Zhengzhou Zhongkeda Refractory Materials Co., Ltd

Mullite Insulation Brick for Kilns & Industrial Furnaces

Lightweight refractory insulation bricks designed to reduce heat loss, lower lining weight and improve thermal efficiency.

• JM23–JM30

• Low Thermal Conductivity

• Standard & Custom Sizes

[Request a Quote - Ask About Grade Selection]

Why Use Lightweight Mullite Insulation Bricks?

Reduce Heat Loss	Reduce Furnace Weight	Improve Energy Efficiency	Maintain High-Temperature Performance
Low thermal conductivity helps reduce heat transfer through the furnace lining.	Lightweight structure reduces the load placed on the furnace or kiln structure.	Better insulation can help reduce heat loss and improve thermal efficiency.	Different grades are available for different furnace temperatures and insulation requirements.

Mullite insulation brick is usually selected as an insulation or backup lining material rather than a replacement for dense hot-face refractory in severe service areas.

Where Are Mullite Insulation Bricks Used?

Lightweight mullite bricks are commonly used as insulation or backup lining in high-temperature furnaces and kilns to reduce heat loss and furnace weight.

• Ceramic & Pottery Kilns：For tunnel kilns, roller kilns, shuttle kilns and pottery kilns where lightweight insulation is required.

• Industrial Furnaces：Used as backup insulation behind dense refractory linings in suitable furnace zones.

• Heat Treatment Furnaces：Suitable for furnace walls, roofs and other insulation areas where low thermal conductivity is required.

• High-Temperature Kilns：Used in kiln insulation systems to reduce heat loss and improve thermal efficiency.

Typical Multi-Layer Lining

Dense Refractory → Mullite Insulation → Steel Shell

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Not sure which grade or lining position is suitable?
Mullite insulation bricks are commonly used behind the hot-face refractory layer to provide thermal insulation and reduce heat transfer to the furnace shell.
[ Ask Our Technical Team ]

Which Mullite Insulation Brick Do You Need?

Grade	Classification Temp.	Main Advantage	Typical Selection
JM23	1350°C	Lightweight & economical	General insulation
JM26	1430°C	Balance of insulation & strength	General high-temp insulation
JM28	1540°C	Higher strength & temperature	More demanding furnace insulation
JM30	1600°C	Higher-temperature insulation	High-temperature furnace areas

The highest classification temperature is not automatically the best choice. Grade selection should consider operating temperature, lining position, mechanical load and required thermal insulation performance.

Key Performance of Mullite Insulation Bricks

Designed to reduce heat loss while providing lightweight, reliable insulation for high-temperature furnaces and kilns.

Low Thermal Conductivity	Lightweight Structure	Energy Efficiency	High-Temperature Stability	Thermal Shock Resistance	Dimensional Stability
Reduces heat transfer and helps keep heat inside the furnace	Lower density reduces lining weight and structural load	Effective insulation helps reduce heat loss and energy consumption	JM23–JM30 grades are available for different temperature requirements	Suitable grades can withstand repeated heating and cooling	Maintains stable dimensions under suitable service conditions

Designed to maintain stable dimensions under suitable service conditions.

Technical Data
Technical Data of JM23–JM30 Mullite Insulation Bricks

Item	JM23	JM26	JM28	JM30
Al₂O₃(%)	38-44	50-58	65-70	65-70
Fe₂O₃(%)	1.0	0.9	0.8	0.7
Classification Temperature(℃)	1260	1430	1540	1650
Bulk Density(g/cm³)	0.6-1.0	0.6-1.0	0.6-1.0	0.6-1.0
Reheating Linear Change(%)CT-30℃*8h	1250℃ -0.5	1400℃ -0.5	1500℃ -0.5	1550℃ -0.5
Cold Crushing Strength(Mpa)	3.0-4.5	3.0-4.5	3.0-4.5	3.0-4.5
Modulus of Rupture(Mpa)	1.5	1.7	1.8	2.0
Thermal conductivity400℃(W/m.k)	0.25	0.27	0.32	0.41
Thermal Expansion1000℃(%)	0.5	0.7	0.8	0.9

Standard & Custom

Standard & Custom Mullite Insulation Bricks

Send us your drawing, dimensions or kiln design for specification confirmation.

[ Send Your Drawing ]

How to Choose the Right Mullite Insulation Brick?

01 Operating Temperature What is the actual operating temperature of the lining?

02 Lining Position Is the brick used as backup insulation, side wall insulation, roof insulation or another furnace area?

03 Mechanical Load Will the brick carry structural or lining load?

04 Thermal Conductivity How much insulation performance is required?

Mullite Insulation Bricks for Your Project

From grade selection to custom dimensions and export packaging, we support project-specific requirements directly from our factory.

Asked Questions About Mullite Insulation Bricks

What is a mullite insulation brick used for?

Mullite insulation bricks are mainly used as insulation or backup lining in furnaces and kilns to reduce heat loss and lining weight.

What is the difference between JM23, JM26, JM28 and JM30?

The main differences are classification temperature, bulk density, strength and thermal conductivity. Higher JM grades are generally selected for more demanding temperature and mechanical conditions.

How do I choose the right JM grade?

Consider the operating temperature, installation position, mechanical load and required insulation performance. Send us your application details and we can help recommend a suitable grade.

Can mullite insulation bricks be used as a hot-face lining?

They are generally used as insulation or backup lining rather than replacing dense hot-face refractory materials in severe service areas.

What is the thermal conductivity of your mullite insulation bricks?

Our JM23–JM30 grades have different thermal conductivity values. Please refer to the technical data table for the specific grade.

Can you manufacture custom sizes and shapes?

Yes. We can manufacture straight, wedge, arch and other special-shaped mullite insulation bricks according to drawings or dimensions.

Can I order samples before a bulk purchase?

Yes. Sample orders can be discussed according to the required grade, size and application.

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Not Sure Which Mullite Insulation Brick You Need?

Tell us your furnace or kiln type, operating temperature, insulation position, required size and quantity. Our technical team can help you evaluate the suitable grade and specification.