Lightweight castables are typically produced using aluminate cement, high-alumina fines, and ceramsite, together with selected additives. They can also be formulated with lightweight materials such as perlite, vermiculite, refractory fibers, lightweight mullite, and alumina hollow spheres to meet the requirements of different service temperatures.
Due to their low density, relatively low strength, and low thermal conductivity, lightweight castables are mainly used as thermal insulation layers in industrial furnace linings. However, the service temperature varies depending on the raw materials and bulk density of the castable.
Among these materials, lightweight mullite castables and alumina hollow sphere castables offer the highest service temperatures, reaching up to 1500 °C. In certain lightweight furnace lining designs, these materials can even be used directly as the working layer.
According to the type of raw materials used, refractory aggregates can be classified into the following categories:
●Clay aggregates
●High-alumina aggregates
●Siliceous aggregates
●Basic aggregates
●Special aggregates
●Thermal insulating aggregates
Key Physicochemical Properties of Lightweight Castables (Part 1)
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Project |
HX-LW0.6 |
HX-LW0.8 |
HX-LW1.0 |
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Al2O3(%) ≥ |
25 |
25 |
30 |
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Bulk Density (g/cm3) |
110°C x16h |
0.6 |
0.8 |
1.0 |
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Compressive Strength (MPa) ≥ |
110°C x16h |
- |
1 |
3 |
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1000°C x3h |
- |
1(800℃x3h) |
3 |
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Linear Rate of Change (%) |
1000°C x3h |
- |
0~-0.1 (800℃x3h) |
0~-1.0 |
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700℃ Thermal Conductivity [W/(m·K)] ≤ |
0.25 |
0.28 |
0.35 |
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Long-term Operating Temperature(℃) |
800 |
900 |
1000 |
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Purpose |
Furnace Roof Insulation Layer |
Furnace Lining |
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Key Physicochemical Properties of Lightweight Castables (Part 2)
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Project |
HX-LW1.2 |
HX-LW1.3 |
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Al2O3(%) ≥ |
30 |
35 |
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Bulk Density (g/cm3) |
110°C x16h |
1.2 |
1.3 |
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Compressive Strength (MPa) ≥ |
110°C x16h |
4 |
5 |
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1300°C x3h |
4(1200℃x3h) |
6(1200℃x3h) |
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Linear Rate of Change (%) |
1300°C x3h |
0~-0.8(1200℃x3h) |
0~-0.8(1200℃x3h) |
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700℃ Thermal Conductivity [W/(m·K)] ≤ |
0.38 |
0.40 |
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Long-term Operating Temperature (℃) |
1200 |
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Purpose |
Furnace Lining |
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Key Physicochemical Properties of Lightweight Castables (Part 3)
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Project |
HX-LW1.5 |
HX-LW1.8 |
HX-LW2.0 |
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Al2O3(%) ≥ |
35 |
45 |
45 |
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Bulk Density (g/cm3) |
110°C x16h |
1.5 |
1.8 |
2.0 |
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Compressive Strength (MPa) ≥ |
110°C x16h |
7 |
12 |
18 |
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1300°C x3h |
10(1250℃x3h) |
15 |
22 |
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Linear Rate of Change (%) |
1300°C x3h |
0~-0.8 (1250℃x3h) |
-0.8~+0.5 |
-0.8~+0.5 |
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700℃ Thermal Conductivity [W/(m·K)] ≤ |
0.48 |
0.70 |
0.75 |
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Long-term Operating Temperature (℃) |
1250 |
1300 |
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Purpose |
Furnace Lining |
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●Low Bulk Density:
Compared with conventional refractory castables, lightweight castables have a significantly lower bulk density, which effectively reduces the overall weight of the furnace lining. This makes them particularly suitable for large furnaces or equipment with strict structural load-bearing requirements.
●Low Thermal Conductivity:
The material features a uniform microporous structure that effectively interrupts heat conduction paths, significantly reducing heat loss and improving the overall thermal efficiency of the furnace.
●Monolithic Casting Construction:
By adopting integral (monolithic) casting, the problems of mortar joints and thermal bridging commonly found in traditional brick masonry linings are eliminated, resulting in a more continuous and stable insulation layer.
●Convenient Installation:
The material can be installed using conventional casting methods and is suitable for large-area applications and complex structural sections, offering excellent on-site workability.
Lightweight castables are often used in combination with wear-resistant castables, high alumina castables, or low cement castables to form multi-layer composite furnace lining structures, providing both thermal insulation and structural protection.
Typical Applications:
●Power industry: Insulation layers for boiler walls and flue systems
●Cement industry: Insulation layers for rotary kilns, preheaters, and calciners
●Metallurgical industry: Backing linings of heating furnaces and heat treatment furnaces
●Petrochemical industry: Energy-saving insulation linings for high-temperature equipment and process furnaces
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Over 30 years of experience in refractory materials and thermal insulation system applications
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Integrated production capabilities Dedicated production lines for lightweight raw materials and monolithic refractory products |
Stable product quality Consistent performance with high batch-to-batch reliability |
Technical support services Providing furnace lining design, material selection, and construction guidance |
Customized solutions Available for specific requirements in bulk density, strength, and thermal conductivity |
Packaging:
Available in 50 kg bags, ton bags, palletized packaging, or sealed packaging. Customized packaging options are available upon request.
Storage:
Store in a dry and well-ventilated environment to prevent moisture absorption. The product maintains stable performance under proper storage conditions.
Q1: Can lightweight castables be used directly as a working layer?
A: Generally, lightweight castables are mainly used as insulation layers. The working layer is typically constructed using wear-resistant or high-strength refractory materials.
Q2: What is the service temperature range of lightweight castables?
A: The service temperature depends on the specific formulation and can cover medium- to high-temperature applications. The appropriate grade should be selected according to the actual operating conditions.
Q3: What advantages do lightweight castables have compared with lightweight refractory bricks?
A: Monolithic casting construction reduces joints, improves insulation continuity, and enhances construction efficiency.
Q4: Can lightweight castables be used together with other castables?
A: Yes. They are commonly used in combination with wear-resistant castables, high-strength refractory castables, or low-cement castables to form composite furnace lining structures.
Q5: Do you support customized bulk density and thermal conductivity?
A: Yes. Custom formulations can be developed based on furnace type, operating temperature, and energy-saving requirements.
Q6: Will the insulation performance decrease over time?
A: Under normal operating conditions and proper heating procedures, the thermal conductivity changes very little, and the insulation performance remains stable over long-term service.
Q7: Can fluidity be improved by adding more water during construction?
A: Not recommended. Excessive water will damage the internal structure of the material, leading to increased drying shrinkage, reduced strength, and poorer insulation performance. The water addition should strictly follow the product instructions.
Q8: Can lightweight castables be applied to vertical walls or ceilings?
A: Yes. Depending on the formulation and construction method, they can be applied to furnace walls, arches, and ceilings as insulation layers.
Q9: What are the main differences between lightweight castables and heavyweight castables?
A:Lightweight castables: Designed for thermal insulation and weight reduction, with low thermal conductivity; typically used as insulation layers or backing linings.
Heavyweight castables: Designed for high strength, wear resistance, and refractoriness, typically used as working layers exposed to high temperature and abrasion.
Q10: Do you support OEM/ODM cooperation?
A: Yes. We fully support OEM and ODM partnerships and can provide flexible solutions ranging from product customization to full supply-chain support based on customer requirements.
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