High alumina lightweight brick is a low-density insulating refractory brick designed for backup linings, furnace insulation and thermal barriers. It combines an alumina-based refractory composition with a controlled lightweight structure, helping reduce heat transfer while maintaining the mechanical strength required for a supported insulation layer.
Highland’s LG series includes five density grades from LG-1.0 to LG-0.6. The supplied reference data identifies 42% minimum Al2O3, density from 1.0 to 0.6 g/cm3, and thermal conductivity from 0.50 to 0.30 W/m·K at 350±25°C. The appropriate grade depends on the required insulation performance, compressive load, installation position and operating temperature.
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High Alumina Lightweight Brick Guide
| 1. Product definition | What Is a High Alumina Lightweight Insulating Brick? |
| 2. Technical data | High Alumina Lightweight Brick Technical Data Sheet |
| 3. Performance | Performance of Lightweight High Alumina Insulation Brick |
| 4. Comparison | Lightweight vs Dense High Alumina Brick |
| 5. Applications | Industrial Applications |
| 6. Price and purchasing | Price of Lightweight High Alumina Insulating Brick |
| 7. Grade selection | How to Select the Right LG Grade |
| 8. FAQ | Frequently Asked Questions |
A high alumina lightweight insulating brick is a refractory insulation product made with alumina-bearing raw materials and a controlled lightweight pore structure. Its purpose is to reduce heat transfer through the lining while providing sufficient strength for the mechanical support conditions of the installation.
Compared with a dense working brick, a high alumina lightweight insulation brick has a lower bulk density and lower thermal conductivity. This makes it more suitable for backup linings, thermal barriers and protected insulation zones than for direct exposure to molten materials, heavy abrasion or strong mechanical impact.
The LG series uses five density grades. The higher-density end provides greater compressive strength, while the lower-density end provides lower thermal conductivity. The correct balance depends on the lining design, support conditions, working temperature and required heat-loss control.
This product should be understood as a specialized lightweight refractory brick, not as a direct substitute for every dense high alumina working lining. In a multilayer furnace system, dense refractory materials generally protect the hot face while high alumina lightweight bricks provide insulation behind the working layer.
The following table presents the supplied reference indicators for the LG density grades. The fourth grade is shown as LG-0.7 to match the supplied density sequence of 1.0, 0.9, 0.8, 0.7 and 0.6 g/cm3. Confirm the final model naming and batch values on the current technical data sheet before purchase.
| Item | LG-1.0 | LG-0.9 | LG-0.8 | LG-0.7 | LG-0.6 |
|---|---|---|---|---|---|
| Al2O3 (%) not less than | 42 | 42 | 42 | 42 | 42 |
| Fe2O3 (%) not greater than | 2.0 | 2.0 | 2.0 | 2.0 | 2.0 |
| Volume Density (g/cm3) | 1.0 | 0.9 | 0.8 | 0.7 | 0.6 |
| Compressive Strength at Room Temperature (MPa not less than) | 40 | 35 | 30 | 25 | 20 |
| Reheating-Line Change Test Temperature (°C) | 1400 | 1400 | 1400 | 1350 | 1350 |
| Thermal Conductivity (W/m·K) @350±25°C not greater than | 0.50 | 0.45 | 0.35 | 0.35 | 0.30 |
The reheating-line change temperature is a test condition and should not be treated as an unconditional continuous service temperature. The stated product use temperature is below 1350°C, subject to grade, furnace design, atmosphere, mechanical load and installation conditions. Final model naming and batch properties should be confirmed on the order TDS.
The performance of a high alumina lightweight insulation brick is determined by the relationship between chemical composition, density, pore structure and mechanical strength. A suitable grade should provide the required thermal barrier without exceeding the load capacity of the installation.
Lower density reduces the amount of solid material through the insulation layer and generally supports lower heat transfer. The LG-0.6 grade represents the lowest density in this reference series, while LG-1.0 provides a denser and stronger structure. Density selection should follow the lining design and support conditions rather than insulation performance alone.
The controlled lightweight structure reduces heat transfer through the brick. In the supplied reference data, thermal conductivity is not greater than 0.50 W/m·K for LG-1.0 and not greater than 0.30 W/m·K for LG-0.6 when tested at 350±25°C. Test temperature matters when comparing different suppliers’ data.
Lower density improves insulation but reduces compressive strength within this product series. LG-1.0 has a reference room-temperature compressive strength of not less than 40 MPa, while LG-0.6 has a reference value of not less than 20 MPa. This difference should be considered when bricks are installed vertically, placed under load or handled frequently.
The alumina-based composition supports elevated-temperature stability, but lightweight bricks should be protected from severe abrasion, direct molten-material contact and concentrated mechanical impact. Actual chemical resistance depends on the atmosphere, dust, alkali exposure and service environment. A batch TDS and lining review should be used for final selection.
Although both products are based on alumina-containing refractory materials, lightweight and dense high alumina bricks perform different functions in a furnace lining. The comparison below explains why a lightweight high alumina insulating brick is usually selected for a backup or insulation layer rather than as a universal hot-face replacement.
| Aspect | High Alumina Lightweight Brick | Dense High Alumina Brick |
|---|---|---|
| Primary role | Backup lining, insulation layer and thermal barrier | Working lining or hot-face protection, subject to grade and design |
| Density | LG reference range: 0.6–1.0 g/cm3 | Higher and product-specific |
| Thermal conductivity | Lower within the lightweight grade range | Generally higher than lightweight grades, subject to TDS |
| Mechanical strength | Grade-dependent; lower-density grades have lower CCS | Generally higher, subject to grade |
| Direct abrasion | Limited; protect with a suitable working layer | More suitable for severe mechanical duty, grade-dependent |
| Main design purpose | Reduce heat transfer and shell heat loss | Resist heat, load, abrasion and chemical exposure |
In a multilayer lining, dense high alumina brick may protect the hot face while high alumina lightweight brick provides insulation behind it. The correct interface, support and expansion arrangement must be confirmed in the lining design.
High alumina lightweight bricks are used where insulation performance is important and the material can be protected from severe direct abrasion or molten-material contact. The final grade should be selected against the actual lining position and operating conditions.
May be used in selected preheater, calciner or shell-insulation zones where heat loss reduction is required and mechanical exposure is controlled. The burning zone requires a separate working-lining assessment.
Used as a backup lining behind dense refractory materials in reheating furnaces and soaking pits. Grade selection should consider heat-up, shutdown cycles, support load and installation direction.
May support protected insulation zones where stable thermal performance is needed. It should not be treated as a direct replacement for AZS or other materials in molten-glass contact areas.
Can be evaluated for protected backup insulation in reformers, incinerators, boilers and related high-temperature units after checking atmosphere, temperature and mechanical support.
For any application, provide the furnace type, lining location, operating temperature, atmosphere, support condition and required dimensions before confirming the LG grade.
The price of lightweight high alumina insulating brick depends on the LG density grade, dimensions, order quantity, shape, packaging and destination. Lower-density grades may have different unit economics from higher-strength grades because forming, handling, inspection and packing requirements change with the product structure.
For an accurate quotation, the buyer should specify the required LG grade or target density, brick dimensions, total quantity, special shapes, packaging requirement and destination. A project-based quotation is more useful than comparing a general price per piece without confirming density and size.
Quotation information
No fixed retail price is shown because the final quotation depends on the confirmed product specification and project terms.
The lightest grade is not automatically the correct grade. Grade selection should balance thermal insulation and the mechanical support available in the lining system.
Provide the furnace drawing or lining position together with the operating conditions. This allows the grade selection to be reviewed as part of the complete refractory system instead of as an isolated brick purchase.
It is a low-density alumina-based insulating refractory brick designed mainly for backup linings and thermal barriers. Its lightweight structure reduces heat transfer, while the selected density grade provides the strength required by the supported lining system.
High alumina lightweight brick is mainly used for backup insulation because it has lower density and lower thermal conductivity. Dense high alumina brick is generally used where the lining must resist greater mechanical load, abrasion or chemical exposure. The correct choice depends on the lining position and furnace design.
In the supplied reference data, LG-0.6 has the lowest listed thermal conductivity, not greater than 0.30 W/m·K at 350±25°C. It also has the lowest listed compressive strength in the series, so adequate mechanical support must be confirmed before selection.
It is generally used as an insulation or backup lining and should not automatically replace a dense working lining in areas exposed to severe abrasion, direct molten material contact or heavy mechanical impact. Confirm the complete lining design and operating conditions before use.
Provide the LG grade or target density, dimensions, shape, quantity, packaging requirement and destination. The quotation depends on the confirmed product specification and order terms, so a general price per piece is not sufficient for accurate comparison.
Send your LG grade or target density, operating temperature, lining position, required dimensions, compressive load, quantity and destination. Our team can review the suitable lightweight insulation grade for your project.
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