Alumina-silicon carbide carbon brick resistant to slag erosion and its preparation method

Abstract

The application relates to the technical field of aluminum silicon carbide carbon bricks, and particularly discloses a slag-erosion-resistant aluminum silicon carbide carbon brick and a preparation method thereof; the slag-erosion-resistant aluminum silicon carbide carbon brick comprises the following raw materials: 60-80 parts of high-alumina bauxite, 15-20 parts of silicon carbide, 2-8 parts of boron nitride, 1-4 parts of mesoporous silicon dioxide, 3-6 parts of a binder and 1-2 parts of a lubricating dispersant; the preparation method is as follows: the high-alumina bauxite and the silicon carbide are uniformly mixed, the boron nitride and the mesoporous silicon dioxide are uniformly stirred to obtain a mixture; the binder and the lubricating dispersant are uniformly mixed to obtain a mixed solution, the mixed solution is added into the mixture, and the mixture is uniformly mixed; after temperature rising, pressure forming, baking and drying, a finished carbon brick is obtained; the carbon brick has good slag-erosion resistance and high-temperature resistance; under the condition of cyclic high temperature and low temperature, the brick body is not easily eroded by molten slag, the cracking and peeling problems of the brick body are prevented, and the service life of the lining brick body in a ladle is prolonged.

Description

Technical Field

[0001] This application relates to the field of aluminum silicon carbide carbon brick technology, and more specifically, it relates to an aluminum silicon carbide carbon brick resistant to slag erosion and a method for preparing the same. Background Technology

[0002] A ladle is a casting device used in foundry workshops. It receives molten iron in front of the furnace and is then transported by a crane to the mold for casting.

[0003] Alumina silicon carbide bricks are mainly used for the lining of molten iron ladles. Alumina silicon carbide bricks are a type of non-fired product formed at high temperatures. During the transfer of molten iron ladles, after a long period of use, the bricks of the lining are easily corroded by molten iron. Furthermore, under the conditions of rapid high and low temperature conversion, thermal shock damage is likely to occur. Combined with the erosion of molten slag, the bricks are prone to cracking and peeling.

[0004] Therefore, the question is how to prepare a new type of aluminum silicon carbide brick that has good slag erosion resistance and high temperature resistance, so that the brick is not easily eroded by molten slag under cyclic high and low temperature conditions, prevents the brick from cracking and peeling, and extends the service life of the lining brick of the molten iron ladle. Summary of the Invention

[0005] In order to prepare a new type of aluminum silicon carbide carbon brick with good slag erosion resistance and high temperature resistance, so that the brick is not easily eroded by molten slag under cyclic high temperature and low temperature conditions, preventing cracking and peeling of the brick and extending the service life of the lining brick of the molten iron ladle, this application provides an aluminum silicon carbide carbon brick resistant to slag erosion and its preparation method.

[0006] In a first aspect, this application provides an aluminum silicon carbide carbon brick resistant to slag erosion, employing the following technical solution:

[0007] A silicon carbide aluminum carbide carbon brick resistant to slag erosion, the silicon carbide aluminum carbide carbon brick comprising the following raw materials in parts by weight: 60-80 parts of high alumina vanadium clay, 15-20 parts of silicon carbide, 2-8 parts of boron nitride, 1-4 parts of mesoporous silica, 3-6 parts of binder, and 1-2 parts of lubricating dispersant.

[0008] By adopting the above technical solution, the combination of high-alumina vanadium oxide and silicon carbide gives the finished carbon bricks high strength, good high-temperature resistance, and slag erosion resistance. Under high-temperature conditions, even if there is some expansion inside the carbon brick, the partial flexibility of boron nitride and mesoporous silica buffers the thermal expansion and contraction, thus minimizing the occurrence of thermal shock cracking. At the same time, the lubricating effect of boron nitride and lubricating dispersants minimizes the adhesion of iron slag and other substances to the surface of the carbon brick, thereby minimizing the entry of iron slag into the interior of the carbon brick and affecting its structural density, further ensuring the carbon brick's resistance to slag erosion. Even under cyclic high and low temperature conditions, the brick body is not easily eroded by molten slag, preventing cracking and spalling, and extending the service life of the lining bricks of the molten iron ladle.

[0009] Preferably, the boron nitride is made of porous boron nitride, polyvinyl alcohol solution and alumina fiber in a mass ratio of 1:0.05-0.1:0.1-0.2.

[0010] By adopting the above technical solution, porous boron nitride, polyvinyl alcohol solution, and alumina fiber are combined. The bonding effect of polyvinyl alcohol solution facilitates the adhesion of alumina fiber to the surface of porous boron nitride. The flexibility of alumina fiber further enhances the flexibility of boron nitride. During thermal shock, it can buffer the impact force, thereby minimizing the cracking of carbon bricks. Furthermore, alumina fiber and porous boron nitride have good heat resistance, making it less prone to cracking and peeling of carbon bricks under high temperature and low temperature cycling conditions. This ensures the strength of carbon bricks while preventing iron slag from entering the interior of the carbon bricks, improving the carbon bricks' resistance to slag erosion and extending their service life.

[0011] At high temperatures, porous boron nitride exhibits micro-expansion properties, which not only fills the micropores inside carbon bricks, increasing structural density, preventing iron slag infiltration, and improving slag erosion resistance, but also utilizes the porosity of porous boron nitride to easily adsorb gaseous substances produced by the thermal decomposition of substances such as polyvinyl alcohol at high temperatures. This reduces the impact of gases on the internal density of carbon bricks, thereby ensuring the strength of carbon bricks while improving their slag erosion resistance and extending their service life.

[0012] Preferably, the porous boron nitride has an average particle size of 20-30 μm and the alumina fiber has an average length of 30-40 μm.

[0013] By adopting the above technical solution, the particle size of porous boron nitride and the length of alumina fibers are limited, so that alumina fibers are wrapped and distributed on the surface of porous boron nitride. When subjected to thermal shock, the thermal conductivity of alumina fibers along their length direction, combined with the thermal conductivity of porous boron nitride, slows down the cooling rate after high temperature. Combined with the flexibility of alumina fibers, this further prevents carbon bricks from cracking, peeling and other problems.

[0014] Preferably, the mesoporous silica is made of mesoporous silica particles, triethylenetetramine solution and graphite powder in a mass ratio of 1:0.01-0.05:0.05-0.1.

[0015] By adopting the above technical solution, mesoporous silica particles, triethylenetetramine solution, and graphite powder are combined. The bonding effect of triethylenetetramine solution facilitates the adhesion of graphite powder to the surface of mesoporous silica particles. The high strength of mesoporous silica increases the strength of carbon bricks, while the flexibility of graphite powder buffers impact forces. Simultaneously, its lubricating effect resists the adhesion of iron slag to the inner wall of carbon bricks. Thus, under conditions of high density and surface lubrication, the carbon bricks' resistance to slag erosion is improved.

[0016] Preferably, the average particle size of the mesoporous silica particles is 10-25 μm, and the average particle size of the graphite powder is 1-3 μm.

[0017] By adopting the above technical solution, the particle size of mesoporous silica particles and the average particle size of graphite powder are limited, ensuring both the graphite powder filling effect and the lubrication effect, thereby giving the carbon brick high strength and good slag erosion resistance.

[0018] Preferably, the adhesive is composed of an amino resin liquid and an organosilicon resin liquid in a mass ratio of 1:0.5-1.

[0019] By adopting the above technical solution, amino resin liquid and organosilicon resin liquid are combined. After the amino resin and organosilicon resin are thermocured, it is easy to bond high-alumina bauxite, silicon carbide, boron nitride and other substances together. In addition, during the thermocuring process of amino resin and organosilicon resin, a network structure is formed through the cross-linking reaction between molecules. The network structure is stable and not easily affected by thermal shock, which ensures the density of carbon bricks, thus giving carbon bricks high strength and good resistance to slag erosion.

[0020] The combination of amino resin liquid and organosilicon resin allows the amino resin to carbonize at high temperatures, forming carbon that fills the interior of the carbon brick, ensuring its strength and density. The silicon in the organosilicon resin has high strength, which further improves the thermal shock resistance and slag erosion resistance of the carbon brick. At high temperatures, the gases generated by the decomposition of solvents and other substances can circulate and be stored in the pores of the network structure, porous boron nitride, and mesoporous silica, minimizing the risk of gas cracking the internal structure of the carbon brick. This ensures the structural density of the carbon brick, making it difficult for iron slag to enter the internal structure, thus improving the slag erosion resistance of the carbon brick and extending its service life.

[0021] The combination of mesoporous silica and organosilicon resin in liquid phase utilizes the filling and heat insulation effects of silicon to partially block heat, thereby controlling the temperature rise of carbon bricks after contact with molten iron. Combined with the thermal conductivity of materials such as boron nitride and silicon carbide, the carbon bricks heat up and cool down slowly, thus reducing the impact of thermal shock on the structural stability of the carbon bricks. Furthermore, the reinforcing effect of silicon filling gives the carbon bricks high strength and good resistance to slag erosion, thereby extending the service life of the carbon bricks.

[0022] Preferably, the lubricating dispersant is composed of ethanol and water in a mass ratio of 1:0.5-1.

[0023] By adopting the above technical solution, ethanol and water can not only reduce the viscosity of the binder and improve the dispersion effect of the binder among substances such as high-alumina vanadium, silicon carbide, and boron nitride, but also improve the mixing uniformity between raw materials, thereby increasing the structural density of carbon bricks and giving carbon bricks advantages such as high strength, high temperature resistance, and high slag erosion resistance.

[0024] Triethylenetetramine is soluble in alcohol, while polyvinyl alcohol is soluble in water. Boron nitride, mesoporous silica, and binders, along with lubricating dispersants and high-temperature conditions, promote the cross-linking and bonding of boron nitride, mesoporous silica, and binders. This increases the density of the cross-linked network, which also provides a space for the gas generated by thermal decomposition, without affecting the strength of the carbon brick or causing it to crack. The micro-expansion effect of mesoporous silica and boron nitride, combined with the carbonization of polyvinyl alcohol and amino resins, can fill the pores generated by thermal decomposition, thus preventing cracking and peeling of the carbon brick during long-term high and low temperature use, ensuring its thermal shock resistance and extending its service life.

[0025] Secondly, this application provides a method for preparing slag-resistant silicon carbide aluminum bricks, employing the following technical solution:

[0026] A method for preparing a slag-resistant silicon carbide aluminum carbon brick includes the following steps:

[0027] S1. Weigh out high-alumina bauxite and silicon carbide, mix and stir evenly, then add boron nitride and mesoporous silica and continue stirring evenly to obtain a mixture;

[0028] S2. Weigh the binder and lubricant dispersant and mix them evenly to obtain a mixture. Add the mixture to the aggregate and mix evenly. After heating, pressing, molding, baking and drying, the finished carbon brick is obtained.

[0029] By adopting the above technical solution, the powder materials are first mixed and stirred evenly, and then the binder and lubricating dispersant are mixed evenly, so that the binder has good fluidity and can be evenly distributed in the mixture. As the temperature rises and the material is pressed into shape, the ethanol and water gradually evaporate, increasing the viscosity of the binder. Combined with the pressing process, the solvent content in the carbon brick is low, the structure is relatively compact, and it has good resistance to slag erosion. After baking, not only does the solvent evaporate, but the binder is also cured, so that the carbon brick has good structural stability and high resistance to slag erosion.

[0030] Preferably, the addition rate of the mixture in S2 is 30-60 g / min, and the stirring speed of the mixture is 200-300 r / min.

[0031] By adopting the above technical solution, the addition rate of the mixture is limited in conjunction with the stirring rate of the mixture, so that the binder is evenly dispersed in substances such as high-alumina vanadium, silicon carbide, and boron nitride. The internal structure of the carbon brick has a high density, which gives the carbon brick high strength while also providing good high-temperature resistance, slag erosion resistance, and thermal shock resistance.

[0032] Preferably, the baking temperature in S2 is 180-220℃.

[0033] By adopting the above technical solution, substances such as polyethylene glycol are also thermally decomposed, which improves the structural density while removing excess solvent substances and ensuring the carbon brick's resistance to slag erosion.

[0034] In summary, this application has the following beneficial effects:

[0035] 1. The combination of high-alumina vanadium oxide and silicon carbide gives the finished carbon bricks high strength, good high-temperature resistance, and slag erosion resistance. Under high-temperature conditions, even if there is some expansion inside the carbon brick, the partial flexibility of boron nitride and mesoporous silica buffers the thermal expansion and contraction, thus minimizing the risk of thermal shock cracking. At the same time, the lubricating effect of boron nitride and lubricating dispersants minimizes the adhesion of iron slag and other substances to the surface of the carbon brick, thereby preventing iron slag from entering the interior of the carbon brick and affecting its structural density. This further ensures the carbon brick's resistance to slag erosion. Even under cyclic high and low temperature conditions, the brick body is not easily eroded by molten slag, preventing cracking and spalling, and extending the service life of the lining bricks in the molten iron ladle.

[0036] 2. The combination of porous boron nitride, polyvinyl alcohol solution, and alumina fiber utilizes the bonding effect of the polyvinyl alcohol solution to facilitate the adhesion of alumina fiber to the surface of porous boron nitride. The flexibility of the alumina fiber further enhances the flexibility of boron nitride, which can buffer the impact force during thermal shock, thereby minimizing the cracking of carbon bricks. Furthermore, the alumina fiber and porous boron nitride have good heat resistance, making it less prone to cracking and peeling of carbon bricks under high and low temperature cycling conditions. This ensures the strength of carbon bricks while preventing iron slag from entering the interior of the carbon bricks, improving the carbon bricks' resistance to slag erosion and extending their service life.

[0037] 3. The combination of mesoporous silica particles, triethylenetetramine solution, and graphite powder utilizes the binding effect of triethylenetetramine solution to facilitate the adhesion of graphite powder to the surface of mesoporous silica particles; the high strength of mesoporous silica enhances the strength of the carbon brick, while the flexibility of graphite powder buffers impact forces. Furthermore, its lubricating effect resists the adhesion of iron slag to the inner wall of the carbon brick. Thus, the high density combined with surface lubrication improves the carbon brick's resistance to slag erosion. Detailed Implementation

[0038] The present application will be further described in detail below with reference to the embodiments.

[0039] Example of boron nitride preparation

[0040] Preparation Example 1: Boron nitride was prepared by the following method:

[0041] 0.08 kg of polyvinyl alcohol solution was uniformly sprayed onto the surface of 1 kg of porous boron nitride. The average particle size of the porous boron nitride was 25 μm, and the porosity was 15%-20%. The polyvinyl alcohol solution was a 1% (w / w) aqueous solution of polyvinyl alcohol. This yielded loaded porous boron nitride. Then, 0.15 kg of alumina fiber was added. The alumina fiber had an average length of 35 μm and an average diameter of 20 nm. The alumina fiber was added at a rate of 30 g / min. During the addition process, the loaded porous boron nitride was stirred at a speed of 120 r / min. After drying and dispersion, the finished boron nitride was obtained and passed through a 150-mesh sieve.

[0042] Preparation Example 2: The difference between this preparation example and Preparation Example 1 is that:

[0043] 0.05 kg of polyvinyl alcohol solution was uniformly sprayed onto the surface of 1 kg of porous boron nitride. The average particle size of the porous boron nitride was 20 μm, and the porosity was 15%-20%. The polyvinyl alcohol solution was a 1% (w / w) aqueous solution of polyvinyl alcohol. This yielded loaded porous boron nitride. Then, 0.1 kg of alumina fiber was added. The alumina fiber had an average length of 30 μm and an average diameter of 20 nm. The alumina fiber was added at a rate of 30 g / min. During the addition process, the loaded porous boron nitride was stirred at a speed of 120 r / min. After drying and dispersion, the finished boron nitride was obtained and passed through a 150-mesh sieve.

[0044] Preparation Example 3: The difference between this preparation example and Preparation Example 1 is that:

[0045] 0.1 kg of polyvinyl alcohol solution was uniformly sprayed onto the surface of 1 kg of porous boron nitride. The average particle size of the porous boron nitride was 30 μm, and the porosity was 15%-20%. The polyvinyl alcohol solution was a 1% (w / w) aqueous solution of polyvinyl alcohol. This yielded loaded porous boron nitride. Then, 0.2 kg of alumina fiber was added. The alumina fiber had an average length of 40 μm and an average diameter of 20 nm. The alumina fiber was added at a rate of 30 g / min. During the addition process, the loaded porous boron nitride was stirred at a speed of 120 r / min. After drying and dispersion, the finished boron nitride was obtained and passed through a 100-mesh sieve.

[0046] Preparation example of mesoporous silica

[0047] The graphite powder in the following raw materials was purchased from Beijing Gaoke New Materials Technology Co., Ltd.; other raw materials and equipment are commercially available.

[0048] Preparation Example 4: Mesoporous silica was prepared by the following method:

[0049] 0.03 kg of triethylenetetramine solution was uniformly sprayed onto the surface of 1 kg of mesoporous silica particles. The average particle size of the mesoporous silica particles was 20 μm. The triethylenetetramine solution was a 1% (w / w) triethylenetetramine ethanol solution, thus obtaining loaded mesoporous silica. Then, 0.08 kg of graphite powder with an average particle size of 2 μm was added at a rate of 60 g / min. During the addition process, the loaded mesoporous silica was stirred at a speed of 120 r / min. After drying and dispersion, the finished mesoporous silica was obtained and passed through a 200-mesh sieve.

[0050] Preparation Example 5: The difference between this preparation example and Preparation Example 4 is that:

[0051] 0.01 kg of triethylenetetramine solution was uniformly sprayed onto the surface of 1 kg of mesoporous silica particles. The average particle size of the mesoporous silica particles was 10 μm. The triethylenetetramine solution was a 1% (w / w) triethylenetetramine ethanol solution, thus obtaining loaded mesoporous silica. Then, 0.05 kg of graphite powder with an average particle size of 2 μm was added at a rate of 60 g / min. During the addition process, the loaded mesoporous silica was stirred at a speed of 120 r / min. After drying and dispersion, the finished mesoporous silica was obtained and passed through a 200-mesh sieve.

[0052] Preparation Example 6: The difference between this preparation example and Preparation Example 4 is that:

[0053] 0.05 kg of triethylenetetramine solution was uniformly sprayed onto the surface of 1 kg of mesoporous silica particles. The average particle size of the mesoporous silica particles was 20 μm. The triethylenetetramine solution was a 1% (w / w) triethylenetetramine ethanol solution, thus obtaining loaded mesoporous silica. Then, 0.1 kg of graphite powder with an average particle size of 2 μm was added at a rate of 60 g / min. During the addition process, the loaded mesoporous silica was stirred at a speed of 120 r / min. After drying and dispersion, the finished mesoporous silica was obtained and passed through a 200-mesh sieve.

[0054] Example

[0055] The amino resin liquid in the following raw materials was purchased from Jining Sanshi Biotechnology Co., Ltd., and is thermosetting; the organosilicon resin liquid was purchased from Jinan Dahui Chemical Technology Co., Ltd.; other raw materials and equipment are commercially available.

[0056] Example 1: An aluminum silicon carbide carbon brick resistant to slag erosion:

[0057] The mixture consisted of 70 kg of high-alumina vanadium oxide, 18 kg of silicon carbide, 5 kg of boron nitride, 3 kg of mesoporous silica, 5 kg of binder, and 1.5 kg of lubricant and dispersant. The high-alumina vanadium oxide was composed of fine, medium, and coarse powders in a mass ratio of 0.5:0.5:1, with the fine powder having an average particle size of 100 μm, the medium powder having an average particle size of 1 mm, and the coarse powder having an average particle size of 3 mm. The silicon carbide was composed of microparticles, medium particles, and large particles in a mass ratio of 0.2:1:0.8, with the microparticles having an average particle size of 50 μm, the medium particles having an average particle size of 200 μm, and the large particles having an average particle size of 1 mm. The boron nitride used was the boron nitride prepared in Preparation Example 1, and the mesoporous silica used was the mesoporous silica prepared in Preparation Example 4. The binder consisted of an amino resin solution and an organosilicon resin solution in a mass ratio of 1:0.5. The lubricant and dispersant consisted of ethanol and water in a mass ratio of 1:0.5, with the ethanol having a mass fraction of 75%.

[0058] The preparation method is as follows:

[0059] S1. Weigh out high-alumina bauxite and silicon carbide, mix and stir evenly, then add boron nitride and mesoporous silica and continue stirring evenly to obtain a mixture;

[0060] S2. Weigh the binder and lubricant dispersant and mix them evenly to obtain a mixture. Add the mixture to the material mixture at a rate of 40 g / min and a stirring rate of 250 r / min. After mixing evenly, a composite material is obtained. Place the composite material in a mold and press it into shape using a brick press at 80°C to form a green body. Bake the green body at 200°C for 24 hours. After drying, the finished carbon brick is obtained.

[0061] Example 2: The difference between this example and Example 1 is that:

[0062] The mixture consisted of 60 kg of high-alumina vanadium oxide, 15 kg of silicon carbide, 2 kg of boron nitride, 1 kg of mesoporous silica, 3 kg of binder, and 1 kg of lubricant / dispersant. The boron nitride used was the boron nitride prepared in Preparation Example 2, and the mesoporous silica used was the mesoporous silica prepared in Preparation Example 5. The binder was composed of an amino resin solution and an organosilicon resin solution in a mass ratio of 1:0.5. The lubricant / dispersant was composed of ethanol and water in a mass ratio of 1:0.5, with the ethanol having a mass fraction of 75%.

[0063] During the preparation process:

[0064] S2. Weigh the binder and lubricant dispersant and mix them evenly to obtain a mixture. Add the mixture to the material mixture at a rate of 30 g / min and a stirring rate of 200 r / min. After mixing evenly, a composite material is obtained. Place the composite material in a mold and press it into shape using a brick press at 80°C to form a green body. Bake the green body at 180°C for 24 hours. After drying, the finished carbon brick is obtained.

[0065] Example 3: The difference between this example and Example 1 is that:

[0066] The mixture consisted of 80 kg of high-alumina vanadium oxide, 20 kg of silicon carbide, 8 kg of boron nitride, 4 kg of mesoporous silica, 6 kg of binder, and 2 kg of lubricant and dispersant. The boron nitride used was the boron nitride prepared in Preparation Example 3, and the mesoporous silica used was the mesoporous silica prepared in Preparation Example 6. The binder was composed of an amino resin liquid and an organosilicon resin liquid in a mass ratio of 1:1. The lubricant and dispersant was composed of ethanol and water in a mass ratio of 1:1, with the ethanol having a mass fraction of 75%.

[0067] During the preparation process:

[0068] S2. Weigh the binder and lubricant dispersant and mix them evenly to obtain a mixture. Add the mixture to the material mixture at a rate of 60 g / min and a stirring rate of 300 r / min. After mixing evenly, a composite material is obtained. Place the composite material in a mold and press it into shape using a brick press at 80°C to form a green body. Bake the green body at 220°C for 24 hours. After drying, the finished carbon brick is obtained.

[0069] Example 4: The difference between this example and Example 1 is that:

[0070] No alumina fibers were added during the preparation of boron nitride.

[0071] Example 5: The difference between this example and Example 1 is that:

[0072] No graphite powder was added during the preparation of mesoporous silica.

[0073] Example 6: The difference between this example and Example 1 is that:

[0074] In the preparation of mesoporous silica, an equal mass of ethyl cellulose solution was used to replace the triethylenetetramine solution.

[0075] Example 7: The difference between this example and Example 1 is that:

[0076] No amino resin was added to the adhesive raw materials.

[0077] Example 8: The difference between this example and Example 1 is that:

[0078] The lubricating dispersant is water.

[0079] Comparative Example

[0080] Comparative Example 1: The difference between this comparative example and Example 1 is that:

[0081] The boron nitride in the raw material is commercially available boron nitride with a porosity of less than 2%.

[0082] Comparative Example 2: This comparative example differs from Example 1 in that:

[0083] The raw materials are made by replacing mesoporous silica with an equal mass of silica, resulting in a silica porosity of less than 1%.

[0084] Comparative Example 3: This comparative example differs from Example 1 in that:

[0085] No boron nitride or mesoporous silica was added to the raw materials.

[0086] Performance testing

[0087] 1. Compressive strength test

[0088] Alumina silicon carbide carbon bricks were prepared using the preparation methods of Examples 1-8 and Comparative Examples 1-3, respectively. The compressive strength was tested and the data were recorded in accordance with GB / T5027.

[0089] 2. High-temperature flexural strength test

[0090] Alumina silicon carbide carbon bricks were prepared using the preparation methods of Examples 1-8 and Comparative Examples 1-3, respectively. The high-temperature flexural strength was tested and the data were recorded in accordance with GB / T3001.

[0091] 3. Thermal shock resistance testing

[0092] Alumina silicon carbide carbon bricks were prepared using the preparation methods of Examples 1-8 and Comparative Examples 1-3, respectively. They were subjected to thermal shock five times under conditions of high temperature 1500℃ and low temperature 25℃, and then the compressive strength was tested again and the data were recorded.

[0093] 4. Density detection

[0094] Alumina silicon carbide carbon bricks were prepared using the preparation methods of Examples 1-8 and Comparative Examples 1-3, respectively. The bulk density was tested and the data were recorded in accordance with GB / T2997.

[0095] 5. Slag erosion resistance test

[0096] Aluminosilicate carbon bricks were prepared using the methods of Examples 1-8 and Comparative Examples 1-3, respectively. They were kept in molten iron at 1500℃ for 10 hours, and the erosion ratio was detected and the data was recorded. Erosion ratio = eroded area / total sample area * 100%.

[0097] Table 1 Performance Test Table

[0098]

[0099]

[0100] As can be seen from Examples 1-3 and Table 1, carbon bricks have high strength and high strength after thermal shock, indicating good thermal shock resistance. They also have high density and good erosion resistance.

[0101] Combining Examples 1 and 4-8 with Table 1, it can be seen that in Example 4, no alumina fibers were added during the boron nitride preparation process. Compared to Example 1, the compressive strength and flexural strength of Example 4 were lower than those of Example 1. The difference between the compressive strength of Example 4 and the compressive strength after thermal shock was greater than the corresponding difference in Example 1. The density was lower than that of Example 1, and the erosion ratio was greater than that of Example 1. This indicates that the combination of alumina fibers, porous boron nitride, and polyvinyl alcohol solution, utilizing the flexibility of alumina fibers, can buffer the impact force during thermal shock, thereby minimizing the cracking problem of carbon bricks. Furthermore, alumina fibers and porous boron nitride have good heat resistance, making it less likely for carbon bricks to crack or peel off under high temperature and low temperature cycling conditions. Combined with the micro-expansion property of porous boron nitride, it fills the carbon brick structure, improving the carbon brick's resistance to slag erosion while extending its service life.

[0102] In Example 5, no graphite powder was added during the preparation of mesoporous silica. Compared to Example 1, the compressive strength and flexural strength of Example 5 were lower than those of Example 1. The difference between the compressive strength of Example 5 and the compressive strength after thermal shock was greater than the corresponding difference in Example 1. The density of Example 5 was lower than that of Example 1, and the erosion ratio was greater than that of Example 1. This indicates that the combination of graphite powder and mesoporous silica particles utilizes the higher strength of mesoporous silica to improve the strength of the carbon brick. Combined with the flexibility of graphite powder, it can buffer the impact force. At the same time, its lubricating effect resists the adhesion of iron slag to the inner wall of the carbon brick. Thus, under the condition of higher density and surface lubrication, the slag erosion resistance of the carbon brick is improved.

[0103] In Example 6, during the preparation of mesoporous silica, the triethylenetetramine solution was replaced with an equal mass of ethyl cellulose solution. Compared to Example 1, the compressive strength and flexural strength of Example 6 were lower than those of Example 1. The difference between the compressive strength of Example 6 and the compressive strength after thermal shock was greater than the corresponding difference in Example 1. The density of Example 6 was lower than that of Example 1, and the erosion ratio was greater than that of Example 1. This indicates that the triethylenetetramine solution can not only promote the curing of the binder and improve the density of the carbon brick structure, but also improve the cross-linking and bonding of boron nitride, mesoporous silica, and binder, thereby further improving the strength, slag erosion resistance, and thermal shock resistance of the carbon brick, giving it a longer service life.

[0104] In Example 7, no amino resin was added to the binder raw materials. Compared with Example 1, the compressive strength and flexural strength of Example 7 were lower than those of Example 1. The difference between the compressive strength of Example 7 and the compressive strength after thermal shock was greater than the corresponding difference in Example 1. The density was lower than that of Example 1, and the erosion ratio was greater than that of Example 1. This indicates that the combination of amino resin and silicone resin has a dense cross-linked network, which improves the strength and slag erosion resistance of carbon bricks. Furthermore, under the action of high-temperature molten iron, the amino resin carbonizes to form a carbon layer, which is convenient to fill inside the carbon brick, ensuring the structural density and strength of the carbon brick. In addition, the amino resin can improve the thermal shock resistance.

[0105] In Example 8, the lubricant and dispersant was water. Compared to Example 1, the compressive strength and flexural strength of Example 8 were lower than those of Example 1. The difference between the compressive strength of Example 8 and the compressive strength after thermal shock was greater than the corresponding difference in Example 1. The density was lower than that of Example 1, and the erosion ratio was greater than that of Example 1. This indicates that ethanol and water can reduce the viscosity of the binder and improve the mixing uniformity between raw materials. Furthermore, the addition of ethanol facilitates the dissolution of triethylenetetramine. Combined with high temperature conditions, it promotes the cross-linking and bonding of boron nitride, mesoporous silica, binder, and other substances, improving the density of the cross-linked network. At the same time, the cross-linked network can also provide a space for the gas generated by thermal decomposition, but it does not easily affect the strength of the carbon brick or cause it to crack. This makes the carbon brick less prone to cracking and peeling during long-term high and low temperature use, thus extending the service life of the carbon brick.

[0106] Combining Example 1 and Comparative Examples 1-3 with Table 1, it can be seen that the boron nitride in the raw material of Comparative Example 1 is commercially available boron nitride with a porosity of less than 2%. Compared with Example 1, the compressive strength and flexural strength of Comparative Example 1 are lower than those of Example 1. The difference between the compressive strength and the compressive strength after thermal shock in Comparative Example 1 is greater than the corresponding difference in Example 1. The density is lower than that in Example 1, and the erosion ratio is greater than that in Example 1. This indicates that the presence of porous boron nitride can not only store excess gas and provide channels for gas flow, but also the micro-expansion effect under high temperature conditions can fill the internal cracks of the carbon brick, thereby ensuring the slag erosion resistance of the carbon brick, preventing the carbon brick from cracking, and extending the service life of the carbon brick.

[0107] In Comparative Example 2, the same mass of silica was used to replace mesoporous silica in the raw materials. The porosity of the silica was less than 1%. Compared with Example 1, although the compressive strength and flexural strength of Comparative Example 2 were slightly greater than those of Example 1, the difference between the compressive strength and the compressive strength after thermal shock was greater than the corresponding difference in Example 1, and the erosion rate was greater than that of Example 1. This indicates that although silica has higher strength than mesoporous silica, the degree of bonding and cross-linking between silica and other substances is worse than that of mesoporous silica. Furthermore, after thermal shock, the silica surface lacks a flexible buffer material, which easily leads to cracking of the carbon bricks, affecting the erosion resistance and post-thermal shock strength of the carbon bricks.

[0108] Comparative Example 3 did not contain boron nitride or mesoporous silica. Compared to Example 1, Comparative Example 3 had lower compressive strength and flexural strength, but the difference between its compressive strength and the compressive strength after thermal shock was greater than that of Example 1. Its density was also lower, and its erosion rate was higher. This indicates that the addition of boron nitride and mesoporous silica, combined with the flexibility of boron nitride and the porous storage effect of mesoporous silica, buffers thermal expansion and contraction, thus minimizing thermal shock cracking. Simultaneously, the lubricating effect of boron nitride and the lubricating dispersant helps prevent iron slag and other substances from adhering to the carbon brick surface, thus preventing iron slag from entering the carbon brick and affecting its structural density. This further ensures the carbon brick's resistance to slag erosion, preventing cracking and spalling even under cyclic high and low temperature conditions, extending the service life of the lining bricks in the molten iron ladle.

[0109] This specific embodiment is merely an explanation of this application and is not intended to limit it. After reading this specification, those skilled in the art can make modifications to this embodiment without contributing any inventive step, but such modifications are protected by patent law as long as they fall within the scope of the claims of this application.

Claims

1. A silicon carbide alumina brick resistant to slag erosion, characterized in that, The aluminum silicon carbide carbon brick comprises the following raw materials in parts by weight: 60-80 parts high-alumina vanadium clay, 15-20 parts silicon carbide, 2-8 parts boron nitride, 1-4 parts mesoporous silica, 3-6 parts binder, and 1-2 parts lubricant and dispersant; the boron nitride is made from porous boron nitride, polyvinyl alcohol solution, and alumina fibers in a mass ratio of 1:0.05-0.1:0.1-0.2; the mesoporous silica is made from mesoporous silica particles, triethylenetetramine solution, and graphite powder in a mass ratio of 1:0.01-0.05:0.05-0.1; and the lubricant and dispersant is composed of ethanol and water in a mass ratio of 1:0.5-1.

2. The aluminum silicon carbide carbon brick resistant to slag erosion according to claim 1, characterized in that, The porous boron nitride has an average particle size of 20-30 μm, and the alumina fibers have an average length of 30-40 μm.

3. The aluminum silicon carbide carbon brick resistant to slag erosion according to claim 1, characterized in that, The average particle size of the mesoporous silica particles is 10-25 μm, and the average particle size of the graphite powder is 1-3 μm.

4. The aluminum silicon carbide carbon brick resistant to slag erosion according to claim 1, characterized in that, The adhesive is composed of an amino resin liquid and an organosilicon resin liquid in a mass ratio of 1:0.5-1.

5. A method for preparing an aluminum silicon carbide carbon brick resistant to slag erosion according to any one of claims 1-4, characterized in that, Includes the following steps: S1. Weigh out high-alumina bauxite and silicon carbide, mix and stir evenly, then add boron nitride and mesoporous silica and continue stirring evenly to obtain a mixture; S2. Weigh the binder and lubricant dispersant and mix them evenly to obtain a mixture. Add the mixture to the aggregate and mix evenly. After heating, pressing, molding, baking and drying, the finished carbon brick is obtained.

6. The method for preparing a slag-resistant silicon carbide carbon brick according to claim 5, characterized in that, The addition rate of the mixture in S2 is 30-60 g / min, and the stirring speed of the mixture is 200-300 r / min.

7. The method for preparing a slag-resistant silicon carbide carbon brick according to claim 5, characterized in that, The baking temperature in S2 is 180-220℃.

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