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# Corundum Self-Flowing Castables: The “Flowing Guardians” of High-Temperature Industries In high‑temperature industrial sectors such as steelmaking, power generation, and building materials & chemical engineering, the construction of refractory linings with complex geometries has long been a persistent pain point in the industry. Traditional vibratory castables suffer from insufficient fluidity, making it difficult to fully fill thin-walled sections, irregularly shaped areas, or regions densely packed with anchors and embedded components. Moreover, manual vibration is not only inefficient but also prone to material segregation due to improper operation, which can significantly shorten the service life of the lining. The advent of corundum self‑flowing castables—with their unique properties of “self‑weight flow and automatic spreading”—has provided a highly efficient and reliable solution for high‑temperature industries. ### I. The Material’s Essence: A Fusion of Corundum Aggregate and Rheology Corundum self‑flowing castables are unshaped refractory materials formulated using high‑purity corundum (Al₂O₃ content ≥ 90%) as the aggregate, combined with optimized particle gradation and the addition of ultrafine powders and high‑efficiency dispersants. At the core of their design lies the “solid–fluid theory”: by carefully controlling the appropriate proportions of coarse particles (1–5 mm), medium particles (0.1–1 mm), and fine powder (<0.088 mm), coupled with the filling effect of ultrafine powders such as α‑Al₂O₃ micro powder and silica fume, these castables form a particle packing structure characterized by low porosity and high fluidity. The addition of polycarboxylate superplasticizers and other dispersants reduces interparticle friction, enabling the material to form a suspension akin to a fluid once water is added—allowing it to flow and degas entirely under its own weight. Take, for example, the JK‑Z1 product from Luoyang Jinkai Refractory Materials Co., Ltd.: its chemical composition boasts an Al₂O₃ + MgO content exceeding 90%, with a volume density of ≥ 3.0 g/cm³ after 110°C drying, a compressive strength of ≥ 30 MPa at room temperature, and a flexural strength of ≥ 5 MPa. This delicate balance between high strength and excellent fluidity stems from the precise control of the “flow–strength” trade-off during material design: while ultrafine powders fill pores and enhance densification, they also undergo high‑temperature sintering to form ceramic bonding phases, thereby strengthening the material’s microstructure. ### II. Performance Advantages: A Comprehensive Upgrade from Construction Efficiency to Service Life 1. **Flow Characteristics Without Vibration** Traditional vibratory castables rely on external vibration to compact the mold; in contrast, corundum self‑flowing castables require only water and mixing before they can rely on their own weight to flow and automatically spread into every nook and cranny of complex structures. For instance, when sealing the gaps around the permeable brick seats on the sidewalls of a ladle, self‑flowing castables can penetrate even the narrowest spaces between anchors, forming a dense, defect‑free lining while eliminating the risk of brick joint cracking caused by vibration. 2. **A Revolutionary Leap in Construction Efficiency** Self‑flowing castables support pump‑based construction, with a single pump truck capable of pouring more than 50 cubic meters per hour—more than three times the efficiency of traditional manual vibration. In the construction of continuous casting tundish linings, adopting self‑flowing castables can reduce the construction cycle from 72 hours to just 24 hours, all without the need to erect vibration platforms, significantly lowering labor intensity and noise pollution. 3. **Optimized Performance Across the Entire Lifecycle** By adding nano‑Al₂O₃ (at a dosage of 2%), the formation of CA₂ phases at intermediate temperatures and flaky CA₆ phases at high temperatures can be promoted, boosting the 1300°C flexural strength to 14.0 MPa. Experimental data show that ladle linings constructed with self‑flowing castables can withstand over 120 heats—extending service life by 40% compared to conventional materials—while also improving erosion resistance and scouring performance by 30%. ### III. Application Scenarios: Covering the Entire High‑Temperature Industrial Chain 1. **Steel Metallurgy** - Ladles: Self‑flowing castables are used to line thin‑walled areas such as the bottom, sidewalls, and around the seating bricks, effectively addressing the issue of steel leakage common in traditional brick‑masonry structures. - Blast Furnaces: Self‑flowing castables are employed in areas like the tapping spout and iron ladle, where they can withstand the erosive action of molten iron at temperatures exceeding 1500°C, achieving a service life of up to 18 months. - Continuous Casting Tundishes: A 30–60 mm thick layer of self‑flowing castable is applied as the working lining, allowing for rapid replacement and minimizing downtime. 2. **Power Generation** - Circulating Fluidized Bed Boilers: Self‑flowing castables are used in the furnace chamber, burnout zone, and cyclone separators, where they can endure the abrasive wear of 850°C circulating ash with a wear coefficient ≤ 5 cm³. - Waste Incineration Furnaces: Self‑flowing castables are utilized in the combustion chamber and flue gas ducts, offering resistance to acidic gas corrosion and thermal shock (withstanding ≥ 20 cycles of water cooling at 1100°C). 3. **Building Materials & Chemical Engineering** - Cement Rotary Kilns: Self‑flowing castables are applied to the kiln mouth and cooler, capable of withstanding high temperatures of 1400°C and the erosive action of raw materials. - Glass Melting Furnaces: Self‑flowing castables are used in the pool walls and flow channels, helping to minimize structural failure caused by glass melt penetration. ### IV. Technological Evolution: From Basic Formulations to Customized Solutions As industrial demands continue to evolve, corundum self‑flowing castables have branched out into multiple specialized variants, including explosion‑proof quick‑setting types, steel fiber‑reinforced types, and low‑cement types. For example, when constructing the roof of a reheating furnace, adding stainless steel fibers (at a dosage of 1–2%) can significantly enhance the material’s thermal shock resistance, preventing cracking caused by rapid heating and cooling; in CAS‑OB refining stations, adopting low‑cement formulations (with CaO content < 2%) can reduce material softening at high temperatures, thereby extending the lining’s service life. These products comply with GB/T 4513‑2014 standards, and certain models have obtained EU CE certification. Take Luoyang Jinkai as an example: its annual production capacity of 15,000 tons of self‑flowing castables is supported by a fully automated batching system and high‑temperature test furnaces, enabling customization of parameters such as Al₂O₃ content (50–90%) and operating temperature (1400–1600°C) based on customer-specific conditions—and providing end‑to‑end services ranging from material supply to construction guidance. ### V. Future Prospects: Dual Drivers of Intelligence and Greenness With the advancement of Industry 4.0 and the pursuit of “dual carbon” goals, corundum self‑flowing castables are evolving toward greater intelligence and environmental sustainability. On one hand, IoT technology is being leveraged to enable real‑time monitoring of the construction process, ensuring precise control over material fluidity and setting time; on the other hand, low‑energy consumption sintering processes and recyclable aggregates are being developed to reduce the environmental impact of material production.

Corundum–Silicon Carbide Castable I. Product Type Classification Standard Grade (AG-20) Composition: Corundum Aggregate (85–90%) + Fine Silicon Carbide Powder (15–20%) Volumetric Density: 2.9–3.1 g/cm³ Operating Temperature: ≤1450℃ Enhanced Grade (AG-30H) Silicon carbide content increased to 25–30% Resistance to slag erosion improved by 40% Thermal shock stability ≥35 cycles (water quench at 1100℃) New Composite Material Nano-SiC modification (3–5% nano‑silicon carbide added) Thermal shock resistance reaches 50 cycles Thermal conductivity reduced to 2.1 W/(m·K) II. Intelligent Production Process Pre‑Processing System for Raw Materials AI sorting of corundum aggregate (Al₂O₃ ≥ 98.5%) Surface oxidation treatment of silicon carbide (SiO₂ coating ≤ 1 μm) Innovative Mixing Processes Dry Mixing: Planetary Mixer (200 rpm, 3 minutes) Wet Mixing: Ultrasonic Assisted Dispersion (water addition ≤ 6.5%) Digital Curing System Humidity Control: RH ≥ 95% at 25 ± 2°C Microwave‑Assisted Accelerated Setting (initial setting time shortened to 40 minutes) III. Core Applications Application Area Typical Application Locations Performance Characteristics Nonferrous Metals Aluminum Electrolysis Cell Side Walls Resistance to cryolite attack exceeding 8 years Iron and Steel Metallurgy Hot Metal Ladle Impact Zone Service life up to 800 heats Eco‑Energy Incinerator Throat 50% improvement in Cl‑corrosion resistance Photovoltaic Glass Furnace Flow Channel Glass contamination ≤ 0.3 ppm IV. Performance Advantage Analysis Comparison with Traditional Materials Slag Resistance: 3 times superior to high‑alumina castables Wear Resistance: Volumetric wear ≤ 0.5 cm³ (ASTM C704) Thermal Conductivity: 4.5 W/(m·K) at 1000℃ Economic Benefits Construction Efficiency: Spray application rate up to 2 m³/h Maintenance Costs: 60% lower than brick lining structures V. Physical and Chemical Specifications 1. Basic Parameters (AG-30H Grade): - Compressive Strength: 110°C × 24 hours ≥ 60 MPa - Linear Change Rate: 1600°C × 3 hours ±0.3% High‑Temperature Performance: - Flexural Strength (1400°C): ≥ 12 MPa - Strength Retention After Thermal Shock: ≥ 80% (30 cycles) Special Indicators: - Alkali Resistance (K₂CO₃): Penetration depth ≤ 2 mm/100 hours - CO Decomposition Resistance: Weight loss ≤ 0.5%/200 hours

Corundum Wear-Resistant Castable I. Main Product Types Standard Type (GJ-18 Series) Composition: Electrofused Corundum Aggregate (Al₂O₃ ≥ 90%) Binding System: Pure Calcium Aluminate Cement + α-Al₂O₃ Fine Powder Volumetric Density: 3.2 ± 0.1 g/cm³ Operating Temperature: ≤1800℃ Composite Reinforced Type (GJ-18F) 5–8% Silicon Carbide Fine Powder Added Wear Resistance Enhanced by 50% (ASTM C704 Test) Thermal Shock Resistance: ≥15 Cycles (Water Quench at 1100℃) Nano‑Modified Type (2025 New Technology) 2–3% Nano‑ZrO₂ Incorporated High‑Temperature Flexural Strength Increased by 80% (≥12 MPa at 1600℃) Construction Performance Optimized (Flowability ≥ 280 mm) II. Modern Production Processes Intelligent Batch Mixing System Aggregate Grading AI Optimization (3–1 mm : 1–0.1 mm : <0.1 mm = 4:3:3) Moisture Control Accuracy: ±0.3% Active Powder Treatment Superfine Powder Specific Surface Area ≥ 6000 cm²/g (BET Method) Nano‑Additive Pre‑Dispersion Technology Quality Control System Online Particle Size Analysis (Laser Diffraction Method) Automatic Packaging Moisture Content Monitoring (≤0.5%) III. Applications Application Field Service Location Technical Benefits New Energy Lithium Battery Material Sintering Kiln Service Life Extended to 5 Years Environmental Protection Hazardous Waste Incineration Cyclone Separator Wear Resistance Improved by a Factor of 3 Civil Engineering Materials Cement Kiln Third Air Duct Maintenance Cycle Extended by 60% Metallurgy Blast Furnace Taphole Iron Throughput Exceeds 200,000 Tons IV. Performance Advantage Comparison Comparison with Traditional Materials Wear Resistance: 0.5 cm³ (ASTM C704) vs. 3.2 cm³ (High‑Alumina Castable) Thermal Shock Stability: 25 Cycles vs. 8 Cycles (Water Quench at 1100℃) Erosion Resistance: K₂O Penetration Depth ≤ 1 mm/100 h Economic Analysis Construction Efficiency: Rapid Curing Possible (50℃/h) Total Cost: 40–50% Lower Than Prefabricated Components V. Physicochemical Specifications (GB/T 2026–GJ) 1. Physical Properties: - Volumetric Density: 3.15–3.25 g/cm³ (110℃ × 24 h) - Compressive Strength: ≥80 MPa (1100℃ × 3 h) High‑Temperature Performance: - Flexural Strength (1600℃): ≥8 MPa - Linear Change Rate: ±0.3% (1600℃ × 3 h) Special Indicators: - Wear Volume (ASTM C704): ≤0.8 cm³ - Thermal Conductivity (1000℃): 2.8 W/(m·K)

Corundum Castables I. Major Product Types Standard Corundum Castables Al₂O₃ Content: 85–90% Typical Formulation: White Corundum Aggregate (60%) + Tabular Corundum Powder (30%) + Pure Calcium Aluminate Cement (7–10%) Low-Cement Corundum Castables (LCC Series) Cement Content: ≤5% Ultrafine Powder Additives: Silica Fume + α-Al₂O₃ Micro Powder (D50 ≤ 1 μm) Chromium-Containing Corundum Composite Castables Cr₂O₃ Content: 8–15% Slag Penetration Resistance: Improved by a factor of three compared to conventional formulations New Nanomodified Products Addition of 3–5% Nano-Al₂O₃ Coated Aggregates Thermal Shock Resistance: Up to 35 cycles (water quench at 1100°C) II. Advanced Production Processes Intelligent Batch Mixing System Real-Time Control via Laser Particle Size Analysis (Aggregate Gradation) Error Control: ±0.3% for Key Components Composite Bonding Technology Cement–Sol–Gel Composite System: Binder Composition: - Pure Calcium Aluminate Cement: 4–6% - Silica Sol (SiO₂, 30%): 2–3% - Aluminum Sol (Al₂O₃, 20%): 1–2% Directional Fiber Reinforcement Stainless Steel Fibers (0.2 × 15 mm), added at 1–2% Three-Dimensional Random Orientation (Improves Crack Resistance by 50%) III. Application Scenarios Application Field 典型 Locations Technical Specifications Petrochemical Industry Catalytic Cracking Unit Lining Wear Resistance ≤ 0.5 mm/year Nonferrous Metals Aluminum Electrolysis Cell Side Walls Resistance to Na₃AlF₆ Erosion Clean Energy Waste Incineration Furnace Combustion Chamber Temperature Resistance ≥ 1600°C Aerospace Rocket Engine Test Stand Thermal Shock Resistance ≥ 50 Cycles IV. Performance Advantage Comparison Comparison with Traditional Castables Compressive Strength: 110 MPa vs. 60 MPa (110°C × 24 h) High-Temperature Flexural Strength: 18 MPa vs. 8 MPa (1400°C) Economic Analysis Construction Efficiency: Pumping Rate Reaches 3 m³/h (compared to 1.5 m³/h for traditional materials) Maintenance Cycle: Extended to 2–3 times that of conventional materials V. Physicochemical Properties 1. Basic Performance (LCC-90 Type): - Bulk Density: 3.05 ± 0.05 g/cm³ (GB/T 2998–2025) - Linear Change: -0.2% to +0.3% (1600°C × 3 h) Mechanical Properties: - Compressive Strength: ≥ 80 MPa (110°C) - High-Temperature Flexural Strength: ≥ 12 MPa (1400°C) 3. Special Indicators: - CO Erosion Resistance: Strength Loss ≤ 15% (1000°C × 200 h) - Thermal Conductivity: 2.8 W/(m·K) (800°C)

Anti‑Seepage Castables: The “Protective Shield” for Industrial Kilns In high‑temperature industrial applications, kilns, furnaces, and other equipment are subjected to the relentless onslaught of molten metals, corrosive gases, and furnace slag over extended periods. The anti‑seepage performance of their lining materials directly determines both equipment lifespan and production efficiency. As a high‑performance refractory material, anti‑seepage castables leverage their unique combination of low permeability, low thermal conductivity, and exceptional thermal shock resistance—making them a core component in extending kiln life and ensuring operational safety. Material Characteristics: Dual Assurance of Low Permeability and High Stability The core advantage of anti‑seepage castables lies in their meticulously engineered formulations and specialized manufacturing processes. Utilizing calcined clay as the refractory aggregate and tertiary alumina clinker as the fine powder, these castables are further enhanced with ultrafine powders and silica‑ or feldspar‑based anti‑seepage additives. Calcium aluminate cement—such as CA‑50—is employed as the binder, while dispersants are added to optimize workability, ultimately yielding a dense, compact microstructure. This structure endows the material with two key characteristics: First, extremely low permeability. In aluminum electrolysis cells, the penetration of molten aluminum and electrolyte (containing Na and NaF) can compromise the refractory lining; however, anti‑seepage castables effectively block infiltration pathways by forming nepheline within the pores. Experimental data reveal that, after being held at 950°C for 96 hours, the thickness of the reaction layer—i.e., the depth of penetration—was significantly lower than that of conventional materials, resulting in an anti‑seepage performance improvement of more than 30%. Second, outstanding thermal stability. With its low thermal conductivity, the material minimizes heat loss and reduces energy consumption; meanwhile, its thermal expansion coefficient is well matched to carbon cathode materials, ensuring dimensional stability even at temperatures exceeding 850°C. Its thermal shock resistance—its ability to withstand cracking under alternating cycles of heating and cooling—is superior to that of ordinary refractory bricks. Application Scenarios: Broad Coverage from Aluminum Electrolysis to Multi‑Metal Smelting The application of anti‑seepage castables has spread across numerous high‑temperature industrial sectors, with the following being among their core use cases: 1. Aluminum Electrolysis Cells: Serving as a barrier between the side carbon blocks and the insulation layer, anti‑seepage castables are directly applied onto the bottom insulation layer, replacing traditional refractory bricks and Al₂O₃ layers. Beyond simply preventing molten aluminum from penetrating, these castables also play a crucial role in reducing electrolysis cell energy consumption through their insulating properties—after all, if the electrolyte seeps into the insulation layer, the thermal conductivity can increase by more than 50%, leading to a sharp spike in power usage. A case study from an aluminum smelting company shows that, following the adoption of anti‑seepage castables, electrolysis cell life was extended from 3 years to 5 years, while electricity consumption per ton of aluminum decreased by 200 kWh. 2. Melting and Holding Furnaces for Aluminum: At locations where molten aluminum comes into direct contact with furnace bottoms and walls, anti‑seepage castables can effectively protect the working lining and insulation bricks from erosion. For example, after a certain automotive parts foundry repaired its melting furnace using anti‑seepage castables, the furnace lining replacement cycle was extended from 1 year to 2.5 years, with annual maintenance costs reduced by 400,000 RMB. 3. Lead and Copper Smelting Industries: Tailored to the varying chemical environments of different furnace linings, anti‑seepage castables can be adjusted by modifying aggregate compositions—such as increasing SiO₂ content—to better withstand acidic or alkaline corrosion. However, their volumetric stability and thermal shock resistance remain critical performance indicators. For instance, after a copper smelter applied anti‑seepage castables to the sidewalls of its flash furnace, the furnace lining crack rate dropped by 60%, while operating rates increased by 15%. Construction Advantages: Dual Value—Rapid Repair and Efficient Operation The ease of construction is a major driver behind the widespread adoption of anti‑seepage castables. Unlike traditional refractory bricks, which require over 72 hours of baking, anti‑seepage castables employ a cast‑in‑place process—allowing rapid heating to operating temperature immediately after installation, without the need for prolonged curing. This not only shortens furnace downtime by more than 50% but also enables quick recovery of production. Furthermore, the material’s high degree of plasticity allows it to conform perfectly to complex geometries—such as the irregular corners of electrolysis cells or the curved furnace bottoms of melting aluminum furnaces—minimizing the risk of leakage caused by improper joint treatment. In repair scenarios, the advantages of anti‑seepage castables become even more pronounced. For example, when a localized leak occurred in an aluminum plant’s electrolysis cell, a partial repair using anti‑seepage castables restored production in just 24 hours—compared to over 3 days required by conventional methods, resulting in direct economic savings exceeding one million RMB. Technological Evolution: From Single Functionality to Enhanced Multifunctional Performance As industrial demands continue to evolve, anti‑seepage castables are shifting from simple anti‑seepage capabilities toward multifunctional performance enhancements. For instance, adding silicon carbide micropowders can boost wear resistance, making these castables suitable for high‑abrasion environments such as cupolas; alternatively, incorporating nano‑alumina can reinforce thermal shock resistance, enabling optimal performance in industrial furnaces that experience frequent start‑ups and shutdowns. Moreover, the development of eco‑friendly binders—such as low‑cement or cement‑free systems—further reduces volatile emissions at high temperatures, aligning with the growing trend toward green manufacturing. Conclusion: The “Longevity Code” for Industrial Kilns From aluminum electrolysis to multi‑metal smelting, from new furnace linings to repair and reinforcement—anti‑seepage castables, with their exceptional anti‑seepage performance, thermal stability, and ease of construction, have become an indispensable “protective shield” for high‑temperature industrial operations. As materials science advances, the performance boundaries of these castables will continue to expand, providing stronger support for efficient, safe, and low‑carbon operation of industrial kilns.

Low-Cement Refractory Castables I. Main Product Types and Definition Standards Standard Low-Cement Type (LCC Series) Cement Content: 3–8% (CaO: 1–3%) Bonding System: Aluminate Cement + Alumina Micro Powder (≤5 μm) Typical Formulation: High-Alumina Aggregate (Al₂O₃ ≥ 75%) + Silica Fume (2–5%) Ultra-Low-Cement Type (ULCC Series) Cement Content: 1–3% (CaO < 1%) Utilizes Sol-Gel Bonding Technology (Silica Sol/Alumina Sol) Water Requirement Reduced to 4–5% (compared to the traditional 8–10%) 2025 New Nanoreinforced Type Incorporates Nano-SiO₂/Al₂O₃ Composite Powder (3–8%) Mid-Temperature Strength Increased by 50% (Compressive Strength ≥ 80 MPa at 800°C) II. Modern Production Process Flow Raw Material Preprocessing System Aggregate Grading: 5–10 mm (30%), 1–5 mm (40%), ≤1 mm (30%) Ultrafine Powders (D50 ≤ 2 μm) are Air-Graded Innovative Construction Techniques Self-Leveling Technology (Flowability ≥ 280 mm) Low-Temperature Curing (Construction Possible in 5°C Environments) III. Application Fields Application Industry Typical Applications Technical Benefits New Energy Batteries Sintering Furnace Linings for Ternary Materials Lifespan Extended to 3 Years Hydrogen Energy Equipment -Alkali-Resistant Layers for Electrolyzers 60% Improved Resistance to NaOH Erosion Semiconductors Heat Treatment Furnaces for Silicon Carbide Wafers Pollution Control – Class 10 Environmental Protection Hazardous Waste Melting Furnaces Acid Resistance (pH 1–14) IV. Performance Advantage Comparison Comparison with Traditional Castables High-Temperature Strength: Flexural Strength at 1600°C – 15 MPa vs. 5 MPa Thermal Shock Stability: 50 Cycles (Water Quench at 1100°C) vs. 15 Cycles Construction Performance: Water Requirement Reduced by 40% Economic Analysis Material Costs: 20–30% Higher Than Conventional Products Overall Benefits: Maintenance Intervals Extended by a Factor of 3 V. Key Physicochemical Indicators (GB/T 2026–LCC) 1. Physical Properties: - Bulk Density: 2.4–2.8 g/cm³ (dried at 110°C) - Apparent Porosity: ≤18% (ULCC Series: ≤15%) Mechanical Properties: - Compressive Strength: ≥60 MPa (at 110°C) → ≥30 MPa (at 1400°C) - High-Temperature Flexural Strength (at 1600°C): ≥10 MPa Special Indicators: - Linear Change Rate: ±0.5% (at 1600°C for 3 hours) - Thermal Conductivity: 1.2–1.8 W/(m·K) (at 800°C)

Overview of Non-Stick Aluminum Castables Non-stick aluminum castables are a class of high-performance refractory materials specifically designed for aluminum and aluminum alloy smelting and casting equipment. Their core characteristic is their ability to effectively resist aluminum melt penetration and chemical erosion, thereby reducing slag formation and aluminum adhesion, significantly extending equipment service life and improving production efficiency. Main Types Low-Cement/Extra-Low-Cement Bonded Non-Stick Aluminum Castables These castables utilize high-purity corundum, mullite, or spinel as the primary raw materials, with cement content controlled between 3% and 8% (in extra-low-cement formulations, cement content is ≤3%). Characteristics: Low porosity (≤15%), excellent resistance to permeation. Phosphate-Bonded Non-Stick Aluminum Castables These castables employ phosphoric acid or aluminum phosphate as the binder, supplemented with anti-wetting agents such as BaSO₄ and Cr₂O₃. Characteristics: At high temperatures, they form a dense phosphate ceramic phase, offering outstanding resistance to aluminum melt erosion. Silicon Nitride/Silicon Carbide–Reinforced Non-Stick Aluminum Castables Si₃N₄ or SiC (5%–15%) is incorporated as an anti-wetting component. Characteristics: Exceptional wear resistance and thermal shock resistance, making them ideal for molten aluminum furnaces that experience frequent start‑stops. Nano‑Modified Non-Stick Aluminum Castables Nano-Al₂O₃ or nano-SiO₂ is added to fill micro‑pores and enhance density. Characteristics: Extremely strong resistance to permeation, though at a higher cost. Production Process Raw Material Selection Primary Raw Materials: Electrofused corundum (Al₂O₃ ≥ 99%), sintered mullite (Al₂O₃ ≥ 72%), magnesium aluminate spinel (MgO ≥ 28%). Additives: Anti‑wetting agents such as BaSO₄ and Cr₂O₃; water‑reducing agents (polycarboxylate salts). Proportioning and Mixing Particle Gradation: Coarse particles (3–1 mm) account for 40%–50%, while fine powders (≤0.088 mm) make up 20%–30%. Mixing: Dry mixing for 3–5 minutes, followed by wet mixing for 8–10 minutes after adding water (or binder). Shaping and Curing Vibration casting is used for shaping, with curing lasting 24 hours under conditions of humidity ≥90% and temperature 20–25°C. For phosphate‑bonded castables, post‑curing involves baking at 200–300°C to achieve full hardening. Baking Schedule Low‑Temperature Stage (0–300°C): Slow heating rate (≤20°C/h) to remove free water. Medium‑High Temperature Stage (300–1200°C): A heating rate of 50°C/h promotes the formation of the ceramic phase. Application Scenarios Aluminum Smelting Equipment Aluminum melting furnace linings, flow channels, and distributor liners. Characteristics: Reduces aluminum melt penetration and extends furnace life—up to 2–3 times longer than traditional materials. Casting Systems Aluminum holding furnaces, ladle systems, and filtration boxes. Advantages: Minimizes slag formation and enhances casting purity. 再生 Aluminum Industry Waste aluminum recycling furnaces and aluminum slag treatment equipment. Demand: Even stronger corrosion resistance, given the high impurity content in scrap aluminum. Performance Advantages Resistance to Aluminum Melt Penetration By incorporating additives such as Cr₂O₃ and BaSO₄, the contact angle exceeds 110°, significantly reducing wettability. Chemical Erosion Resistance Erosion rates caused by melts containing Al, Mg, Si, etc., are less than 0.5 mm/year (compared to 2–3 mm/year for traditional materials). Thermal Shock Stability After undergoing 30 or more cycles of water quenching at 1100°C without cracking (compared to fewer than 10 cycles for standard castables). Energy Efficiency and Environmental Protection With a low thermal conductivity (1.5–2.0 W/m·K), these castables minimize heat loss. Typical Physical and Chemical Properties Property Low‑Cement Type Phosphate Type SiC‑Reinforced Type Al₂O₃ Content (%) ≥85 ≥80 ≥75 Volumetric Density (g/cm³) 2.8–3.0 2.7–2.9 2.6–2.8 Compressive Strength (MPa) ≥80 (at 110°C) ≥70 (at 110°C) ≥90 (at 110°C) ≥60 (at 1400°C) ≥50 (at 1400°C) ≥70 (at 1400°C) Porosity (%) ≤15 ≤18 ≤12 Resistance to Aluminum Melt Penetration (mm)* ≤1.0 ≤0.5 ≤0.3 Thermal Shock Resistance (cycles) 20–30 15–25 30–50 *Note: The permeation depth test was conducted by statically immersing the material in 800°C aluminum melt for 24 hours. Summary Through optimized raw material selection and advanced bonding systems, non-stick aluminum castables deliver exceptional resistance to aluminum melt penetration and corrosion, making them widely applicable in high‑temperature equipment across the aluminum industry. Future development directions include nano‑technology modifications and the research and development of chromium‑free, environmentally friendly formulations.