Micro-porous mullite-silicon carbide reinforced castable for blast furnace main trough

Abstract

The application discloses a micro-porous mullite-silicon carbide reinforced blast furnace tap hole castable, and belongs to the technical field of refractory materials, which is used for solving the technical problem that the fluidity of the castable and the high-temperature resistance of the cast product need to be improved in the prior art; the application comprises the following components in parts by weight: fused brown corundum 50-54 parts, fused brown corundum powder 3-5 parts, white corundum powder 4-6 parts, silicon carbide 16-18 parts, alumina micropowder 6-8 parts, boron carbide 0.2-0.6 parts, modified graphite 1-3 parts, silica micropowder 2-3 parts, elemental silicon powder 1-3 parts, modified silica sol 2-4 parts and water reducing agent 0.2-0.5 parts; the application is characterized in that boron carbide, modified silica sol and modified graphite are added into the castable, and the components are matched with each other, so that the fluidity of the castable is improved, and the high-temperature resistance of the cast product is improved.

Description

Technical Field

[0001] This invention relates to the field of refractory materials technology, specifically to a blast furnace tapping main trench castable based on microporous mullite-silicon carbide reinforcement. Background Technology

[0002] The main iron trough at the blast furnace taphole is a channel for guiding high-temperature molten iron and slag. The function of the main iron trough is to separate the molten iron from the slag. The slag in the trough enters the slag discharge trough from the top of the skimmer beam, and the molten iron flows through the molten iron channel at the bottom of the skimmer beam, thus achieving the separation of iron and slag.

[0003] As the refractory material lining the tapping trough, the castable refractory for the tapping trough is subjected to high-temperature scouring and chemical erosion by molten iron and slag during use. At the same time, it is subjected to repeated hot and cold cycles over a long period of time, which makes it prone to cracking and spalling. The main reasons for this phenomenon are the low strength and poor oxidation resistance of the material. Therefore, its performance directly determines the service life of the tapping trough, and thus the production capacity and efficiency of the blast furnace. Thus, the tapping trough material is one of the key refractory materials affecting blast furnace production.

[0004] During blast furnace ironmaking, slag is formed. Slag is an alkaline oxide that readily reacts with the refractory material of the taphole to form a liquid phase, weakening the erosion resistance of the main taphole material and exacerbating corrosion. To improve the slag erosion resistance of the refractory material used in the taphole, carbon materials and calcium aluminate cement are usually added to the main taphole castable as binders. Although carbon materials have high thermal conductivity and low coefficient of thermal expansion, they have poor oxidation resistance and water does not wet the graphite surface, resulting in extremely poor graphite dispersion in water. This affects the important construction performance of the castable, namely its fluidity. Castables using calcium aluminate cement as a binder introduce a certain amount of CaO, which forms low-melting-point substances during high-temperature use, affecting the service life of the castable material. To better improve the performance and service life of Al2O3-SiC-C castables, their resistance to chemical erosion by high-temperature slag, oxidation resistance, and fluidity need to be further improved.

[0005] To address this technical deficiency, a solution is proposed. Summary of the Invention

[0006] The purpose of this invention is to provide a blast furnace tapping main channel castable based on microporous mullite-silicon carbide reinforcement, which solves the technical problem that the fluidity of the castable and the high temperature resistance of the castable products need to be improved in the prior art.

[0007] The objective of this invention can be achieved through the following technical solution: a blast furnace tapping main trough castable based on microporous mullite-silicon carbide reinforcement, comprising the following components by weight: 50-54 parts of fused brown fused alumina, 3-5 parts of fused brown fused alumina powder, 4-6 parts of white fused alumina powder, 16-18 parts of silicon carbide, 6-8 parts of alumina micro powder, 0.2-0.6 parts of boron carbide, 1-3 parts of modified graphite, 2-3 parts of silica micro powder, 1-3 parts of elemental silicon powder, 120-140 parts of modified silica sol, and 0.2-0.5 parts of water-reducing agent.

[0008] Furthermore, the blast furnace tapping main trough castable based on microporous mullite-silicon carbide reinforcement is characterized in that the particle size of fused brown fused alumina is 5-8 mm, the particle size of fused brown fused alumina powder is 0.5-1 mm, the particle size of white fused alumina powder is 0.001-0.044 mm, the particle size of silicon carbide is 1-3 mm, the particle size of alumina micro powder is 0.5-1 μm, the particle size of boron carbide is 1-3 mm, the particle size of modified graphite is 200 mesh, the particle size of silica micro powder is 200 mesh, the particle size of elemental silicon powder is 0.001-0.037 mm, and the water-reducing agent is polycarboxylate.

[0009] The reaction mechanism of boron carbide is as follows:

[0010] The increased amount of B4C fine powder results in more retained C, leading to a greater amount of β-SiC generated during the reaction, and consequently, a higher high-temperature flexural strength. During heat treatment, boron-containing silicate glass phase is easily formed, and an anti-oxidation film is more readily formed on the surface. B4C oxidizes before C and Si, reducing the oxidation reaction of C and Si and protecting C and Si. This increases the amount of β-SiC generated at high temperatures, thus increasing the high-temperature flexural strength of the material.

[0011] Furthermore, the blast furnace tapping main trough castable based on microporous mullite-silicon carbide reinforcement is characterized in that the modified silica sol is obtained by the following steps:

[0012] A1. Add silane coupling agent, ethanol solvent, and deionized water to a magnetic stirrer and stir. Raise the stirring temperature of the magnetic stirrer to 50-60℃ and keep the reaction at this temperature for 1-2 hours to obtain the pre-supported body.

[0013] A2. Add the preform and silica sol to a grinding and dispersing mixer and stir. Add acetic acid solution to adjust the pH of the system to 5-6. Raise the temperature of the grinding and dispersing mixer to 50-60℃ and keep it at this temperature for 1-2 hours to obtain the modified silica sol.

[0014] The synthesis reaction mechanism of modified silica sol is as follows:

[0015] During the heating process, as moisture evaporates, the silica sol forms a Si-O-Si gel network structure, resulting in gelation. With continued heating, adsorbed water and structural water in the silica sol are lost. After the water in the water-based colloid is removed, the remaining gel becomes a highly active binder framework. SiC is oxidized to form a SiO2 protective film, increasing the bulk density of the castable and reducing the apparent porosity. The hydrolysis of the silane coupling agent promotes the condensation of silica sol particles. High-temperature treatment promotes the continuous generation of mullite, which has a large aspect ratio and a denser structure, significantly improving the thermal shock resistance and volume stability of the castable.

[0016] Furthermore, the aforementioned blast furnace tapping main channel castable based on microporous mullite-silicon carbide reinforcement is characterized in that the silane coupling agent is methyltrimethoxysilane, and the ratio of silane coupling agent, ethanol solvent, and deionized water is 10-20g:60-100mL:20-60mL, with a magnetic stirrer speed of 650r / min; the silica sol is an alkaline silica sol binder with a particle size of 10-20nm, pH=9.5, and density of 1.20g·cm³. -3 The grinding and dispersing mixer speed was 400 r / min, the ratio of preform to silica sol was 9 mL:10 mL, and the acetic acid solution concentration was 0.1 mol / L.

[0017] Furthermore, the blast furnace tapping main trough castable based on microporous mullite-silicon carbide reinforcement is characterized in that the modified graphite is obtained by the following steps:

[0018] B1. Wash the flake graphite with deionized water until neutral, dry it in a vacuum drying oven to constant weight, and grind and screen the flake graphite to obtain pretreated flake graphite.

[0019] B2. A mixed viscous solution is prepared by pretreatment of flake graphite, metallic silicon, silicon carbide micro powder and organic polymer binder, followed by post-treatment to obtain a modified flake graphite precursor.

[0020] B3. Add the modified flake graphite precursor and surfactant KS1055 to the reactor and stir. Set the stirring speed to 550-600 r / min and age for 3-5 h. Then, the modified graphite is obtained through post-treatment.

[0021] Furthermore, the blast furnace tapping main channel castable based on microporous mullite-silicon carbide reinforcement is characterized in that, in step B1, the flake graphite is 198 flake graphite with a particle size of 80-100 mesh, and the vacuum drying oven temperature is 100-110℃.

[0022] Furthermore, the blast furnace tapping main trough castable based on microporous mullite-silicon carbide reinforcement is characterized in that, in step B2, the metallic silicon is 98% metallic silicon, the silicon carbide particle size is 2-5μm, the polymer binder is one of epoxy resin and acrylic resin, the weight ratio of pretreated flake graphite, metallic silicon, silicon carbide micro powder and organic polymer binder is 12-14g:1-2g:1-2g:50-60mL, and the post-treatment operation includes: putting the mixed viscous liquid into a muffle furnace, raising the temperature of the muffle furnace to 500-800℃, holding it for 5-6 hours, cooling and discharging, crushing, and passing it through a 100-mesh sieve to obtain the modified flake graphite precursor.

[0023] Furthermore, the blast furnace tapping main channel castable based on microporous mullite-silicon carbide reinforcement is characterized in that, in step B3, the ratio of modified flake graphite precursor to surfactant KS1055 is 10-15g:50-60mL; the post-treatment method includes: after aging, filtration, washing the filter cake with purified water until neutral and then drying it, transferring the filter cake to a drying oven at a temperature of 80-90℃, vacuum drying to constant weight, pulverizing, and passing it through a 100-mesh sieve to obtain modified graphite.

[0024] The synthesis mechanism of modified flake graphite precursor is as follows:

[0025] When graphite is mixed with metallic silicon and silicon carbide micropowder as nuclei, under the action of external force, the graphite and other refractory materials are bonded to the surface of the nuclei through the binding force of the binder. As the nuclei grow, they become large particles with a certain density and strength. The amount of water added is significantly reduced, thus the density is correspondingly improved, which improves the problems of low graphite density and poor filling properties, and also has a high oxidation temperature.

[0026] The synthesis mechanism of modified graphite is as follows:

[0027] The change in wettability of a solid surface is due to the adsorption of surfactants at the solid-liquid interface, which causes the molecules to be neatly oriented on the solid surface to form an adsorption layer. For flake graphite, the surfactant molecules adsorbed on the oleophilic surface have their oleophilic groups facing the graphite surface and their aqueous groups facing the aqueous solution, which transforms the original oleophilic solid surface into a hydrophilic solid surface, reduces the contact angle between the liquid and the solid, and improves the wettability of graphite in water.

[0028] The present invention has the following beneficial effects:

[0029] 1. The microporous mullite-silicon carbide reinforced blast furnace tapping main trough castable of the present invention, by adding boron carbide to the castable, promotes sintering and easily forms an anti-oxidation film on the surface of the castable by generating boron oxide and boron-containing silicate glass phase during heat treatment. B4C can oxidize before C and Si, reduce the oxidation reaction of carbon and silicon, and protect carbon and silicon. As a result, the amount of β-SiC generated at high temperature increases, and the oxidation resistance, high temperature resistance and flexural strength of the castable also increase.

[0030] 2. The blast furnace tapping main trough castable based on microporous mullite-silicon carbide reinforcement of the present invention modifies the silica sol by adding a coupling agent. This allows the silica ether generated by the reaction of the coupling agent with silica particles to have strong oleophilicity on the surface of the silica particles, enhancing the compatibility of the silica sol with organic matter. At the same time, it also provides a flexible surface layer for the silica sol, which allows the stress between the silica sol surface layers to be transmitted evenly, thereby enhancing the strength and toughness of the silica sol material and effectively preventing material cracking. Meanwhile, the hydrolysis of the silane coupling agent promotes the condensation of silica sol particles, and the mullite phase is continuously generated during high-temperature treatment. At the same time, all elemental silicon powder reacts and is converted into silicon carbide, silicon dioxide, and mullite. In addition, silicon carbide and mullite whiskers are generated in situ in the pores and gaps inside the original layer, improving the thermal shock stability, high-temperature and room-temperature strength of the castable and thus extending its service life.

[0031] 3. The blast furnace tapping main trough castable of the present invention, based on microporous mullite-silicon carbide reinforcement, is modified by adding metallic silicon, silicon carbide micro powder and surfactant to graphite. The spinel coating formed on the surface of flake graphite has good compatibility with the oxide matrix, which improves the bonding between the aggregate and the matrix of the castable, thereby improving the load-bearing softening performance of the castable. At the same time, the presence of the surface coating also acts as a barrier to prevent oxygen diffusion, improving the oxidation resistance of the castable. As the nuclei grow, they become large particles with a certain density and strength, and the water addition is significantly reduced, thus the density is correspondingly improved, which improves the problems of low graphite density and poor filling, thereby improving the wettability of water on modified graphite and improving the fluidity of the castable. Detailed Implementation

[0032] The technical solution of the present invention will be clearly and completely described below with reference to the embodiments. 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 skilled in the art without creative effort are within the scope of protection of the present invention.

[0033] The surfactant used in this invention is selected from Shandong Polymer Chemical Co., Ltd., commercial brand name KS1055;

[0034] The epoxy resin is bisphenol A type epoxy resin E-51;

[0035] The acrylic resin was selected from Foshan Shengchuangda Chemical Co., Ltd., under the commercial brand name B-692.

[0036] Example 1

[0037] The preparation method of the blast furnace tapping main trough castable based on microporous mullite-silicon carbide reinforcement in this embodiment includes the following steps:

[0038] S1. Prefabrication

[0039] Weigh out 100g of methyltrimethoxysilane, 600mL of ethanol solvent, and 200mL of deionized water, and add them to a magnetic stirrer. Raise the stirring temperature to 50℃ and maintain the reaction temperature for 1 hour, with the magnetic stirrer speed at 650 rpm. The silica sol is an alkaline silica sol binder with a particle size of 10nm, pH = 9.5, and density of 1.20 g·cm³. -3 The precast body is obtained.

[0040] S2, Preparation of modified silica sol

[0041] Weigh out 900 mL of the preform and 1000 mL of silica sol, add them to a grinding and dispersing mixer and stir. Add acetic acid solution to adjust the pH of the system to 5. Raise the temperature of the grinding and dispersing mixer to 50℃ and keep it at that temperature for 1 hour. The grinding and dispersing mixer speed is 400 r / min to obtain the modified silica sol.

[0042] S3. Preparation of pretreated flake graphite

[0043] The flake graphite was washed with deionized water until neutral, dried in a vacuum drying oven at 100°C until constant weight, and then ground and screened to obtain pretreated flake graphite.

[0044] S4. Preparation of modified flake graphite precursor

[0045] Weigh out 120g of treated flake graphite, 10g of metallic silicon, 10g of silicon carbide micro powder, and 500mL of organic polymer binder to form a mixed viscous liquid. Place the mixed viscous liquid into a muffle furnace, raise the temperature of the muffle furnace to 500-800℃, keep it at that temperature for 5-6 hours, cool it down and discharge it, crush it, and pass it through a 200-mesh sieve to obtain the modified flake graphite precursor.

[0046] S5. Preparation of modified graphite

[0047] Weigh 100g of modified flake graphite precursor and 5500mL of surfactant KS105 and add them to the reaction vessel and stir. Set the stirring speed to 550r / min and age for 3h. Filter the mixture and wash the filter cake with purified water until neutral. Then dry the filter cake and transfer it to a drying oven at 80℃. Vacuum dry the filter cake to constant weight, pulverize it, and pass it through a 200-mesh sieve to obtain modified graphite.

[0048] S6. Preparation of casting refractory

[0049] Weigh out the following by weight: 50 parts of fused brown fused alumina with a particle size of 5-8mm, 3 parts of fused brown fused alumina powder with a particle size of 0.5-1mm, 4 parts of white fused alumina powder with a particle size of 0.001-0.044mm, 16 parts of silicon carbide with a particle size of 1-3mm, 6 parts of alumina micro powder with a particle size of 0.5-1mm, 0.2 parts of boron carbide with a particle size of 1-3mm, 1 part of modified graphite with a particle size of 200 mesh, 2 parts of silica micro powder with a particle size of 200 mesh, 1 part of elemental silica powder with a particle size of 0.001-0.037mm, and 0.2 parts of polycarboxylate. Pour the mixture into a cement mortar mixer and stir. Add 120 parts of modified silica sol to the cement mortar mixer and mix evenly to obtain the castable.

[0050] Example 2

[0051] The preparation method of the blast furnace tapping main trough castable based on microporous mullite-silicon carbide reinforcement in this embodiment includes the following steps:

[0052] S1. Prefabrication

[0053] Weigh out 100g of methyltrimethoxysilane, 600mL of ethanol solvent, and 200mL of deionized water, and add them to a magnetic stirrer. Raise the stirring temperature to 50℃ and maintain the reaction temperature for 1 hour, with the magnetic stirrer speed at 650 rpm. The silica sol is an alkaline silica sol binder with a particle size of 10nm, pH = 9.5, and density of 1.20 g·cm³. -3 The precast body is obtained.

[0054] S2, Preparation of modified silica sol

[0055] Weigh out 900 mL of the preform and 1000 mL of silica sol, add them to a grinding and dispersing mixer and stir. Add acetic acid solution to adjust the pH of the system to 5. Raise the temperature of the grinding and dispersing mixer to 50℃ and keep it at that temperature for 1 hour. The grinding and dispersing mixer speed is 400 r / min to obtain the modified silica sol.

[0056] S3. Preparation of pretreated flake graphite

[0057] The flake graphite was washed with deionized water until neutral, dried in a vacuum drying oven at 100°C until constant weight, and then ground and screened to obtain pretreated flake graphite.

[0058] S4. Preparation of modified flake graphite precursor

[0059] Weigh out 120g of treated flake graphite, 10g of metallic silicon, 10g of silicon carbide micro powder, and 500mL of organic polymer binder to form a mixed viscous liquid. Place the mixed viscous liquid into a muffle furnace, raise the temperature of the muffle furnace to 500-800℃, keep it at that temperature for 5-6 hours, cool it down and discharge it, crush it, and pass it through a 200-mesh sieve to obtain the modified flake graphite precursor.

[0060] S5. Preparation of modified graphite

[0061] Weigh 100g of modified flake graphite precursor and 5500mL of surfactant KS105 and add them to the reaction vessel and stir. Set the stirring speed to 550r / min and age for 3h. Filter the mixture and wash the filter cake with purified water until neutral. Then dry the filter cake and transfer it to a drying oven at 80℃. Vacuum dry the filter cake to constant weight, pulverize it, and pass it through a 200-mesh sieve to obtain modified graphite.

[0062] S6. Preparation of casting refractory

[0063] Weigh out the following by weight: 52 parts of fused brown fused alumina with a particle size of 5-8mm, 4 parts of fused brown fused alumina powder with a particle size of 0.5-1mm, 5 parts of white fused alumina powder with a particle size of 0.001-0.044mm, 17 parts of silicon carbide with a particle size of 1-3mm, 7 parts of alumina micro powder with a particle size of 0.5-1mm, 0.4 parts of boron carbide with a particle size of 1-3mm, 2 parts of modified graphite with a particle size of 200 mesh, 2 parts of silica micro powder with a particle size of 200 mesh, 2 parts of elemental silica powder with a particle size of 0.001-0.037mm, and 0.3 parts of polycarboxylate. Pour the mixture into a cement mortar mixer and stir. Add 130 parts of modified silica sol to the cement mortar mixer and mix evenly to obtain the castable.

[0064] Example 3

[0065] The preparation method of the blast furnace tapping main trough castable based on microporous mullite-silicon carbide reinforcement in this embodiment includes the following steps: corresponding modifications and adjustments

[0066] S1. Prefabrication

[0067] Weigh out 100g of methyltrimethoxysilane, 600mL of ethanol solvent, and 200mL of deionized water, and add them to a magnetic stirrer. Raise the stirring temperature to 50℃ and maintain the reaction temperature for 1 hour, with the magnetic stirrer speed at 650 rpm. The silica sol is an alkaline silica sol binder with a particle size of 10nm, pH = 9.5, and density of 1.20 g·cm³. -3 The precast body is obtained.

[0068] S2, Preparation of modified silica sol

[0069] Weigh out 900 mL of the preform and 1000 mL of silica sol, add them to a grinding and dispersing mixer and stir. Add acetic acid solution to adjust the pH of the system to 5. Raise the temperature of the grinding and dispersing mixer to 50℃ and keep it at that temperature for 1 hour. The grinding and dispersing mixer speed is 400 r / min to obtain the modified silica sol.

[0070] S3. Preparation of pretreated flake graphite

[0071] The flake graphite was washed with deionized water until neutral, dried in a vacuum drying oven at 100°C until constant weight, and then ground and screened to obtain pretreated flake graphite.

[0072] S4. Preparation of modified flake graphite precursor

[0073] Weigh out 120g of treated flake graphite, 10g of metallic silicon, 10g of silicon carbide micro powder, and 500mL of organic polymer binder to form a mixed viscous liquid. Place the mixed viscous liquid into a muffle furnace, raise the temperature of the muffle furnace to 500-800℃, keep it at that temperature for 5-6 hours, cool it down and discharge it, crush it, and pass it through a 200-mesh sieve to obtain the modified flake graphite precursor.

[0074] S5. Preparation of modified graphite

[0075] Weigh 100g of modified flake graphite precursor and 5500mL of surfactant KS105 and add them to the reaction vessel and stir. Set the stirring speed to 550r / min and age for 3h. Filter the mixture and wash the filter cake with purified water until neutral. Then dry the filter cake and transfer it to a drying oven at 80℃. Vacuum dry the filter cake to constant weight, pulverize it, and pass it through a 200-mesh sieve to obtain modified graphite.

[0076] S6. Preparation of casting refractory

[0077] Weigh out the following by weight: 54 parts of fused brown fused alumina with a particle size of 5-8mm, 5 parts of fused brown fused alumina powder with a particle size of 0.5-1mm, 6 parts of white fused alumina powder with a particle size of 0.001-0.044mm, 18 parts of silicon carbide with a particle size of 1-3mm, 8 parts of alumina micro powder with a particle size of 0.5-1mm, 0.6 parts of boron carbide with a particle size of 1-3mm, 3 parts of modified graphite with a particle size of 200 mesh, 3 parts of silica micro powder with a particle size of 200 mesh, 3 parts of elemental silica powder with a particle size of 0.001-0.037mm, and 0.5 parts of polycarboxylate. Pour the mixture into a cement mortar mixer and stir. Add 140 parts of modified silica sol to the cement mortar mixer and mix evenly to obtain the castable.

[0078] Comparative Example 1

[0079] The difference between this comparative example and Example 3 is that the blast furnace tapping main channel castable based on microporous mullite-silicon carbide reinforcement used does not contain a silane coupling agent in step S1.

[0080] Comparative Example 2

[0081] The difference between this comparative example and Example 3 is that the blast furnace tapping main trough castable based on microporous mullite-silicon carbide reinforcement used does not contain a surfactant in step S5.

[0082] Comparative Example 3

[0083] The difference between this comparative example and Example 3 is that the blast furnace tapping main trough castable based on microporous mullite-silicon carbide reinforcement used does not contain boron carbide in step S6.

[0084] Performance testing:

[0085] According to GB / T4513.4-2017 "Unshaped Refractory Materials - Part 4: Determination of Flowability of Castables", the flow value of the castable sample was determined.

[0086] The castable was poured into a mold and vibrated to form the product. It was then cured at room temperature for 24 hours and demolded for another 24 hours to obtain a microporous mullite-silicon carbide reinforced blast furnace tapping main channel castable product sample. According to GB / T4513.6-2017 "Unshaped refractories - Part 6: Determination of physical properties", the linear shrinkage rate, flexural strength and compressive strength of the castable product sample after heat treatment at 1500℃ were tested. The specific test results are shown in Table 1 below.

[0087] Table 1 - Performance Test Data of Samples

[0088]

[0089]

[0090] Data Analysis:

[0091] Comparative analysis of the data in Table 1 shows that the flow value of the blast furnace tapping main trough castable based on microporous mullite-silicon carbide reinforcement of this invention reaches 220 mm. After heat treatment at 1500℃, the cold flexural strength of the castable sample reaches 14.2 MPa, the compressive strength reaches 93.9 MPa, and the hot flexural strength reaches 4.8 MPa. The permanent linear change rate of the blast furnace tapping main trough castable based on microporous mullite-silicon carbide reinforcement reaches 0.2%. All performance test data are better than the comparative example, indicating that this invention modifies silica sol through the sol-gel method, and generates a composite material by adding boron carbide powder and modified graphite powder at high temperature. This improves the problems of poor hydrophilicity and difficulty in dispersion of graphite, and also enhances the high-temperature flexural strength, oxidation and corrosion resistance of the castable, thus extending its service life.

[0092] The preferred embodiments of the present invention disclosed above are merely illustrative of the invention. These preferred embodiments do not exhaustively describe all details, nor do they limit the invention to specific implementations. Clearly, many modifications and variations can be made based on the content of this specification. This specification selects and specifically describes these embodiments to better explain the principles and practical applications of the invention, thereby enabling those skilled in the art to better understand and utilize the invention. The invention is limited only by the claims and their full scope and equivalents.

Claims

1. A blast furnace tapping main trench castable based on microporous mullite-silicon carbide reinforcement, characterized in that, It comprises the following components by weight: 50-54 parts fused brown fused alumina, 3-5 parts fused brown fused alumina powder, 4-6 parts white fused alumina powder, 16-18 parts silicon carbide, 6-8 parts alumina micro powder, 0.2-0.6 parts boron carbide, 1-3 parts modified graphite, 2-3 parts silica micro powder, 1-3 parts elemental silica powder, 120-140 parts modified silica sol, and 0.2-0.5 parts water-reducing agent; The modified silica sol is obtained by the following steps: A1. Add silane coupling agent, ethanol solvent, and deionized water to a magnetic stirrer and stir. Raise the stirring temperature of the magnetic stirrer to 50-60℃ and keep the reaction at this temperature for 1-2 hours to obtain the preform. A2. Add the preform and silica sol to a grinding and dispersing mixer and stir. Add acetic acid solution to adjust the pH of the system to 5-6. Raise the temperature of the grinding and dispersing mixer to 50-60℃ and keep it at this temperature for 1-2 hours to obtain the modified silica sol. The modified graphite is obtained by the following steps: B1. Wash the flake graphite with deionized water until neutral, dry it in a vacuum drying oven to constant weight, and grind and screen the flake graphite to obtain pretreated flake graphite. B2. A mixed viscous solution composed of pretreated flake graphite, metallic silicon, silicon carbide, and organic polymer binder is prepared by post-treatment to obtain a modified flake graphite precursor. B3. Add the modified flake graphite precursor and surfactant KS1055 to the reactor and stir. Set the stirring speed to 550-600 r / min and age for 3-5 h. Then, the modified graphite is obtained through post-treatment.

2. The blast furnace tapping main trench castable based on microporous mullite-silicon carbide reinforcement according to claim 1, characterized in that, The particle size of fused brown fused alumina is 5-8 mm, the particle size of fused brown fused alumina powder is 0.5-1 mm, the particle size of white fused alumina powder is 0.001-0.044 mm, the particle size of silicon carbide is 1-3 mm, the particle size of alumina micro powder is 0.5-1 μm, the particle size of boron carbide is 1-3 mm, the particle size of modified graphite is 200 mesh, the particle size of silica micro powder is 200 mesh, the particle size of elemental silica powder is 0.001-0.037 mm, and the water-reducing agent is polycarboxylate.

3. The blast furnace tapping main trench castable based on microporous mullite-silicon carbide reinforcement according to claim 1, characterized in that, The silane coupling agent is methyltrimethoxysilane, and the ratio of silane coupling agent, ethanol solvent, and deionized water is 10-20g:60-100mL:20-60mL. The magnetic stirrer speed is 650r / min. The silica sol is an alkaline silica sol binder with a particle size of 10-20nm, pH=9.5, and density of [missing information]. The grinding and dispersing mixer speed is 400 r / min, the ratio of preform to silica sol is 9-10 mL: 10-11 mL, and the acetic acid solution concentration is 0.1 mol / L.

4. The blast furnace tapping main trench castable based on microporous mullite-silicon carbide reinforcement according to claim 1, characterized in that, In step B1, the particle size of the flake graphite is 80-100 mesh, and the temperature of the vacuum drying oven is 100-110℃.

5. The blast furnace tapping main trench castable based on microporous mullite-silicon carbide reinforcement according to claim 1, characterized in that, In step B2, the silicon carbide particle size is 2-5 μm, the organic polymer binder is one of epoxy resin and acrylic resin, and the ratio of pretreated flake graphite, metallic silicon, silicon carbide and organic polymer binder is 12-14g:1-2g:1-2g:50-60mL. The post-treatment operation includes: putting the mixed viscous liquid into a muffle furnace, raising the temperature of the muffle furnace to 500-800℃, holding it at that temperature for 5-6 hours, cooling and discharging the material, crushing it, and passing it through a 200-mesh sieve to obtain the modified flake graphite precursor.

6. The blast furnace tapping main trench castable based on microporous mullite-silicon carbide reinforcement according to claim 1, characterized in that, In step B3, the ratio of the modified flake graphite precursor to the surfactant KS1055 is 10-15g:50-60mL. The post-treatment method includes: aging followed by filtration, washing the filter cake with purified water until neutral, drying it, transferring the filter cake to a drying oven at 80-90℃, vacuum drying to constant weight, pulverizing, and passing it through a 200-mesh sieve to obtain modified graphite.

Images