Insulating Castable
Insulating Castables consist of a lightweight, highly porous aggregate (e.g., expanded clay/shale, perlite, vermiculite, bubble alumina, or lightweight fireclay) and a binding system, usually based on Calcium Aluminate Cement (CAC). The density is significantly lower than that of dense castables.
| AGGREGATE TYPE | DENSITY (After Firing) | KEY FEATURE | PRIMARY ADVANTAGE |
| Lightweight Clay/Shale | 1.0 – 1.5 g/cm3 | Economical, low end insulation | Cost-effective thermal barrier |
| Porous Alumina/Bubble | 0.8 – 1.2 g/cm3 | Higher refractoriness, better strength | Insulation in hotter zones |
| Vermiculite/Perlite | 0.4 – 0.8 g/cm3 | Ultra-low density | Maximum thermal efficiency (but lower T) |
Key Properties and Performance
| PROPERTY | TYPICAL PERFORMANCE | MECHANISM OF ADVANTAGE |
| Thermal Conductivity ($\text{T}_{\text{C}}$) | EXTREMELY LOW | High apparent porosity ($\text{AP}$) and low bulk density trap air, which is a poor heat conductor. |
| Thermal Shock Resistance | EXCELLENT | High porosity and lower modulus of elasticity allow the material to easily absorb thermal stresses. |
| Cold Crushing Strength (CCS) | MODERATE | Sufficient for backing layers or light-load working linings, but much lower than dense castables. |
| Service Temperature | MODERATE to HIGH | Varies widely based on aggregate; typically between $\sim 1000^{\circ}\text{C}$ and $1600^{\circ}\text{C}$. |
Insulating Castable
Advantages and Key Characteristics
Insulating Castables are vital for optimizing furnace performance by increasing energy efficiency and protecting the outer steel shell from excessive heat.
- Superior Energy Efficiency: The low thermal conductivity (Tc) significantly reduces the amount of heat lost through the furnace walls. This translates directly into lower fuel consumption and reduced operating costs.
- Reduces Shell Temperature: By minimizing heat transfer, the castable keeps the outer steel casing of the furnace at a safe, low temperature, protecting personnel and prolonging the life of the steel structure itself.
- Rapid Heating/Cooling: Due to the low thermal mass (less material to heat up), furnaces lined with insulating castables can achieve operating temperature faster, increasing production throughput.
- Versatile and Seamless Lining: Like all castables, they can be poured, gunned, or troweled to create a seamless, monolithic layer, eliminating the thermal leakage points (joints) inherent in insulating brick linings.
Typical Industries and Applications
This castable is used in almost all high-temperature processes as a thermal barrier:
- Ferrous/Non-Ferrous Industry: Backup insulation lining in EAFs, ladles, holding furnaces, and reheating furnaces.
- Ceramics & Glass Industry: Kiln crowns, doors, car tops, and general furnace shell linings.
- Petrochemical & Chemical: Reactor linings and furnace headers where precise temperature control and energy savings are critical.
Furnace Areas and Service Zones
They are specified for protection, structure, or specialized low-load working zones:
- BACKUP LINING: Placed between the dense working lining and the steel shell (the most common application).
- FURNACE DOORS AND VESTIBULES: Low-load, high-thermal-shock areas requiring light weight and fast heat-up.
- LOW-TEMPERATURE WORKING LINING: Used as the hot face lining in furnaces operating below 1200°C (e.g., heat treatment, stress relieving).
Key Data Sheet Properties to Consider
Selection criteria focus on thermal performance and density:
- Thermal Conductivity (Tc): CRITICAL VALUE. Must be specified at the service temperature (e.g., Tc at 800°C) and should be as low as possible (e.g., 0.2 – 0.5 W / (m.K)).
- Bulk Density (BD) and Apparent Porosity (AP): CRITICAL VALUE. Look for low BD (e.g., < 1.0 g/cm3) and high AP> 50%) to maximize insulation.
- Maximum Service Temperature (MST): Must be suitable for the temperature at the hot face of the insulating layer (not the core furnace temperature).
- Cold Crushing Strength (CCS): Should be sufficient to support the weight of the dense working lining and the outer shell forces.
Technical Guidance: Insulating castables, like all hydraulic castables, require a strict, slow dry-out and heat-up schedule due to their porosity, which holds a significant amount of water. Never use an insulating castable as a working lining in a high-wear or high-load zone, as its low strength and high porosity make it susceptible to abrasion, erosion, and chemical penetration.
✨ Customization Services
We offer product customization services, allowing you to tailor the appearance, dimensions, or specific markings of items like refractory shapes or bricks. This includes options for incorporating specific geometric requirements to ensure seamless integration into your process systems.
🔬 Sampling for Testing & Validation
Free product samples are available for thorough testing and validation. This allows you to confirm the quality, compatibility, and performance of our materials—such as specific bricks, castables, or raw materials—before committing to a full order.
💡 Expertise in Refractory Solutions
Leverage our deep expertise to receive detailed, application-specific refractory solutions. We move beyond just selling products by providing comprehensive plans that encompass material selection, installation guidance, and performance optimization to maximize the lifespan and efficiency of your high-temperature processes.
Rabatec products are exclusively manufactured in facilities that have achieved rigorous ISO certifications across Quality (ISO 9001), Environmental Management, and Occupational Health & Safety. This commitment ensures every product, from refractory bricks to specialized equipment, meets the highest global benchmarks for performance, sustainability, and workplace safety.
📦 Logistics Excellence: Shipping, Packaging, and Marking
Minimizing Risk: We manage all logistics to minimize handling touchpoints and transit shock. Our carriers are pre-vetted for their experience in transporting heavy, fragile, and sensitive industrial materials.
Traceability: Every shipment includes comprehensive documentation and tracking information, providing end-to-end visibility and ensuring precise delivery coordination for your site.
Protection is Paramount: Our packaging strictly follows industry standards to prevent damage, corner chipping, and moisture absorption—especially critical for materials like Basic Refractory Bricks and Refractory Mortars & Mixes.
Robust Palletization: Products are secured on fumigated, high-strength export pallets (e.g., 1100x950mm or similar sturdy dimensions) using heavy-duty strapping and durable protective wrapping (polyethylene sheeting, cardboard, etc.) to withstand long-distance travel and multiple loadings.
Moisture Control: Sensitive materials are protected with appropriate sealing and, where necessary, desiccants or moisture-vapor proof enclosures to maintain the product's integrity until installation.
Clear Identification: All outer packaging is clearly marked on multiple sides with large, legible text for immediate identification and safe handling.
Full Traceability: Markings include all essential data points: Product Name, Quality Grade, Batch Number, Quantity, Net/Gross Weight, Order Number, and the Final Destination/Construction Area. This ensures every pallet can be accounted for and correctly staged upon arrival.
Safety & Compliance: We adhere to all regulatory requirements for marking, labeling, and placarding—especially for any items classified as Dangerous Goods—to ensure full compliance with international and domestic transport regulations.
❓ Frequently Asked Questions (FAQ)
Question | Elaborated Answer |
Q: What is the Refractoriness Under Load (RUL) of your refractories? | A: Refractoriness Under Load (RUL) is a critical property that defines the maximum temperature our materials can withstand while under compressive stress before deforming (softening). Since we offer a wide range of materials—from Alumina-Silicate Bricks to high-performance Silicon Carbide Bricks—the RUL varies significantly. For specific product data, please refer to the product data sheet or submit a quote request for the material you are interested in. |
Q: Where are the Rabatec refractories and materials produced? | A: Our products are primarily sourced from specialized manufacturing plants in China. Crucially, these facilities have all undergone rigorous audits and achieved comprehensive ISO certifications (Quality, Environment, and Safety), ensuring that production adheres to the highest global standards for consistency and performance. |
Q: What refractory materials does the company offer? | A: We supply a comprehensive portfolio of advanced refractory solutions, including: Shaped Products: Alumina & Silica Bricks, Basic & Specialized Bricks (e.g., Magnesia), SiC & Structural Ceramics, and Precast Shapes. Monolithic Products: Refractory Castables, Mixes & Mortars. Insulation: Insulation Fibre and High-Performance Insulation Products. |
Q: How should I choose the appropriate refractory material for my application? | A: Selecting the correct refractory is paramount to process efficiency. The choice depends on three key factors: 1. Operating Environment: Maximum process temperature and thermal cycling (shock). 2. Chemical Attack: Type of slag, molten metal, or corrosive gas being handled (acidic, neutral, or basic). 3. Mechanical Stress: Abrasion, erosion, and static load requirements. We recommend utilizing our detailed refractory solutions service to consult with our engineers for an optimized, application-specific recommendation. |
Q: Which monolithic material should I choose when patching an existing lining? | A: For patching and minor repairs, the ideal monolithic material depends on the parent lining material, the patching depth, and the need for a rapid return to service. Common choices include: Refractory Mortars & Mixes (for minor joints/surfaces) or Plastic Refractories (for areas requiring physical compaction). Always choose a patch material chemically compatible with the existing lining to ensure proper bonding and service life. |
Q: Can I receive product samples before placing a major order? | A: Yes. We gladly provide product samples for your internal testing and validation purposes. This ensures you can confirm the quality, composition, and fit of the material—such as our Refractory Castables or Alumina-Silicate Bricks—in your specific operational environment before committing to a bulk purchase. |
Q: Do you provide certifications to verify material quality? | A: Absolutely. We provide product-related inspection certificates and quality assurance documentation upon request. This verifies that your order has passed all internal quality control checks and meets the required material specifications and industry standards. |
Q: What measures are taken for product protection during transport? | A: We ensure quick, reliable transport by using robust, industrial packaging that strictly follows industry standards. This includes high-strength palletization, heavy-duty strapping, and weather-resistant wrapping to protect fragile items like bricks and mixes from corner chipping, mechanical damage, and moisture during transit. |
