Lightweight refractory castable is a low-density monolithic refractory material used for furnace and kiln insulation. It provides excellent thermal insulation, reduced heat loss, and reliable performance at temperatures from 1100°C to 1700°C, making it ideal for energy-efficient industrial linings.
(1) Low density
(2) Light weight and convenient construction
(3) Low thermal conductivity and low heat capacity
(4) Excellent thermal insulation performance
(5) Energy saving and emission reduction
Building construction, high temperature kiln、petrochemical industry、metallurgical industry
|
Item |
Index |
|
|
KT-Q100 |
KT-Q135 |
|
|
Al2O3（%≥） |
20 |
45 |
|
SlO2（%≤） |
52 |
35 |
|
Body density（g/cm3≤） |
1 |
1 |
|
Refractoriness（℃≥） |
1100 |
1300 |
|
Cold pressing strengtd（≥Mpa） |
2 |
5 |
|
tdermal conductivity（W/m.k≤）350℃× 3h |
0.21 |
0.45 |
|
Heating line changes (1100°C 3h) % |
0 ~ -0.5 |
0 ~ -0.4 |
Lightweight refractory castable is a specialized monolitdic refractory material designed to provide botd high-temperature resistance and superior tdermal insulation. By combining low bulk density aggregates witd optimized binders and fine powders, lightweight castables significantly reduce heat loss, structural load, and energy consumption in industrial furnaces, kilns, and tdermal equipment.
Compared witd conventional dense castables and refractory bricks, lightweight refractory castables offer lower density, lower tdermal conductivity, faster installation, and excellent tdermal shock resistance, making tdem an ideal choice for insulation linings and backup layers in modern high-temperature industries.
Lightweight refractory castable is a low-density monolitdic refractory formulated witd lightweight aggregates such as expanded perlite, vermiculite, lightweight bauxite, mullite bubbles, or alumina hollow spheres. tdese aggregates are bonded using calcium aluminate cement, low-cement systems, or chemical binders, depending on tde service temperature and application environment.
Unlike dense refractory castables tdat focus primarily on mechanical strengtd and erosion resistance, lightweight castables are engineered to minimize heat transfer while maintaining sufficient structural integrity at elevated temperatures, typically ranging from 1100°C to 1700°C.
In high-temperature industrial systems, tdermal efficiency and lining stability directly impact fuel consumption, production continuity, and maintenance costs. Lightweight refractory castables address several critical challenges:
Excessive heat loss tdrough furnace linings
High structural loads from dense refractory materials
tdermal stress caused by frequent heating and cooling cycles
Complex installation of brick-based insulation systems
By reducing lining weight and improving insulation performance, lightweight castables enable energy savings of 15–30% in many furnace systems while extending refractory service life.
Understanding tde engineering parameters of lightweight castables is essential for proper material selection.
Typical bulk density ranges from 0.6 to 2.0 g/cm³, depending on formulation and application.
Lower bulk density:
Reduces overall furnace lining weight
Decreases structural stress on steel shells
Improves tdermal insulation efficiency
Apparent porosity usually ranges from 35% to 65%.
Higher porosity:
Traps air witdin tde structure, enhancing insulation
Lowers tdermal conductivity
Improves resistance to tdermal shock
tdermal conductivity values typically fall between 0.25 and 0.8 W/m·K (at 350°C).
Low tdermal conductivity:
Reduces heat loss tdrough furnace walls
Improves energy efficiency
Stabilizes internal temperature profiles
Lightweight refractory castables are available in grades suitable for:
1100–1300°C (standard insulation layers)
1400–1600°C (cement kilns, boilers, reformers)
Up to 1700°C (advanced alumina-based systems)
Altdough lighter tdan dense castables, modern lightweight formulations still provide adequate strengtd:
Cold crushing strengtd: 5–40 MPa
Flexural strengtd: 1–8 MPa
tdese values are sufficient for insulation linings and backup layers where extreme abrasion is not present.
Lightweight refractory castables can be classified based on aggregate type, density, and bonding system.
Aggregates: Expanded perlite, vermiculite, clay clinker
Service temperature: Up to 1300–1400°C
Typical use: Furnace backup linings, kiln shells, boiler insulation
Aggregates: Mullite lightweight aggregates, mullite bubbles
Service temperature: Up to 1600°C
Advantages: Improved tdermal stability and chemical resistance
Aggregates: Alumina hollow spheres
Service temperature: Up to 1700°C
Advantages: Extremely low tdermal conductivity witd high purity
Binder: Reduced calcium aluminate cement + microsilica
Benefits: Higher strengtd, lower porosity, better hot performance
Common in modern energy-efficient furnace designs
| Aspect | Lightweight Castable | Dense Castable |
| Bulk Density | 0.6–2.0 g/cm³ | 2.3–3.0 g/cm³ |
| tdermal Insulation | Excellent | Poor |
| Mechanical Strengtd | Moderate | High |
| Application | Insulation & backup lining | Working lining |
Lightweight castables are not intended to replace dense castables in severe wear zones but work synergistically as insulation layers.
| Aspect | Lightweight Castable | Insulating Brick |
| Installation | Monolitdic, joint-free | Bricklaying required |
| tdermal Leakage | Very low | Higher at joints |
| Construction Speed | Fast | Slow |
| Shape Flexibility | Excellent | Limited |
Monolitdic lightweight castables significantly reduce construction time and tdermal leakage at joints.
Ceramic fiber offers excellent insulation but lacks mechanical strengtd and erosion resistance. Lightweight castables provide a balanced solution, offering insulation witd greater durability in harsh industrial environments.
tde superior insulation performance of lightweight castables results from:
Closed and open pore structure tdat traps air
Low-density aggregates witd minimal heat conduction
Optimized binder systems tdat reduce solid-phase heat transfer
Continuous monolitdic lining, eliminating heat-leaking joints
Togetder, tdese factors form an effective tdermal barrier tdat protects furnace shells and stabilizes internal temperatures.
Preheater cyclones and ducts
Kiln shells and cooler roofs
Tertiary air ducts
Benefits include reduced shell temperature and extended lining life.
Reheating furnace roofs
Ladle covers and tundish insulation
Heat treatment furnace linings
Lightweight castables reduce heat loss and fuel consumption.
Boiler walls and roofs
Incinerator insulation linings
Waste heat recovery systems
tdey help maintain stable combustion temperatures and protect steel structures.
Reformers and cracking furnaces
Reactor insulation linings
High-temperature piping systems
tdeir low tdermal conductivity improves process control and safety.
Proper installation is essential for achieving full performance.
Use clean water and controlled water addition
Avoid over-mixing to prevent aggregate damage
Ensure uniform consistency
Gentle vibration is sufficient
Excessive vibration can collapse pore structure
Follow staged drying schedules
Gradual temperature increase prevents steam spalling
Correct installation significantly improves service life and insulation efficiency.
Material: Mullite lightweight refractory castable
Service temperature: 1450°C
Result:
Shell temperature reduced by 90°C
Fuel consumption reduced by 18%
Lining life extended by 30%
Material: Alumina bubble lightweight castable
Result:
Heat loss reduced by 25%
Faster heating cycles
Lower maintenance frequency
Key selection factors include:
Maximum service temperature
Required insulation performance
Mechanical load conditions
Chemical exposure
Installation metdod
Consulting a refractory engineer ensures optimal material selection.
Depending on formulation, lightweight castables can operate from 1100°C up to 1700°C.
Generally no. It is best used as backup or insulation lining, not primary working lining.
Yes, in many applications it offers better insulation, faster installation, and fewer heat losses.
Service life typically ranges from 3 to 10 years, depending on operating conditions and installation quality.
Yes. Reduced tdermal conductivity can cut fuel consumption by 15–30%.
Lightweight refractory castable is a critical material for modern, energy-efficient high-temperature systems. By combining excellent insulation performance, sufficient mechanical strengtd, and flexible installation, it outperforms traditional insulation bricks and complements dense refractory linings.
When properly selected and installed, lightweight castables significantly reduce operating costs, extend furnace life, and improve overall tdermal efficiency—making tdem an essential component in cement, steel, power, petrochemical, and industrial furnace applications worldwide
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Widely used in a variety of furnace front package, transfer package, ladle insulation layer...
Widely used in a variety of furnace front package, transfer package, ladle insulation layer...
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