Corundum brick with high erosion resistance and preparation method thereof

Abstract

The invention discloses a corundum brick with high corrosion resistance and a preparation method thereof, and belongs to the technical field of refractory materials, hollow nanosphere composite silicon nitride whiskers are added in the preparation process, hollow aminated phenolic resin nanospheres in the hollow nanosphere composite silicon nitride whiskers are provided with hollow pore channels, and in the high-temperature sintering process of the corundum brick, the hollow pore channels in the hollow nanosphere composite silicon nitride whiskers are uniformly distributed, so that the corrosion resistance of the corundum brick is improved. The resin is carbonized and decomposed to further generate uniform micropores / mesopores, so that a graded pore structure of primary pores and derived pores is formed, and the corundum brick has stable and uniform porous property, can block permeation of an erosion medium, and prolongs the service life of the corundum brick; the silicon nitride whiskers have extremely high chemical stability, the tolerance to metal slag, molten glass and acid and alkali erosion media is far higher than that of a corundum matrix, and a composite framework of the silicon nitride whiskers forms a continuous corrosion-resistant network in the corundum brick to directly block a permeation path of the erosion media.

Description

Technical Field

[0001] This invention belongs to the field of refractory materials technology, specifically high erosion-resistant corundum bricks and their preparation method. Background Technology

[0002] Corundum bricks, due to their excellent properties such as high hardness, corrosion resistance, high temperature resistance, wear resistance, and impact resistance, are widely used in the linings and kiln furniture of various high-temperature kilns, including blast furnaces, hot blast stoves, ladle refining furnaces, glass melting furnaces, and petrochemical industrial furnaces. Microporous corundum bricks are made from electrofused dense corundum and electrofused brown corundum as raw materials, with special additives and binders. They are produced using a special microporous manufacturing process, involving molding and high-temperature firing. When used as bricks for ceramic cups in blast furnaces, microporous corundum bricks require good resistance to alkali, slag, and iron erosion.

[0003] Chinese patent application CN118619691A discloses a microporous corundum brick and its preparation method. The microporous structure formed by this method comes partly from the gaps between raw material particles and partly from the pores formed by a small amount of gas generated during the carbonization of modified phenolic resin. This type of microporous structure is random and unstable, and is prone to deformation, merging or collapse under high temperature firing and thermal stress, resulting in limited thermal shock resistance. Summary of the Invention

[0004] The purpose of this invention is to provide a corundum brick with high corrosion resistance and its preparation method. By adding hollow nanospheres composite silicon nitride whiskers during the preparation process, the hollow amino-modified phenolic resin nanospheres in the hollow nanospheres composite silicon nitride whiskers have hollow channels. During the high-temperature sintering process of the corundum brick, the carbonization and decomposition of the resin will further generate uniform micropores / mesopores, forming a hierarchical pore structure of primary pores and derived pores. It has stable and uniform porous properties, which can block the penetration of corrosive media while ensuring its own strength, thus extending the service life of the corundum brick.

[0005] The objective of this invention can be achieved through the following technical solutions:

[0006] The preparation method of high corrosion-resistant corundum bricks includes the following steps:

[0007] Step 1: Using 4-aminophenol and formaldehyde as monomers, an aminophenolic resin is polymerized. Using the aminophenolic resin as a template, a three-dimensional cross-linked shell is formed by alkaline catalytic deposition. Then, the shell is dissolved by ultrasonication with ethanol to form hollow aminophenolic resin nanospheres.

[0008] Step 2: Using silicon nitride whiskers as a carrier, a silicon nitride whisker composite skeleton is obtained by low-temperature sintering of a polystyrene template and fumed silica as a reinforcing phase.

[0009] Step 3: A functionalized silicon nitride whisker composite framework is obtained by treating the silicon nitride whisker composite framework with 3-glycidyl etheroxypropyltrimethoxysilane; then, hollow nanosphere composite silicon nitride whiskers are prepared by catalyzing the ring-opening of the epoxy groups on the surface of the functionalized silicon nitride whisker composite framework with hollow amino phenolic resin nanospheres.

[0010] Step 4: Mix alumina, sodium carbonate, strontium carbonate, quartz sand, hollow nanosphere composite silicon nitride whiskers and epoxy resin for 10-12 minutes to obtain a mixture; then heat the mixture to 2100-2200℃ in a three-phase electric arc furnace to melt it, pour it into a mold, anneal and cool it to obtain a corundum brick with high corrosion resistance.

[0011] Furthermore, the mass ratio of alumina, sodium carbonate, strontium carbonate, quartz sand, hollow nanosphere composite silicon nitride whiskers, and epoxy resin is 95-96:1-2:0.5-1:0.5-1:3-4:2-3.

[0012] Furthermore, the specific preparation steps of the amino-modified phenolic resin are as follows:

[0013] Deionized water and 4-aminophenol were added to a reaction vessel and stirred at 12-15℃ and 500-600 r / min for 10-12 min. Then, formaldehyde solution was added and stirring was continued for 10-12 min. Ammonia water with a concentration of 2.6-2.8 mmol / L was added, and the mixture was heated to 28-30℃ and stirred for 30-40 min. The mixture was then filtered under reduced pressure, and the product was washed 2-4 times with deionized water and freeze-dried at -20℃ for 12-14 h to obtain aminophenolic resin.

[0014] Furthermore, the ratio of deionized water, 4-aminophenol, formaldehyde solution, and ammonia is 42-50L: 160-180g: 100-120mL: 19.5-20mL.

[0015] Furthermore, the specific preparation steps of the hollow amino-modified phenolic resin nanospheres are as follows:

[0016] Aminated phenolic resin and anhydrous ethanol were added to a reaction vessel and stirred at 28-30℃ and 500-600 r / min for 10-12 min. The mixture was then ultrasonically dispersed for 40-60 min, filtered under reduced pressure, and the product was washed 2-4 times with deionized water and freeze-dried at -20℃ for 12-14 h to obtain hollow aminated phenolic resin nanospheres.

[0017] Furthermore, the ratio of amino-modified phenolic resin to anhydrous ethanol is 72-80g:8-10L.

[0018] Furthermore, the specific preparation steps of the silicon nitride whisker composite framework are as follows:

[0019] The composite silicon nitride whisker suspension, γ-aminopropyltriethoxysilane, ethanol, and deionized water were stirred and mixed for 5-7 min, filtered, and the filter cake was washed 2-4 times with deionized water. It was then vacuum dried at 60-70℃ for 1-2 h, heated to 120-130℃ and dried for another 5-7 h. The product was then transferred to a muffle furnace and heated to 220-240℃ at a heating rate of 1-2℃ / min, held for 20-30 min, and then heated to 450-500℃ at a rate of 10-12℃ / min, held for 20-30 min to obtain the silicon nitride whisker composite framework.

[0020] Furthermore, the ratio of the composite silicon nitride whisker suspension, γ-aminopropyltriethoxysilane, ethanol, and deionized water is 100-120 mL: 5-6 mL: 50-60 mL: 20-25 mL.

[0021] Furthermore, the specific preparation steps of the composite silicon nitride whisker suspension are as follows:

[0022] Silicon nitride whiskers and ethanol were added to a reaction vessel and stirred at 28-30℃ and 500-600 r / min for 10-12 min. The mixture was then ultrasonically dispersed for 30-40 min. Polystyrene microspheres and fumed silica were then added and ultrasonically dispersed for 30-40 min. After vacuum filtration, a composite silicon nitride whisker suspension was obtained.

[0023] Furthermore, the ratio of silicon nitride whiskers, ethanol, polystyrene microspheres, and fumed silica is 10-12g: 500-600mL: 3-5g: 0.05-0.07g.

[0024] Furthermore, the specific preparation steps of the functionalized silicon nitride whisker composite framework are as follows:

[0025] Add silicon nitride whisker composite framework, anhydrous ethanol and deionized water to a reaction vessel, stir for 15-20 min at 50-55℃ and 500-600 r / min, then add 3-glycidoxypropyltrimethoxysilane, adjust the pH to 3-4 with hydrochloric acid solution, continue stirring for 6-8 h, filter, wash the precipitate 2-4 times with deionized water and anhydrous ethanol, and vacuum dry at 60-70℃ for 1-2 h to obtain functionalized silicon nitride whisker composite framework.

[0026] Furthermore, the ratio of silicon nitride whisker composite framework, anhydrous ethanol, deionized water and 3-glycidyl etheroxypropyltrimethoxysilane is 20-30g: 800-900mL: 250-300mL: 5-8mL.

[0027] Furthermore, the specific preparation steps of hollow nanospheres composite silicon nitride whiskers are as follows:

[0028] Functionalized silicon nitride whisker composite framework, hollow amino-modified phenolic resin nanospheres and deionized water were added to a reaction vessel and stirred for 20-30 min at 50-60℃ and 500-600 r / min. Then, under a nitrogen atmosphere, stirring was continued for 2-4 h. After filtration, the precipitate was washed 2-4 times with deionized water and anhydrous ethanol and dried under vacuum at 60-70℃ for 1-2 h to obtain hollow nanosphere composite silicon nitride whiskers.

[0029] Furthermore, the ratio of functionalized silicon nitride whisker composite framework, hollow amino-modified phenolic resin nanospheres, and deionized water is 5-6g: 50-80g: 500-600mL.

[0030] The beneficial effects of this invention are:

[0031] 1. The high corrosion-resistant corundum brick prepared by this invention incorporates hollow nanospheres composite silicon nitride whiskers during the preparation process. The hollow amino-modified phenolic resin nanospheres in the hollow nanospheres composite silicon nitride whiskers have hollow channels. During the high-temperature sintering process of the corundum brick, the carbonization and decomposition of the resin further generates uniform micropores / mesopores, forming a hierarchical pore structure of primary pores and derived pores. This results in stable and uniform porous properties, which, while ensuring its own strength, can block the penetration of corrosive media and extend the service life of the corundum brick.

[0032] 2. The chemical essence of the hollow nanosphere composite silicon nitride whiskers of the present invention is an organic-inorganic hybrid network structure in which hollow aminophenolic resin nanospheres and silicon nitride whisker composite skeletons are connected by chemical bonds. Structurally, the aminophenolic resin is dispersed in the network gaps of the silicon nitride whisker skeleton in the form of hollow microspheres. The special structure of hollow nanospheres and silicon nitride whiskers can endow the hollow nanosphere composite silicon nitride whiskers with good porosity and buffering performance, buffer thermal stress, and improve the thermal shock resistance of the final corundum brick.

[0033] 3. The hollow aminophenolic resin nanospheres in the hollow nanosphere composite silicon nitride whiskers of the present invention have hollow channels. During the high-temperature sintering of corundum bricks, the carbonization and decomposition of the resin will further generate uniform micropores / mesopores, forming a hierarchical pore structure of primary pores and derived pores. Furthermore, the three-dimensional cross-linked shell formed by alkaline catalytic deposition using aminophenolic resin as a self-template has a high degree of cross-linking, which leads to the hollow nanosphere composite silicon nitride whiskers being able to indirectly increase the residual carbon content. After carbonization, it can assist epoxy resin in forming a continuous and dense carbon skeleton, which can fill the network gaps of silicon nitride whiskers to form a support structure.

[0034] 4. The silicon nitride whisker composite skeleton of the present invention can serve as a support point for the pores, preventing the channels from collapsing or merging into large pores at high temperatures, thus avoiding defects and maintaining the uniformity and connectivity of the channels. The silicon nitride whiskers themselves have extremely strong chemical stability and are far more resistant to metal slag, glass melt, and acid and alkali corrosive media than the corundum matrix. The composite skeleton forms a continuous corrosion-resistant network inside the corundum brick, directly blocking the penetration path of the corrosive media. Detailed Implementation

[0035] The technical solutions of the present invention will be clearly and completely described below with reference to the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of the present invention.

[0036] Example 1: A method for preparing corundum bricks with high erosion resistance, comprising the following steps:

[0037] S1: Add 42 L of deionized water and 160 g of 4-aminophenol to a reaction vessel, stir at 12 °C and 500 r / min for 10 min, then add 100 mL of formaldehyde solution, continue stirring for 10 min, then add 19.5 mL of 2.6 mmol ammonia water, heat to 28 °C, continue stirring for 30 min, filter under reduced pressure, wash the product twice with deionized water, and freeze-dry at -20 °C for 12 h to obtain aminophenolic resin; Add 72 g of aminophenolic resin and 8 L of anhydrous ethanol to a reaction vessel, stir at 28 °C and 500 r / min for 10 min, ultrasonically disperse for 40 min, filter under reduced pressure, wash the product twice with deionized water, and freeze-dry at -20 °C for 12 h to obtain hollow aminophenolic resin nanospheres.

[0038] S2: Add 10g of silicon nitride whiskers and 500mL of ethanol to a reaction vessel, stir for 10min at 28℃ and 500r / min, and ultrasonically disperse for 30min. Then add 3g of polystyrene microspheres and 0.05g of fumed silica, ultrasonically disperse for 30min, and vacuum filter to obtain a composite silicon nitride whisker suspension. Mix 100mL of the composite silicon nitride whisker suspension, 5mL of γ-aminopropyltriethoxysilane, 50mL of ethanol and 20mL of deionized water for 5min, filter, wash the filter cake twice with deionized water, vacuum dry at 60℃ for 1h, heat to 120℃ and continue drying for 5h, transfer the product to a muffle furnace, heat to 220℃ at a heating rate of 1℃ / min, hold for 20min, and then heat to 450℃ at a rate of 10℃ / min and hold for 20min to obtain a silicon nitride whisker composite framework.

[0039] S3: Add 20g of silicon nitride whisker composite framework, 800mL of anhydrous ethanol and 250mL of deionized water to a reaction vessel, stir for 15min at 50℃ and 500r / min, then add 5mL of 3-glycidyl etheroxypropyltrimethoxysilane, adjust the pH to 3 with hydrochloric acid solution, continue stirring for 6h, filter, wash the precipitate twice with deionized water and anhydrous ethanol, and vacuum dry at 60℃ for 1h to obtain functionalized silicon nitride whisker composite framework.

[0040] S4: Add 5g of functionalized silicon nitride whisker composite framework, 50g of hollow amino-modified phenolic resin nanospheres and 500mL of deionized water to a reaction vessel, stir for 20min at 50℃ and 500r / min, then continue stirring for 2h under nitrogen atmosphere, filter, wash the precipitate twice with deionized water and anhydrous ethanol, and vacuum dry at 60℃ for 1h to obtain hollow nanosphere composite silicon nitride whiskers.

[0041] S5: Mix 95g alumina, 1g sodium carbonate, 0.5g strontium carbonate, 0.5g quartz sand, 1g hollow nanosphere composite silicon nitride whiskers and 2g epoxy resin for 10 minutes to obtain a mixture; then heat the mixture to 2100℃ in a three-phase electric arc furnace to melt it, pour it into a mold, anneal and cool it to obtain a corundum brick with high corrosion resistance.

[0042] Example 2: A method for preparing corundum bricks with high erosion resistance, comprising the following steps:

[0043] S1: 46 L of deionized water and 170 g of 4-aminophenol were added to a reaction vessel and stirred at 13.5 °C and 550 r / min for 11 min. Then, 110 mL of formaldehyde solution was added and stirring was continued for 11 min. Next, 19.75 mL of 2.7 mmol ammonia solution was added, and the mixture was heated to 29 °C and stirred for 35 min. The mixture was then filtered under reduced pressure, and the product was washed three times with deionized water and freeze-dried at -20 °C for 13 h to obtain aminophenolic resin. 76 g of aminophenolic resin and 9 L of anhydrous ethanol were added to a reaction vessel and stirred at 29 °C and 550 r / min for 11 min. The mixture was then ultrasonically dispersed for 50 min and filtered under reduced pressure. The product was washed three times with deionized water and freeze-dried at -20 °C for 13 h to obtain hollow aminophenolic resin nanospheres.

[0044] S2: 11g of silicon nitride whiskers and 550mL of ethanol were added to a reaction vessel and stirred at 29℃ and 550r / min for 11min. The mixture was then ultrasonically dispersed for 35min. 4g of polystyrene microspheres and 0.06g of fumed silica were added and ultrasonically dispersed for 35min. After vacuum filtration, a composite silicon nitride whisker suspension was obtained. 110mL of the composite silicon nitride whisker suspension, 5.5mL of γ-aminopropyltriethoxysilane, 55mL of ethanol, and 22.5mL of deionized water were stirred and mixed for 6min. The mixture was filtered, and the filter cake was washed three times with deionized water. The cake was vacuum dried at 65℃ for 1.5h, then heated to 125℃ and dried for another 6h. The product was transferred to a muffle furnace and heated to 230℃ at a heating rate of 1.5℃ / min, held for 25min, and then heated to 475℃ at a rate of 11℃ / min, held for 25min to obtain a silicon nitride whisker composite framework.

[0045] S3: Add 25g of silicon nitride whisker composite framework, 850mL of anhydrous ethanol and 275mL of deionized water to a reaction vessel, stir for 17.5min at 52.5℃ and 550r / min, then add 6.5mL of 3-glycidyl etheroxypropyltrimethoxysilane, adjust the pH to 3.5 with hydrochloric acid solution, continue stirring for 7h, filter, wash the precipitate three times with deionized water and anhydrous ethanol, and vacuum dry at 65℃ for 1.5h to obtain functionalized silicon nitride whisker composite framework.

[0046] S4: Add 5.5g of functionalized silicon nitride whisker composite framework, 65g of hollow amino-modified phenolic resin nanospheres and 550mL of deionized water to a reaction vessel, stir for 25min at 55℃ and 550r / min, then continue stirring for 3h under nitrogen atmosphere, filter, wash the precipitate three times with deionized water and anhydrous ethanol, and vacuum dry at 65℃ for 1.5h to obtain hollow nanosphere composite silicon nitride whiskers.

[0047] S5: Mix 95.5g alumina, 1.5g sodium carbonate, 0.75g strontium carbonate, 0.75g quartz sand, 1.5g hollow nanosphere composite silicon nitride whiskers and 2.5g epoxy resin for 11 minutes to obtain a mixture; then heat the mixture to 2150℃ in a three-phase electric arc furnace to melt it, pour it into a mold, anneal and cool it to obtain a corundum brick with high corrosion resistance.

[0048] Example 3: A method for preparing corundum bricks with high erosion resistance, comprising the following steps:

[0049] S1: Add 50 L of deionized water and 180 g of 4-aminophenol to a reaction vessel, stir at 15 °C and 600 r / min for 12 min, then add 120 mL of formaldehyde solution, continue stirring for 12 min, then add 20 mL of 2.8 mmol ammonia solution, heat to 30 °C, continue stirring for 40 min, filter under reduced pressure, wash the product 4 times with deionized water, and freeze-dry at -20 °C for 14 h to obtain aminophenolic resin; Add 80 g of aminophenolic resin and 10 L of anhydrous ethanol to a reaction vessel, stir at 30 °C and 600 r / min for 12 min, ultrasonically disperse for 60 min, filter under reduced pressure, wash the product 4 times with deionized water, and freeze-dry at -20 °C for 14 h to obtain hollow aminophenolic resin nanospheres.

[0050] S2: 12g of silicon nitride whiskers and 600mL of ethanol were added to a reaction vessel and stirred at 30℃ and 600r / min for 12min. The mixture was then ultrasonically dispersed for 40min. 5g of polystyrene microspheres and 0.07g of fumed silica were added and ultrasonically dispersed for 40min. After vacuum filtration, a composite silicon nitride whisker suspension was obtained. 120mL of the composite silicon nitride whisker suspension, 6mL of γ-aminopropyltriethoxysilane, 60mL of ethanol, and 25mL of deionized water were stirred and mixed for 7min. The mixture was filtered, and the filter cake was washed four times with deionized water. The cake was vacuum dried at 70℃ for 2h, then heated to 130℃ and dried for another 7h. The product was transferred to a muffle furnace and heated to 240℃ at a heating rate of 2℃ / min. The temperature was held for 30min, and then increased to 500℃ at a rate of 12℃ / min. The temperature was held for 30min to obtain a silicon nitride whisker composite framework.

[0051] S3: Add 30g of silicon nitride whisker composite framework, 900mL of anhydrous ethanol and 300mL of deionized water to a reaction vessel, stir for 20min at 55℃ and 600r / min, then add 8mL of 3-glycidyl etheroxypropyltrimethoxysilane, adjust the pH to 4 with hydrochloric acid solution, continue stirring for 8h, filter, wash the precipitate 4 times with deionized water and anhydrous ethanol, and vacuum dry at 70℃ for 2h to obtain functionalized silicon nitride whisker composite framework.

[0052] S4: Add 6g of functionalized silicon nitride whisker composite framework, 80g of hollow amino-modified phenolic resin nanospheres and 600mL of deionized water to a reaction vessel, stir for 30min at 60℃ and 600r / min, then continue stirring for 4h under nitrogen atmosphere, filter, wash the precipitate 4 times with deionized water and anhydrous ethanol, and vacuum dry at 70℃ for 2h to obtain hollow nanosphere composite silicon nitride whiskers.

[0053] S5: Mix 96g alumina, 2g sodium carbonate, 1g strontium carbonate, 1g quartz sand, 2g hollow nanosphere composite silicon nitride whiskers and 3g epoxy resin for 12 minutes to obtain a mixture; then heat the mixture to 2200℃ in a three-phase electric arc furnace to melt it, pour it into a mold, anneal and cool it to obtain a corundum brick with high corrosion resistance.

[0054] Comparative Example 1: Based on Example 3, the functionalized silicon nitride whisker composite skeleton in step S4 was replaced with the silicon nitride whisker composite skeleton prepared in step S2, while the other steps remained unchanged, and a corundum brick with high corrosion resistance was prepared.

[0055] Comparative Example 2: Based on Example 3, the silicon nitride whisker composite framework in step S3 was replaced with the raw silicon nitride whiskers in step S2.

[0056] 4-Aminophenol was purchased from Sigma-Aldrich, CAS No.: 123-30-8, molecular weight: 109.13.

[0057] The polystyrene microspheres, with a particle size of 20 μm, were purchased from Zhongke Leiming (Beijing) Technology Co., Ltd., item number: PS020000.

[0058] Fumed silica was purchased from Sigma-Aldrich, CAS No.: 112945-52-5, molecular weight: 60.08.

[0059] The microporous corundum bricks prepared in Examples 1-3 and Comparative Examples 1-2 were subjected to performance tests: apparent porosity was tested according to GB / T 2997-2000 standard; compressive strength was tested according to GB / T 5072-2008 standard; slag resistance was tested according to YB / T 117 standard; molten iron erosion index was tested according to YB / T4036 standard; average pore size was tested according to YB / T 118 standard; and thermal shock stability was tested according to YB / T376.1-1995 standard, with higher values ​​indicating better thermal shock stability.

[0060] Table 1

[0061] project Example 1 Example 2 Example 3 Comparative Example 1 Comparative Example 2 Apparent porosity (%) 7.0 6.8 6.5 9.1 10.5 Pressure resistance (MPa) 172 175 179 142 121 Slag resistance (%) 2.7 2.5 2.3 5.2 6.9 Iron erosion index (%) 0.3 0.4 0.3 1.1 1.6 Average pore size (μm) 0.27 0.28 0.29 0.51 0.63 Thermal shock stability 14 15 17 9 7

[0062] As shown in Table 1, the unfunctionalized silicon nitride whisker composite framework in Comparative Example 1 lacks epoxy groups grafted with 3-glycidyl etheroxypropyltrimethoxysilane on its surface, making it unable to react with the amino groups of the hollow amino phenolic resin nanospheres. It can only bind through physical adsorption, resulting in insufficient continuity of the carbon framework and the absence of covalent bond anchoring. The hollow amino phenolic resin nanospheres are prone to local agglomeration in the gaps between the silicon nitride whisker framework. At high temperatures, the resin in the agglomerated areas generates concentrated gas, increasing the apparent porosity and expanding the average pore size. Although the silicon nitride whisker composite framework can provide some support, the gaps at the resin interface cannot completely prevent pore merging, leading to a decrease in compressive strength.

[0063] In Comparative Example 3, the silicon nitride whiskers, lacking polystyrene microspheres for pore formation and fumed silica filling, could not form a three-dimensional network composite framework. Instead, they were merely dispersed fibrous particles. When mixed with hollow amino-modified phenolic resin nanospheres, the whiskers easily agglomerated and could not serve as pore support points. During carbonization, gas production was uneven, carbon framework defects increased, and without the constraint of a three-dimensional composite framework, pore collapse and merging were severe, resulting in increased apparent porosity, increased average pore size, and decreased compressive strength. The unevenly dispersed silicon nitride whiskers could not form a continuous corrosion-resistant network, and slag easily penetrated through the gaps between whisker agglomerations.

[0064] Although embodiments of the invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and variations can be made to these embodiments without departing from the principles and spirit of the invention.

Claims

1. A method for preparing corundum bricks with high erosion resistance, characterized in that, Includes the following steps: Step 1: Aminophenol and formaldehyde are used as monomers to polymerize aminophenolic resin, and then the aminophenolic resin is used as a template to form hollow aminophenolic resin nanospheres by ultrasonic dissolution with ethanol. Step 2: Using silicon nitride whiskers as a carrier, a silicon nitride whisker composite skeleton is obtained by low-temperature sintering of a polystyrene template and fumed silica as a reinforcing phase. Step 3: The silicon nitride whisker composite framework is treated with 3-glycidyl etheroxypropyltrimethoxysilane to obtain a functionalized silicon nitride whisker composite framework; hollow nanosphere composite silicon nitride whiskers are prepared by ring-opening grafting of epoxy groups on the surface of the functionalized silicon nitride whisker composite framework through hollow amino phenolic resin nanospheres. Step 4: Mix alumina, sodium carbonate, strontium carbonate, quartz sand, hollow nanosphere composite silicon nitride whiskers and epoxy resin for 10-12 minutes to obtain a mixture; heat the mixture to 2100-2200℃ to melt it, pour it into a mold, anneal, and cool to obtain a corundum brick with high corrosion resistance.

2. The method for preparing high-erosion-resistant corundum bricks according to claim 1, characterized in that, The mass ratio of alumina, sodium carbonate, strontium carbonate, quartz sand, hollow nanosphere composite silicon nitride whiskers, and epoxy resin is 95-96:1-2:0.5-1:0.5-1:3-4:2-3.

3. The method for preparing high-erosion-resistant corundum bricks according to claim 1, characterized in that, The specific preparation steps of the amino-modified phenolic resin are as follows: Deionized water and 4-aminophenol were added to a reaction vessel and stirred at 12-15℃ and 500-600 r / min for 10-12 min. Then, formaldehyde solution was added and stirring was continued for 10-12 min. Ammonia water with a concentration of 2.6-2.8 mmol / L was added and stirred at 28-30℃ for 30-40 min. The mixture was filtered under reduced pressure, the product was washed, and freeze-dried at -20℃ for 12-14 h to obtain amino-modified phenolic resin.

4. The method for preparing high-erosion-resistant corundum bricks according to claim 3, characterized in that, The ratio of deionized water, 4-aminophenol, formaldehyde solution, and ammonia is 42-50L: 160-180g: 100-120mL: 19.5-20mL.

5. The method for preparing high-erosion-resistant corundum bricks according to claim 1, characterized in that, The specific preparation steps of the hollow amino-modified phenolic resin nanospheres are as follows: Aminated phenolic resin and anhydrous ethanol were added to a reaction vessel and stirred for 10-12 min at 28-30℃ and 500-600 r / min. The mixture was then ultrasonically dispersed for 40-60 min, filtered under reduced pressure, and the product was washed 2-4 times with deionized water and freeze-dried at -20℃ for 12-14 h to obtain hollow aminated phenolic resin nanospheres. The ratio of the amino-modified phenolic resin to anhydrous ethanol is 72-80g:8-10L.

6. The method for preparing high-erosion-resistant corundum bricks according to claim 1, characterized in that, The specific preparation steps of the silicon nitride whisker composite framework are as follows: The composite silicon nitride whisker suspension, γ-aminopropyltriethoxysilane, ethanol and deionized water were stirred and mixed for 5-7 min, filtered, and the filter cake was washed with deionized water 2-4 times. It was then vacuum dried at 60-70℃ for 1-2 h, heated to 120-130℃ and dried for another 5-7 h. The product was transferred to a muffle furnace and heated to 220-240℃ at a heating rate of 1-2℃ / min, held for 20-30 min, and then heated to 450-500℃ at a rate of 10-12℃ / min, held for 20-30 min to obtain the silicon nitride whisker composite framework. The ratio of the composite silicon nitride whisker suspension, γ-aminopropyltriethoxysilane, ethanol and deionized water is 100-120 mL: 5-6 mL: 50-60 mL: 20-25 mL.

7. The method for preparing high-erosion-resistant corundum bricks according to claim 6, characterized in that, The specific preparation steps of the composite silicon nitride whisker suspension are as follows: Silicon nitride whiskers and ethanol were added to a reaction vessel and stirred at 28-30℃ and 500-600 r / min for 10-12 min. The mixture was then ultrasonically dispersed for 30-40 min. Polystyrene microspheres and fumed silica were then added and ultrasonically dispersed for 30-40 min. After vacuum filtration, a composite silicon nitride whisker suspension was obtained. The ratio of silicon nitride whiskers, ethanol, polystyrene microspheres and fumed silica is 10-12g: 500-600mL: 3-5g: 0.05-0.07g.

8. The method for preparing high-erosion-resistant corundum bricks according to claim 1, characterized in that, The specific preparation steps of the functionalized silicon nitride whisker composite framework are as follows: Add silicon nitride whisker composite framework, anhydrous ethanol and deionized water to a reaction vessel, stir for 15-20 min at 50-55℃ and 500-600 r / min, then add 3-glycidoxypropyltrimethoxysilane, adjust the pH to 3-4 with hydrochloric acid solution, continue stirring for 6-8 h, filter, wash the precipitate 2-4 times with deionized water and anhydrous ethanol, and vacuum dry at 60-70℃ for 1-2 h to obtain functionalized silicon nitride whisker composite framework; The ratio of the silicon nitride whisker composite framework, anhydrous ethanol, deionized water and 3-glycidyl etheroxypropyltrimethoxysilane is 20-30g: 800-900mL: 250-300mL: 5-8mL.

9. The method for preparing high-erosion-resistant corundum bricks according to claim 1, characterized in that, The specific preparation steps for the hollow nanosphere composite silicon nitride whiskers are as follows: Functionalized silicon nitride whisker composite framework, hollow amino-modified phenolic resin nanospheres and deionized water were added to a reaction vessel and stirred for 20-30 min at 50-60℃ and 500-600 r / min. Then, under a nitrogen atmosphere, stirring was continued for 2-4 h. After filtration, the precipitate was washed 2-4 times with deionized water and anhydrous ethanol and dried under vacuum at 60-70℃ for 1-2 h to obtain hollow nanosphere composite silicon nitride whiskers. The ratio of the functionalized silicon nitride whisker composite framework, hollow amino-modified phenolic resin nanospheres, and deionized water is 5-6g: 50-80g: 500-600mL.

10. High corrosion-resistant corundum brick, characterized in that, It is prepared by the preparation method described in any one of claims 1-9.