High-aluminum preform and method for manufacturing the same

Abstract

This invention discloses a high-alumina precast component and its preparation method. The high-alumina precast component, by weight percentage, comprises the following raw materials: 28%-38% high-alumina recycled ball pellets, 10%-15% alumina-carbon sliding plate recycled pellets, 8%-15% bauxite aggregate, 3%-6% kyanite, 2%-5% silicon carbide, 5%-10% α-alumina powder, 3%-8% calcium aluminate cement, 3%-7% silica fume, 0.1%-0.3% water-reducing agent, 1%-2% toughening agent, 0.05%-0.2% explosion-proof fiber, and 0.02%-0.04% explosion-proof agent. The water-reducing agent is sodium tripolyphosphate; the toughening agent is stainless steel fiber; and the explosion-proof agent is metallic aluminum powder. The beneficial effects of this invention are: effectively reducing the hydration of recycled alumina-carbon sliding plate pellets, completing the processing and recycling of waste alumina-carbon sliding plate bricks and high-alumina hot blast furnace balls, saving raw materials, and improving the slag resistance and thermal shock resistance of the product.

Description

Technical Field

[0001] This invention relates to the field of refractory materials and the recycling of waste refractory materials, specifically a high-alumina preform and its preparation method. Background Technology

[0002] High-alumina precast components are shaped refractory parts precast in a factory using high-alumina refractory castables that are precast, cured, and baked. They possess the high refractoriness, high-temperature strength, and chemical stability of high-alumina materials, while also offering the convenience of construction and controllable performance due to prefabrication. The raw material is primarily high-alumina bauxite, often reinforced with steel fibers, corundum, spinel, and other reinforcing components, suitable for high-temperature conditions of 1300-1770°C. Cast-molded high-alumina precast components are widely used in steelmaking tundishes for retaining walls, impact plates, and seat bricks. During use, they are subjected to prolonged erosion and corrosion by molten steel, and their quality and performance directly affect the normal operation of continuous casting machines.

[0003] Currently, the main aggregates used in the production of existing high-alumina refractory castable precast components are 75 or 85 high-alumina bauxite. Considering that the product is consumed once and the amount used in the process is large, it has a significant impact on the cost of intermediate refractory materials. The high cost of raw materials also affects the product's market competitiveness.

[0004] Currently, waste sliding plate bricks generated by steel mills are only used in anhydrous products such as resins. The application scope and usage of waste sliding plate bricks are small, resulting in resource waste and environmental pollution.

[0005] Existing aluminum-carbon sliding plate bricks have not been widely used in various castables and precast components because the problem of residual carbon hydration cannot be solved.

[0006] Therefore, developing high-performance precast products and ensuring controllable product quality is an effective way to guarantee stable production in user industries, and it is also an urgent problem to be solved in the refractory materials industry. Summary of the Invention

[0007] The purpose of this invention is to provide a high-alumina precast component with superior structural design quality, ease of processing, low manufacturing cost, and convenient operation. This is achieved through the use of low-melting-point explosion-proof fibers, foamed explosion-proof agents, and toughening agents, along with process improvements such as rapid heating and drainage. This effectively reduces the hydration of recycled aluminum-carbon sliding plate particles, enabling the processing and recycling of waste aluminum-carbon sliding plate bricks and high-alumina hot blast furnace balls. This saves raw materials, significantly reduces the raw material costs of precast products, and results in high-alumina precast components with improved slag resistance and thermal shock resistance, along with its preparation method.

[0008] This invention discloses a high-alumina precast component, the raw materials for which, by weight percentage, are: 28%-38% high-alumina spherical recycled pellets, 10%-15% alumina-carbonaceous sliding plate recycled pellets, 8%-15% bauxite aggregate, 3%-6% kyanite, 2%-5% silicon carbide, 5%-10% α-alumina powder, 3%-8% calcium aluminate cement, 3%-7% silica fume, 0.1%-0.3% water-reducing agent, 1%-2% toughening agent, 0.05%-0.2% explosion-proof fiber, and 0.02%-0.04% explosion-proof agent.

[0009] The high-alumina spherical recycled granules have a particle size of 5-15mm and ≥200 mesh, and an Al2O3 content of ≥70%; the alumina-carbon sliding plate recycled granules have a particle size of 1-3mm and 3-5mm, and an Al2O3 content of ≥95%; the bauxite aggregate has a particle size of 0-1mm, and an Al2O3 content of 75%; the kyanite has a particle size of 60 mesh, and an Al2O3 content of 55%; the silicon carbide has a particle size of 325 mesh, and a purity of 90%; the α-alumina powder has a particle size of 3-5μm; the calcium aluminate cement has an aluminum content of 68%-72%, and the refractoriness of the cement paste is 1650°-1690°; the silica fume has a SiO2 content of 95%.

[0010] The water-reducing agent is sodium tripolyphosphate; the toughening agent is stainless steel fiber; and the explosion-proof agent is metallic aluminum powder.

[0011] The melting point of the explosion-proof fiber is 160-170℃.

[0012] By incorporating recycled waste alumina-carbon sliding plate bricks into the raw materials for refractory castable precast components, 1-3mm and 3-5mm alumina-carbon particles are obtained through sorting and crushing. High-alumina balls from waste hot blast stoves are introduced, and 5-15mm high-alumina particles are obtained through sorting and crushing. High-alumina ball powder with a fineness of over 200 mesh is obtained through sorting and grinding. Through rational proportioning design, the product design incorporates the maximum amount of waste refractory material particles, effectively eliminating the adverse effects of waste refractory materials on the product. Simultaneously, it maximizes the utilization of beneficial elements in the residual carbon of the recycled refractory materials, improving the product's resistance to slag erosion and melting loss. This achieves comprehensive and efficient reuse of waste refractory materials, reducing raw material costs by over 60%, resulting in significant direct economic benefits.

[0013] Low-melting-point explosion-proof fibers, foamed explosion-proof agents, and toughening agents are used to enhance the explosion-proof properties of the product during rapid drying. Explosion-proof fibers can effectively improve the material's explosion resistance and prevent cracking during drying and heating. Foamed explosion-proof agents can form a porous structure during rapid drying, which helps to release moisture slowly, thereby reducing internal pressure and preventing cracking. Toughening agents can improve the material's impact strength and flexibility, reduce brittleness, thereby reducing the possibility of cracking during rapid drying and improving the processing quality of prefabricated parts.

[0014] The obtained refractory castable precast parts, by weight percentage: Al2O3 ≥ 60%, bulk density ≥ 2.4 g / cm³ 3 At room temperature (200℃×24h), the compressive strength is ≥20Mpa and the flexural strength is ≥4Mpa; at high temperature (1500℃×3h), the compressive strength is ≥30Mpa and the flexural strength is ≥6Mpa. The product's performance well meets the requirements of on-site production and has the conditions and value for promotion.

[0015] A method for preparing a high-alumina preform includes the following steps: S1. The recycled waste aluminum-carbon sliding bricks are removed by removing the iron rings and surface debris from the external parts. The bricks are then crushed by a crusher with rollers. During the crushing process, the iron impurities in the recycled waste aluminum-carbon sliding bricks are removed. After screening, recycled aluminum-carbon sliding brick granules with particle sizes of 1-3mm and 3-5mm are obtained. S2. The recycled waste high-alumina hot blast furnace balls are removed by removing the slag and surface impurities. They are then crushed by a double roller crusher. During the crushing process, iron impurities in the recycled waste high-alumina balls are removed. After screening, recycled high-alumina ball granules with a particle size of 5-15mm are obtained. S3. The 5-15mm high-alumina ball regenerated particles obtained in step S2 are processed by grinding equipment to obtain high-alumina ball powder with a particle size of 200 mesh or more; S4. The physicochemical properties of particle size distribution, bulk density, and chemical composition of the aluminum-carbon recycled granules with particle sizes of 1-3 mm and 3-5 mm obtained in step S1, the high-alumina sphere recycled granules with particle size of 5-15 mm obtained in step S2, and the high-alumina sphere powder with a particle size of more than 200 mesh obtained in step S3 are tested. S5. Add bauxite aggregate, kyanite, silicon carbide, α-alumina powder, calcium aluminate cement, silica fume, explosion-proof fiber, explosion-proof agent, toughening agent, and water-reducing agent to the recycled aluminum carbon slide plate granules with particle sizes of 1-3mm and 3-5mm obtained in step S1, the recycled high alumina ball granules with particle size of 5-15mm obtained in step S2, and the high alumina ball powder with a particle size of 200 mesh or more obtained in step S3 in proportion. Mix them in a mixer and after mixing for 8-10 minutes, discharge and bag them. The metering error should be controlled within 25±0.25kg. Set aside for later use. S6. Transport the material obtained after mixing in step S5 to the precast casting production line. According to the amount of precast casting production, add it to the mixer and dry mix for 1-2 minutes. Add 5%-7% water and mix for 2-3 minutes to prepare for material feeding and vibration molding. S7. After placing the precast mold, open the mixer's discharge port and turn on the vibrating table. Vibrate while discharging the material to evenly distribute the well-mixed mud across the mold frame. The vibration time should be no less than 30 seconds, until the surface of the precast part has small air bubbles, a smooth surface, and uniform particle distribution. S8. The preforms obtained in step S7 are transported to the curing area for natural curing. The curing time with the mold is controlled at 12-24 hours, and the curing time after demolding is controlled at 36-48 hours. The curing environment temperature is controlled at 15-25℃. The mold is kept level during the curing process. According to the characteristics of the product production process, the curing time is shortened by more than 24 hours, and the baking time is reduced by more than 24 hours, which effectively improves production capacity, reduces power and energy consumption, and has obvious indirect benefits. S9. Stack the cured precast parts in the kiln car for baking, ensuring a minimum spacing of 20mm between each part. The baking curve is as follows: from room temperature to 140℃, control the baking time within 10 hours, hold for 2 hours; from 140℃ to 320℃, control the baking time within 12 hours, hold for 2 hours, then cool to below 50℃ before removing from the kiln. Properly spacing the precast parts in the kiln car ensures even heat distribution. Simultaneously, adjust the baking curve to minimize drying and baking time while ensuring sufficient moisture removal, thus reducing the time for hydration reactions of impurities such as carbon in the recovered particles.

[0016] The preform parameters obtained in step S9 are characterized by, by weight percentage: Al2O3 ≥ 60%, and bulk density ≥ 2.4 g / cm³. 3 At room temperature (200℃×24h), the compressive strength is ≥20MPa and the flexural strength is ≥4MPa; at high temperature (1500℃×3h), the compressive strength is ≥30MPa and the flexural strength is ≥6MPa.

[0017] By optimizing the curing and baking process curves of prefabricated components, moisture removal is accelerated, reducing product hydration, powdering, cracking, and fissures. The relevant technical methods are being used for the first time in the relevant product fields and industries, and have a good leading and demonstrative effect.

[0018] Beneficial effects of this invention: 1) By adding recycled waste alumina-carbon sliding plate bricks to the raw materials for refractory casting precast components, 1-3mm and 3-5mm alumina-carbon particles are obtained through sorting and crushing; high-alumina balls from waste hot blast stoves are introduced, and 5-15mm high-alumina particles are obtained through sorting and crushing; high-alumina ball powder with a fineness of over 200 mesh is obtained through sorting and grinding. Through reasonable proportioning design, the product design introduces the maximum amount of waste refractory material particles, effectively eliminating the adverse effects of waste refractory materials on the product. At the same time, it maximizes the utilization of beneficial elements in the residual carbon of recycled refractory materials, improves the product's resistance to slag erosion and melting loss, realizes the comprehensive and efficient reuse of waste refractory materials, reduces the raw material cost of the product by more than 60%, and has significant direct economic benefits.

[0019] 2) Low-melting-point explosion-proof fibers, foamed explosion-proof agents, and toughening agents are used to improve the explosion-proof properties of the product during the rapid drying process. Explosion-proof fibers can effectively improve the explosion resistance of the material and prevent cracking during the drying and heating process. Foamed explosion-proof agents can form a porous structure during rapid drying, which helps to release moisture slowly, thereby reducing internal pressure and preventing cracking. Toughening agents can improve the impact strength and flexibility of the material and reduce brittleness, thereby reducing the possibility of cracking during rapid drying and improving the processing quality of prefabricated parts.

[0020] 3) By optimizing the curing and baking process curves of prefabricated parts, the moisture discharge is accelerated, reducing the generation of hydration, powdering, cracking and fissures in the product. The relevant technical methods are used for the first time in the relevant product fields and industries, and have a good leading and demonstration effect.

[0021] 4) The obtained refractory castable precast parts, by weight percentage: Al2O3 ≥ 60%, bulk density ≥ 2.4 g / cm³ 3 At room temperature (200℃×24h), the compressive strength is ≥20Mpa and the flexural strength is ≥4Mpa; at high temperature (1500℃×3h), the compressive strength is ≥30Mpa and the flexural strength is ≥6Mpa. The product's performance well meets the requirements of on-site production and has the conditions and value for promotion.

[0022] 5) This method is easy to process, has low processing and manufacturing costs, and is convenient to operate. By adopting technologies such as low melting point explosion-proof fibers, foamed explosion-proof agents and toughening agents, and through process improvements such as rapid heating and drainage, it effectively reduces the hydration of recycled aluminum carbon slide plate particles, completes the processing and recycling of waste aluminum carbon slide plate bricks and high alumina hot blast furnace balls, saves raw materials, significantly reduces the raw material cost of precast products, and improves the slag resistance and thermal shock resistance of the obtained precast products. Detailed Implementation

[0023] Example 1. This invention discloses a high-alumina precast component, the raw materials for which, by weight percentage, are: 28% high-alumina spherical recycled pellets, 10% alumina-carbonaceous sliding plate recycled pellets, 8% bauxite aggregate, 3% kyanite, 2% silicon carbide, 5% α-alumina powder, 3% calcium aluminate cement, 3% silica fume, 0.1% water-reducing agent, 1% toughening agent, 0.05% explosion-proof fiber, and 0.02% explosion-proof agent.

[0024] The high-alumina spherical recycled granules have a particle size of 5-15mm and ≥200 mesh, and an Al2O3 content of ≥70%; the alumina-carbon sliding plate recycled granules have a particle size of 1mm and 3mm, and an Al2O3 content of ≥95%; the bauxite aggregate has a particle size of 0-1mm, and an Al2O3 content of 75%; the kyanite has a particle size of 60 mesh, and an Al2O3 content of 55%; the silicon carbide has a particle size of 325 mesh, and a purity of 90%; the α-alumina powder has a particle size of 3μm; the calcium aluminate cement has an aluminum content of 68%, and the refractoriness of the cement paste is 1650°-1690°; the silica fume has a SiO2 content of 95%.

[0025] The water-reducing agent is sodium tripolyphosphate; the toughening agent is stainless steel fiber; and the explosion-proof agent is metallic aluminum powder.

[0026] By incorporating recycled waste alumina-carbon sliding plate bricks into the raw materials for refractory castable precast components, 1mm and 3mm alumina-carbon particles are obtained through sorting and crushing. High-alumina balls from waste hot blast stoves are introduced, and 5mm high-alumina particles are obtained through sorting and crushing. High-alumina ball powder with a fineness of over 200 mesh is obtained through sorting and grinding. Through rational proportioning design, the product design incorporates the maximum amount of waste refractory material particles, effectively eliminating the adverse effects of waste refractory materials on the product. Simultaneously, it maximizes the utilization of beneficial elements in the residual carbon of the recycled refractory materials, improving the product's resistance to slag erosion and melting loss. This achieves comprehensive and efficient reuse of waste refractory materials, reducing raw material costs by more than 60%, resulting in significant direct economic benefits.

[0027] Low-melting-point explosion-proof fibers, foamed explosion-proof agents, and toughening agents are used to enhance the explosion-proof properties of the product during rapid drying. Explosion-proof fibers can effectively improve the material's explosion resistance and prevent cracking during drying and heating. Foamed explosion-proof agents can form a porous structure during rapid drying, which helps to release moisture slowly, thereby reducing internal pressure and preventing cracking. Toughening agents can improve the material's impact strength and flexibility, reduce brittleness, thereby reducing the possibility of cracking during rapid drying and improving the processing quality of prefabricated parts.

[0028] The obtained refractory castable precast components, by weight percentage: Al2O3 ≥ 60%, bulk density ≥ 2.4 g / cm³ 3 At room temperature (200℃×24h), the compressive strength is ≥20Mpa and the flexural strength is ≥4Mpa; at high temperature (1500℃×3h), the compressive strength is ≥30Mpa and the flexural strength is ≥6Mpa. The product's performance well meets the requirements of on-site production and has the conditions and value for promotion.

[0029] A method for preparing a high-alumina preform includes the following steps: S1. The recycled waste aluminum-carbon sliding bricks are removed by removing the iron rings and surface debris from the external parts. The bricks are then crushed by a crusher with rollers. During the crushing process, the iron impurities in the recycled waste aluminum-carbon sliding bricks are removed. After screening, recycled aluminum-carbon sliding brick granules with particle sizes of 1-3mm and 3-5mm are obtained. S2. The recycled waste high-alumina hot blast furnace balls are removed by removing the slag and surface impurities. They are then crushed by a double roller crusher. During the crushing process, iron impurities in the recycled waste high-alumina balls are removed. After screening, the recycled high-alumina ball granules with a particle size of 5mm are obtained. S3. The 5mm high-alumina sphere regenerated particles obtained in step S2 are processed by grinding equipment to obtain high-alumina sphere powder with a particle size of 200 mesh or more; S4. The particle size distribution, bulk density, and chemical composition of the aluminum-carbon recycled granules with particle sizes of 1 mm and 3 mm obtained in step S1, the high-alumina sphere recycled granules with a particle size of 5 mm obtained in step S2, and the high-alumina sphere powder with a particle size of more than 200 mesh obtained in step S3 are tested. S5. Add bauxite aggregate, kyanite, silicon carbide, α-alumina powder, calcium aluminate cement, silica fume, explosion-proof fiber, explosion-proof agent, toughening agent, and water-reducing agent to the recycled aluminum carbon slide plate granules with particle sizes of 1mm and 3mm obtained in step S1, the recycled high alumina ball granules with a particle size of 5mm obtained in step S2, and the high alumina ball powder with a particle size of 200 mesh or more obtained in step S3. Mix them in a mixer according to the proportion. After mixing for 8-10 minutes, discharge and bag the material. The metering error should be controlled within 25±0.25kg. Set aside for later use. S6. Transport the material obtained after mixing in step S5 to the precast casting production line. According to the amount of precast casting production, add it to the mixer and dry mix for 1-2 minutes. Add 5%-7% water and mix for 2-3 minutes to prepare for material feeding and vibration molding. S7. After placing the precast mold, open the mixer's discharge port and turn on the vibrating table. Vibrate while discharging the material to evenly distribute the well-mixed mud across the mold frame. The vibration time should be no less than 30 seconds, until the surface of the precast part has small air bubbles, a smooth surface, and uniform particle distribution. S8. The preforms obtained in step S7 are transported to the curing area for natural curing. The curing time with the mold is controlled at 12-24 hours, and the curing time after demolding is controlled at 36-48 hours. The curing environment temperature is controlled at 15-25℃. The mold is kept level during the curing process. According to the characteristics of the product production process, the curing time is shortened by more than 24 hours, and the baking time is reduced by more than 24 hours, which effectively improves production capacity, reduces power and energy consumption, and has obvious indirect benefits. S9. Stack the cured precast parts in the kiln car for baking, ensuring a minimum spacing of 20mm between each part. The baking curve is as follows: from room temperature to 140℃, control the baking time within 10 hours, hold for 2 hours; from 140℃ to 320℃, control the baking time within 12 hours, hold for 2 hours, then cool to below 50℃ before removing from the kiln. Properly spacing the precast parts in the kiln car ensures even heat distribution. Simultaneously, adjust the baking curve to minimize drying and baking time while ensuring sufficient moisture removal, thus reducing the time for hydration reactions of impurities such as carbon in the recovered particles.

[0030] The preform parameters obtained in step S9 are characterized by, by weight percentage: Al2O3 ≥ 60%, bulk density ≥ 2.4 g / cm³. 3 At room temperature (200℃×24h), the compressive strength is ≥20MPa and the flexural strength is ≥4MPa; at high temperature (1500℃×3h), the compressive strength is ≥30MPa and the flexural strength is ≥6MPa.

[0031] The recycled aluminum-carbon sliding plate bricks mentioned above are mainly waste aluminum-carbon sliding plate bricks recycled from steelmaking converters and ladles. The high-alumina balls used are mainly waste high-alumina hot blast stove balls recycled after the dismantling of blast furnace hot blast stoves, and their material is mainly aluminum oxide.

[0032] The melting point of the explosion-proof fiber is 160-170℃.

[0033] The crusher is a jaw crusher; the mixer is a planetary mixer.

[0034] Example 2 This invention discloses a high-alumina precast component, the raw materials for which, by weight percentage, are: 38% high-alumina spherical recycled pellets, 15% alumina-carbonaceous sliding plate recycled pellets, 15% bauxite aggregate, 6% kyanite, 5% silicon carbide, 10% α-alumina powder, 8% calcium aluminate cement, 7% silica fume, 0.3% water-reducing agent, 2% toughening agent, 0.2% explosion-proof fiber, and 0.04% explosion-proof agent.

[0035] The high-alumina spherical recycled granules have a particle size of 5-15mm and ≥200 mesh, and an Al2O3 content of ≥70%; the alumina-carbon sliding plate recycled granules have a particle size of 3mm and 5mm, and an Al2O3 content of ≥95%; the bauxite aggregate has a particle size of 0-1mm, and an Al2O3 content of 75%; the kyanite has a particle size of 60 mesh, and an Al2O3 content of 55%; the silicon carbide has a particle size of 325 mesh, and a purity of 90%; the α-alumina powder has a particle size of 5μm; the calcium aluminate cement has an aluminum content of 72%, and the refractoriness of the cement paste is 1650°-1690°; the silica fume has a SiO2 content of 95%.

[0036] The water-reducing agent is sodium tripolyphosphate; the toughening agent is stainless steel fiber; and the explosion-proof agent is metallic aluminum powder.

[0037] By incorporating recycled waste alumina-carbon sliding plate bricks into the raw materials for refractory castable precast components, 3mm and 5mm alumina-carbon particles are obtained through sorting and crushing. High-alumina balls from waste hot blast stoves are introduced, and 15mm high-alumina particles are obtained through sorting and crushing. High-alumina ball powder with a fineness of over 200 mesh is obtained through sorting and grinding. Through rational proportioning design, the product design incorporates the maximum amount of waste refractory material particles, effectively eliminating the adverse effects of waste refractory materials on the product. Simultaneously, it maximizes the utilization of beneficial elements from residual carbon in the recycled refractory materials, improving the product's resistance to slag erosion and melting loss. This achieves comprehensive and efficient reuse of waste refractory materials, reducing raw material costs by over 60%, resulting in significant direct economic benefits.

[0038] Low-melting-point explosion-proof fibers, foamed explosion-proof agents, and toughening agents are used to enhance the explosion-proof properties of the product during rapid drying. Explosion-proof fibers can effectively improve the material's explosion resistance and prevent cracking during drying and heating. Foamed explosion-proof agents can form a porous structure during rapid drying, which helps to release moisture slowly, thereby reducing internal pressure and preventing cracking. Toughening agents can improve the material's impact strength and flexibility, reduce brittleness, thereby reducing the possibility of cracking during rapid drying and improving the processing quality of prefabricated parts.

[0039] The obtained refractory castable precast components, by weight percentage: Al2O3 ≥ 60%, bulk density ≥ 2.4 g / cm³ 3 At room temperature (200℃×24h), the compressive strength is ≥20Mpa and the flexural strength is ≥4Mpa; at high temperature (1500℃×3h), the compressive strength is ≥30Mpa and the flexural strength is ≥6Mpa. The product's performance well meets the requirements of on-site production and has the conditions and value for promotion.

[0040] A method for preparing a high-alumina preform includes the following steps: S1. The recycled waste aluminum-carbon sliding bricks are removed by removing the iron rings and surface debris from the external parts. The bricks are then crushed by a crusher with rollers. During the crushing process, the iron impurities in the recycled waste aluminum-carbon sliding bricks are removed. After screening, recycled aluminum-carbon sliding brick pellets with particle sizes of 3mm and 5mm are obtained. S2. The recycled waste high-alumina hot blast furnace balls are removed by removing the slag and surface impurities. They are then crushed by a double roller crusher. During the crushing process, iron impurities in the recycled waste high-alumina balls are removed. After screening, high-alumina ball recycled granules with a particle size of 15mm are obtained. S3. The 15mm high-alumina sphere regenerated particles obtained in step S2 are processed by grinding equipment to obtain high-alumina sphere powder with a particle size of 200 mesh or more; S4. The particle size distribution, bulk density, and chemical composition of the aluminum-carbon recycled granules with particle sizes of 3 mm and 5 mm obtained in step S1, the high-alumina sphere recycled granules with a particle size of 15 mm obtained in step S2, and the high-alumina sphere powder with a particle size of more than 200 mesh obtained in step S3 are tested. S5. Add bauxite aggregate, kyanite, silicon carbide, α-alumina powder, calcium aluminate cement, silica fume, explosion-proof fiber, explosion-proof agent, toughening agent, and water-reducing agent to the recycled aluminum carbon slide plate granules with particle sizes of 3mm and 5mm obtained in step S1, the recycled high alumina ball granules with a particle size of 15mm obtained in step S2, and the high alumina ball powder with a particle size of 200 mesh or more obtained in step S3. Mix them in a mixer according to the proportion. After mixing for 8-10 minutes, discharge and bag the material. The metering error should be controlled within 25±0.25kg. Set aside for later use. S6. Transport the material obtained after mixing in step S5 to the precast casting production line. According to the amount of precast casting production, add it to the mixer and dry mix for 1-2 minutes. Add 5%-7% water and mix for 2-3 minutes to prepare for material feeding and vibration molding. S7. After placing the precast mold, open the mixer's discharge port and turn on the vibrating table. Vibrate while discharging the material to evenly distribute the well-mixed mud across the mold frame. The vibration time should be no less than 30 seconds, until the surface of the precast part has small air bubbles, a smooth surface, and uniform particle distribution. S8. The preforms obtained in step S7 are transported to the curing area for natural curing. The curing time with the mold is controlled at 12-24 hours, and the curing time after demolding is controlled at 36-48 hours. The curing environment temperature is controlled at 15-25℃. The mold is kept level during the curing process. According to the characteristics of the product production process, the curing time is shortened by more than 24 hours, and the baking time is reduced by more than 24 hours, which effectively improves production capacity, reduces power and energy consumption, and has obvious indirect benefits. S9. Stack the cured precast parts in the kiln car for baking, ensuring a minimum spacing of 20mm between each part. The baking curve is as follows: from room temperature to 140℃, control the baking time within 10 hours, hold for 2 hours; from 140℃ to 320℃, control the baking time within 12 hours, hold for 2 hours, then cool to below 50℃ before removing from the kiln. Properly spacing the precast parts in the kiln car ensures even heat distribution. Simultaneously, adjust the baking curve to minimize drying and baking time while ensuring sufficient moisture removal, thus reducing the time for hydration reactions of impurities such as carbon in the recovered particles.

[0041] The preform parameters obtained in step S9 are characterized by, by weight percentage: Al2O3 ≥ 60%, bulk density ≥ 2.4 g / cm³. 3 At room temperature (200℃×24h), the compressive strength is ≥20MPa and the flexural strength is ≥4MPa; at high temperature (1500℃×3h), the compressive strength is ≥30MPa and the flexural strength is ≥6MPa.

[0042] The recycled aluminum-carbon sliding plate bricks mentioned above are mainly waste aluminum-carbon sliding plate bricks recycled from steelmaking converters and ladles. The high-alumina balls used are mainly waste high-alumina hot blast stove balls recycled after the dismantling of blast furnace hot blast stoves, and their material is mainly aluminum oxide.

[0043] The melting point of the explosion-proof fiber is 160-170℃.

[0044] The crusher is a jaw crusher; the mixer is a planetary mixer.

Claims

1. A high-alumina preform, characterized in that, The raw materials for its preparation, by weight percentage, include: high-alumina recycled spherical pellets: 28%-38%, alumina-carbon recycled spherical pellets: 10%-15%, bauxite aggregate: 8%-15%, kyanite: 3%-6%, silicon carbide: 2%-5%, α-alumina powder: 5%-10%, calcium aluminate cement: 3%-8%, silica fume: 3%-7%, water-reducing agent: 0.1%-0.3%, toughening agent: 1%-2%, explosion-proof fiber: 0.05%-0.2%, and explosion-proof agent: 0.02%-0.04%.

2. The high-alumina preform as described in claim 1, characterized in that: The high-alumina spherical recycled granules have a particle size of 5-15mm and ≥200 mesh, and an Al2O3 content of ≥70%; the alumina-carbon sliding plate recycled granules have a particle size of 1-3mm and 3-5mm, and an Al2O3 content of ≥95%; the bauxite aggregate has a particle size of 0-1mm, and an Al2O3 content of 75%; the kyanite has a particle size of 60 mesh, and an Al2O3 content of 55%; the silicon carbide has a particle size of 325 mesh, and a purity of 90%; the α-alumina powder has a particle size of 3-5μm; the calcium aluminate cement has an aluminum content of 68%–72%, and the refractoriness of the cement paste is 1650°–1690°; the silica fume has a SiO2 content of 95%.

3. The high-alumina preform as described in claim 1, characterized in that: The water-reducing agent is sodium tripolyphosphate; the toughening agent is stainless steel fiber; and the explosion-proof agent is metallic aluminum powder.

4. The high-alumina preform as described in claim 1, characterized in that: The melting point of the explosion-proof fiber is 160-170℃.

5. The method for preparing a high-alumina preform as described in claim 1, characterized in that: Includes the following steps: S1. The recycled waste aluminum-carbon sliding bricks are removed by removing the iron rings and surface debris from the external parts. The bricks are then crushed by a crusher with rollers. During the crushing process, the iron impurities in the recycled waste aluminum-carbon sliding bricks are removed. After screening, recycled aluminum-carbon sliding brick granules with particle sizes of 1-3mm and 3-5mm are obtained. S2. The recycled waste high-alumina hot blast furnace balls are removed by removing the slag and surface impurities. They are then crushed by a double roller crusher. During the crushing process, iron impurities in the recycled waste high-alumina balls are removed. After screening, recycled high-alumina ball granules with a particle size of 5-15mm are obtained. S3. The 5-15mm high-alumina ball regenerated particles obtained in step S2 are processed by grinding equipment to obtain high-alumina ball powder with a particle size of 200 mesh or more; S4. Perform physicochemical index testing on the particle size distribution, bulk density, and chemical composition of the aluminum-carbon recycled granules with particle sizes of 1-3 mm and 3-5 mm obtained in step S1, the high-alumina sphere recycled granules with particle size of 5-15 mm obtained in step S2, and the high-alumina sphere powder with a particle size of more than 200 mesh obtained in step S3. S5. Add bauxite aggregate, kyanite, silicon carbide, α-alumina powder, calcium aluminate cement, silica fume, explosion-proof fiber, explosion-proof agent, toughening agent, and water-reducing agent to the recycled aluminum carbon slide plate granules with particle sizes of 1-3mm and 3-5mm obtained in step S1, the recycled high alumina ball granules with particle size of 5-15mm obtained in step S2, and the high alumina ball powder with a particle size of 200 mesh or more obtained in step S3. Mix them in a mixer according to the proportion. After mixing for 8-10 minutes, discharge and bag the material. The metering error should be controlled within 25±0.25kg. Set aside for later use. S6. Transport the material obtained after mixing in step S5 to the precast casting production line. According to the amount of precast casting production, add it to the mixer and dry mix for 1-2 minutes. Add 5%-7% water and mix for 2-3 minutes to prepare for material feeding and vibration molding. S7. After placing the precast mold, open the mixer's discharge port and turn on the vibrating table. Vibrate while discharging the material to evenly distribute the well-mixed mud across the mold frame. The vibration time should be no less than 30 seconds. Stop when the surface of the precast part has small air bubbles, a smooth surface, and evenly distributed particles. S8. Transport the preform obtained in step S7 to the curing area for natural curing. The curing time with the mold is controlled at 12-24 hours, and the curing time after demolding is controlled at 36-48 hours. The curing environment temperature is controlled at 15-25℃. Ensure the mold is level during the curing process. S9. Place the cured precast parts into the kiln car for baking. The distance between each precast part should not be less than 20mm. Baking curve: control the temperature from room temperature to 140℃ within 10 hours, hold for 2 hours, control the temperature from 140℃ to 320℃ within 12 hours, hold for 2 hours, and then cool down to below 50℃ before removing from the kiln.

6. The method for preparing a high-alumina preform as described in claim 5, characterized in that: The preform parameters obtained in step S9 are characterized by, by weight percentage: Al2O3 ≥ 60%, bulk density ≥ 2.4 g / cm³. 3 At room temperature (200℃×24h), the compressive strength is ≥20MPa and the flexural strength is ≥4MPa; at high temperature (1500℃×3h), the compressive strength is ≥30MPa and the flexural strength is ≥6MPa.