A slag-erosion-resistant amorphous refractory and a method for manufacturing the same

Abstract

The application belongs to the technical field of refractory materials, and discloses a slag-erosion-resistant amorphous refractory material and a preparation method thereof. The material comprises, in terms of weight fractions, aggregate 60-80 parts, composite binder 10-15 parts, functional additive 5-25 parts, water reducing agent 0.5-1.2 parts, retarder 0.1-0.4 parts and water 5.0-7.0 parts. The composite binder is composed of modified silica sol and calcium aluminate cement at a mass ratio of (1.5-2.5):1, and the functional additive comprises silicon nitride powder and zirconia powder. Through the synergistic effect of the composite binder system and the multi-phase slag-resistant component, the problems of incompatibility of the binder of the traditional material, low medium-temperature strength, easy setting and poor slag resistance are effectively solved, the full-temperature strength stability, the molten slag erosion resistance and the construction reliability of the material are significantly improved, and the material is suitable for the high-temperature kiln lining under severe working conditions such as blast furnaces, ladles, steel ladles and aluminum smelting furnaces.

Description

Technical Field

[0001] This invention belongs to the field of refractory materials technology, specifically relating to an unshaped refractory material with excellent slag erosion resistance and its preparation method. Background Technology

[0002] With the rapid development of high-temperature industries, higher requirements have been placed on the service life and operational stability of refractory materials. Slag erosion is one of the main causes of refractory material damage. Especially in metallurgical processes, components such as CaO, SiO2, and FeO in slag are prone to react with refractory materials, causing structural spalling and performance degradation.

[0003] In existing technologies, corundum or corundum-silica monolithic refractories bonded with calcium aluminate cement are widely used. However, their room-temperature strength depends on cement hydration products, making them susceptible to environmental influences during medium- and low-temperature curing. Furthermore, they generate low-melting-point phases at high temperatures, affecting slag resistance and thermal shock stability. In addition, traditional bonding systems require prolonged moisture retention after construction, resulting in long construction cycles and limiting their application in fast-paced production. In recent years, silica sol bonding technology has attracted attention due to its advantages such as high bonding strength, no decrease in medium-temperature strength, and good workability. However, ordinary silica sol has a low pH value and poor stability, and when used in combination with calcium aluminate cement, it is prone to rapid setting, making it difficult to achieve long-term workability. Therefore, constructing a composite bonding system using modified silica sol and calcium aluminate cement has become one of the research directions for improving the comprehensive performance of monolithic refractories.

[0004] However, existing silica sol-cement composite systems still suffer from poor dispersibility, stringent curing requirements, and insufficient resistance to slag penetration. How to achieve stable bonding of materials over a wide temperature range and significantly improve their resistance to slag erosion and penetration through component design and process control is a pressing technical challenge that needs to be addressed. Summary of the Invention

[0005] The purpose of this application is to provide an unshaped refractory material and its preparation method that has excellent construction performance, maintains high strength and stability, and has excellent resistance to slag erosion.

[0006] In order to overcome the problems existing in the background art and achieve the above-mentioned objectives, this application adopts the following technical solution: A slag-resistant monolithic refractory material, comprising the following components by weight: 60-80 parts aggregate; 10-15 parts of composite binder; 5-25 parts of functional admixture; Water-reducing agent: 0.5-1.2 parts; 0.1-0.4 parts of retarder; 5.0-7.0 parts water; The composite binder is composed of modified silica sol and calcium aluminate cement in a mass ratio of (1.5-2.5):1. The functional additives include silicon nitride powder and zirconium oxide powder.

[0007] The above scheme ensures that the material possesses sufficient mechanical strength (aggregate support), good workability and bonding strength (composite binder), and potential resistance to slag erosion by limiting the proportions of each component. By combining modified silica sol with calcium aluminate cement in a specific ratio, the critical threshold of acid-base compatibility is addressed, preventing flash setting. Combined with a retarder, this extends the construction window to meet on-site pouring requirements.

[0008] Furthermore, the modified silica sol is a silica sol modified with silane coupling agent KH-560, with a solid content of 25-35%; the calcium aluminate cement is CA-70 type calcium aluminate cement.

[0009] By limiting the types of modified silica sol and calcium aluminate cement, sufficient SiO2 network structure can be formed after dehydration, providing high bonding strength.

[0010] Furthermore, the aggregate comprises fused alumina and silicon carbide; wherein the particle size of the fused alumina comprises one of 5-15 mm, 1-5 mm, or a mixture thereof.

[0011] Furthermore, by weight, the functional additive also includes 1-3 parts of nano-alumina powder and 4-8 parts of silicon micropowder.

[0012] Furthermore, the amount of silicon nitride powder added is 3-7 parts, and the amount of zirconium oxide powder added is 3.0-6.0 parts.

[0013] Furthermore, the water-reducing agent is a polycarboxylate-based water-reducing agent, especially a polyether-type polycarboxylate water-reducing agent with sulfonate groups in the side chain.

[0014] Furthermore, the retarder is aluminum citrate.

[0015] This application also discloses a method for preparing an anti-slag corrosion composite binder monolithic refractory material, comprising the following steps: (1) Raw material pretreatment: Dry the aggregate to a moisture content of ≤0.5%; (2) Segmented mixing: The aggregate is put into a forced mixer for dry mixing, then silica powder and nano alumina powder are added and mixed evenly, then modified silica sol, water-reducing agent, retarder and water are added and mixed, and finally calcium aluminate cement and silicon nitride powder are added and mixed evenly to obtain the mixture. (3) Molding: Inject the mixture into the mold and use vibration molding or casting molding to remove air bubbles; (4) Curing: After the green body is left to cure, it is demolded, then dried by gradient heating and fired at high temperature to obtain the slag-resistant monolithic refractory material.

[0016] Furthermore, in step (4), the gradient heating drying process is performed: The temperature was increased from room temperature to 110℃ at a rate of 20-30℃ / h, and held for 12-24 hours. The temperature was increased from 110℃ to 600℃ at a heating rate of 30-40℃ / h, and held for 10-20h. The temperature is increased from 600℃ to 1450℃ at a heating rate of 50-60℃ / h, held for 2-5 hours, and then cooled with the furnace.

[0017] Furthermore, in step (3), the vibration frequency of the vibration molding is 40-60Hz, and the vibration duration is 2-5 minutes.

[0018] This invention effectively solves the problems of incompatibility of binders, low mid-temperature strength, easy flash solidification and poor slag resistance of traditional materials by combining a composite bonding system with multiphase anti-slag components. It significantly improves the strength stability, slag erosion resistance and construction reliability of the material across the entire temperature range, and is suitable for high-temperature kiln linings under harsh conditions such as blast furnaces and molten iron ladles.

[0019] The core technological improvement of this invention: 1. Innovation of composite binder system: Breaking through the limitations of traditional single binder, a composite system of "modified silica sol + CA-70 calcium aluminate cement" is adopted. By optimizing the ratio of the two (mass ratio 2:1), the synergistic improvement of room temperature strength and high temperature performance is achieved.

[0020] 2. Functional component optimization and proportion adjustment: Silicon nitride powder is introduced as an anti-slag functional component, forming a three-dimensional skeleton structure of "high temperature resistance, erosion resistance and corrosion resistance" with corundum and silicon carbide; aggregate particles are optimized, and nano alumina powder and silicon micro powder are used to fill the gaps to improve the material density; polyether-type polycarboxylate superplasticizer with sulfonate groups in the side chain is selected to reduce the amount of water added while improving the fluidity of the material.

[0021] 3. Segmented optimization of preparation process: The innovative "segmented speed-controlled stirring + gradient temperature curing" process is adopted. During the stirring stage, the aggregate, fine powder, liquid components and functional components are added in sequence, and the speed and time are adjusted in segments to ensure uniform mixing of components. During the curing stage, the temperature is controlled in segments at 20℃ / h, 30℃ / h and 50℃ / h to avoid structural defects caused by thermal stress concentration and promote the full progress of high-temperature reaction.

[0022] This application is particularly applicable to parts of blast furnaces, ladles of iron, ladles of steel, and aluminum smelting furnaces that are susceptible to erosion by slag or molten metal, and solves the problems existing in the prior art, producing corresponding technical effects: 1. Solve the problem of poor slag erosion resistance of traditional monolithic refractory materials: Through the synergistic effect of composite binder and silicon nitride powder, a dense high-temperature protective layer is formed, which hinders molten slag penetration and erosion. The slag erosion resistance depth is significantly reduced compared with traditional solutions, and it can be adapted to extreme slag erosion conditions in metallurgy, chemical industry and other fields.

[0023] 2. Solving the problem of insufficient thermal shock stability of materials: Through the synergistic effect of thermal conductivity of silicon carbide and silicon nitride, combined with optimized particle size distribution and process control, the thermal shock resistance cycle is ≥30 times, which is more than 100% higher than the traditional solution, avoiding peeling and cracking caused by temperature fluctuations.

[0024] 3. Solving the contradiction between room temperature strength and high temperature performance: A single binder is difficult to balance room temperature construction strength and high temperature service performance. This patented composite binder system achieves a room temperature compressive strength of 45.8MPa and a high temperature compressive strength of 102.4MPa, both of which are superior to traditional solutions, meeting the dual requirements of construction and service.

[0025] 4. Solving the problem of balancing material flowability and density: Traditional water-reducing agents have low water reduction rates, which can easily lead to poor material flowability or high porosity. The polycarboxylate-based water-reducing agent selected in this patent reduces the amount of water added to 6.0 parts, achieves a flow value of 192 mm, and reduces the apparent porosity to 12.5%, thus achieving an optimized balance between flowability and density. Detailed Implementation

[0026] The present application will be further illustrated by the following embodiments, but the scope of protection of the present application is not limited to the embodiments.

[0027] The modified silica sol and polycarboxylate superplasticizer used in the examples were prepared by the applicant; the remaining raw materials were all commercially available.

[0028] Preparation Example 1: Modified Silica Sol Raw materials for the preparation of modified silica sol: Raw material name Specifications and Models source Mass ratio (based on a total mass of 100 parts) Common alkaline silica sol Solid content 30%, particle size 10-20nm, pH=9-10 Domestic professional manufacturer of silica sol, meeting industrial-grade standards 95.0 copies Silane coupling agent KH-560 Purity ≥ 98%, Industrial Grade Domestic fine chemical enterprises 4.5 copies Acetic acid Concentration 36%, industrial grade Domestic chemical raw material suppliers 0.5 copies Deionized water Conductivity ≤10μS / cm The company has its own pure water preparation equipment. Adjust as needed (control system solids content 30%) Preparation process: (1) Pretreatment: Add 95.0 parts of ordinary alkaline silica sol to a three-necked flask equipped with a stirrer and a thermometer, heat to 40±2℃, stir at low speed (100r / min) for 10min to remove dissolved bubbles in the system; (2) Hydrolysis of coupling agent: Mix 4.5 parts of silane coupling agent KH-560 with 5 parts of deionized water, add 0.5 parts of acetic acid to adjust the pH to 4-5, stir at room temperature for 20 minutes to fully hydrolyze the coupling agent to generate active groups containing hydroxyl groups; (3) Grafting modification: The hydrolyzed coupling agent solution was slowly added dropwise to the pretreated silica sol. The dropping rate was controlled at 1 mL / min. During the dropping process, the system temperature was maintained at 40±2℃, the stirring speed was increased to 200 r / min, and the reaction was continued for 2 h. (4) Neutralization and stabilization: After the reaction is completed, the pH of the system is adjusted to 6-8 with 0.1 mol / L sodium hydroxide solution, and stirring is continued for 30 min to stabilize the modified silica sol system; (5) Finished product collection: Filter the system after reaction (using a 200-mesh sieve) to remove a small amount of insoluble impurities and obtain a modified silica sol with a solid content of 30% and a particle size of 10-20nm. Store it in a sealed container away from light for later use.

[0029] The core purpose and effects of modification: By grafting the epoxy groups of the silane coupling agent KH-560 onto the hydroxyl groups on the surface of silica sol, organic-inorganic composite groups are introduced onto the surface of silica sol particles. On the one hand, this enhances the chemical bonding ability with the hydration products of calcium aluminate cement, thereby increasing the bonding strength at room temperature. On the other hand, it improves the interfacial compatibility between silica sol and corundum and silicon carbide aggregates, preventing the formation of low-melting-point phases due to interfacial separation at high temperatures, ensuring that it transforms into a dense mullite phase at high temperatures, and strengthening the resistance to slag corrosion.

[0030] Preparation Example 2: Polycarboxylate-based water-reducing agent Traditional naphthalene-based water-reducing agents are widely used in refractory materials, but they suffer from problems such as low water reduction rate, significant negative impact on strength, and poor environmental performance, easily leading to insufficient material density and easy penetration and erosion by slag liquid. The polycarboxylate-based water-reducing agent selected in this application is compatible with composite binder systems, achieving high water reduction rate at low dosages while improving the density of the material's microstructure.

[0031] Traditional polycarboxylate superplasticizers are mostly used in concrete systems, but they have poor compatibility with the high-alumina and high-silica components of refractory materials, easily leading to problems such as insufficient dispersibility and rapid slump loss. The superplasticizer in this application is designed to be compatible with refractory material systems through the following modifications: (1) Introducing sulfonate groups into the side chain: improves the solubility and dispersion stability of the water-reducing agent in the alkaline refractory material system, and avoids the attenuation of the water-reducing effect due to changes in the pH of the system; (2) Optimize the side chain length: Select polyoxyethylene ether side chains with a molecular weight of 2000 to balance dispersibility and adsorption, ensure the coating and dispersion effect on corundum and silicon carbide aggregates, and at the same time not affect the coagulation reaction of the composite binder. (3) Control the carboxyl group density of the main chain: By adjusting the copolymerization ratio of acrylic acid and maleic anhydride, the water-reducing agent molecules can not only have strong dispersing ability (reduce the amount of water added), but also form a synergistic dispersion effect with fine powders such as nano alumina powder and silicon micro powder, thereby improving the overall fluidity and density of the material.

[0032] Its basic parameters are shown in the table below: Parameter name Specific indicators Testing basis type Polyether-type polycarboxylate superplasticizer (side chain contains sulfonate groups) Solid content 40%±1% GB / T8077-2012 Water reduction rate ≥30% (when the dosage is 0.8 parts) GB / T8077-2012 (Testing of Refractory Material Systems) Molecular structure The main chain is an acrylic acid-maleic anhydride copolymer, the side chain is a polyoxyethylene ether (molecular weight 2000), and it is grafted with sulfonate groups. Gel permeation chromatography (GPC) test pH value 6-7 GB / T8077-2012 Chloride ion content ≤0.01% GB / T8077-2012 Adaptation System Corundum-Silicon Carbide-Composite Binder (Modified Silica Sol + CA-70 Calcium Aluminate Cement) System Targeted compatibility testing Example 1:

[0033] This embodiment provides an anti-slag corrosion composite binder unshaped refractory material and its preparation method.

[0034] 1. Raw material ratio (by weight): Aggregates: 35 parts of fused dense corundum (5-15mm), 20 parts of fused dense corundum (1-5mm), and 12 parts of silicon carbide (0.1-1mm); Composite binder: 8 parts of the modified silica sol obtained in Preparation Example 1, and 4 parts of CA-70 type calcium aluminate cement; Functional additives: 5 parts silicon nitride powder, 3.5 parts zirconium oxide powder, 2 parts nano alumina powder, and 6 parts silicon micro powder; Water-reducing agent: 0.8 parts of the polyether-type polycarboxylate water-reducing agent (with sulfonate groups in the side chain) obtained in Preparation Example 2; Retarder: 0.3 parts aluminum citrate; Water: 6.0 parts.

[0035] 2. Preparation method: (1) Raw material pretreatment: Dry the above aggregates at 110℃ for 24 hours to make their moisture content ≤0.5%; seal and store all powdered raw materials (including functional admixtures, water-reducing agents and retarder) for moisture protection and later use.

[0036] (2) Segmented mixing: The dried aggregate was put into a forced mixer and dry-mixed for 3 minutes at a speed of 20 r / min; Add silica powder and nano alumina powder, and continue mixing for 5 minutes at 35 r / min to ensure that the powder is evenly coated on the surface of the aggregate. Modified silica sol, polyether-type polycarboxylate superplasticizer, aluminum citrate retarder and water are premixed evenly to form a liquid component, and then added to a mixer and stirred at high speed of 50 r / min for 8 minutes. Finally, add CA-70 calcium aluminate cement and silicon nitride powder, and stir at 35 r / min for 4 minutes to obtain a uniform and fluid mixture.

[0037] (3) Molding: Inject the mixture into a standard mold, place it on a vibration table and vibrate at a frequency of 50Hz and an amplitude of 2mm for 3 minutes to fully remove air bubbles and compact the molding to obtain a blank.

[0038] (4) Curing and firing: Demolding is performed after the green body has been cured at room temperature for 24 hours. After demolding, the green body is placed in an oven / kiln and dried and fired according to the following gradient temperature regime: The temperature was increased from room temperature to 110℃ at a rate of 20℃ / h and held for 24 hours. The temperature was increased from 110℃ to 600℃ at a rate of 30℃ / h and held for 12 hours. The temperature was increased from 600℃ to 1450℃ at a rate of 50℃ / h and held for 3 hours. After firing, the material is cooled to room temperature in the furnace to obtain the slag-resistant monolithic refractory material product described in this invention.

[0039] Key process control points and their functions:

[0040] Example 2: The amount of silicon nitride was adjusted to 3 parts, and the remaining components and preparation method were the same as in Example 1.

[0041] Example 3: The amount of silicon nitride was adjusted to 7 parts, and the remaining components and preparation method were the same as in Example 1.

[0042] Example 4: The zirconium oxide powder was adjusted to 3.0 parts, and the remaining components and preparation method were the same as in Example 1.

[0043] Example 5: The zirconium oxide powder was adjusted to 4.0 parts, and the remaining components and preparation method were the same as in Example 1.

[0044] Comparative Example 1 (using only calcium aluminate cement as a binder) This comparative example is used to illustrate the performance differences between a single calcium aluminate cement bonding system and the composite binder system of the present invention.

[0045] Raw material ratio (by weight): The aggregates, functional admixtures, water-reducing agents, retarders, and their dosages are the same as in Example 1; Binder: 12 parts of CA-70 calcium aluminate cement (replacing 8 parts of modified silica sol and 4 parts of cement in Example 1, while maintaining the same total binder dosage). Water: 6.0 parts.

[0046] Preparation method: Except for the different binder components, the rest is the same as in Example 1.

[0047] Comparative Example 2 (using only modified silica sol as a binder) This comparative example is used to illustrate the performance differences between the single modified silica sol binding system and the composite binder system of the present invention.

[0048] Raw material ratio (by weight): The aggregates, functional admixtures, water-reducing agents, retarders, and their dosages are the same as in Example 1; Binder: 12 parts modified silica sol (replacing 8 parts modified silica sol and 4 parts cement in Example 1). Water: 5.0 parts (the amount of water used is slightly reduced because there is no need for cement hydration).

[0049] Preparation method: Except for the different binder components and water content, the rest is the same as in Example 1 (no cement needs to be added at the end during mixing).

[0050] Comparative Example 3: The water-reducing agent in Example 1 was replaced with a naphthalene-based water-reducing agent, and the water was increased to 7.8 parts. The remaining components and preparation method were the same as in Example 1.

[0051] Comparative Example 4: Without adding silicon nitride, the remaining components and preparation method are the same as in Example 1.

[0052] Comparative Example 5: Without adding zirconium oxide powder, the remaining components and preparation method are the same as in Example 1.

[0053] Performance testing: Multiple performance tests were performed on the sample obtained in Example 1, and the results are shown in the table below: Testing items Testing standards Test results unit Remark Fire resistance GB / T7322-1997 ≥2000 ℃ Meets the requirements of high-temperature working conditions in metallurgy and chemical industry Softening temperature under load (0.2MPa, 4% deformation) GB / T5989-2008 1680 ℃ Excellent structural stability at high temperatures Thermal shock resistance (1100℃ water cooling, number of cycles) GB / T30873-2014 ≥30 Second-rate No cracks or peeling Depth of resistance to slag erosion (1450℃×5h) GB / T8931-2007 3.1 mm Rotary slag etching test Slag penetration resistance depth (1450℃×5h) GB / T8931-2007 5.2 mm Rotary slag etching test Bulk density (110℃×24h) GB / T2997-2015 3.08 g / cm³ High density Bulk density (1450℃×3h) GB / T2997-2015 3.12 g / cm³ The density increases slightly after high temperature. room temperature compressive strength (110℃×24h) GB / T5072-2008 45.8 MPa High initial strength High temperature compressive strength (1450℃×3h) GB / T5072-2008 102.4 MPa Excellent high-temperature strength retention Flexural strength at room temperature (110℃×24h) GB / T5072-2008 8.6 MPa - High-temperature flexural strength (1450℃×3h) GB / T5072-2008 18.2 MPa - Linear rate of change (1450℃×3h) GB / T5988-2007 +0.25 % It meets the national standard requirement of ±0.5% and has good volume stability. Apparent porosity (110℃×24h) GB / T2997-2015 12.5 % Low porosity and strong impermeability Fire resistance GB / T7322-1997 ≥2000 ℃ Zirconia powder enhances high-temperature stability to meet the high-temperature requirements of metallurgical and chemical industries. Performance comparison of the sample obtained in Example 1 with the traditional method: The traditional solution uses mainstream slag-resistant monolithic refractory materials on the market (corundum-silicon carbide system, single calcium aluminate cement binder). The comparative testing conditions are all after heat treatment at 1450℃ for 3 hours, and the slag resistance is tested according to GB / T8931-2007 standard (1450℃ for 5 hours).

[0054] Performance indicators Example 1 Sample Traditional technical solutions Performance improvement Load softening temperature (°C) 1680 1580 6.3% Thermal shock resistance (number of cycles) ≥30 15 ≥100% Depth of resistance to slag erosion (mm) 3.1 8.5 63.5% Slag penetration resistance depth (mm) 5.2 13.8 62.3% High-temperature pressure resistance (MPa) 102.4 78.6 30.3% Bulk density (g / cm³) 3.12 2.95 5.8% Linear rate of change (%) +0.25 +0.42 Stability improved by 40.5% Apparent porosity (%) 12.5 18.8 33.5% Experiment 1: Comparison of the performance of different binder systems Example 1, Comparative Example 1, and Comparative Example 2 used different binders, and their performance results are compared as follows: binder system room temperature compressive strength (MPa) High-temperature pressure resistance (MPa) Depth of resistance to slag erosion (mm) Comparative Example 1: Single CA-70 calcium aluminate cement 42.5 85.3 8.2 Comparative Example 2: Single Modified Silica Sol 28.6 98.7 6.5 Example 1: Composite binder (8:4) 45.8 102.4 3.1 The data shows that the composite binder system has better strength at both room temperature and high temperature than the single system, and its slag erosion resistance depth is reduced by 62.2% compared with the single calcium aluminate cement system, which significantly improves the slag erosion resistance performance.

[0055] Traditional monolithic refractory materials often use a single binder. For example, using only calcium aluminate cement can easily lead to the formation of low-melting-point phases at high temperatures, resulting in decreased slag resistance. Using only silica sol results in insufficient strength at room temperature, making the materials prone to breakage after construction. This patent employs a composite binder system, which, through the synergistic effect of modified silica sol and calcium aluminate cement, balances both room-temperature construction performance and high-temperature service performance.

[0056] Experiment 2: Performance comparison of the water-reducing agent of this application and traditional naphthalene-based water-reducing agents The performance comparison between Comparative Example 1 and Comparative Example 3 is as follows: Types of water-reducing agents Water volume (portions) Flow value (mm) Apparent porosity (%) Slag penetration resistance depth (mm) Comparative Example 3: Naphthalene-based water-reducing agent 7.8 165 18.2 5.8 Example 1: Polycarboxylate superplasticizer 6.0 192 12.5 2.3 Data shows that the water-reducing agent selected in this patent can reduce the amount of water added by 23.1%, increase the flow value by 16.4%, reduce the apparent porosity by 31.3%, and reduce the slag penetration depth by 60.3%, effectively solving the technical problems of insufficient water reduction rate and poor material density of traditional water-reducing agents.

[0057] Traditional naphthalene-based water-reducing agents are widely used in refractory materials, but they suffer from problems such as low water reduction rate, significant negative impact on strength, and poor environmental performance, easily leading to insufficient material density and easy penetration and erosion by slag liquid. This patent selects a polyether-type polycarboxylate water-reducing agent with sulfonate groups in the side chain, which is adapted to a composite binder system, and can achieve a high water reduction rate at low dosage, while improving the density of the material's microstructure.

[0058] Experiment 3: Performance Comparison of Silicon Nitride Powders with Different Contents Slag resistance of different silicon nitride powder contents in Comparative Examples 1, 2, 3 and 4: slag corrosion test at 1450℃ for 5 hours, according to GB / T8931-2007 standard; results are as follows: Silicon nitride powder content (parts) Erosion depth (mm) Penetration depth (mm) Percentage of eroded area (%) Comparative Example 4 (without silicon nitride) 7.5 12.3 28.6 Example 1 3.1 5.2 8.9 Example 2 4.8 8.5 16.3 Example 3 2.9 4.9 8.2 Data shows that the anti-slag corrosion performance is significantly improved after adding silicon nitride powder. When the dosage is 5 parts, the corrosion depth is reduced by 58.7% compared with the system without silicon nitride. Furthermore, the performance improvement is small when the dosage is further increased. Considering both cost and performance, 5 parts is determined as the benchmark dosage.

[0059] Traditional slag-resistant refractory materials often improve their performance by increasing the corundum content, but this is costly and their thermal shock resistance tends to decrease. Silicon nitride powder has excellent chemical inertness and does not react with components such as CaO and MgO in molten slag. Furthermore, at high temperatures, it can react with alumina to form alumina-nitrogen compounds, creating a dense protective layer that hinders slag penetration.

[0060] Experiment 4: Comparison of high-temperature performance with different zirconium oxide powder contents Comparison of high-temperature performance of different zirconium oxide powder contents in Examples 1, 4, 5 and Comparative Example 5: After heat treatment at 1450℃ for 3 hours, tests were conducted according to the corresponding national standards; the results are as follows: Zirconia powder content (parts) Load softening temperature (°C) High-temperature pressure resistance (MPa) High-temperature linear change rate (%) Comparative Example 5 (Zirconium oxide-free powder) 1620 92.8 +0.38 Example 1 1680 102.4 +0.25 Example 4 1650 98.5 +0.30 Example 5 1690 103.6 +0.24 Data shows that when 3.5 parts of zirconia powder are added, the load softening temperature is increased by 3.7% compared with the system without additives, the high temperature compressive strength is increased by 10.3%, the linear change rate is reduced by 34.2%, and the high temperature volume stability is significantly optimized, which precisely matches the core requirements of the patented high temperature resistance, while avoiding the cost increase and construction performance decline caused by excessive dosage.

[0061] Traditional refractory materials are prone to structural failure at high temperatures due to phase transformation and the formation of low-melting-point phases, and their load softening temperature is insufficient to meet the requirements of extreme high-temperature conditions. This patent uses stabilized zirconia powder, which can form a synergistic high-temperature structure with composite binders and aggregates, suppressing volume distortion of the material at high temperatures, while improving the load softening temperature and high-temperature strength, thus extending the service life of the material in extreme high-temperature environments.

[0062] The above embodiments are only used to illustrate the technical solutions of this application, and are not intended to limit it. Although this application 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 or all of the technical features therein; and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of this application.

Claims

1. A slag-erosion-resistant monolithic refractory material, characterized in that, By weight, it includes the following components: 60-80 parts aggregate; 10-15 parts of composite binder; 5-25 parts of functional admixture; Water-reducing agent: 0.5-1.2 parts; 0.1-0.4 parts of retarder; 5.0-7.0 parts water; The composite binder is composed of modified silica sol and calcium aluminate cement in a mass ratio of (1.5-2.5):

1. The functional additives include silicon nitride powder and zirconium oxide powder.

2. The slag-resistant monolithic refractory material according to claim 1, characterized in that, The modified silica sol is a silica sol modified with silane coupling agent KH-560, with a solid content of 25-35%; the calcium aluminate cement is CA-70 type calcium aluminate cement.

3. The slag-resistant monolithic refractory material according to claim 1, characterized in that, The aggregate comprises fused alumina and silicon carbide; wherein the particle size of the fused alumina comprises one of 5-15 mm, 1-5 mm, or a mixture thereof.

4. The slag-resistant monolithic refractory material according to claim 1, characterized in that, By weight, the functional additive also includes 1-3 parts of nano-alumina powder and 4-8 parts of silicon micro powder.

5. The slag-resistant monolithic refractory material according to claim 1, characterized in that, The amount of silicon nitride powder added is 3-7 parts, and the amount of zirconium oxide powder added is 3.0-6.0 parts.

6. The slag-resistant monolithic refractory material according to claim 1, characterized in that, The water-reducing agent is a polycarboxylate-based water-reducing agent.

7. The slag-resistant monolithic refractory material according to claim 1, characterized in that, The retarder is aluminum citrate.

8. A method for preparing the slag-resistant monolithic refractory material as described in any one of claims 1-7, characterized in that, Includes the following steps: (1) Raw material pretreatment: Dry the aggregate to a moisture content of ≤0.5%; (2) Segmented mixing: The aggregate is put into a forced mixer for dry mixing, then silica powder and nano alumina powder are added and mixed evenly, then modified silica sol, water-reducing agent, retarder and water are added and mixed, and finally calcium aluminate cement and silicon nitride powder are added and mixed evenly to obtain the mixture. (3) Molding: Inject the mixture into the mold and use vibration molding or casting molding to remove air bubbles; (4) Curing: After the green body is left to cure, it is demolded, then dried by gradient heating and fired at high temperature to obtain the slag-resistant monolithic refractory material.

9. The method for preparing the slag-resistant monolithic refractory material according to claim 8, characterized in that, In step (4), the gradient temperature drying is performed: The temperature was increased from room temperature to 110℃ at a rate of 20-30℃ / h, and held for 12-24 hours. The temperature was increased from 110℃ to 600℃ at a heating rate of 30-40℃ / h, and held for 10-20h. The temperature is increased from 600℃ to 1450℃ at a heating rate of 50-60℃ / h, held for 2-5 hours, and then cooled with the furnace.

10. The method for preparing the slag-resistant monolithic refractory material according to claim 8, characterized in that, In step (3), the vibration frequency of the vibration molding is 40-60Hz and the vibration duration is 2-5 minutes.

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