Impregnation-free alkaline sliding plate brick and preparation method thereof
The non-impregnated alkaline sliding plate bricks prepared by specific components and processes have solved the shortcomings of sliding plate bricks in terms of resistance to alkaline erosion, non-impregnation, and thermal shock stability, thus meeting the requirements of high-performance and low-pollution steelmaking and reducing production energy consumption and costs.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- WUXI NANFANG REFRACTORIES CO LTD
- Filing Date
- 2026-02-02
- Publication Date
- 2026-05-12
AI Technical Summary
Existing sliding bricks are insufficient in terms of resistance to alkaline erosion, impregnation resistance, thermal shock stability, and low oxidation, and cannot meet the dual requirements of the steelmaking industry for high performance and low pollution.
Alkaline slide bricks without impregnation are made using specific components and gradations, including fused magnesia, forsterite, fused spinel, boron carbide, and nano-α-Al2O3 powder. They are prepared through high-pressure molding, gradient drying, and low-temperature firing processes to form a dense structure, avoiding the asphalt impregnation process and achieving a combination of environmental protection and high performance.
It improves resistance to MnO erosion, reduces damage rate and coefficient of thermal expansion, enhances thermal shock resistance and density, meets the requirements of high performance and environmental protection, and reduces production energy consumption and costs.
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Abstract
Description
Technical Field
[0001] This invention relates to the field of refractory materials based on inorganic materials, and more specifically to an impregnation-free alkaline sliding plate brick and its preparation method. Background Technology
[0002] As a critical component in continuous casting production, the performance of sliding block bricks directly determines the cleanliness of molten steel, the number of consecutive casting heats, and the stability of safe production. Currently, the mainstream sliding blocks in the industry suffer from three major irreconcilable technical challenges: 1. Environmental shortcomings of traditional alkaline sliding plates (magnesium-carbon system): Although they can resist alkaline corrosion such as CaO and MnO, they need to undergo "asphalt vacuum pressure impregnation + high temperature dry distillation" process to improve density. The tar volatiles (benzo[a]pyrene, phenols) generated in the process not only pollute the environment (emission concentration exceeds national standards by 5-8 times), but also endanger the health of operators. Moreover, the product will still release toxic gases when used after impregnation, which does not meet the requirements of the "green steelmaking" policy. 2. Alkali resistance defects of non-impregnation sliding plates (aluminum-carbon / aluminum-zirconium-carbon system): Existing non-impregnation technologies mostly use alumina as the base material. When casting calcium-treated steel, Al2O3 and SiO2 easily react with CaO in the molten steel to form CaO-Al2O3-SiO2 system low-melting-point substances (melting point only 1200-1350℃), which leads to roughening and steel inclusion on the sliding plate surface. The number of consecutive casting heats is only 2-4, far lower than the industry requirement of 5-8 heats. 3. Bottleneck of thermal shock stability of magnesium materials: Pure magnesium sliding plates are prone to cracking under rapid cooling and heating conditions due to their large coefficient of thermal expansion (1.5%-1.8% thermal expansion rate at 20-1000℃). A large amount of graphite needs to be added to improve thermal shock resistance. However, graphite will form a loose layer due to oxidation and carbon loss, which will accelerate the penetration and erosion of molten steel, thus falling into a contradictory cycle of "anti-thermal shock - anti-erosion".
[0003] Existing technologies only optimize "corrosion resistance" or "environmental friendliness" without forming a synergistic technology system of "alkaline nature + no impregnation + thermal shock resistance + low oxidation", which cannot meet the current steelmaking industry's dual demand for "high performance + low pollution". Summary of the Invention
[0004] To address the aforementioned problems, the present invention aims to provide an alkaline, corrosion-resistant, impregnation-free, environmentally friendly, low-expansion, and thermal shock-resistant impregnation-free alkaline sliding plate brick and its preparation method.
[0005] According to one aspect of the present invention, an impregnation-free alkaline sliding plate brick is provided, comprising the following components by weight percentage: 97% fused magnesia: 65%-70% Forsterite: 4%-6% Fused spinel: 5%-7% Boron carbide: 2%-3% Nano α-Al2O3 micro powder: 3%-5% Modified thermoplastic resin: 3%-4% Ceramic adhesive: 3%-5% Flake graphite: 2%-3% Aluminum-magnesium alloy powder: 1%-2% High-temperature asphalt powder: 1%-2%, In addition, thermoplastic resin: 3%-4%, Resin reinforcing agent: 0.3%-0.5%. In some embodiments, the particle size distribution of 97 electrofused magnesia is as follows: 3-1mm, 22%-25%; 2-1mm, 10%-13%; 1-0.5mm, 8%-10%; 0.5-0mm, 7%-9%; 200 mesh, 18%-20%; Particle bulk density ≥68%.
[0006] In some implementations, the particle size distribution of each component is as follows: Fused spinel ≥200 mesh; Forsterite ≥200 mesh; Boron carbide is 325 mesh; Nano-α-Al₂O₃ has a size of 1 μm; Flake graphite is 300 mesh; Aluminum-magnesium alloy powder ≥180 mesh; High-temperature asphalt powder is 200 mesh; The ceramic adhesive is 180 mesh. Both the thermoplastic resin and the resin reinforcing agent are low-viscosity liquids with a viscosity of 12,000-15,000 MPa. s.
[0007] According to one aspect of the present invention, a method for preparing an impregnated alkaline sliding plate brick is provided, characterized by comprising the following steps; S1. Component pretreatment: 97 fused magnesia, forsterite and fused spinel are crushed and screened according to their gradation to remove adsorbed moisture and set aside. S2, phased mixing; S3, High-pressure molding; S4, gradient drying; S5, low-temperature firing; S6, Post-processing.
[0008] In some embodiments, in step S1, the particle size deviation is ≤5%; boron carbide is dried at 120°C for 2 hours.
[0009] In some implementations, step S2, the staged mixing includes the following steps: First stage, skeleton mixing: Add coarse 3-1mm and 21mm fused magnesia particles to a high-speed mixer at 150r / min and mix for 4-6 minutes. Second stage, filling and mixing: Add 1-0.5mm, 0.5-0mm, 200 mesh fine particles of 97 electrofused magnesia, forsterite, and electrofused spinel, reduce the speed to 100r / min, and mix for 8-10 minutes; Third stage, functional mixing: Add boron carbide, nano α-Al2O3, graphite, aluminum-magnesium alloy powder, and high-temperature asphalt powder, and mix for 10-12 minutes at a speed of 80 r / min. Fourth stage, bonding and mixing: Finally, add the modified thermoplastic resin and resin reinforcing agent, and mix for 5-8 minutes at a speed of 60 r / min.
[0010] In some implementations, the high-pressure molding in step S3 is as follows: a 1500-ton spiral brick press is used, and the pressure is applied in three stages: initial pressure of 30MPa followed by 5s, medium pressure of 80MPa followed by 8s, and final pressure of 120MPa followed by 10s, with a green body bulk density ≥2.75g / cm³.
[0011] In some implementations, gradient drying in step S4 includes the following steps: Pre-drying: Air dry for 24 hours to remove surface free water; Gradient heating: Increase the temperature to 60℃ in 1 hour and hold for 10 hours to remove adsorbed water; then slowly increase the temperature to 120℃ in 18 hours and hold for 15 hours to remove crystal water; increase the temperature to 180℃ in 10 hours and hold for 20 hours to initially cure the resin; the total drying time is 58-63 hours.
[0012] In some implementations, the low-temperature firing in step S5 includes the following steps: Heating phase: The temperature is raised to 580℃±10℃ at a constant rate over 16 hours, with the heating rate controlled at 36℃ / h; Insulation stage: Insulate for 18 hours; Cooling phase: The temperature is uniformly reduced to room temperature over 24 hours at a rate of 24℃ / h.
[0013] In some implementations, the processing in step S6 includes: finishing the brick body and encasing the finished brick in an iron shell.
[0014] This invention discloses a non-impregnated alkaline sliding plate brick and its preparation method. Compared with existing technologies, in the continuous casting of calcium-treated steel, the damage rate is reduced by 50% compared to traditional aluminum-zirconium-carbon sliding plate bricks, and the number of consecutive castings can reach 6-8 heats (compared to only 2-4 heats with traditional methods); in the casting of high-oxygen steel, the resistance to MnO corrosion is improved by 45%. Comprehensive physical properties: room temperature pressure resistance ≥190MPa (industry average 150MPa), room temperature bulk density ≥3.0g / cm³ (industry average 2.8g / cm³), 1400℃ high temperature flexural strength ≥14MPa (industry average 10MPa), porosity ≤3% (industry average 6%-8%). Thermal shock stability: No cracks after 15 water cooling cycles at 1100℃ (traditional magnesium-carbon sliding plates ≤ 8 cycles), and the coefficient of thermal expansion is reduced to 1.1%-1.3% (traditional magnesium sliding plates 1.5%-1.8%). Detailed Implementation
[0015] The present invention will be further described below with reference to specific embodiments.
[0016] The non-impregnated alkaline sliding tile comprises the following components by weight percentage: 97 Fused Magnesia: 65%-70%, its core function is to provide a basic alkaline framework to resist CaO erosion. It uses high-temperature sintered crystalline fused magnesia with a refractoriness of over 2800℃, replacing traditional amorphous magnesia and improving volume stability by 40%. Forsterite: 4%-6%, its core function is to adjust the coefficient of thermal expansion and improve high-temperature strength. Forsterite, with a thermal expansion rate of 0.8%-1.0%, is compounded with fused magnesia to resolve the contradiction between "alkalinity and thermal shock". Fused spinel: 5%-7%, its core function is to form MgO-Al2O3 solid solution, inhibit the formation of low-melting-point substances, control the Al2O3 content ≥72%, and avoid the reaction of excessive Al2O3 with CaO; Boron carbide: 2%-3%, its core function is to resist oxidation, wear resistance and inhibit graphite oxidation. It replaces traditional silicon carbide / aluminum powder, improves oxidation resistance by 60%, and improves wear resistance by utilizing its high hardness (Mohs 9.3). Nano α-Al2O3 micro powder: 3%-5%, its core function is to fill micropores and achieve impregnation-free densification. It uses 1μm-level micro powder to form a three-level stack of "coarse-fine-nano" with the base material, reducing the porosity to below 3%. Modified thermoplastic resin: 3%-4%, its core function is to provide adhesion, and the residual carbon content is stable. The resin is modified with silane, and the residual carbon rate is increased to 48%±2%, replacing asphalt as a carbon source. Ceramic adhesive: 3%-5%, its core function is to improve the strength of the green body and prevent molding cracks. Inorganic and organic composite adhesives can improve the strength of the green body by 50% without relying on impregnation to increase strength. Flake graphite: 2%-3%, its core function is to reduce the elastic modulus and improve thermal shock stability. 300-mesh large flake graphite is selected and works in conjunction with magnesium olivine to achieve thermal shock stability (1100℃ water cooling cycle) of more than 15 times. Aluminum-magnesium alloy powder: 1%-2%, its core function is to generate MgAl2O4 spinel in situ to fill the pores, control the Al content to 50±3%, and react in situ during the firing process, improving densification efficiency by 30%; High-temperature asphalt powder: 1%-2%, its core function is to provide additional residual carbon, optimize carbon distribution, and replace liquid asphalt with solid asphalt powder to avoid volatile pollution, while being evenly dispersed in the matrix.
[0017] In addition, thermoplastic resin: 3%-4%, Resin reinforcing agent: 0.3%-0.5%. In some embodiments, the particle size distribution of 97 electrofused magnesia is as follows: 3-1mm, 22%-25%, playing a role in forming the skeleton; 2-1mm, 10%-13%, serving to fill the gaps in the skeleton; 1-0.5mm, 8%-10%, serving as primary filler; 0.5-0mm, 7%-9%, serving as a secondary filler; 200 mesh, 18%-20%, serves as a third-level filler; Particle bulk density ≥68%.
[0018] The particle size distribution of each component is as follows: Fused spinel ≥200 mesh; Forsterite ≥200 mesh; Boron carbide is 325 mesh; Nano-α-Al₂O₃ has a size of 1 μm; Flake graphite is 300 mesh; Aluminum-magnesium alloy powder ≥180 mesh; High-temperature asphalt powder is 200 mesh; The ceramic adhesive is 180 mesh. Both the thermoplastic resin and the resin reinforcing agent are low-viscosity liquids with a viscosity of 12,000-15,000 MPa. s. Forms an ultrafine filling layer at the "micron-nanometer" level, filling the micropores between the base material particles.
[0019] Existing technologies using magnesium slide plates require asphalt impregnation, resulting in severe pollution; they have poor thermal shock stability (water cooling cycle ≤8 times); they rely on asphalt impregnation to fill pores (porosity 6%-8%); single aluminum powder / silicon powder has low oxidation resistance; the production cycle is 30 days, and it uses 1800 m³ / ton of natural gas.
[0020] This invention employs a non-impregnation design, utilizing modified resin and ceramic adhesives to achieve a synergistic effect of "alkaline corrosion resistance" and "zero-pollution production," resulting in a 100% improvement in environmental friendliness. The synergistic use of magnesium olivine and large-flake graphite, with a cycle life of ≥15 cycles, overcomes the contradiction between "thermal shock resistance and corrosion resistance" in magnesium materials, improving thermal shock stability by 87.5%. Three-stage particle gradation and nanofilling result in a porosity of ≤3%, achieving a density exceeding that of traditional impregnated products in a non-impregnation state, and improving permeability resistance by 60%. The synergistic use of boron carbide and aluminum-magnesium alloy powder for oxidation resistance increases oxidation efficiency by 60%, reducing carbon loss due to oxidation to below 1.2%. The production cycle is 12-15 days, with natural gas consumption of 30 m³ / ton, shortening the cycle by 50% and reducing energy consumption by 98.3%.
[0021] At the same time, the asphalt impregnation process is completely eliminated, and there is no emission of toxic substances such as benzo[a]pyrene and phenols during the production process. The emission concentration of exhaust gas complies with GB 31573-2015 "Emission Standard of Pollutants for Inorganic Chemical Industry". Low energy consumption: The production cycle is shortened from 30 days to 12-15 days, natural gas consumption is reduced from 1800m³ / ton to 30m³ / ton, annual production capacity is increased by 100%, and energy consumption cost per ton of product is reduced by more than 2000 yuan; The consumption of refractory materials per ton of steel has been reduced from 2.5 kg to 1.4 kg, resulting in a cost reduction of 2.5 yuan per ton of steel. Based on a steel plant with an annual output of 10 million tons, this translates to annual cost savings of 25 million yuan.
[0022] Table 1: Formulations of Examples 1-3 (by weight): Table 2. Physicochemical property test results of Examples 1-3: In summary, it can be seen that Formula 2 has the best overall performance. Its room temperature pressure resistance, density, high temperature flexural strength and number of continuous castings all reach their peak values, and its porosity is the lowest. It fully meets the requirements of continuous casting of highly corrosive steel grades, and the production process is pollution-free and energy-efficient.
[0023] According to one aspect of the present invention, a method for preparing an impregnated alkaline sliding plate brick is provided, characterized by comprising the following steps; S1. Component pretreatment: 97 fused magnesia, forsterite and fused spinel are crushed and screened according to their gradation to remove adsorbed moisture and set aside. S2, phased mixing; S3, High-pressure molding; S4, gradient drying; S5, low-temperature firing; S6, Post-processing.
[0024] In step S1, the particle size deviation is ≤5%; boron carbide is dried at 120℃ for 2 hours.
[0025] In step S2, the phased mixing includes the following steps: First stage, skeleton mixing: Add coarse 3-1mm and 21mm fused magnesia particles to a high-speed mixer at 150r / min and mix for 4-6 minutes. Second stage, filling and mixing: Add 1-0.5mm, 0.5-0mm, 200 mesh fine particles of 97 electrofused magnesia, forsterite, and electrofused spinel, reduce the speed to 100r / min, and mix for 8-10 minutes; Third stage, functional mixing: Add boron carbide, nano α-Al2O3, graphite, aluminum-magnesium alloy powder, and high-temperature asphalt powder, and mix for 10-12 minutes at a speed of 80 r / min. Fourth stage, bonding and mixing: Finally, add the modified thermoplastic resin and resin reinforcing agent, and mix for 5-8 minutes at a speed of 60 r / min.
[0026] In step S3, the high-pressure molding process is as follows: a 1500-ton spiral brick press is used, and the pressure is applied in three stages: initial pressure of 30MPa followed by 5s, medium pressure of 80MPa followed by 8s, and final pressure of 120MPa followed by 10s. The green body bulk density is ≥2.75g / cm³.
[0027] The gradient drying process in step S4 includes the following steps: Pre-drying: Air dry for 24 hours to remove surface free water; Gradient heating: Increase the temperature to 60℃ in 1 hour and hold for 10 hours to remove adsorbed water; then slowly increase the temperature to 120℃ in 18 hours and hold for 15 hours to remove crystal water; increase the temperature to 180℃ in 10 hours and hold for 20 hours to initially cure the resin; the total drying time is 58-63 hours.
[0028] The low-temperature firing process in step S5 includes the following steps: Heating phase: The temperature is raised to 580℃±10℃ at a constant rate over 16 hours, with the heating rate controlled at 36℃ / h; Insulation stage: Insulate for 18 hours; Cooling phase: The temperature is uniformly reduced to room temperature over 24 hours at a rate of 24℃ / h.
[0029] Step S6 includes the following processing steps: fine finishing of the bricks and encasing the finished bricks in iron shells.
[0030] The above descriptions are merely some embodiments of the present invention. It should be noted that those skilled in the art can make other modifications and improvements without departing from the inventive concept of the present invention, and these all fall within the protection scope of the present invention.
Claims
1. An alkaline sliding plate brick that does not require impregnation, characterized in that, By weight percentage, it includes the following components: 97% fused magnesia: 65%-70% Forsterite: 4%-6% Fused spinel: 5%-7% Boron carbide: 2%-3% Nano α-Al2O3 micro powder: 3%-5% Modified thermoplastic resin: 3%-4% Ceramic adhesive: 3%-5% Flake graphite: 2%-3% Aluminum-magnesium alloy powder: 1%-2% High-temperature asphalt powder: 1%-2%, In addition, thermoplastic resin: 3%-4%, Resin reinforcing agent: 0.3%-0.5%.
2. The impregnation-free alkaline sliding plate brick according to claim 1, characterized in that, The particle size distribution of the 97 electrofused magnesia is as follows: 3-1mm, 22%-25%; 2-1mm, 10%-13%; 1-0.5mm, 8%-10%; 0.5-0mm, 7%-9%; 200 mesh, 18%-20%; The particle bulk density is ≥68%.
3. The alkaline slide block without impregnation according to claim 2, characterized in that, The particle size distribution of each component is as follows: The fused spinel is ≥200 mesh; The forsterite is ≥200 mesh; The boron carbide is 325 mesh; The nano-α-Al₂O₃ has a size of 1 μm; The flake graphite is 300 mesh; The aluminum-magnesium alloy powder has a mesh size of ≥180. The high-temperature asphalt powder is 200 mesh; The ceramic adhesive is 180 mesh. Both the thermoplastic resin and the resin reinforcing agent are low-viscosity liquids with a viscosity of 12000-15000 MPa. s.
4. The method for preparing the impregnated alkaline sliding plate brick according to any one of claims 1-3, characterized in that, Includes the following steps; S1. Component pretreatment: 97 fused magnesia, forsterite and fused spinel are crushed and screened according to their gradation to remove adsorbed moisture and set aside. S2, phased mixing; S3, High-pressure molding; S4, gradient drying; S5, low-temperature firing; S6, Post-processing.
5. The method for preparing the impregnated alkaline sliding plate brick according to claim 4, characterized in that, In step S1, the particle size deviation is ≤5%; boron carbide is dried at 120°C for 2 hours.
6. The method for preparing the impregnation-free alkaline sliding plate brick according to claim 4, characterized in that, In step S2, the phased mixing includes the following steps: First stage, skeleton mixing: Add coarse 3-1mm and 21mm fused magnesia particles to a high-speed mixer at 150r / min and mix for 4-6 minutes. Second stage, filling and mixing: Add 1-0.5mm, 0.5-0mm, 200 mesh fine particles of 97 electrofused magnesia, forsterite, and electrofused spinel, reduce the speed to 100r / min, and mix for 8-10 minutes; Third stage, functional mixing: Add boron carbide, nano α-Al2O3, graphite, aluminum-magnesium alloy powder, and high-temperature asphalt powder, and mix for 10-12 minutes at a speed of 80 r / min. Fourth stage, bonding and mixing: Finally, add the modified thermoplastic resin and resin reinforcing agent, and mix for 5-8 minutes at a speed of 60 r / min.
7. The method for preparing the impregnated alkaline sliding plate brick according to claim 4, characterized in that, In step S3, the high-pressure molding process is as follows: a 1500-ton spiral brick press is used, and the pressure is applied in three stages: initial pressure of 30MPa followed by 5s, medium pressure of 80MPa followed by 8s, and final pressure of 120MPa followed by 10s. The green body bulk density is ≥2.75g / cm³.
8. The method for preparing the impregnated alkaline sliding plate brick according to claim 4, characterized in that, The gradient drying process in step S4 includes the following steps: Pre-drying: Air dry for 24 hours to remove surface free water; Gradient heating: Increase the temperature to 60℃ in 1 hour and hold for 10 hours to remove adsorbed water; then slowly increase the temperature to 120℃ in 18 hours and hold for 15 hours to remove crystal water; increase the temperature to 180℃ in 10 hours and hold for 20 hours to initially cure the resin; the total drying time is 58-63 hours.
9. The method for preparing the impregnated alkaline sliding plate brick according to claim 4, characterized in that, The low-temperature firing process in step S5 includes the following steps: Heating phase: The temperature is raised to 580℃±10℃ at a constant rate over 16 hours, with the heating rate controlled at 36℃ / h; Insulation stage: Insulate for 18 hours; Cooling phase: The temperature is uniformly reduced to room temperature over 24 hours at a rate of 24℃ / h.
10. The method for preparing the impregnation-free alkaline sliding plate brick according to claim 4, characterized in that, Its features are, The processing in step S6 includes: fine processing of the brick body and encasing the finished brick in an iron shell.