention, the technical solution adopted by the present invention is as follows:

[0010] The first aspect of the present invention provides a low-dimensional mullite phase reinforced silicon carbide-aluminate refractory product. The raw material composition of the low-dimensional mullite phase reinforced silicon carbide-aluminate refractory product is as follows, calculated by mass percentage: 50% to 85% aggregate, 6% to 35% matrix, 1% to 10% binder, 0.1% to 6% additive, and 0.1% to 1% water reducer accounting for the total mass of the above raw materials; the binder is hydrated aluminum oxide, and the additive is at least one of ammonium molybdate, boron oxide, aluminum fluoride, silicon micropowder, tungsten oxide, and molybdenum oxide.

[0011] According to the above-mentioned low-dimensional mullite phase reinforced silicon carbide-aluminate refractory product, preferably, the particle size of the aggregate is 0.075-3 mm, and the particle size of the matrix is less than 0.075 mm.

[0012] According to the above-mentioned low-dimensional mullite phase reinforced silicon carbide-aluminate refractory product, preferably, the Al2O3 content of the hydrated alumina is greater than 98%.

[0013] According to the above-mentioned low-dimensional mullite phase reinforced silicon carbide-aluminate refractory product, preferably, the aggregate is at least one of corundum particles, silicon carbide particles, magnesia alumina spinel particles, and calcium hexaaluminate particles.

[0014] According to the above-mentioned low-dimensional mullite phase reinforced silicon carbide-aluminate refractory product, preferably, the matrix is at least one of corundum fine powder, silicon carbide fine powder, activated alumina fine powder, magnesia alumina spinel fine powder, and calcium hexaaluminate fine powder.

[0015] According to the above-mentioned low-dimensional mullite phase reinforced silicon carbide-aluminate refractory product, preferably, the water reducer is at least one of a naphthalene-based water reducer and a polycarboxylate water reducer.

[0016] According to the above-mentioned low-dimensional mullite phase reinforced silicon carbide-aluminate refractory products, preferably, the raw material composition of the low-dimensional mullite phase reinforced silicon carbide-aluminate refractory products is, by weight percentage, 50% to 70% silicon carbide particles, 1% to 15% corundum particles, 1% to 15% corundum fine powder, 3% to 10% activated alumina fine powder, 1% to 10% binder, 0.1% to 6% additives, and 0.1% to 1% of a water reducer accounting for the total weight of the above-mentioned raw materials.

[0017] According to the above-mentioned low-dimensional mullite phase reinforced silicon carbide-aluminate refractory product, preferably, the additive is aluminum fluoride.

[0018] According to the above-mentioned low-dimensional mullite phase reinforced silicon carbide-aluminate refractory product, more preferably, the raw material composition of the low-dimensional mullite phase reinforced silicon carbide-aluminate refractory product is, by mass percentage, 63% silicon carbide particles, 10% corundum particles, 12.9% corundum fine powder, 5% activated alumina fine powder, 5% hydrated alumina, 4.1% aluminum fluoride, plus 0.3% of the total mass of the above raw materials. Water reducer.

[0019] According to the aforementioned low-dimensional mullite phase reinforced silicon carbide-aluminate refractory product, the corundum is preferably one of white corundum (Al2O3 in white corundum ≥ 97.5%), tabular corundum (Al2O3 in tabular corundum ≥ 99%), industrial aluminate (Al2O3 in industrial aluminate ≥ 98%), sub-white corundum (Al2O3 in sub-white corundum ≥ 98%), and brown corundum (Al2O3 in brown corundum ≥ 94.5%). More preferably, the corundum is tabular corundum or white corundum; most preferably, the corundum is tabular corundum.

[0020] According to the above-mentioned low-dimensional mullite phase reinforced silicon carbide-aluminate refractory product, preferably, the silicon carbide particles are formed by mixing silicon carbide particles with a particle size of 1 to 3 mm and silicon carbide particles with a particle size of 0.1 to 1 mm in a mass ratio of 5:4.

[0021] According to the above-mentioned low-dimensional mullite phase reinforced silicon carbide-aluminate refractory product, preferably, the particle size of the corundum particles is 0.1-1 mm; the particle size of the corundum fine powder is <0.075 mm, the particle size of the activated alumina fine powder is <0.075 mm, the particle size of the binder is <0.075 mm, and the particle size of the additive is <0.075 mm.

[0022] The second aspect of the present invention provides a method for preparing the low-dimensional mullite phase reinforced silicon carbide-aluminate refractory product according to the first aspect, comprising the following steps:

[0023] (1) mixing aggregate, matrix, binder, additive and water reducing agent uniformly to obtain a mixture, adding water to the mixture, stirring and mixing uniformly to obtain a wet mix;

[0024] (2) pouring the wet mixture into a mold, curing at room temperature, demoulding, and drying to obtain a green body;

[0025] (3) calcining the green body at 1000-1600° C. for 1-10 hours in a carbon-buried atmosphere to obtain a low-dimensional mullite phase reinforced silicon carbide-aluminate refractory product.

[0026] A third aspect of the present invention provides a use of the low-dimensional mullite phase reinforced silicon carbide-aluminate refractory product according to the first aspect in a gasifier.

[0027] Preferably, the low-dimensional mullite phase reinforced silicon carbide-aluminate refractory product is used in the lining of a gasifier.

[0028] Compared with the prior art, the present invention has the following advantages:

[0029] (1) The present invention uses hydrated alumina as a binder. The hydration product Al(OH)3 generated by the hydration of hydrated alumina will migrate to the surface of the matrix SiC particles and form a continuous Al-OH-Si composite gel structure with the SiO2 oxide layer on the surface of the SiC particles, which facilitates the demolding and drying of the green body. During the sintering process, the Al-OH-Si composite gel structure generates a continuous mullite phase in situ, connecting the aluminosilicate and SiC particles, thereby improving the high-temperature strength and wear resistance. In addition, using hydrated alumina as a binder avoids the environmental pollution caused by the decomposition of conventional resin binders at high temperatures to produce toxic gases, which is conducive to green production. At the same time, hydrated alumina as a binder can be used to prepare the green body by casting, avoiding press molding, reducing production costs, and improving production efficiency and yield rate.

[0030] (2) The hydrated alumina binder of the present invention and the additives produce a synergistic effect. Through staged temperature-controlled sintering under a carbon-buried atmosphere, the catalyst generated by the reaction at high temperature catalyzes the reaction between SiO2 on the surface of the SiC particles and the aluminate particles, and in situ generates a low-dimensional mullite phase, such as mullite whiskers. Its core reaction mechanism is to utilize the gas-solid mechanism of the additive AlF3 to promote the growth of the low-dimensional mullite phase along the c-axis direction. This mechanism effectively avoids the problem of agglomeration of the added whiskers and enhances the structural uniformity inside the composite material. The whiskers grown in situ guided by the additive AlF3 present a fine forked interdigital morphology. This three-dimensional interlocking network structure can significantly reduce the microcracks generated after thermal shock, thereby improving the thermal shock stability and residual strength of the material. The continuous low-dimensional mullite phase is generated in situ and coated on the surface of the SiC particles, thereby increasing the interface thermal resistance and reducing the thermal conductivity of the composite material. The thermal expansion coefficients between the interface layer and the SiC particles and the aluminosilicate particles do not match, which will form microcracks that can slowly release thermal stress, thereby improving the thermal shock resistance of the composite material.

[0031] (3) The low-dimensional mullite phase generated by the present invention can form a gradient bond with aluminate (such as magnesium aluminum spinel, calcium hexaaluminate) particles, aluminum oxide and SiC particles to establish a multi-scale mechanical support system. The whiskers not only form a gradient interface with the matrix material, but also significantly reduce the microcracks generated after thermal shock through this interlocking network structure, thereby improving the thermal shock stability and residual strength of the composite material. The low-dimensional mullite phase has excellent resistance to oxidation and water-oxygen corrosion, thereby avoiding rapid degradation and performance degradation of the material in high temperature and humid environments.

[0032] (4) The bulk density of the low-dimensional mullite phase reinforced silicon carbide-aluminate refractory product of the present invention is 3.1 to 3.4 g / cm 3The room-temperature flexural strength reaches 9.6-23.5 MPa, the room-temperature compressive strength reaches 72.5-115 MPa, and the erosion rate reaches 5.3%-19.1%. The post-firing linear change is 0.54%-0.87%. Compared with the existing technology, the product of the present invention is low-cost, high-strength, good interfacial bonding, and excellent resistance to glass melt corrosion. The present invention achieves high strength, high thermal conductivity, and strong resistance to oxidation and water-oxygen corrosion in the composite material, thus meeting the long-term operation requirements of the gasifier. BRIEF DESCRIPTION OF THE DRAWINGS

[0033] Figure 1 This is a scanning electron microscope secondary electron image of the refractory product prepared in Examples 1-3 of the present invention;

[0034] Figure 2 This is a secondary electron image of a refractory product prepared in comparative example 5-1 of the present invention, taken using a scanning electron microscope. DETAILED DESCRIPTION

[0035] The following examples are intended only to further illustrate the present invention. It should be noted that all technical and scientific terms used herein have the same meanings as in the art to which the present invention pertains, unless otherwise specified. Experimental methods in the following examples, where specific conditions are not specified, were based on conventional techniques in the art or the conditions recommended by the manufacturer. Reagents and instruments used, where the manufacturer is not specified, are commercially available conventional products.

[0036] In order to enable those skilled in the art to more clearly understand the technical solution of the present invention, the technical solution of the present invention will be described in detail below with reference to specific embodiments.

[0037] Example 1: Discussion on the dosage of binder hydrated alumina

[0038] In order to study the effect of the amount of hydrated alumina as a binder in silicon carbide-aluminate refractory products on the performance of silicon carbide-aluminate refractory products reinforced with low-dimensional mullite phase, the present invention carried out Examples 1-1 to 1-5. The specific contents of Examples 1-1 to 1-5 are as follows:

[0039] Example 1-1:

[0040] A low-dimensional mullite-reinforced silicon carbide-aluminate refractory product, comprising, by weight percentage, 63% silicon carbide particles, 10% corundum particles with a particle size of 0.1-1 mm, 14.9% corundum fine powder with a particle size of <0.075 mm, 5% activated alumina fine powder with a particle size of <0.075 mm, 3% binder with a particle size of <0.075 mm, 3.5% silicon micropowder with a particle size of <0.075 mm, 0.6% aluminum fluoride with a particle size of <0.075 mm, and 0.3% of the total weight of a water reducer. The corundum is tabular corundum (with Al2O3 content ≥99%), the binder is hydrated alumina, the additives are silicon micropowder and aluminum fluoride, and the water reducer is FS-20.

[0041] The silicon carbide particles are formed by mixing silicon carbide particles with a particle size of 1 to 3 mm and silicon carbide particles with a particle size of 0.1 to 1 mm in a mass ratio of 5:4.

[0042] The preparation method of the low-dimensional mullite phase reinforced silicon carbide-aluminate refractory product comprises the following specific steps:

[0043] (1) mixing silicon carbide particle aggregate, corundum particle aggregate, corundum fine powder matrix, activated alumina fine powder matrix, binder, silicon micropowder additive, aluminum fluoride additive and water reducer to obtain a mixture, adding water to the mixture, stirring and mixing to obtain a wet mixture;

[0044] (2) pouring the wet mixture into a mold, curing at room temperature, demoulding, and drying to obtain a green body;

[0045] (3) calcining the green body at 1450° C. for 3 h in a carbon-buried atmosphere to obtain a low-dimensional mullite phase reinforced silicon carbide-aluminate refractory product.

[0046] Example 1-2:

[0047] A low-dimensional mullite-reinforced silicon carbide-aluminate refractory product, comprising, by weight percentage, 63% silicon carbide particles, 10% corundum particles with a particle size of 0.1-1 mm, 13.9% corundum fine powder with a particle size of <0.075 mm, 5% activated alumina fine powder with a particle size of <0.075 mm, 4% binder with a particle size of <0.075 mm, 3.5% silicon micropowder with a particle size of <0.075 mm, 0.6% aluminum fluoride with a particle size of <0.075 mm, and 0.3% of the total weight of a water reducer. The corundum is tabular corundum (with Al2O3 content ≥99%), the binder is hydrated alumina, the additives are silicon micropowder and aluminum fluoride, and the water reducer is FS-20.

[0048] The silicon carbide particles are formed by mixing silicon carbide particles with a particle size of 1 to 3 mm and silicon carbide particles with a particle size of 0.1 to 1 mm in a mass ratio of 5:4.

[0049] The preparation method of the low-dimensional mullite phase reinforced silicon carbide-aluminate refractory product is the same as that of Example 1-1.

[0050] Example 1-3:

[0051] A low-dimensional mullite-reinforced silicon carbide-aluminate refractory product, comprising, by weight percentage, 63% silicon carbide particles, 10% corundum particles with a particle size of 0.1-1 mm, 12.9% corundum fine powder with a particle size of less than 0.075 mm, 5% activated alumina fine powder with a particle size of less than 0.075 mm, 5% binder with a particle size of less than 0.075 mm, 3.5% silicon micropowder with a particle size of less than 0.075 mm, 0.6% aluminum fluoride with a particle size of less than 0.075 mm, and 0.3% of the total weight of a water reducer. The corundum is tabular corundum (with Al2O3 content ≥ 99%), the binder is hydrated alumina, the additives are silicon micropowder and aluminum fluoride, and the water reducer is FS-20.

[0052] The silicon carbide particles are formed by mixing silicon carbide particles with a particle size of 1 to 3 mm and silicon carbide particles with a particle size of 0.1 to 1 mm in a mass ratio of 5:4.

[0053] The preparation method of the low-dimensional mullite phase reinforced silicon carbide-aluminate refractory product is the same as that of Example 1-1.

[0054] Example 1-4:

[0055] A low-dimensional mullite-reinforced silicon carbide-aluminate refractory product, comprising, by weight percentage, 63% silicon carbide particles, 10% corundum particles with a particle size of 0.1-1 mm, 11.9% corundum fine powder with a particle size of <0.075 mm, 5% activated alumina fine powder with a particle size of <0.075 mm, 6% binder with a particle size of <0.075 mm, 3.5% silicon micropowder with a particle size of <0.075 mm, 0.6% aluminum fluoride with a particle size of <0.075 mm, and 0.3% of the total weight of a water reducer. The corundum is tabular corundum (with Al2O3 content ≥99%), the binder is hydrated alumina, the additives are silicon micropowder and aluminum fluoride, and the water reducer is FS-20.

[0056] The silicon carbide particles are formed by mixing silicon carbide particles with a particle size of 1 to 3 mm and silicon carbide particles with a particle size of 0.1 to 1 mm in a mass ratio of 5:4.

[0057] The preparation method of the low-dimensional mullite phase reinforced silicon carbide-aluminate refractory product is the same as that of Example 1-1.

[0058] Example 1-5:

[0059] A low-dimensional mullite-reinforced silicon carbide-aluminate refractory product, comprising, by weight percentage, 63% silicon carbide particles, 10% corundum particles with a particle size of 0.1-1 mm, 10.9% corundum fine powder with a particle size of less than 0.075 mm, 5% activated alumina fine powder with a particle size of less than 0.075 mm, 7% binder with a particle size of less than 0.075 mm, 3.5% silicon micropowder with a particle size of less than 0.075 mm, 0.6% aluminum fluoride with a particle size of less than 0.075 mm, and 0.3% of the total weight of a water reducer. The corundum is tabular corundum (with Al2O3 content ≥ 99%), the binder is hydrated alumina, the additives are silicon micropowder and aluminum fluoride, and the water reducer is FS-20.

[0060] The silicon carbide particles are formed by mixing silicon carbide particles with a particle size of 1 to 3 mm and silicon carbide particles with a particle size of 0.1 to 1 mm in a mass ratio of 5:4.

[0061] The preparation method of the low-dimensional mullite phase reinforced silicon carbide-aluminate refractory product is the same as that of Example 1-1.

[0062] The mechanical properties of the silicon carbide-aluminate refractory products prepared by calcining the green bodies of Examples 1-1 to 1-5 were tested. The mechanical properties testing methods included: bulk density according to GB / T 2999-2016; room-temperature flexural strength according to GB / T 3001-2017; post-firing linear change according to GB / T 5988-2007; room-temperature compressive strength according to GB / T 5072-2008; erosion rate using the static crucible method; thermal conductivity according to GB / T 5990-2006; and residual strength retention according to GB / 30873-2014. The mechanical properties test results are shown in Table 1.

[0063] Table 1 shows the mechanical properties test results of silicon carbide-aluminate refractory products prepared in Examples 1-1 to 1-5.

[0064]

[0065] In Examples 1-1 to 1-5, the corrosion resistance of the silicon carbide-aluminate refractory products prepared by increasing the amount of hydrated alumina initially increased but then decreased. This is because, while hydrated alumina with a content of 6% or more increases oxidation resistance, incomplete water release during sintering results in an uneven structure and the formation of pores, which compromises the corrosion resistance of the silicon carbide-aluminate refractory products and increases the corrosion rate. The synergistic effect of hydrated alumina and additives increases the bulk density and reduces the porosity of the silicon carbide-aluminate refractory products. The dense structure reduces the pores in the heat conduction path, reducing the thermal conductivity of the silicon carbide-aluminate refractory products. Alumina with a content of 4% or less fails to form a sufficient sintered structure, resulting in insufficient cementitious phase and weak interparticle bonding. This results in lower compressive and flexural strengths, lower bulk density, higher corrosion rates, and poorer corrosion resistance. A hydrated alumina content of 4% to 6% enhances the high-temperature stability of silicon carbide-aluminate refractory products, forming stable mullite or other high-temperature-resistant phases. This optimizes various performance characteristics, including increased compressive strength, flexural strength, high-temperature performance, erosion resistance, and improved bulk density, making it the ideal range. A hydrated alumina content of 6% or greater causes a significant volume expansion of the silicon carbide-aluminate refractory product, leading to a slight decrease in high-temperature flexural strength and room-temperature compressive strength. This also affects bulk density, resulting in a less dense structure, more pores and cracks, and a decrease in performance.

[0066] Example 2: Discussion on Corundum Types

[0067] In order to study the effect of the type of corundum in silicon carbide-aluminate refractory products on the performance of silicon carbide-aluminate refractory products reinforced with low-dimensional mullite phase, the present invention carried out Examples 2-1 to 2-4. The specific contents of Examples 2-1 to 2-4 are as follows:

[0068] Example 2-1:

[0069] A low-dimensional mullite-reinforced silicon carbide-aluminate refractory product, comprising, by weight percentage, 63% silicon carbide particles, 10% corundum particles with a particle size of 0.1-1 mm, 12.9% corundum fine powder with a particle size of less than 0.075 mm, 5% activated alumina fine powder with a particle size of less than 0.075 mm, 5% binder with a particle size of less than 0.075 mm, 3.5% silicon micropowder with a particle size of less than 0.075 mm, 0.6% aluminum fluoride with a particle size of less than 0.075 mm, and 0.3% of the total weight of a water reducer. The corundum is white corundum (with an Al2O3 content of ≥97.5%), the binder is hydrated alumina, the additives are silicon micropowder and aluminum fluoride, and the water reducer is FS-20.

[0070] The silicon carbide particles are formed by mixing silicon carbide particles with a particle size of 1 to 3 mm and silicon carbide particles with a particle size of 0.1 to 1 mm in a mass ratio of 5:4.

[0071] The preparation method of the low-dimensional mullite phase reinforced silicon carbide-aluminate refractory product is the same as that of Example 1-1.

[0072] Example 2-2:

[0073] A low-dimensional mullite-reinforced silicon carbide-aluminate refractory product, comprising, by weight percentage, 63% silicon carbide particles, 10% corundum particles with a particle size of 0.1-1 mm, 12.9% corundum fine powder with a particle size <0.075 mm, 5% activated alumina fine powder with a particle size <0.075 mm, 5% binder with a particle size <0.075 mm, 3.5% silicon micropowder with a particle size <0.075 mm, 0.6% aluminum fluoride with a particle size <0.075 mm, and 0.3% of the total weight of a water reducer. The corundum is industrial aluminate (with Al2O3 ≥98%), the binder is hydrated alumina, the additives are silicon micropowder and aluminum fluoride, and the water reducer is FS-20.

[0074] The silicon carbide particles are formed by mixing silicon carbide particles with a particle size of 1 to 3 mm and silicon carbide particles with a particle size of 0.1 to 1 mm in a mass ratio of 5:4.

[0075] The preparation method of the low-dimensional mullite phase reinforced silicon carbide-aluminate refractory product is the same as that of Example 1-1.

[0076] Example 2-3:

[0077] A low-dimensional mullite-reinforced silicon carbide-aluminate refractory product, comprising, by weight percentage, 63% silicon carbide particles, 10% corundum particles with a particle size of 0.1-1 mm, 12.9% corundum fine powder with a particle size of less than 0.075 mm, 5% activated alumina fine powder with a particle size of less than 0.075 mm, 5% binder with a particle size of less than 0.075 mm, 3.5% silicon micropowder with a particle size of less than 0.075 mm, 0.6% aluminum fluoride with a particle size of less than 0.075 mm, and 0.3% of the total weight of a water reducer. The corundum is sub-white corundum (with Al2O3 ≥ 98%), the binder is hydrated alumina, the additives are silicon micropowder and aluminum fluoride, and the water reducer is FS-20.

[0078] The silicon carbide particles are formed by mixing silicon carbide particles with a particle size of 1 to 3 mm and silicon carbide particles with a particle size of 0.1 to 1 mm in a mass ratio of 5:4.

[0079] The preparation method of the low-dimensional mullite phase reinforced silicon carbide-aluminate refractory product is the same as that of Example 1-1.

[0080] Example 2-4:

[0081] A low-dimensional mullite-reinforced silicon carbide-aluminate refractory product, comprising, by weight percentage, 63% silicon carbide particles, 10% corundum particles with a particle size of 0.1-1 mm, 12.9% corundum fine powder with a particle size of less than 0.075 mm, 5% activated alumina fine powder with a particle size of less than 0.075 mm, 5% binder with a particle size of less than 0.075 mm, 3.5% silicon micropowder with a particle size of less than 0.075 mm, 0.6% aluminum fluoride with a particle size of less than 0.075 mm, and 0.3% of the total weight of a water reducer. The corundum is brown corundum (with an Al2O3 content of ≥94.5%), the binder is hydrated alumina, the additives are silicon micropowder and aluminum fluoride, and the water reducer is FS-20.

[0082] The silicon carbide particles are formed by mixing silicon carbide particles with a particle size of 1 to 3 mm and silicon carbide particles with a particle size of 0.1 to 1 mm in a mass ratio of 5:4.

[0083] The preparation method of the low-dimensional mullite phase reinforced silicon carbide-aluminate refractory product is the same as that of Example 1-1.

[0084] The mechanical properties of the silicon carbide-aluminate refractory products prepared after calcining the green bodies of Examples 2-1 to 2-4 and 1-3 were tested (the testing method was the same as that of Example 1). The test results are shown in Table 2.

[0085] Table 2 shows the mechanical properties test results of silicon carbide-aluminate refractory products prepared in Examples 2-1 to 2-4 and 1-3.

[0086]

[0087] High-purity corundum promotes the uniform formation of low-dimensional mullite phase, forming a continuous ceramic bond, and significantly improving mechanical properties and corrosion resistance. The silicon carbide-aluminate refractory products prepared using plate-like corundum in Example 1-3 have the best overall performance, because their high purity and structural characteristics significantly improve the corrosion resistance, flexural resistance and compressive strength of silicon carbide-aluminate refractory products. At the same time, they maintain low post-firing linear changes and high volume density, high residual strength retention, and significantly reduced thermal conductivity. The silicon carbide-aluminate refractory products prepared using white corundum particles in Example 2-1 have performance close to that of silicon carbide-aluminate refractory products prepared using plate-like corundum, and can be used as a lower-cost alternative. The silicon carbide-aluminate refractory products prepared using industrial aluminate in Example 2-2 and the silicon carbide-aluminate refractory products prepared using sub-white corundum in Example 2-3 have medium performance. The silicon carbide-aluminate refractory products prepared using brown corundum in Example 2-4 have the weakest performance, which may introduce defects or inhomogeneous phases, resulting in performance degradation.

[0088] Example 3: Discussion of substrate types

[0089] In order to study the effect of matrix type in silicon carbide-aluminate refractory products on the performance of silicon carbide-aluminate refractory products reinforced with low-dimensional mullite phase, the present invention carried out Examples 3-1 and 3-2. The specific contents of Examples 3-1 and 3-2 are as follows:

[0090] Example 3-1:

[0091] A low-dimensional mullite-reinforced silicon carbide-aluminate refractory product, comprising, by weight percentage, 63% silicon carbide particles, 10% corundum particles with a particle size of 0.1-1 mm, 12.9% corundum fine powder with a particle size of less than 0.075 mm, 5% magnesia-alumina spinel fine powder with a particle size of less than 0.075 mm, 5% binder with a particle size of less than 0.075 mm, 3.5% silicon micropowder with a particle size of less than 0.075 mm, 0.6% aluminum fluoride with a particle size of less than 0.075 mm, and 0.3% of the total weight of a water reducer. The corundum is tabular corundum (with Al2O3 content ≥ 99%), the binder is hydrated alumina, the additives are silicon micropowder and aluminum fluoride, and the water reducer is FS-20.

[0092] The silicon carbide particles are formed by mixing silicon carbide particles with a particle size of 1 to 3 mm and silicon carbide particles with a particle size of 0.1 to 1 mm in a mass ratio of 5:4.

[0093] The preparation method of the low-dimensional mullite phase reinforced silicon carbide-aluminate refractory product is the same as that of Example 1-1.

[0094] Example 3-2:

[0095] A low-dimensional mullite-reinforced silicon carbide-aluminate refractory product, comprising, by weight percentage, 63% silicon carbide particles, 10% corundum particles with a particle size of 0.1-1 mm, 12.9% corundum fine powder with a particle size <0.075 mm, 5% calcium hexaaluminate fine powder with a particle size <0.075 mm, 5% binder with a particle size <0.075 mm, 3.5% silicon micropowder with a particle size <0.075 mm, 0.6% aluminum fluoride with a particle size <0.075 mm, and 0.3% of the total weight of a water reducer. The corundum is tabular corundum (with Al2O3 content ≥99%), the binder is hydrated alumina, the additives are silicon micropowder and aluminum fluoride, and the water reducer is FS-20.

[0096] The silicon carbide particles are formed by mixing silicon carbide particles with a particle size of 1 to 3 mm and silicon carbide particles with a particle size of 0.1 to 1 mm in a mass ratio of 5:4.

[0097] The preparation method of the low-dimensional mullite phase reinforced silicon carbide-aluminate refractory product is the same as that of Example 1-1.

[0098] The mechanical properties of the silicon carbide-aluminate refractory products prepared after calcining the green bodies of Example 3-1, Example 3-2 and Example 1-3 were tested (the testing method was the same as that of Example 1), and the test results are shown in Table 3.

[0099] Table 3 shows the mechanical properties test results of silicon carbide-aluminate refractory products prepared in Example 3-1, Example 3-2 and Example 1-3.

[0100]

[0101] The silicon carbide-aluminate refractory products prepared in Example 1-3 using fine corundum powder and activated alumina powder as the matrix raw materials exhibit the best overall performance. The activated alumina powder promotes the uniform formation of the mullite phase, forming a continuous three-dimensional network structure, enhancing mechanical properties and erosion resistance, but its ability to buffer thermal shock is limited. Example 3-1 uses fine corundum powder and fine magnesia-alumina spinel powder as the matrix raw materials. While MgO reacts with the SiC surface oxide layer to form a high-melting-point protective layer, improving thermal shock resistance, its reactivity with Al₂O₃ is reduced, resulting in a decrease in the low-dimensional mullite phase and a slight decrease in the flexural strength of the silicon carbide-aluminate refractory product. Example 3-2 uses fine corundum powder and fine calcium hexaaluminate powder as the matrix raw materials. The CaO in the calcium hexaaluminate powder reacts with SiO₂ to form a stable protective layer, inhibiting SiC oxidation and improving oxidation resistance. However, the CaO may react with water vapor to form Ca(OH)₂, introducing microcracks and reducing the flexural strength of the silicon carbide-aluminate refractory product.

[0102] Example 4: Discussion on the types of additives

[0103] In order to study the effect of the type of additives in silicon carbide-aluminate refractory products on the performance of silicon carbide-aluminate refractory products reinforced with low-dimensional mullite phase, the present invention carried out Examples 4-1 to 4-5. The specific contents of Examples 4-1 to 4-5 are as follows:

[0104] Example 4-1:

[0105] A low-dimensional mullite-reinforced silicon carbide-aluminate refractory product, comprising, by weight percentage, 63% silicon carbide particles, 10% corundum particles with a particle size of 0.1-1 mm, 12.9% corundum fine powder with a particle size <0.075 mm, 5% activated alumina fine powder with a particle size <0.075 mm, 5% binder with a particle size <0.075 mm, 3.5% silicon micropowder with a particle size <0.075 mm, 0.6% ammonium molybdate with a particle size <0.075 mm, and 0.3% of the total weight of a water reducer. The corundum is tabular corundum (with Al2O3 content ≥99%), the binder is hydrated alumina, the additives are silicon micropowder and ammonium molybdate, and the water reducer is FS-20.

[0106] The silicon carbide particles are formed by mixing silicon carbide particles with a particle size of 1 to 3 mm and silicon carbide particles with a particle size of 0.1 to 1 mm in a mass ratio of 5:4.

[0107] The preparation method of the low-dimensional mullite phase reinforced silicon carbide-aluminate refractory product is the same as that of Example 1-1.

[0108] Example 4-2:

[0109] A low-dimensional mullite-reinforced silicon carbide-aluminate refractory product, comprising, by weight percentage, 63% silicon carbide particles, 10% corundum particles with a particle size of 0.1-1 mm, 12.9% corundum fine powder with a particle size <0.075 mm, 5% activated alumina fine powder with a particle size <0.075 mm, 5% binder with a particle size <0.075 mm, 3.5% silicon micropowder with a particle size <0.075 mm, 0.6% boron oxide with a particle size <0.075 mm, and 0.3% of the total weight of a water reducer. The corundum is tabular corundum (with Al2O3 content ≥99%), the binder is hydrated alumina, the additives are silicon micropowder and boron oxide, and the water reducer is FS-20.

[0110] The silicon carbide particles are formed by mixing silicon carbide particles with a particle size of 1 to 3 mm and silicon carbide particles with a particle size of 0.1 to 1 mm in a mass ratio of 5:4.

[0111] The preparation method of the low-dimensional mullite phase reinforced silicon carbide-aluminate refractory product is the same as that of Example 1-1.

[0112] Example 4-3:

[0113] A low-dimensional mullite-reinforced silicon carbide-aluminate refractory product, comprising, by weight percentage, 63% silicon carbide particles, 10% corundum particles with a particle size of 0.1-1 mm, 12.9% corundum fine powder with a particle size <0.075 mm, 5% activated alumina fine powder with a particle size <0.075 mm, 5% binder with a particle size <0.075 mm, 4.1% silicon micropowder with a particle size <0.075 mm, and 0.3% of the total weight of the raw materials, including a water reducer. The corundum is tabular corundum (with Al2O3 ≥99%), the binder is hydrated alumina, the additive is silicon micropowder, and the water reducer is FS-20.

[0114] The silicon carbide particles are formed by mixing silicon carbide particles with a particle size of 1 to 3 mm and silicon carbide particles with a particle size of 0.1 to 1 mm in a mass ratio of 5:4.

[0115] The preparation method of the low-dimensional mullite phase reinforced silicon carbide-aluminate refractory product is the same as that of Example 1-1.

[0116] Example 4-4:

[0117] A low-dimensional mullite-reinforced silicon carbide-aluminate refractory product, comprising, by weight percentage, 63% silicon carbide particles, 10% corundum particles with a particle size of 0.1-1 mm, 12.9% corundum fine powder with a particle size <0.075 mm, 5% activated alumina fine powder with a particle size <0.075 mm, 5% binder with a particle size <0.075 mm, 3.5% silicon micropowder with a particle size <0.075 mm, 0.6% molybdenum oxide with a particle size <0.075 mm, and 0.3% of the total weight of a water reducer. The corundum is tabular corundum (with Al2O3 content ≥99%), the binder is hydrated alumina, the additives are silicon micropowder and molybdenum oxide, and the water reducer is FS-20.

[0118] The silicon carbide particles are formed by mixing silicon carbide particles with a particle size of 1 to 3 mm and silicon carbide particles with a particle size of 0.1 to 1 mm in a mass ratio of 5:4.

[0119] The preparation method of the low-dimensional mullite phase reinforced silicon carbide-aluminate refractory product is the same as that of Example 1-1.

[0120] Example 4-5:

[0121] A low-dimensional mullite-reinforced silicon carbide-aluminate refractory product, comprising, by weight percentage, 63% silicon carbide particles, 10% corundum particles with a particle size of 0.1-1 mm, 12.9% corundum fine powder with a particle size <0.075 mm, 5% activated alumina fine powder with a particle size <0.075 mm, 5% binder with a particle size <0.075 mm, 3.5% silicon micropowder with a particle size <0.075 mm, 0.6% tungsten oxide with a particle size <0.075 mm, and 0.3% of the total weight of a water reducer. The corundum is tabular corundum (with Al2O3 content ≥99%), the binder is hydrated alumina, the additives are silicon micropowder and tungsten oxide, and the water reducer is FS-20.

[0122] The silicon carbide particles are formed by mixing silicon carbide particles with a particle size of 1 to 3 mm and silicon carbide particles with a particle size of 0.1 to 1 mm in a mass ratio of 5:4.

[0123] The preparation method of the low-dimensional mullite phase reinforced silicon carbide-aluminate refractory product is the same as that of Example 1-1.

[0124] Comparative Example 4-1:

[0125] A low-dimensional mullite phase reinforced silicon carbide-aluminate refractory product. Calculated by mass percentage, the raw material composition of the low-dimensional mullite phase reinforced silicon carbide-aluminate refractory product is:

[0126] 63% silicon carbide particles, 10% corundum particles with a particle size of 0.1-1mm, 17% corundum fine powder with a particle size of <0.075mm, 5% activated alumina fine powder with a particle size of <0.075mm, 5% binder with a particle size of <0.075mm, no additives, and 0.3% of the total weight of a water reducer. The corundum is tabular corundum (with Al2O3 ≥99%), the binder is hydrated alumina, and the water reducer is FS-20.

[0127] The silicon carbide particles are formed by mixing silicon carbide particles with a particle size of 1 to 3 mm and silicon carbide particles with a particle size of 0.1 to 1 mm in a mass ratio of 5:4.

[0128] The preparation method of the low-dimensional mullite phase reinforced silicon carbide-aluminate refractory product is the same as that of Example 1-1.

[0129] The mechanical properties of the silicon carbide-aluminate refractory products prepared after calcining the green bodies of Examples 4-1 to 4-5, Comparative Example 4-1 and Example 1-3 were tested (the testing method was the same as that of Example 1), and the test results are shown in Table 4.

[0130] Table 4 shows the mechanical properties test results of silicon carbide-aluminate refractory products prepared in Examples 4-1 to 4-5, Comparative Example 4-1 and Example 1-3.

[0131]

[0132] The catalytic efficiency of the additive directly affects the formation of the mullite whisker network. The silicon carbide-aluminate refractory product prepared by using silicon micropowder + ammonium molybdate as additives in Example 4-1 performs best in mechanical properties and post-firing linear changes, but the cost is relatively high. Ammonium molybdate, as a high-efficiency catalyst, significantly improves the aspect ratio of mullite whiskers and enhances mechanical properties, but the cost is relatively high and it is not suitable for conventional applications. The silicon carbide-aluminate refractory product prepared by using silicon micropowder + aluminum fluoride as additives in Example 1-3 has the best comprehensive performance and is suitable for conventional applications. The F released by aluminum fluoride - Reduce the activation energy of mullite reaction, promote the uniform growth of mullite whiskers, and form an interlocking network structure. Example 4-2 uses silicon micropowder + boron oxide as additives, and liquid phase sintering promotes densification, but may form a glass phase and reduce high-temperature stability. Example 4-3 uses silicon micropowder to directly provide Si source without other additives. Example 4-5 uses silicon micropowder + tungsten oxide, and Example 4-4 uses silicon micropowder + molybdenum oxide to enhance oxidation resistance, but the generation of mullite phase is low. Overall, it is most appropriate to use aluminum fluoride and silicon micropowder as additives. When no additives are added to Comparative Example 4-1, under the action of hydrated alumina alone, the amount of mullite phase generated is small and unevenly distributed, the bonding between particles is weak, and there are more pores, which leads to reduced performance of silicon carbide-aluminate refractory products.

[0133] The low-dimensional mullite phase reinforced silicon carbide-aluminate refractory products prepared in Examples 1-3 and Comparative Example 4-1 of the present invention were analyzed using a scanning electron microscope. The microscopic morphology of the fracture surface is shown in FIG. Figure 1 、 Figure 2 As shown. Figure 1 It can be seen that the appropriate aluminum fluoride additive and hydrated alumina binder work synergistically to promote the formation of a low-dimensional mullite phase with a high aspect ratio. Figure 2It can be seen that when hydrated alumina is used alone without additives, the amount of mullite produced is small and unevenly distributed. The hydrated alumina binder and additives work synergistically. Through staged temperature-controlled sintering in a carbon-buried atmosphere, the high-temperature reaction generates a catalyst that catalyzes the reaction between SiO2 on the surface of the SiC particles and the aluminate particles, forming a low-dimensional mullite phase in situ. The silicon micropowder additive supplements the Si source through the reaction, promoting the uniform formation of the low-dimensional mullite phase. It also fills the gaps between the aggregates and reduces the material's porosity. The aluminum fluoride additive releases AlF3 gas during sintering, reducing the activation energy for the formation of the low-dimensional mullite phase and promoting the growth of interlocking mullite whiskers along the c-axis. The silicon micropowder and aluminum fluoride additives synergistically increase the whisker density, forming a continuous three-dimensional network.

[0134] Example 5: Discussion on the dosage of aluminum fluoride additive

[0135] In order to study the effect of the amount of aluminum fluoride additive in silicon carbide-aluminate refractory products on the performance of silicon carbide-aluminate refractory products reinforced with low-dimensional mullite phase, the present invention carried out Examples 5-1 and 5-2. The specific contents of Examples 5-1 and 5-2 are as follows:

[0136] Example 5-1:

[0137] A low-dimensional mullite-reinforced silicon carbide-aluminate refractory product, comprising, by weight percentage, 63% silicon carbide particles, 10% corundum particles with a particle size of 0.1-1 mm, 12.3% corundum fine powder with a particle size of less than 0.075 mm, 5% activated alumina fine powder with a particle size of less than 0.075 mm, 5% binder with a particle size of less than 0.075 mm, 3.5% silicon micropowder with a particle size of less than 0.075 mm, 1.2% aluminum fluoride with a particle size of less than 0.075 mm, and 0.3% of the total weight of a water reducer. The corundum is tabular corundum (with Al2O3 content ≥ 99%), the binder is hydrated alumina, the additives are silicon micropowder and aluminum fluoride, and the water reducer is FS-20.

[0138] The silicon carbide particles are formed by mixing silicon carbide particles with a particle size of 1 to 3 mm and silicon carbide particles with a particle size of 0.1 to 1 mm in a mass ratio of 5:4.

[0139] The preparation method of the low-dimensional mullite phase reinforced silicon carbide-aluminate refractory product is the same as that of Example 1-1.

[0140] Example 5-2:

[0141] A low-dimensional mullite-reinforced silicon carbide-aluminate refractory product, comprising, by weight percentage, 63% silicon carbide particles, 10% corundum particles with a particle size of 0.1-1 mm, 11.7% corundum fine powder with a particle size of less than 0.075 mm, 5% activated alumina fine powder with a particle size of less than 0.075 mm, 5% binder with a particle size of less than 0.075 mm, 3.5% silicon micropowder with a particle size of less than 0.075 mm, 1.8% aluminum fluoride with a particle size of less than 0.075 mm, and 0.3% of the total weight of a water reducer. The corundum is tabular corundum (with Al2O3 content ≥ 99%), the binder is hydrated alumina, the additives are silicon micropowder and aluminum fluoride, and the water reducer is FS-20.

[0142] The silicon carbide particles are formed by mixing silicon carbide particles with a particle size of 1 to 3 mm and silicon carbide particles with a particle size of 0.1 to 1 mm in a mass ratio of 5:4.

[0143] The preparation method of the low-dimensional mullite phase reinforced silicon carbide-aluminate refractory product is the same as that of Example 1-1.

[0144] The mechanical properties of the refractory products prepared after calcining the green bodies of Example 5-1, Example 5-2, and Example 1-3 were tested (the testing method was the same as that of Example 1). The test results are shown in Table 5.

[0145] Table 5 shows the mechanical properties test results of silicon carbide-aluminate refractory products prepared in Example 5-1, Example 5-2 and Example 1-3.

[0146]

[0147] As shown in Table 5, the silicon carbide-aluminate refractory products prepared in Examples 1-3 with the addition of 0.6% aluminum fluoride additive exhibit significantly superior performance compared to the silicon carbide-aluminate refractory products prepared in Examples 5-1 and 5-2 with the addition of 1.2% and 1.8% aluminum fluoride additives, respectively. This is because an appropriate amount of aluminum fluoride additive helps form a low-dimensional mullite phase with a high aspect ratio. These low-dimensional mullite whiskers can fill the matrix and significantly enhance the mechanical properties of the silicon carbide-aluminate refractory product. Excessive addition of aluminum fluoride can lead to abnormal growth or irregular morphology of the low-dimensional mullite whiskers, weakening the reinforcement effect.

[0148] Finally, it should be noted that the above embodiments are merely preferred embodiments of the present invention and are not intended to limit the present invention in any other manner. Any person skilled in the art may utilize the above technical content as a guide to make changes or modifications. These are equivalent embodiments of equivalent modifications. However, any simple modifications, equivalent changes, and modifications to the above embodiments that do not depart from the technical concept of the present invention and are based on the technical essence of the present invention remain within the scope of protection of the claims of the present invention.

Claims

1. A low-dimensional mullite phase reinforced silicon carbide-aluminate refractory product, characterized in that: Calculated by weight percentage, the raw material composition of the low-dimensional mullite phase reinforced silicon carbide-aluminate refractory product is: 50% to 85% aggregate, 6% to 35% matrix, 1% to 10% binder, 0.1% to 6% additives, plus 0.1% to 1% of a water reducer accounting for the total weight of the above raw materials; the binder is hydrated alumina, and the additive is at least one of ammonium molybdate, boron oxide, aluminum fluoride, silicon powder, tungsten oxide, and molybdenum oxide.

2. The low-dimensional mullite phase reinforced silicon carbide-aluminate refractory product according to claim 1, characterized in that: The aggregate is at least one of corundum particles, silicon carbide particles, magnesia alumina spinel particles, and calcium hexaaluminate particles.

3. The low-dimensional mullite phase reinforced silicon carbide-aluminate refractory product according to claim 2, characterized in that: The matrix is at least one of corundum fine powder, silicon carbide fine powder, activated alumina fine powder, magnesium aluminum spinel fine powder, and calcium hexaaluminate fine powder.

4. The low-dimensional mullite phase reinforced silicon carbide-aluminate refractory product according to claim 3, characterized in that: The water reducer is at least one of a naphthalene-based water reducer and a polycarboxylic acid water reducer.

5. The low-dimensional mullite phase reinforced silicon carbide-aluminate refractory product according to claim 4, characterized in that: Calculated by mass percentage, the raw material composition of the low-dimensional mullite phase reinforced silicon carbide-aluminate refractory product is: 50% to 70% silicon carbide particles, 1% to 15% corundum particles, 1% to 15% corundum fine powder, 3% to 10% activated alumina fine powder, 1% to 10% binder, 0.1% to 6% additives, and 0.1% to 1% of the total mass of the above raw materials. Water reducer.

6. The low-dimensional mullite phase reinforced silicon carbide-aluminate refractory product according to claim 5, characterized in that: The corundum is one of white corundum, plate corundum, industrial aluminate, sub-white corundum and brown corundum.

7. The low-dimensional mullite phase reinforced silicon carbide-aluminate refractory product according to claim 5, characterized in that: The silicon carbide particles are formed by mixing silicon carbide particles with a particle size of 1 to 3 mm and silicon carbide particles with a particle size of 0.1 to 1 mm in a mass ratio of 5:

4.

8. The low-dimensional mullite phase reinforced silicon carbide-aluminate refractory product according to claim 5, characterized in that: The Al2O3 content of the hydrated alumina is greater than 98%; the particle size of the corundum particles is 0.1-1 mm; the particle size of the corundum fine powder is less than 0.075 mm, the particle size of the activated alumina fine powder is less than 0.075 mm, the particle size of the binder is less than 0.075 mm, and the particle size of the additive is less than 0.075 mm.

9. A method for preparing the low-dimensional mullite phase reinforced silicon carbide-aluminate refractory product according to any one of claims 1 to 8, characterized in that: The following steps are involved: (1) mixing aggregate, matrix, binder, additive and water reducing agent uniformly to obtain a mixture, adding water to the mixture, stirring and mixing uniformly to obtain a wet mix; (2) pouring the wet mixture into a mold, curing at room temperature, demoulding, and drying to obtain a green body; (3) calcining the green body at 1000-1600° C. for 1-10 hours in a carbon-buried atmosphere to obtain a low-dimensional mullite phase reinforced silicon carbide-aluminate refractory product.

10. Use of the low-dimensional mullite phase reinforced silicon carbide-aluminate refractory product according to any one of claims 1 to 8 in a gasifier.

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