Micro-expansion aluminum silicon carbide carbon brick and preparation method thereof

Abstract

The invention discloses a micro-expansion aluminum silicon carbide carbon brick and a preparation method thereof, and belongs to the field of aluminum silicon carbide carbon bricks, and the micro-expansion aluminum silicon carbide carbon brick is prepared from the following raw materials: 25-35 parts of high bauxite, 31-49 parts of brown aluminum oxide, 8-12 parts of aluminum magnesium spinel, 6-10 parts of crystalline flake graphite, 6-12 parts of silicon carbide, 2-4 parts of fused magnesite, 4-5 parts of a binder and 2-3 parts of a composite antioxidant. The binding agent is obtained by premixing modified phenolic resin and rare earth oxide according to the mass ratio of 1: (0.4-0.6), and the modified phenolic resin is prepared by modifying phenolic resin through molybdenum sulfide. According to the prepared aluminum silicon carbide carbon brick, the erosion resistance of the aluminum silicon carbide carbon brick can be improved, the phenomena of iron permeation and brick falling in the using process of the aluminum silicon carbide carbon brick are effectively reduced, and a new technical path is provided for long-life and high-reliability application of the aluminum silicon carbide carbon brick in a high-temperature equipment lining.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of aluminum silicon carbide carbon bricks, in particular to a micro-expansion aluminum silicon carbide carbon brick and a preparation method thereof. BACKGROUND

[0002] The aluminum silicon carbide carbon brick is difficult to overcome the technical bottlenecks of poor structural stability at high temperature and short service life in the lining application of key equipment such as a ladle and a mixing car, which seriously affects the operation efficiency and running safety of high-temperature molten iron in the process of holding and transportation.

[0003] In the prior art, the addition of metal silicon, aluminum and other antioxidants to improve the oxidation resistance of the material, or the adjustment of particle size distribution to optimize the density, can improve the mechanical strength and high-temperature resistance of the aluminum silicon carbide carbon brick to a certain extent, but under the repeated heating-cooling cycle and the action of molten iron, some micro-cracks are easily generated in the brick body, these micro-cracks and the pores left after the volatilization or carbonization of the binder at high temperature are interconnected and gradually expanded, and a loose layer is easily formed on the surface of the brick body, which provides a channel for the penetration of molten iron and causes the brick joint problem, which limits the service life and safety and reliability of the existing aluminum silicon carbide carbon brick.

[0004] Therefore, there is no effective and systematic solution to the problem of iron penetration and brick falling caused by the high and low temperature expansion and contraction of the aluminum silicon carbide carbon brick body, which is difficult to meet the harsh demand of large-scale and efficient production on refractory materials. SUMMARY

[0005] Therefore, the technical problem to be solved by the present application is to provide a micro-expansion aluminum silicon carbide carbon brick and a preparation method thereof, which can improve the erosion resistance of the aluminum silicon carbide carbon brick and effectively reduce the iron penetration and brick falling phenomenon during the use of the aluminum silicon carbide carbon brick.

[0006] To solve the above technical problems, the present application provides the following technical solutions:

[0007] A micro-expansion aluminum silicon carbide carbon brick is prepared from the following raw materials in parts by weight: 25-35 parts of high alumina bauxite, 31-49 parts of brown corundum, 8-12 parts of aluminum magnesium spinel, 6-10 parts of flaky graphite, 6-12 parts of silicon carbide, 2-4 parts of electric smelting magnesite, 4-5 parts of a binder and 2-3 parts of a composite antioxidant; the high alumina bauxite, brown corundum, aluminum magnesium spinel and silicon carbide all contain two types of particle sizes, namely particle materials and fine powder materials, the binder is obtained by premixing modified phenolic resin and rare earth oxides in a mass ratio of 1:0.4-0.6, and the modified phenolic resin is prepared by modifying phenolic resin with molybdenum sulfide.

[0008] Further, the modified phenolic resin is prepared by the following steps:

[0009] A1. Mix dimethyldimethoxysilane with water, adjust pH to 2-3, heat to 30-40℃, stir for 20-40 minutes, add molybdenum sulfide, heat to 50-60℃, stir for 30-60 minutes, to obtain a modified liquid;

[0010] A2. Add a mixture of phenolic resin and tetrahydrofuran to the modified liquid, stir for 1.5-2.5 hours, to obtain modified phenolic resin.

[0011] Further, the mass ratio of phenolic resin to molybdenum sulfide in step A2 is 100:4-6.

[0012] Further, the mass ratio of dimethyldimethoxysilane, water and molybdenum sulfide in step A1 is 1:1.8-2.2:4-6.

[0013] Further, the rare earth oxide is a mixture of samarium oxide and dysprosium oxide with a mass ratio of 100:0.4-0.6.

[0014] Further, the granular material in brown corundum includes 2-4 parts of particles with a particle size greater than or equal to 3mm and less than or equal to 5mm, and 14-20 parts of particles with a particle size greater than or equal to 1mm and less than 3mm, and the fine powder material in brown corundum includes 5-9 parts of fine powder with a particle size greater than or equal to 0.074mm and less than 1mm, and 10-16 parts of fine powder with a particle size less than 0.074mm.

[0015] Further, the alumina-magnesia spinel is a mixture of one or both of fused alumina-magnesia spinel and sintered alumina-magnesia spinel; the alumina-magnesia spinel includes 5-7 parts of granular material with a particle size greater than or equal to 0.074mm and less than 1mm, and 3-5 parts of fine powder material with a particle size less than 0.074mm; the content of the sum of alumina and magnesium oxide in the alumina-magnesia spinel is greater than or equal to 90wt%.

[0016] Further, the particle size of the fused magnesia is less than 0.074mm, and the content of magnesium oxide in the fused magnesia is greater than or equal to 97wt%.

[0017] Further, the composite antioxidant is a mixture of metal silicon powder and aluminum powder with a mass ratio of 1.5-2.5:1.

[0018] The present application also provides a preparation method of micro-expansion aluminum silicon carbide carbon brick, for preparing the micro-expansion aluminum silicon carbide carbon brick described in the above scheme, which comprises the following contents:

[0019] S1: Prepare raw materials according to the proportion, mix the granular material in bauxite, brown corundum, alumina-magnesia spinel and silicon carbide to obtain mixed dry material A for standby; mix the fine powder material in bauxite, brown corundum, alumina-magnesia spinel and silicon carbide, then add fused magnesia and composite antioxidant for mixing to obtain mixed dry material B;

[0020] S2: adding the binding agent to the mixed dry material A, then adding the flaky graphite, and then adding the mixed dry material B, and mixing in a mixing mill to obtain a mixture, and then aging the mixture for 6 hours;

[0021] S3: forming the mixture into a green body in a mold;

[0022] S4: drying the green body, and obtaining the micro-expansion aluminum silicon carbide carbon brick after the drying is completed.

[0023] The technical scheme of the present application achieves the following beneficial technical effects:

[0024] 1. The micro-expansion aluminum silicon carbide carbon brick provided by the present application realizes the combined effect of particle size gradation, composite oxidizing agent and modified binding agent through scientific proportioning of raw materials and optimized design of the preparation method, which not only improves the erosion resistance of the aluminum silicon carbide carbon brick, but also produces internal expansion and overall stable volume effect under high-temperature service environment, offsets the shrinkage stress of the brick during temperature change, effectively controls the generation and expansion of micro-cracks, and reduces the iron infiltration and brick falling phenomenon during the use of the aluminum silicon carbide carbon brick.

[0025] 2. The aluminum magnesium spinel and the fused magnesia produce a macroscopic expansion effect at high temperatures, and the modified phenolic resin and the rare earth oxide in the binding agent produce a microscopic expansion effect, which can fill the pores in the brick and effectively offset the shrinkage stress of the brick during repeated temperature cycles, significantly inhibit the initiation and expansion of micro-cracks, and enable the brick to maintain structural integrity under repeated thermal cycling and iron water scouring conditions, thereby significantly reducing the risk of iron infiltration and brick falling, and greatly extending the service life of the aluminum silicon carbide carbon brick.

[0026] 3, Rare earth oxides refine silicon carbide whiskers, promote silicon carbide grain growth, improve thermal shock performance. The samarium oxide in the rare earth oxide can assist sintering, promote structure densification, improve high temperature mechanical properties, dysprosium oxide as a stabilizer can inhibit the crystal transformation at high temperature, reduce the risk of cracking caused by volume change, after the premixing of the rare earth oxide and the modified phenolic resin, the rare earth oxide can effectively fill the pores left after the high temperature carbonization of the modified phenolic resin, form a skeleton structure with high strength, form a strong bonding interface with other aggregates, improve the overall density and structural integrity of the brick body, in addition, the modified agent prepared by the hydrolyzate of dimethyldimethoxysilane and molybdenum sulfide makes the obtained modified phenolic resin have high residual carbon rate and high compatibility, which can improve the dispersion performance of the rare earth oxide after premixing, reduce the porosity, and the introduction of molybdenum sulfide can improve the erosion resistance of the brick body, so that the rare earth oxide obtains a certain sliding ability, forms a dense structure system that can freely expand and deform, realizes the volume compensation of high and low temperature changes, avoids the generation of microcracks and loose layers, therefore, the combination of modified phenolic resin and rare earth oxide can produce a synergistic effect, realize the significant improvement of the thermal shock performance and erosion resistance of aluminum silicon carbide carbon brick. BRIEF DESCRIPTION OF DRAWINGS

[0027] Figure 1 The actual photo of the micro-expansion aluminum silicon carbide carbon brick prepared in Example 1 of the present application after thermal shock resistance test for 5 times;

[0028] Figure 2 The actual photo of the micro-expansion aluminum silicon carbide carbon brick prepared in Comparative Example 1 of the present application after thermal shock resistance test for 5 times;

[0029] Figure 3 The actual photo of the micro-expansion aluminum silicon carbide carbon brick prepared in Comparative Example 2 of the present application after thermal shock resistance test for 5 times;

[0030] Figure 4 The actual photo of the micro-expansion aluminum silicon carbide carbon brick prepared in Comparative Example 3 of the present application after thermal shock resistance test for 5 times;

[0031] Figure 5 The actual photo of the micro-expansion aluminum silicon carbide carbon brick prepared in Comparative Example 4 of the present application after thermal shock resistance test for 5 times. DETAILED DESCRIPTION

[0032] Example 1

[0033] A micro-expanded silicon carbide aluminum carbon brick is prepared from the following raw materials by weight: 30 parts high-alumina bauxite (20 parts of granules with a particle size greater than or equal to 3 mm and less than or equal to 5 mm and 10 parts of fine powder with a particle size greater than or equal to 1 mm and less than 3 mm), 40 parts brown corundum (3 parts of granules with a particle size greater than or equal to 3 mm and less than or equal to 5 mm and 17 parts of granules with a particle size greater than or equal to 1 mm and less than 3 mm, 7 parts of fine powder with a particle size greater than or equal to 0.074 mm and less than 1 mm and 13 parts of fine powder with a particle size less than 0.074 mm), and 10 parts fused alumina-magnesium spinel (6 parts of granules with a particle size greater than or equal to 0.074 mm and less than 1 mm and 4 parts of fine powder with a particle size less than 0.074 mm; the alumina and oxide in the alumina-magnesium spinel are... The micro-expanded aluminum silicon carbide carbon brick is prepared by the following steps: (1 part magnesium content greater than 90 wt%), 8 parts flake graphite, 9 parts silicon carbide (6 parts granular material with a particle size greater than or equal to 0.074 mm and less than 1 mm, and 3 parts fine powder with a particle size less than 0.074 mm), 3 parts fused magnesia (particle size less than 0.074 mm, with a magnesium oxide content greater than 97 wt%), 4.5 parts binder, and 2.5 parts composite antioxidant (a mixture of metallic silicon powder and aluminum powder in a mass ratio of 2:1, passed through a 100-mesh sieve). The binder is prepared by premixing modified phenolic resin and rare earth oxides in a mass ratio of 2:1. The rare earth oxides are a mixture of samarium oxide and dysprosium oxide in a mass ratio of 100:0.5, and the particle size of the rare earth oxides is less than or equal to 0.074 mm.

[0034] S1: Prepare the raw materials according to the ratio. Mix the granular materials of high-alumina bauxite, brown fused alumina, aluminum-magnesium spinel and silicon carbide for 3 minutes to obtain mixed dry material A, which is set aside. Mix the fine powder materials of high-alumina bauxite, brown fused alumina, aluminum-magnesium spinel and silicon carbide for 2 minutes, then add fused magnesia and composite antioxidant and mix for 2 minutes to obtain mixed dry material B.

[0035] S2: Add binder to dry mixture A and wet mix for 3 minutes, then add flake graphite and mix for 5 minutes, then add dry mixture B and mix in a mixing mill for 20 minutes to obtain the mixture. Let it rest for 6 hours.

[0036] S3: The mixture is molded in a mold to form a blank. The molding pressure is 350MPa and the molding temperature is 25℃.

[0037] S4: Dry the green body in a drying tunnel kiln at a temperature of 180℃ for 24 hours. After drying, micro-expanded silicon carbide aluminum bricks are obtained.

[0038] The modified phenolic resin is prepared by the following steps:

[0039] A1. Mix dimethyldimethoxysilane with water, adjust the pH to 2-3, heat to 35°C, stir for 30 minutes, add 3-6 μm molybdenum sulfide, wherein the mass ratio of dimethyldimethoxysilane, water and molybdenum sulfide is 1:2:5, heat to 55°C, stir for 45 minutes to obtain the modified solution;

[0040] A2. Add a mixture of phenolic resin and tetrahydrofuran in a mass ratio of 1:1 to the modified liquid. The phenolic resin is 5320H phenolic resin for refractory materials (purchased from Weilin New Material Technology Co., Ltd.). The mass ratio of phenolic resin to molybdenum sulfide in step A1 is 100:5. Stir for 2 hours to obtain modified phenolic resin.

[0041] Example 2

[0042] A micro-expanded silicon carbide aluminum carbon brick is prepared from the following raw materials by weight: 25 parts high-alumina bauxite (18 parts of granules with a particle size greater than or equal to 3 mm and less than or equal to 5 mm and 7 parts of fine powder with a particle size greater than or equal to 1 mm and less than 3 mm), 31 parts brown corundum (2 parts of granules with a particle size greater than or equal to 3 mm and less than or equal to 5 mm and 14 parts of granules with a particle size greater than or equal to 1 mm and less than 3 mm, 5 parts of fine powder with a particle size greater than or equal to 0.074 mm and less than 1 mm and 10 parts of fine powder with a particle size less than 0.074 mm), and 8 parts fused alumina-magnesium spinel (5 parts of granules with a particle size greater than or equal to 0.074 mm and less than 1 mm and 3 parts of fine powder with a particle size less than 0.074 mm; the alumina and magnesium oxide in the alumina-magnesium spinel are... The micro-expanded aluminum silicon carbide carbon brick is prepared by the following steps: (The total content is greater than 90 wt%), 6 parts of flake graphite, 6 parts of silicon carbide (4 parts of granular material with a particle size greater than or equal to 0.074 mm and less than 1 mm and 2 parts of fine powder with a particle size less than 0.074 mm), 2 parts of fused magnesia (particle size less than 0.074 mm, with a magnesium oxide content greater than 97 wt%), 4 parts of binder, and 2 parts of composite antioxidant (a mixture of metallic silicon powder and aluminum powder in a mass ratio of 1.5:1, passed through a 100-mesh sieve); the binder is obtained by premixing modified phenolic resin and rare earth oxides in a mass ratio of 1:0.4, the rare earth oxides being a mixture of samarium oxide and dysprosium oxide in a mass ratio of 100:0.4, and the particle size of the rare earth oxides being less than or equal to 0.074 mm;

[0043] S1: Prepare the raw materials according to the ratio. Mix the granular materials of high-alumina bauxite, brown fused alumina, aluminum-magnesium spinel and silicon carbide for 3 minutes to obtain mixed dry material A, which is set aside. Mix the fine powder materials of high-alumina bauxite, brown fused alumina, aluminum-magnesium spinel and silicon carbide for 2 minutes, then add fused magnesia and composite antioxidant and mix for 2 minutes to obtain mixed dry material B.

[0044] S2: Add binder to dry mixture A and wet mix for 3 minutes, then add flake graphite and mix for 5 minutes, then add dry mixture B and mix in a mixing mill for 20 minutes to obtain the mixture. Let it rest for 6 hours.

[0045] S3: The mixture is molded in a mold to form a blank. The molding pressure is 350MPa and the molding temperature is 25℃.

[0046] S4: Dry the green body in a drying tunnel kiln at a temperature of 180℃ for 24 hours. After drying, micro-expanded silicon carbide aluminum bricks are obtained.

[0047] The modified phenolic resin is prepared by the following steps:

[0048] A1. Mix dimethyldimethoxysilane with water, adjust the pH to 2-3, heat to 30°C, stir for 40 minutes, add 3-6 μm molybdenum sulfide, wherein the mass ratio of dimethyldimethoxysilane, water and molybdenum sulfide is 1:1.8:4, heat to 50°C, stir for 60 minutes to obtain the modified solution;

[0049] A2. Add a mixture of phenolic resin and tetrahydrofuran in a mass ratio of 1:1 to the modified liquid. The phenolic resin is 5320H phenolic resin for refractory materials (purchased from Weilin New Material Technology Co., Ltd.). The mass ratio of phenolic resin to molybdenum sulfide in step A1 is 100:4. Stir for 2.5 hours to obtain modified phenolic resin.

[0050] Example 3

[0051] A micro-expanded silicon carbide aluminum carbon brick is prepared from the following raw materials by weight: 35 parts of high-alumina bauxite (22 parts of granules with a particle size greater than or equal to 3 mm and less than or equal to 5 mm and 13 parts of fine powder with a particle size greater than or equal to 1 mm and less than 3 mm), 49 parts of brown corundum (4 parts of granules with a particle size greater than or equal to 3 mm and less than or equal to 5 mm and 20 parts of granules with a particle size greater than or equal to 1 mm and less than 3 mm, 9 parts of fine powder with a particle size greater than or equal to 0.074 mm and less than 1 mm and 16 parts of fine powder with a particle size less than 0.074 mm), and 12 parts of fused alumina-magnesium spinel (7 parts of granules with a particle size greater than or equal to 0.074 mm and less than 1 mm and 5 parts of fine powder with a particle size less than 0.074 mm; the alumina and magnesium oxide in the alumina-magnesium spinel are... The micro-expanded aluminum silicon carbide carbon brick is prepared by the following steps: (The total content is greater than 90 wt%), 10 parts of flake graphite, 12 parts of silicon carbide (8 parts of granular material with a particle size greater than or equal to 0.074 mm and less than 1 mm and 4 parts of fine powder with a particle size less than 0.074 mm), 4 parts of fused magnesia (particle size less than 0.074 mm, with a magnesium oxide content greater than 97 wt%), 5 parts of binder, and 3 parts of composite antioxidant (a mixture of metallic silicon powder and aluminum powder in a mass ratio of 2.5:1, passed through a 100-mesh sieve); the binder is obtained by premixing modified phenolic resin and rare earth oxides in a mass ratio of 1:0.6, the rare earth oxides being a mixture of samarium oxide and dysprosium oxide in a mass ratio of 100:0.6, and the particle size of the rare earth oxides being less than or equal to 0.074 mm;

[0052] S1: Prepare the raw materials according to the ratio. Mix the granular materials of high-alumina bauxite, brown fused alumina, aluminum-magnesium spinel and silicon carbide for 3 minutes to obtain mixed dry material A, which is set aside. Mix the fine powder materials of high-alumina bauxite, brown fused alumina, aluminum-magnesium spinel and silicon carbide for 2 minutes, then add fused magnesia and composite antioxidant and mix for 2 minutes to obtain mixed dry material B.

[0053] S2: Add binder to dry mixture A and wet mix for 3 minutes, then add flake graphite and mix for 5 minutes, then add dry mixture B and mix in a mixing mill for 20 minutes to obtain the mixture. Let it rest for 6 hours.

[0054] S3: The mixture is molded in a mold to form a blank. The molding pressure is 350MPa and the molding temperature is 25℃.

[0055] S4: Dry the green body in a drying tunnel kiln at a temperature of 180℃ for 24 hours. After drying, micro-expanded silicon carbide aluminum bricks are obtained.

[0056] The modified phenolic resin is prepared by the following steps:

[0057] A1. Mix dimethyldimethoxysilane with water, adjust the pH to 2-3, heat to 40℃, stir for 20 minutes, add 3-6 μm molybdenum sulfide, wherein the mass ratio of dimethyldimethoxysilane, water and molybdenum sulfide is 1:2.2:6, heat to 60℃, stir for 30 minutes to obtain the modified solution;

[0058] A2. Add a mixture of phenolic resin and tetrahydrofuran in a mass ratio of 1:1 to the modified liquid. The phenolic resin is 5320H phenolic resin for refractory materials (purchased from Weilin New Material Technology Co., Ltd.). The mass ratio of phenolic resin to molybdenum sulfide in step A1 is 100:6. Stir for 1.5 hours to obtain modified phenolic resin.

[0059] Comparative Example 1

[0060] The only difference between this comparative example and Example 1 is that no rare earth oxides were added in the preparation of the binder; that is, the binder is a modified phenolic resin.

[0061] Comparative Example 2

[0062] The only difference between this comparative example and Example 1 is that the phenolic resin was not modified in the preparation of the binder; that is, the modified phenolic resin was replaced with ordinary phenolic resin. Specifically, the binder was prepared by premixing phenolic resin and rare earth oxides in a mass ratio of 2:1. The phenolic resin was refractory-specific phenolic resin 5320H (purchased from Weilin New Material Technology Co., Ltd.), and the rare earth oxides were a mixture of samarium oxide and dysprosium oxide in a mass ratio of 100:0.5.

[0063] Comparative Example 3

[0064] The only difference between this comparative example and Example 1 is that the modified phenolic resin and rare earth oxides were not premixed in the preparation of the binder, as detailed below:

[0065] A micro-expanded silicon carbide aluminum carbon brick, by weight, is prepared from the following raw materials: 30 parts high-alumina bauxite (20 parts of granules with a particle size greater than or equal to 3 mm and less than or equal to 5 mm, and 10 parts of fine powder with a particle size greater than or equal to 1 mm and less than 3 mm), 40 parts brown corundum (3 parts of granules with a particle size greater than or equal to 3 mm and less than or equal to 5 mm, and 17 parts of granules with a particle size greater than or equal to 1 mm and less than 3 mm, 7 parts of fine powder with a particle size greater than or equal to 0.074 mm and less than 1 mm, and 13 parts of fine powder with a particle size less than 0.074 mm), and 10 parts fused alumina-magnesia spinel (6 parts of granules with a particle size greater than or equal to 0.074 mm and less than 1 mm, and 13 parts of fine powder with a particle size less than 0.074 mm). The following are the ingredients and preparation steps: 4 parts fine powder of 74mm; 8 parts flake graphite, 9 parts silicon carbide (6 parts granules with a particle size greater than or equal to 0.074mm and less than 1mm and 3 parts fine powder with a particle size less than 0.074mm); 3 parts fused magnesia (particle size less than 0.074mm, with a magnesium oxide content greater than or equal to 97wt%); 3 parts modified phenolic resin; 1.5 parts rare earth oxides; and 2.5 parts composite antioxidant (a mixture of metallic silicon powder and aluminum powder in a mass ratio of 2:1, sieved through a 100-mesh sieve); the rare earth oxides are a mixture of samarium oxide and dysprosium oxide in a mass ratio of 100:0.5;

[0066] S1: Prepare the raw materials according to the ratio. Mix the granular materials of high-alumina bauxite, brown fused alumina, aluminum-magnesium spinel and silicon carbide for 3 minutes to obtain mixed dry material A, which is set aside. Mix the fine powder materials of high-alumina bauxite, brown fused alumina, aluminum-magnesium spinel and silicon carbide for 2 minutes, then add rare earth oxides, fused magnesia and composite antioxidant and mix for 2 minutes to obtain mixed dry material B.

[0067] S2: Add modified phenolic resin to the dry mixture A and wet mix for 3 minutes, then add flake graphite and mix for 5 minutes, then add the dry mixture B and mix in a mixing mill for 20 minutes to obtain the mixture. Let it stand for 6 hours.

[0068] S3: The mixture is molded in a mold to form a blank. The molding pressure is 350MPa and the molding temperature is 25℃.

[0069] S4: Dry the green body in a drying tunnel kiln at a temperature of 180℃ for 24 hours. After drying, micro-expanded silicon carbide aluminum bricks are obtained.

[0070] The modified phenolic resin is prepared by the following steps:

[0071] A1. Mix dimethyldimethoxysilane with water, adjust the pH to 2-3, heat to 35°C, stir for 30 minutes, add 3-6 μm molybdenum sulfide, wherein the mass ratio of dimethyldimethoxysilane, water and molybdenum sulfide is 1:2:5, heat to 55°C, stir for 45 minutes to obtain the modified solution;

[0072] A2. Add a mixture of phenolic resin and tetrahydrofuran in a mass ratio of 1:1 to the modified liquid. The phenolic resin is 5320H phenolic resin for refractory materials (purchased from Weilin New Material Technology Co., Ltd.). The mass ratio of phenolic resin to molybdenum sulfide in step A1 is 100:5. Stir for 2 hours to obtain modified phenolic resin.

[0073] Comparative Example 4

[0074] The only difference between this comparative example and Example 1 is that rare earth oxides were not added in the preparation of the binder, and the phenolic resin was not modified. That is, the binder is refractory-specific phenolic resin 5320H (purchased from Weilin New Material Technology Co., Ltd.).

[0075] Proof of effectiveness

[0076] Table 1 shows the performance comparison results of the micro-expansion silicon carbide aluminum carbide bricks prepared in Examples 1-3 and Comparative Examples 1-4 when used as molten iron ladle bricks:

[0077] Table 1

[0078]

[0079] Results Analysis

[0080] Analysis of Examples 1-3 and Comparative Examples 1-4, and in conjunction with the data in Table 1, shows that the micro-expansion aluminum silicon carbide carbon bricks (Examples 1-3) provided by the present invention have a high-temperature flexural strength of over 9.3 MPa and a compressive strength of over 33.1 MPa after 5 thermal shocks, which are significantly higher than those of Comparative Examples 1-4. At the same time, comprehensive analysis of Examples 1, Comparative Examples 1, 2, and 4 shows that the modified phenolic resin and rare earth oxides can produce a synergistic effect after premixing, which can significantly improve the high-temperature flexural strength and the compressive strength after 5 thermal shocks.

[0081] Obviously, the above embodiments are merely illustrative examples for clear explanation and are not intended to limit the implementation. Those skilled in the art will recognize that other variations or modifications can be made based on the above description. It is neither necessary nor possible to exhaustively list all possible implementations here. However, obvious variations or modifications derived therefrom are still within the scope of protection of the claims of this patent application.

Claims

1. A micro-expansion aluminum silicon carbide carbon brick, characterized in that, The product is prepared by weight from the following components: 25-35 parts high-alumina bauxite, 31-49 parts brown corundum, 8-12 parts aluminum-magnesium spinel, 6-10 parts flake graphite, 6-12 parts silicon carbide, 2-4 parts fused magnesia, 4-5 parts binder, and 2-3 parts composite antioxidant. The high-alumina bauxite, brown corundum, aluminum-magnesium spinel, and silicon carbide all contain both granular and fine powder materials. The binder is obtained by premixing modified phenolic resin and rare earth oxides at a mass ratio of 1:0.4-0.

6. The modified phenolic resin is prepared by modifying phenolic resin with molybdenum sulfide.

2. The micro-expansion silicon carbide aluminum brick according to claim 1, characterized in that, The modified phenolic resin is prepared by the following steps: A1. Mix dimethyldimethoxysilane with water, adjust the pH to 2-3, heat to 30-40℃, stir for 20-40 minutes, add molybdenum sulfide, heat to 50-60℃, stir for 30-60 minutes to obtain the modified solution; A2. Add a mixture of phenolic resin and tetrahydrofuran to the modified solution and stir for 1.5 to 2.5 hours to obtain modified phenolic resin.

3. The micro-expansion silicon carbide aluminum brick according to claim 2, characterized in that, In step A2, the mass ratio of phenolic resin to molybdenum sulfide in step A1 is 100:4-6.

4. The micro-expansion silicon carbide aluminum brick according to claim 2, characterized in that, In step A1, the mass ratio of dimethyldimethoxysilane, water, and molybdenum sulfide is 1:1.8–2.2:4–6.

5. The micro-expansion silicon carbide aluminum brick according to claim 1, characterized in that, The rare earth oxide is a mixture of samarium oxide and dysprosium oxide in a mass ratio of 100:0.4 to 0.

6.

6. The micro-expansion silicon carbide aluminum brick according to claim 1, characterized in that, The granular material in brown fused alumina includes 2-4 parts of particles with a particle size greater than or equal to 3 mm and less than or equal to 5 mm, and 14-20 parts of particles with a particle size greater than or equal to 1 mm and less than 3 mm. The fine powder material in brown fused alumina includes 5-9 parts of fine powder with a particle size greater than or equal to 0.074 mm and less than 1 mm, and 10-16 parts of fine powder with a particle size less than 0.074 mm.

7. The micro-expansion silicon carbide aluminum brick according to claim 1, characterized in that, Aluminum-magnesium spinel is one or a mixture of two types of fused aluminum-magnesium spinel and sintered aluminum-magnesium spinel; aluminum-magnesium spinel includes 5 to 7 parts of granular material with a particle size greater than or equal to 0.074 mm and less than 1 mm and 3 to 5 parts of fine powder with a particle size less than 0.074 mm; the sum of alumina and magnesium oxide in aluminum-magnesium spinel is greater than or equal to 90 wt%.

8. The micro-expansion silicon carbide aluminum brick according to claim 1, characterized in that, The particle size of fused magnesia is less than 0.074 mm, and the magnesium oxide content in fused magnesia is greater than or equal to 97 wt%.

9. The micro-expansion silicon carbide aluminum brick according to claim 1, characterized in that, The composite antioxidant is a mixture of silicon powder and aluminum powder in a mass ratio of 1.5 to 2.5:

1.

10. A method for preparing micro-expanded silicon carbide aluminum carbon bricks, used to prepare the micro-expanded silicon carbide aluminum carbon bricks according to any one of claims 1 to 9, characterized in that, Includes the following: S1: Prepare raw materials according to the ratio. Mix the granular materials of high-alumina bauxite, brown fused alumina, aluminum-magnesium spinel and silicon carbide to obtain mixed dry material A, which is set aside. Mix the fine powder materials of high-alumina bauxite, brown fused alumina, aluminum-magnesium spinel and silicon carbide, and then add fused magnesia and composite antioxidant to mix to obtain mixed dry material B. S2: Add binder to dry mixture A and wet mix, then add flake graphite and mix, then add dry mixture B and mix in a mixing mill to obtain a mixture. S3: The mixture is shaped in a mold to form a blank; S4: Dry the green body to obtain the micro-expanded silicon carbide aluminum carbon brick.

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