A composite stabilized barium aluminozizate cement binder, its preparation method and application

Abstract

This invention discloses a composite stabilized barium aluminozizate cement binder, its preparation method, and its application, relating to the field of metallurgical refractory materials technology. It comprises the following raw materials in parts by weight: 12-17 parts alumina micropowder, 55-60 parts barium sulfate, 24-28 parts zirconium oxide micropowder, 1-5 parts yttrium oxide fine powder, and 1-5 parts lanthanum oxide fine powder. The composite stabilized barium aluminozizate cement binder of this invention improves the volume stability of traditional unstable barium aluminozizate cement-bonded ladle working lining carbon-free corundum spinel precast blocks under rapid temperature changes during use by introducing yttrium oxide and lanthanum oxide from rare earth oxides, thereby enhancing the stability of the cement and the finished product.

Description

Technical Field

[0001] This invention relates to the field of metallurgical refractory materials technology, specifically to a composite stabilized barium aluminozizate cement binder, its preparation method, and its application. Background Technology

[0002] Steel ladles are used in steel mills and foundries to receive molten steel before open-hearth furnaces, electric furnaces, or converters, for ladle refining, and for continuous casting. Steel ladles play a crucial role in the iron and steel metallurgical system, and their service life directly determines smelting efficiency.

[0003] The ladle is an indispensable high-temperature vessel in steelmaking, serving to hold molten steel and perform secondary refining. With the increasing demand for low-carbon steel, ultra-low-carbon steel, and other specialty steels, there is a growing requirement for the ladle's working lining to possess excellent resistance to slag and molten steel corrosion, and to prevent secondary contamination of the molten steel.

[0004] Currently, there are three main types of working linings used in large and medium-sized refining ladles: 1) Ladle bottom and wall working linings use aluminum-magnesium-carbon and magnesium-aluminum-carbon bricks, while the slag line uses magnesium-carbon bricks; 2) Ladle bottom and wall working linings use carbon-free corundum spinel castables, while the slag line uses low-carbon magnesium-carbon bricks; 3) Ladle bottom and wall working linings use carbon-free corundum spinel precast blocks, while the slag line uses low-carbon magnesium-carbon bricks.

[0005] Currently, domestic precast carbon-free corundum spinel blocks for ladle working linings generally adopt two bonding methods: 1) bonding with pure calcium aluminate cement. Pure calcium aluminate cement introduces a certain amount of CaO. When the ladle working lining casting temperature is >1600℃, the CaO in the cement will form a series of low-melting phases such as anorthite. Simultaneously, at temperatures above 1100℃, the CaO will cause the MgO in the material to... Al₂O₃ spinel decomposes to produce 12CaO 7Al2O3 and 3CaO Low-melting-point phases such as Al2O3 form a network of channels, accelerating the erosion and structural spalling of the ladle working lining refractory. Furthermore, many uncontrollable factors exist in the on-site casting of the ladle working lining refractory, such as the amount of water added, stirring time, vibration time, and baking, resulting in significant fluctuations in the quality of the ladle working lining. This leads to frequent ladle unpacking, disrupting the steel plant's smelting production rhythm. 2) Cement-free bonding using ρ-Al2O3 micropowder is problematic because ρ-Al2O3 micropowder is the only alumina micropowder with hydration capabilities. Its production process inherently makes its hydration unstable and highly sensitive to temperature changes, resulting in inconsistent setting times and uneven porosity in the finished product. Since the strength of hydrated ρ-Al2O3 micropowder is lower than that of pure calcium aluminate cement, a certain proportion of 3-5% silica fume is added as a binder to ensure the demolding strength of the precast blocks at room temperature. However, the working temperature of the ladle lining is >1600℃. The addition of silica fume introduces a certain amount of SiO2, increasing the proportion of low-melting-point silicate phases in the carbon-free corundum spinel precast block material. This promotes the formation of an interconnected network of low-temperature silicate phases within the carbon-free corundum spinel precast block material. This microstructure of Al2O3-MgO... Al2O3-based refractories hinder solid-solid bonding, reducing high-temperature strength and thermal shock resistance of carbon-free corundum spinel precast blocks. Furthermore, the formation of an interconnected network of silicate low-temperature phases creates slag erosion channels, further diminishing the slag erosion resistance of the corundum spinel precast blocks. This leads to accelerated erosion and structural spalling of the carbon-free corundum spinel precast blocks used as ladle linings, resulting in frequent ladle dismantling and disrupting the steel plant's smelting production schedule.

[0006] Meanwhile, barium aluminate has a melting temperature of 1815℃, and barium zirconate has a melting temperature of 2600℃, both being high-temperature substances; in the BaO-Al2O3-ZrO2 system, the aluminate BaO Al2O3 and 3BaO Al2O3 possesses hydration and setting properties, but barium monoaluminate cement, due to its properties in the synthesis of 3BaO... In Al2O3 formation, free BaO is often present, which leads to cement volume instability and easily damages the cement paste structure. In addition, 3BaO... Al₂O₃ exhibits high hydration activity, causing the binder to solidify rapidly; the addition of barium zirconate to barium aluminate can promote the activation of the cement hydration process, in addition to the mono-barium aluminate hydrate BaO Al2O3 6H2O and BaO Al2O3 Besides 7H2O, the presence of barium aluminozirconate also generates hydrates with high barium content, ensuring higher strength and lower softening properties in the cement paste. However, the presence of these compounds reduces the proportion of bound water in the cementitious material, thus reducing the amount of water needed while maintaining the mixing state and pouring time of the cement. Therefore, barium aluminozirconate cement is a high-quality binder for precast carbon-free steel ladle working lining blocks, avoiding the adverse effects of the aforementioned different bonding methods. However, during the production of barium aluminozizate cement, unstable monoclinic zirconium oxide is produced. Monoclinic zirconium oxide undergoes a crystal transformation with temperature changes, which is accompanied by volume changes. During heating, the transformation from m-Zr₂O₃ (monoclinic phase) to t-Zr₂O₃ (tetragonal phase) is accompanied by approximately 3% volume shrinkage; during cooling, the transformation from t-Zr₂O₃ (tetragonal phase) to m-Zr₂O₃ (monoclinic phase) is accompanied by approximately 5% volume expansion. This reversible crystal transformation of zirconium oxide has the following effects: During the calcination and preparation of cement, the shrinkage and expansion of zirconium oxide during heating and cooling severely affect the calcination process, thus impacting the stability of cement quality; In traditional barium aluminozizate cement, the temperature of the ladle during molten steel transfer and continuous casting exceeds 1600℃, while the temperature during empty ladle operation is between 500-600℃. The repeated volume effects caused by the unstable zirconium oxide crystal transformation during use can lead to product cracking.

[0007] Therefore, providing a stable barium aluminozizate cement binder is a technical problem that urgently needs to be solved in this field. Summary of the Invention

[0008] To address the aforementioned problems, this invention provides a composite stabilized barium aluminozizate cement binder, its preparation method, and its application.

[0009] To achieve the above objectives, the present invention adopts the following technical solution:

[0010] A composite stabilized barium aluminozizate cement binder comprises the following raw materials in parts by weight: 12-17 parts alumina micro powder, 55-60 parts barium sulfate, 24-28 parts zirconium oxide micro powder, 1-5 parts yttrium oxide fine powder, and 1-5 parts lanthanum oxide fine powder.

[0011] Preferably, the alumina micro powder has an Al2O3 content > 99% and a particle size of 5-10 μm; The barium sulfate described herein contains BaSO4 content > 98% and has a particle size of 600-800 mesh; The zirconium oxide micro powder, wherein Zr2O3 > 95% and the particle size is 1-2 μm; The yttrium oxide fine powder, wherein Y2O3 > 99%, has a particle size of 325 mesh; The lanthanum oxide fine powder has a La2O3 content of >99% and a particle size of 325 mesh.

[0012] Preferably, the composite stabilized barium aluminozizate cement binder contains the following mass percentages: ZrO2 content 24-28%, BaO content 55-60%, Al2O3 content 12-17%, Y2O3 content 1-5%, and La2O3 content 1-5%.

[0013] The preparation method of the composite stabilized barium aluminozizate cement binder described above specifically includes the following steps: (1) Weigh the raw materials according to the stated weight proportions for later use; (2) The raw materials are wet-milled with water to obtain mud slurry, and the mud slurry is dehydrated, granulated and dried to obtain mud material; (3) The clay material is calcined and then crushed to obtain a composite stabilized barium aluminozirconate cement binder.

[0014] Preferably, the mass ratio of the raw materials to water in step (2) is 2:1; The wet milling time is 20-30 minutes; the granulation particle size is 5-10 mm; the drying is carried out at 80-110℃ for more than 8 hours.

[0015] Preferably, the calcination is carried out at 1550-1600℃ for 4-6 hours; the fineness of the pulverization is 18 micrometers, wherein the mass percentage of the residue on the sieve is 5-10%.

[0016] The application of the composite stabilized barium aluminozirconate cement binder described above or the composite stabilized barium aluminozirconate cement binder prepared by the above preparation method in the preparation of carbon-free corundum spinel precast blocks for ladle working linings.

[0017] Preferably, the carbon-free corundum spinel precast block for the ladle working lining comprises the following raw materials in parts by weight: 5-20 parts of 10-20mm white corundum, 10-25 parts of 5-10mm tabular corundum, 10-20 parts of 3-6mm tabular corundum, 10-15 parts of 1-3mm tabular corundum, 10-20 parts of 0-1mm tabular corundum, 0-10 parts of 0.074mm tabular corundum, 10-15 parts of 0.074mm sintered aluminum-magnesium spinel, 2-5 parts of 2.5μm active α-Al2O3 micro powder, 2-5 parts of 4.5μm calcined α-Al2O3 micro powder, 5-15 parts of composite stabilized barium aluminozizate cement binder, 0.1-0.2 parts of water-reducing agent, and 0.05-0.1 parts of explosion-proof fiber.

[0018] Preferably, the white fused alumina contains Al2O3 content > 98 wt% and SiO2 content < 0.2 wt%. The tabular corundum contains Al2O3 content > 99 wt% and SiO2 content < 0.2 wt%. The sintered aluminum-magnesium spinel contains 76-78 wt% Al2O3 and 18-22 wt% MgO.

[0019] The Al2O3 content in both the active α-Al2O3 micro powder and the calcined α-Al2O3 micro powder is >99 wt%. The water-reducing agent is FS10; The explosion-proof fiber has a melting point of <105℃ and a length of 2-4mm.

[0020] Preferably, the preparation method of the carbon-free corundum spinel preform for the ladle working lining includes the following steps: 1) Weigh the raw materials according to the stated weight proportions, mix well, and set aside; 2) After mixing the raw materials obtained in step 1) with water, add them into the mold for molding and curing, and then demold to obtain a demolded precast block; 3) After curing and drying the demolded precast block, carbon-free corundum spinel precast block for ladle working lining is obtained.

[0021] Preferably, the specific steps of in-mold forming in step 2) are as follows: hoist the product mold to the vibration platform, turn on the electromagnetic chuck, wait for the mold to be attracted to the vibration platform and start the vibration motor, add the mixture obtained by mixing with water into the mold in batches, and control the time of each addition to 20-25 seconds. After the addition is completed, adjust the vibration frequency to 30-40 Hz until no large bubbles are generated on the surface of the preform and stop the vibration.

[0022] Preferably, the flow value of the mixture obtained by adding water and kneading in step 2) is 150-180 mm; the curing temperature is 25-35℃, the humidity is 60-7, and the curing time is ≥48h. The temperature for the conditioning process in step 3) is 25-35℃, the humidity is 60-70%, and the time is ≥72h; the temperature for drying is no more than 300℃, and the drying time is ≥80h.

[0023] Compared with the prior art, the present invention has the following beneficial effects: (1) The composite stabilized barium aluminozirconate cement binder of the present invention improves the volume stability of the traditional unstable barium aluminozirconate cement bonded steel ladle working lining carbon-free corundum spinel precast blocks in the face of rapid temperature changes during use by introducing yttrium oxide and lanthanum oxide from rare earth oxides, thereby improving the stability of cement and finished products. (2) The composite stabilized barium aluminozirconate cement of the present invention has high high-temperature performance as a binder, which improves the high-temperature performance of cement-bonded steel ladle working lining carbon-free corundum spinel precast blocks such as pure calcium aluminate cement, p-Al2O3 micro powder, and traditional unstabilized barium aluminozirconate. (3) The stabilized barium aluminozirconate cement of the present invention, as a binder, improves the slag erosion resistance of carbon-free corundum spinel precast blocks for ladle working linings, such as pure calcium aluminate cement, ρ-Al2O3 micro powder, and traditional unstable barium aluminozirconate cement. When using the stabilized barium aluminozirconate cement of the present invention as a binder to produce carbon-free corundum spinel precast blocks for ladle working linings, a series of low-temperature liquid phases, such as CaO brought in by the pure calcium aluminate cement binder and SiO2 brought in by the ρ-Al2O3 micro powder binder, are avoided at high temperatures. The carbon-free corundum spinel precast block material does not have a low-temperature liquid phase network structure, and cannot form slag erosion channels. In addition, the stabilized barium aluminozirconate cement of the present invention contains ZrO2, and zirconium oxide reacts with CaO in the intruding slag at high temperatures to generate high-melting-point solid phase CaO. ZrO2 (melting point 2345℃) forms a layered structure, protecting MgO. Al2O3 (spinel) is not decomposed by CaO, thus fully leveraging the beneficial effects of the main components corundum and spinel. At the same time, it avoids the adverse effects of repeated volume changes caused by the crystal phase transformation of unstable zirconium oxide during the calcination preparation and use as a binder in the finished precast blocks, which can lead to cracking of the products and resistance to slag erosion. (4) This invention uses composite stabilized barium aluminozirconate cement as a binder, which improves the thermal shock performance of carbon-free corundum spinel precast blocks for ladle working linings bonded with pure calcium aluminate cement, ρ-Al2O3 micro powder, and traditional unstable barium aluminozirconate cement. When using the stabilized barium aluminozirconate cement of this invention as a binder to produce carbon-free corundum spinel precast blocks for ladle working linings, it enhances the solid-solid bonding of the corundum spinel precast block material. In addition, the composite stabilized barium aluminozirconate cement contains Y2O3 and La2O3 to form a stable cubic solid solution with ZrO2, and the stable cubic solid solution ZrO2 and MgO There is a thermal expansion mismatch effect between Al2O3 mixed crystals (interlocking crystals) and Al2O3. Therefore, under the rapid cooling and heating conditions during the use of the ladle, when the ladle working lining carbon-free corundum spinel precast block material has an equiaxed macroscopic cracked microcrack stress-relief structure, crack propagation will be suppressed. At the same time, it avoids the adverse effects on thermal shock performance caused by the repeated volume effect of the crystal phase transformation of unstable zirconia during the calcination preparation and as a binder of traditional unstable barium aluminozizate cement during the use of finished precast blocks, which would cause product cracking. (5) The precast carbon-free corundum spinel steel ladle working lining prepared by the present invention was tested and found to have an erosion index of 2-4% and a penetration index of 4.0-6.0% in the static crucible method slag resistance test at 1600℃; the precast carbon-free corundum spinel steel ladle working lining bonded with pure calcium aluminate cement was tested and found to have an erosion index of 18-25% and a penetration index of 28-35% in the static crucible method slag resistance test at 1600℃; the precast carbon-free corundum spinel steel ladle working lining bonded with ρ-Al2O3 was tested and found to have an erosion index of 15-20% and a penetration index of 25-30% in the static crucible method slag resistance test at 1600℃; the precast carbon-free corundum spinel steel ladle working lining bonded with barium aluminozirconate cement stabilized by a single rare earth oxide was tested and found to have an erosion index of 7-15% and a penetration index of 12-25% in the static crucible method slag resistance test at 1600℃. (6) The carbon-free corundum spinel precast block for the ladle working lining prepared by this invention was tested and found to be 1400℃. Flexural strength under 30-minute hot state: 50-70 MPa; Existing carbon-free corundum spinel precast blocks for steel ladle working lining bonded with pure calcium aluminate cement: 1400℃ Flexural strength under 30-minute hot state: 15-20 MPa; Existing ρ-Al2O3 bonded steel ladle working lining carbon-free corundum spinel precast block: 1400℃ Flexural strength under 30-minute hot state: 8-12 MPa; Existing single rare earth oxide stabilized barium aluminozirconate cement bonded steel ladle working lining carbon-free corundum spinel precast blocks: 1400℃ Flexural strength under 30-minute hot state: 20-30 MPa; (7) The carbon-free corundum spinel precast block for the ladle working lining prepared by the present invention was tested and found to be 1100℃. After 12 water cooling cycles over 20 minutes, the residual flexural strength retention rate is 85-90%; Existing carbon-free corundum spinel precast blocks for steel ladle working linings bonded with pure calcium aluminate cement: 1100℃ After 12 water cooling cycles over 20 minutes, the residual flexural strength retention rate was 60-65%; Existing ρ-Al₂O₃ bonded steel ladle working lining carbon-free corundum spinel precast blocks were used at 1100℃. After 12 water cooling cycles over 20 minutes, the residual flexural strength retention rate is 55-70%. Existing single rare earth oxide-stabilized barium alumina-zirconate cement-bonded steel ladle working lining carbon-free corundum spinel precast blocks: 1100℃. After 12 water cooling cycles over 20 minutes, the residual flexural strength retention rate was 70-80%. (8) The carbon-free spinel precast blocks of the steel ladle working lining prepared by the present invention have a longer average life in practical applications, which can improve the utilization rate of the steel ladle, reduce the labor intensity of the steel ladle operator, and also reduce the average cost of the steel ladle. Detailed Implementation

[0024] The following describes embodiments of the present invention. The embodiments described are exemplary and intended to explain the present invention, and are not to be construed as limiting the present invention.

[0025] Raw materials: Alumina micro powder, with an Al2O3 content of 99.5% and a particle size of 5μm; Barium sulfate, with BaSO4 content of 99% and particle size of 800 mesh; Zirconia micro powder, wherein the Zr2O3 content is 95.5% and the particle size is 2μm; Yttrium oxide fine powder, with Y2O3 content of 99.5% and particle size of 325 mesh; Lanthanum oxide fine powder, with a La2O3 content of 99.5% and a particle size of 325 mesh; White fused alumina contains 99% Al2O3 and 0.1% SiO2. Al₂O₃ content in tabular corundum: 99.6%, SiO₂ content: 0.1%; The sintered aluminum-magnesium spinel contains 76.5% Al2O3 and 21.5% MgO.

[0026] The Al2O3 content in both the active α-Al2O3 micro powder and the calcined α-Al2O3 micro powder was 99.6%. The water-reducing agent is FS10; The melting point of the explosion-proof fiber is 95℃, and its length is 3mm. Example 1 This invention provides a method for preparing a stable barium aluminozizate cement-bonded carbon-free precast block for ladle working lining, specifically including the following steps: (1) Take the following by mass: 13 parts of alumina micro powder, 56 parts of barium sulfate, 25 parts of zirconium micro powder, 1 part of yttrium oxide fine powder and 5 parts of lanthanum oxide fine powder. Add water to a ball mill with high-purity alumina lining bricks and high-purity alumina grinding balls on the inner wall and grind together for 20 minutes to homogenize into a slurry. The homogenized slurry is then dehydrated by pressure filtration. The dehydrated slurry is then squeezed into balls (particle size 5-10 mm) and dried in a box dryer at 80°C for 8.5 hours. The dried slurry is then calcined in a rotary kiln at 1580°C for 4 hours. The calcined clinker is then dry-ground in a ball mill with high-purity alumina lining bricks and high-purity alumina grinding balls on the inner wall to obtain a composite stabilized barium aluminozirconate cement binder. (2) Take the following raw materials by mass: 5 parts of white corundum with a particle size of 10-20mm, 22 parts of tabular corundum with a particle size of 5-10mm, 15 parts of tabular corundum with a particle size of 3-6mm, 12 parts of tabular corundum with a particle size of 1-3mm, 14 parts of tabular corundum with a particle size of 0-1mm, 13.8 parts of tabular corundum with a particle size of 0.074mm, 5 parts of sintered magnesium aluminum spinel with a particle size of 0.074mm, 5 parts of activated alumina micro powder with a particle size of 2.5μm, 3 parts of calcined alumina micro powder with a particle size of 4.5μm, 5 parts of composite stabilized barium aluminozizate cement binder, 0.1 parts of water-reducing agent and 0.1 parts of explosion-proof fiber; (3) Premixing: Pour the weighed granular material into the premixer and mix for 3.5 minutes. Then pour in the weighed powder, additives and explosion-proof fiber and mix for another 6 minutes to obtain the mixture. (4) Mixing: Put the mixed material into a wet mixer and mix for 3 minutes. Add water at 3.5 parts by weight of the material and mix for another 6 minutes. The flow value should be controlled at 160 mm. (5) Vibration molding: hoist the product mold to the vibration platform, turn on the electromagnetic chuck, wait for the mold to be attached to the vibration platform and start the vibration motor, add the mixed material obtained by mixing into the mold in batches, control the feeding time for each feeding to 25 seconds, after the feeding is completed, adjust the vibration frequency to 30 Hz, and stop the vibration when there are no large bubbles on the surface of the preform. (6) In-mold curing: The vibrated products are placed in the curing room for curing. The curing temperature is controlled at 25℃, the humidity is controlled at 60%, and the curing time is 48h. (7) Demolding: Lift the product that meets the demolding conditions and has been cured out of the curing room, place it on a flat ground, loosen the fastening screws of the mold, gently tap the precast block with a rubber mallet, and load it into a special kiln car after demolding. (8) Post-molding curing: The kiln car loaded with the demolded precast blocks is pushed into a special curing kiln for curing. The curing temperature is controlled at 25℃, the humidity is controlled at 60%, and the curing time is 72h. (8) Drying: The precast blocks that meet the post-molding curing conditions are pushed into the drying kiln along with the kiln car for drying. The drying temperature is 300℃ and the drying time is 80h, which produces the carbon-free precast blocks of stable barium aluminozirconate cement bonded steel ladle working lining.

[0027] Example 2 This invention provides a method for preparing a stable barium aluminozizate cement-bonded carbon-free precast block for ladle working lining, specifically including the following steps: (1) Take the following by mass: 12 parts of alumina micro powder, 56 parts of barium sulfate, 26 parts of zirconium micro powder, 2 parts of yttrium oxide fine powder and 4 parts of lanthanum oxide fine powder. Add water to a ball mill with high-purity alumina lining bricks and high-purity alumina grinding balls on the inner wall and grind together for 25 minutes to homogenize into a slurry. The homogenized slurry is dewatered by pressure filtration. The dewatered slurry is squeezed into balls (particle size 5-10 mm) and then dried in a box dryer at 90℃ for 10 hours. The dried slurry is calcined at high temperature in a rotary kiln at 1600℃ for 5 hours. The calcined clinker is then dry-ground in a ball mill with high-purity alumina lining bricks and high-purity alumina grinding balls on the inner wall to obtain a composite stabilized barium aluminozirconate cement binder. (2) Take the following raw materials by mass: 10 parts of white corundum with a particle size of 10-20mm, 18 parts of tabular corundum with a particle size of 5-10mm, 13 parts of tabular corundum with a particle size of 3-6mm, 13 parts of tabular corundum with a particle size of 1-3mm, 14 parts of tabular corundum with a particle size of 0-1mm, 10.8 parts of tabular corundum with a particle size of 0.074mm, 5 parts of sintered magnesium aluminum spinel with a particle size of 0.074mm, 5 parts of activated alumina micro powder with a particle size of 2.5μm, 3 parts of calcined alumina micro powder with a particle size of 4.5μm, 8 parts of composite stabilized barium aluminozizate cement binder, 0.1 parts of water-reducing agent and 0.1 parts of explosion-proof fiber; (3) Premixing: Pour the weighed granular material into the premixer and mix for 3.5 minutes. Then pour in the weighed powder, additives and explosion-proof fiber and mix for another 6 minutes to obtain the mixture. (4) Mixing: Put the mixed material into a wet mixer and mix for 3 minutes. Add water at 3.5 parts by weight of the material and mix for another 6 minutes. The flow value should be controlled at 160 mm. (5) Vibration molding: hoist the product mold to the vibration platform, turn on the electromagnetic chuck, wait for the mold to be attached to the vibration platform and start the vibration motor, add the mixed material obtained by mixing into the mold in batches, control the feeding time for each feeding to 25 seconds, after the feeding is completed, adjust the vibration frequency to 30 Hz, and stop the vibration when there are no large bubbles on the surface of the preform. (6) In-mold curing: The vibrated products are placed in the curing room for curing. The curing temperature is controlled at 25℃, the humidity is controlled at 60%, and the curing time is 72h. (7) Demolding: Lift the product that meets the demolding conditions and has been cured out of the curing room, place it on a flat ground, loosen the fastening screws of the mold, gently tap the precast block with a rubber mallet, and load it into a special kiln car after demolding. (8) Post-molding curing: The kiln car loaded with the demolded precast blocks is pushed into a special curing kiln for curing. The curing temperature is controlled at 30℃, the humidity is controlled at 60%, and the curing time is 96 hours. (8) Drying: The precast blocks that meet the post-molding curing conditions are pushed into the drying kiln along with the kiln car for drying. The drying temperature is 300℃ and the drying time is 82h, which produces the carbon-free precast blocks of stable barium aluminozirconate cement bonded steel ladle working lining.

[0028] Example 3 This invention provides a method for preparing a stable barium aluminozizate cement-bonded carbon-free precast block for ladle working lining, specifically including the following steps: (1) Take 15 parts of alumina micro powder, 55 parts of barium sulfate, 24 parts of zirconium micro powder, 5 parts of yttrium oxide fine powder and 1 part of lanthanum oxide fine powder by mass. Add water to a ball mill with high-purity alumina lining bricks and high-purity alumina grinding balls on the inner wall and grind for 25 minutes to homogenize into a slurry. The homogenized slurry is dewatered by pressure filtration. The dewatered slurry is squeezed into balls (particle size 5-10 mm) and then dried in a box dryer at 110℃ for 13 hours. The dried mud is calcined at high temperature in a rotary kiln at 1600℃ for 5.5 hours. The calcined clinker is then dry-ground in a ball mill with high-purity alumina lining bricks and high-purity alumina grinding balls on the inner wall to obtain a composite stabilized barium aluminozirconate cement binder. (2) Take the following raw materials by mass: 10 parts of white corundum with a particle size of 10-20mm, 18 parts of tabular corundum with a particle size of 5-10mm, 13 parts of tabular corundum with a particle size of 3-6mm, 13 parts of tabular corundum with a particle size of 1-3mm, 14 parts of tabular corundum with a particle size of 0-1mm, 8.8 parts of tabular corundum with a particle size of 0.074mm, 5 parts of sintered magnesium aluminum spinel with a particle size of 0.074mm, 5 parts of activated alumina micro powder with a particle size of 2.5μm, 3 parts of calcined alumina micro powder with a particle size of 4.5μm, 10 parts of composite stabilized barium aluminozizate cement binder, 0.1 parts of water-reducing agent, and 0.1 parts of explosion-proof fiber; (3) Premixing: Pour the weighed granular material into the premixer and mix for 5 minutes. Then pour in the weighed powder, additives and explosion-proof fiber and mix for another 7 minutes to obtain the mixture. (4) Mixing: Put the mixed material into a wet mixer and mix for 3 minutes. Add water according to 4 parts by weight of the material and mix for another 6 minutes. The flow value should be controlled at 160 mm. (5) Vibration molding: hoist the product mold to the vibration platform, turn on the electromagnetic chuck, wait for the mold to be attached to the vibration platform and start the vibration motor, add the mixed material obtained by mixing into the mold in batches, control the feeding time for each feeding to 25 seconds, after the feeding is completed, adjust the vibration frequency to 35 Hz, and stop the vibration when there are no large bubbles on the surface of the preform. (6) In-mold curing: The vibrated products are placed in the curing room for curing. The curing temperature is controlled at 30℃, the humidity is controlled at 70%, and the curing time is 72h. (7) Demolding: Lift the product that meets the demolding conditions and has been cured out of the curing room, place it on a flat ground, loosen the fastening screws of the mold, gently tap the precast block with a rubber mallet, and load it into a special kiln car after demolding. (8) Post-molding curing: The kiln car loaded with the demolded precast blocks is pushed into a special curing kiln for curing. The curing temperature is controlled at 30℃, the humidity is controlled at 60%, and the curing time is 93h. (8) Drying: The precast blocks that meet the post-molding curing conditions are pushed into the drying kiln along with the kiln car for drying. The drying temperature is 300℃ and the drying time is 82h, which produces the carbon-free precast blocks of stable barium aluminozirconate cement bonded steel ladle working lining.

[0029] Example 4 This invention provides a method for preparing a stable barium aluminozizate cement-bonded carbon-free precast block for ladle working lining, specifically including the following steps: (1) Take the following by mass: 14 parts of alumina micro powder, 55 parts of barium sulfate, 26 parts of zirconium micro powder, 4 parts of yttrium oxide fine powder, and 2 parts of lanthanum oxide fine powder. Add water to a ball mill with high-purity alumina lining bricks and high-purity alumina grinding balls on the inner wall and grind together for 25 minutes to homogenize into a slurry. The homogenized slurry is then dehydrated by pressure filtration. The dehydrated slurry is then squeezed into balls (particle size 5-10 mm) and dried in a box dryer at 95°C for 11 hours. The dried slurry is then calcined in a rotary kiln at 1580°C for 6 hours. The calcined clinker is then dry-ground in a ball mill with high-purity alumina lining bricks and high-purity alumina grinding balls on the inner wall to obtain a composite stabilized barium aluminozirconate cement binder. (2) Take the following raw materials by mass: 15 parts of white corundum with a particle size of 10-20mm, 12 parts of tabular corundum with a particle size of 5-10mm, 13 parts of tabular corundum with a particle size of 3-6mm, 15 parts of tabular corundum with a particle size of 1-3mm, 15 parts of tabular corundum with a particle size of 0-1mm, 4.9 parts of tabular corundum with a particle size of 0.074mm, 5 parts of sintered magnesium aluminum spinel with a particle size of 0.074mm, 5 parts of activated alumina micro powder with a particle size of 2.5μm, 3 parts of calcined alumina micro powder with a particle size of 4.5μm, 12 parts of composite stabilized barium aluminozizate cement binder, 0.1 parts of water-reducing agent, and 0.1 parts of explosion-proof fiber; (3) Premixing: Pour the weighed granular material into the premixer and mix for 3.5 minutes. Then pour in the weighed powder, additives and explosion-proof fiber and mix for another 6 minutes to obtain the mixture. (4) Mixing: Put the mixed material into a wet mixer and mix for 2 minutes. Add water according to 4 parts by weight of the material and mix for another 6 minutes. The flow value should be controlled at 150 mm. (5) Vibration molding: hoist the product mold to the vibration platform, turn on the electromagnetic chuck, wait for the mold to be attached to the vibration platform and start the vibration motor, add the mixed material obtained by mixing into the mold in batches, control the feeding time of each feeding to 25 seconds, after the feeding is completed, adjust the vibration frequency to 40 Hz, and stop the vibration when there are no large bubbles on the surface of the preform. (6) In-mold curing: The vibrated products are placed in the curing room for curing. The curing temperature is controlled at 30℃, the humidity is controlled at 70%, and the curing time is 72h. (7) Demolding: Lift the product that meets the demolding conditions and has been cured out of the curing room, place it on a flat ground, loosen the fastening screws of the mold, gently tap the precast block with a rubber mallet, and load it into a special kiln car after demolding. (8) Post-molding curing: The kiln car loaded with the demolded precast blocks is pushed into a special curing kiln for curing. The curing temperature is controlled at 30℃, the humidity is controlled at 70%, and the curing time is 96 hours. (8) Drying: The precast blocks that meet the post-molding curing conditions are pushed into the drying kiln along with the kiln car for drying. The drying temperature is 280℃ and the drying time is 82h, which produces the carbon-free precast blocks of stable barium aluminozirconate cement bonded steel ladle working lining.

[0030] Example 5 This invention provides a method for preparing a stable barium aluminozizate cement-bonded carbon-free precast block for ladle working lining, specifically including the following steps: (1) Take the following by mass: 14 parts of alumina micro powder, 55 parts of barium sulfate, 26 parts of zirconium micro powder, 3 parts of yttrium oxide fine powder, and 2 parts of lanthanum oxide fine powder. Add water to a ball mill with high-purity alumina lining bricks and high-purity alumina grinding balls on the inner wall and grind together for 26 minutes to homogenize into a slurry. The homogenized slurry is then dehydrated by pressure filtration. The dehydrated slurry is then squeezed into balls (particle size 5-10 mm) and dried in a box dryer at 100℃ for 12 hours. The dried slurry is then calcined in a rotary kiln at 1580℃ for 5.5 hours. The calcined clinker is then dry-ground in a ball mill with high-purity alumina lining bricks and high-purity alumina grinding balls on the inner wall to obtain a composite stabilized barium aluminozirconate cement binder. (2) Take the following raw materials by mass: 20 parts of white corundum with a particle size of 10-20mm, 10 parts of tabular corundum with a particle size of 5-10mm, 10 parts of tabular corundum with a particle size of 3-6mm, 18 parts of tabular corundum with a particle size of 1-3mm, 10 parts of tabular corundum with a particle size of 0-1mm, 3.8 parts of tabular corundum with a particle size of 0.074mm, 5 parts of sintered magnesium aluminum spinel with a particle size of 0.074mm, 5 parts of activated alumina micro powder with a particle size of 2.5μm, 3 parts of calcined alumina micro powder with a particle size of 4.5μm, 15 parts of composite stabilized barium aluminozizate cement binder, 0.1 parts of water-reducing agent, and 0.1 parts of explosion-proof fiber; (3) Premixing: Pour the weighed granular material into the premixer and mix for 3.5 minutes. Then pour in the weighed powder, additives and explosion-proof fiber and mix for another 6 minutes to obtain the mixture. (4) Mixing: Put the mixed material into a wet mixer and mix for 3 minutes. Add water at 4.5 parts by weight of the material and mix for another 6 minutes. The flow value should be controlled at 180 mm. (5) Vibration molding: hoist the product mold to the vibration platform, turn on the electromagnetic chuck, wait for the mold to be attached to the vibration platform and start the vibration motor, add the mixed material obtained by mixing into the mold in batches, control the feeding time for each feeding to 20 seconds, after the feeding is completed, adjust the vibration frequency to 35 Hz, and stop the vibration when there are no large bubbles on the surface of the preform. (6) In-mold curing: The vibrated products are placed in the curing room for curing. The curing temperature is controlled at 35℃, the humidity is controlled at 65%, and the curing time is 72h. (7) Demolding: Lift the product that meets the demolding conditions and has been cured out of the curing room, place it on a flat ground, loosen the fastening screws of the mold, gently tap the precast block with a rubber mallet, and load it into a special kiln car after demolding. (8) Post-molding curing: The kiln car loaded with the demolded precast blocks is pushed into a special curing kiln for curing. The curing temperature is controlled at 35℃, the humidity is controlled at 60%, and the curing time is 96 hours. (8) Drying: The precast blocks that meet the post-molding curing conditions are pushed into the drying kiln along with the kiln car for drying. The drying temperature is 300℃ and the drying time is 82h, which produces the carbon-free precast blocks of stable barium aluminozirconate cement bonded steel ladle working lining.

[0031] Comparative Example 1-1 The difference from Example 3 is that the following parts by weight are used: 16 parts alumina micro powder, 55 parts barium sulfate, 24 parts zirconium oxide micro powder, and 5 parts yttrium oxide fine powder. The remaining steps and parameters are exactly the same as in Example 3.

[0032] Comparative Example 2-1 The difference from Example 3 is that the following proportions by weight are used: 14 parts alumina micro powder, 55 parts barium sulfate, 26 parts zirconium oxide micro powder, and 4 parts yttrium oxide fine powder. The remaining steps and parameters are exactly the same as in Example 3.

[0033] Comparative Example 3-1 The difference from Example 3 is that the following parts by weight are used: 16 parts alumina micro powder, 55.5 parts barium sulfate, 26 parts zirconium oxide micro powder, and 2.5 parts yttrium oxide fine powder. The remaining steps and parameters are exactly the same as in Example 3.

[0034] Comparative Example 4-1 The difference from Example 3 is that the following proportions by weight are used: 15 parts alumina micro powder, 57 parts barium sulfate, 27 parts zirconium oxide micro powder, and 1 part yttrium oxide fine powder. The remaining steps and parameters are exactly the same as in Example 3.

[0035] Comparative Examples 1-2 The difference from Example 3 is that the following parts by weight are used: 16 parts alumina micro powder, 55 parts barium sulfate, 24 parts zirconium oxide micro powder, and 5 parts lanthanum oxide fine powder. The remaining steps and parameters are exactly the same as in Example 3.

[0036] Comparative Example 2-2 The difference from Example 3 is that the following parts by weight are used: 14 parts alumina micro powder, 55 parts barium sulfate, 26 parts zirconium oxide micro powder, and 4 parts lanthanum oxide fine powder. The remaining steps and parameters are exactly the same as in Example 3.

[0037] Comparative Example 3-2 The difference from Example 3 is that the following parts by weight are used: 16 parts alumina micro powder, 55.5 parts barium sulfate, 26 parts zirconium oxide micro powder, and 2.5 parts lanthanum oxide fine powder. The remaining steps and parameters are exactly the same as in Example 3.

[0038] Comparative Example 4-2 The difference from Example 3 is that the following proportions by weight are used: 15 parts alumina micro powder, 57 parts barium sulfate, 27 parts zirconium oxide micro powder, and 1 part lanthanum oxide fine powder. The remaining steps and parameters are exactly the same as in Example 3.

[0039] Comparative Example 5 The difference from Example 1 is that the composite stabilized barium aluminozizate cement binder is replaced with pure calcium aluminate cement. The pure calcium aluminate cement has an Al2O3 content of 71% and a CaO content of 21%. The remaining steps and parameters are exactly the same as in Example 1.

[0040] Comparative Example 6 The difference from Example 3 is that the composite stabilized barium aluminozizate cement binder is replaced with pure calcium aluminate cement. The pure calcium aluminate cement has an Al2O3 content of 71% and a CaO content of 21%. The remaining steps and parameters are exactly the same as in Example 3.

[0041] Comparative Example 7 The difference from Example 1 is that the raw materials used are: 10 parts of white corundum with a particle size of 10-20 mm, 18 parts of tabular corundum with a particle size of 5-10 mm, 13 parts of tabular corundum with a particle size of 3-6 mm, 13 parts of tabular corundum with a particle size of 1-3 mm, 14 parts of tabular corundum with a particle size of 0-1 mm, 7.8 parts of tabular corundum with a particle size of 0.074 mm, 5 parts of sintered magnesium aluminum spinel with a particle size of 0.074 mm, 5 parts of activated alumina micro powder with a particle size of 2.5 μm, 3 parts of calcined alumina micro powder with a particle size of 4.5 μm, 8 parts of p-Al2O3 micro powder, 3 parts of microsilica powder, 0.1 parts of water-reducing agent, and 0.1 parts of explosion-proof fiber. The ρ-Al2O3 micro powder contains 99.5% Al2O3 and has a particle size of 2.5 μm. The SiO2 content in the microsilica powder was 95.5%, and the particle size was 8 μm. The remaining steps and parameters were exactly the same as in Example 1.

[0042] Comparative Example 8 The difference from Example 1 is that the raw materials used are: 10 parts of white corundum with a particle size of 10-20 mm, 18 parts of tabular corundum with a particle size of 5-10 mm, 13 parts of tabular corundum with a particle size of 3-6 mm, 13 parts of tabular corundum with a particle size of 1-3 mm, 14 parts of tabular corundum with a particle size of 0-1 mm, 7.8 parts of tabular corundum with a particle size of 0.074 mm, 5 parts of sintered magnesium aluminum spinel with a particle size of 0.074 mm, 5 parts of activated alumina micro powder with a particle size of 2.5 μm, 3 parts of calcined alumina micro powder with a particle size of 4.5 μm, 6 parts of p-Al2O3 micro powder, 5 parts of microsilica powder, 0.1 parts of water-reducing agent, and 0.1 parts of explosion-proof fiber. The ρ-Al2O3 micro powder contains 99.5% Al2O3 and has a particle size of 2.5 μm. The SiO2 content in the microsilica powder was 95.5%, and the particle size was 8 μm. The remaining steps and parameters were exactly the same as in Example 3.

[0043] Performance testing The hot flexural strength (MPa) was tested according to GB / T 3002-2004; the slag erosion resistance was tested according to GB / T8931-2007; the thermal shock performance was tested according to GB / T 376.1-1995; the precast blocks prepared by Examples 1-5 and Comparative Examples 1-8 were subjected to relevant performance tests, and the results are shown in Table 1. Table 1 Performance test results of precast blocks from Examples 1-5 and Comparative Examples 1-2

[0044] As shown in Table 1, the precast steel ladle linings made of carbon-free corundum spinel bonded with pure calcium aluminate cement and ρ-Al2O3 micro powder have relatively poor resistance to slag erosion and permeability, thermal shock resistance, and high-temperature performance. The precast steel ladle linings made of carbon-free corundum spinel bonded with barium aluminozirconate cement with added rare earth oxides have better resistance to slag erosion and permeability, thermal shock resistance, and high-temperature performance than the traditional unstable barium aluminozirconate cement-bonded precast steel ladle linings made of carbon-free corundum spinel. Among them, the performance of the precast steel ladle working lining made of carbon-free corundum spinel bonded with composite rare earth oxide stabilized barium alumina zirconate cement is better than that of the precast steel ladle working lining made of carbon-free corundum spinel bonded with single rare earth oxide stabilized barium alumina zirconate cement.

[0045] Practical application experiment: The product of Example 3 above was selected for practical application test in a 100-ton steel ladle of a branch plant of Ansteel. Construction of carbon-free corundum spinel precast blocks for working lining of steel ladle: the precast blocks of working lining of steel ladle were laid on the permanent lining of steel ladle according to the requirements of the number of layers and position. Among them, a 1mm yellow cardboard was placed every 10 bricks of working lining precast blocks of steel ladle wall with the vertical joints staggered. Construction of slag line and rim bricks: Lay the slag line magnesia-carbon bricks and rim magnesia-carbon bricks on the working lining of the steel ladle according to the required number of layers and positions, and use castable refractory to tie the ladle rim area. Baking: Based on the flame length of the steel plant's baking process, it is divided into low heat for 24 hours, medium heat for 24 hours, and high heat for 24 hours, for a total of 72 hours before going online; Results: The carbon-free corundum spinel preform for ladle working lining prepared in the example was applied to a 100-ton ladle at Anshan Iron and Steel Plant No. 2 with an average lifespan of 190 cycles. The average lifespan of the carbon-free corundum spinel preform for ladle working lining in the prior art is 110 cycles. The lifespan of the product of the present invention is significantly higher than that of the carbon-free corundum spinel preform for ladle working lining in the prior art.

[0046] The above embodiments are only used to illustrate the technical solutions of the present invention, and are not intended to limit it. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A composite stabilized barium aluminozizate cement binder, characterized in that, The raw materials include the following parts by weight: 12-17 parts alumina micro powder, 55-60 parts barium sulfate, 24-28 parts zirconium oxide micro powder, 1-5 parts yttrium oxide fine powder, and 1-5 parts lanthanum oxide fine powder.

2. The composite stabilized barium aluminozizate cement binder according to claim 1, characterized in that, The alumina micro powder has an Al2O3 content of >99% and a particle size of 5-10μm. The barium sulfate contains >98% BaSO4 and has a particle size of 600-800 mesh. The zirconium oxide micro powder contains Zr2O3 > 95% and has a particle size of 1-2 μm; The yttrium oxide powder contains Y2O3 > 99% and has a particle size of 325 mesh. The lanthanum oxide fine powder contains more than 99% La2O3 and has a particle size of 325 mesh.

3. The method for preparing a composite stabilized barium aluminozizate cement binder according to any one of claims 1-2, characterized in that, Specifically, the following steps are included: (1) Weigh the raw materials according to the stated weight proportions for later use; (2) The raw materials are wet-milled with water to obtain mud slurry, and the mud slurry is dehydrated, granulated and dried to obtain mud material; (3) The clay material is calcined and then crushed to obtain a composite stabilized barium aluminozirconate cement binder.

4. The preparation method of the composite stabilized barium aluminozizate cement binder according to claim 3, characterized in that, The mass ratio of raw materials to water in step (2) is 2:1; The wet milling time is 20-30 minutes; the granulation particle size is 5-10 mm; the drying is carried out at 80-110℃ for more than 8 hours.

5. The preparation method of the composite stabilized barium aluminozizate cement binder according to claim 3, characterized in that, The calcination is carried out at 1550-1600℃ for 4-6 hours; the fineness of the pulverization is 18 micrometers, and the mass percentage of the residue on the sieve is 5-10%.

6. The application of the composite stabilized barium aluminozizate cement binder as described in any one of claims 1-2 or the composite stabilized barium aluminozizate cement binder obtained by the preparation method described in any one of claims 3-5 in the preparation of carbon-free corundum spinel precast blocks for ladle working linings.

7. The application as described in claim 6, characterized in that, The carbon-free corundum spinel precast block for the ladle working lining comprises the following raw materials in parts by weight: 5-20 parts of 10-20mm white corundum, 10-25 parts of 5-10mm tabular corundum, 10-20 parts of 3-6mm tabular corundum, 10-15 parts of 1-3mm tabular corundum, 10-20 parts of 0-1mm tabular corundum, 0-10 parts of 0.074mm tabular corundum, 10-15 parts of 0.074mm sintered aluminum-magnesium spinel, 2-5 parts of 2.5μm active α-Al2O3 micro powder, 2-5 parts of 4.5μm calcined α-Al2O3 micro powder, 5-15 parts of composite stabilized barium aluminozizate cement binder, 0.1-0.2 parts of water-reducing agent, and 0.05-0.1 parts of explosion-proof fiber.

8. The application according to claim 7, characterized in that, The white fused alumina contains Al2O3 content > 98 wt% and SiO2 content < 0.2 wt%. The tabular corundum contains Al2O3 content > 99 wt% and SiO2 content < 0.2 wt%. The sintered aluminum-magnesium spinel contains 76-78 wt% Al2O3 and 18-22 wt% MgO. The Al2O3 content in both the active α-Al2O3 micro powder and the calcined α-Al2O3 micro powder is >99 wt%. The water-reducing agent is FS10; The explosion-proof fiber has a melting point of <105℃ and a length of 2-4mm.

9. The application according to claim 7, characterized in that, The preparation method of the carbon-free corundum spinel precast block for the ladle working lining includes the following steps: 1) Weigh the raw materials according to the stated weight proportions, mix well, and set aside; 2) After mixing the raw materials obtained in step 1) with water, add them into the mold for molding and curing, and then demold to obtain a demolded precast block; 3) After curing and drying the demolded precast block, carbon-free corundum spinel precast block for ladle working lining is obtained.

10. The application according to claim 9, characterized in that, The flow value of the mixture obtained by adding water and kneading in step 2) is 150-180 mm; the curing temperature is 25-35℃, the humidity is 60-7, and the curing time is ≥48h. The temperature for the conditioning process in step 3) is 25-35℃, the humidity is 60-70%, and the time is ≥72h; the temperature for drying is no more than 300℃, and the drying time is ≥80h.

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