Understanding High Alumina Insulating Bricks

May 30, 2023

High Alumina Insulating Brick

High alumina insulating bricks are a type of refractory material made with alumina levels typically between 55% to 99%. Their composition of alpha alumina (Al2O3) gives them the ability to withstand high temperatures while also providing thermal insulation properties.

High alumina levels mean these bricks can operate continuously at temperatures up to 1,700°C/3,090°F. Their low thermal conductivity helps reduce heat loss and save energy in high temperature furnaces and kilns. As alumina content increases, the service life and insulating properties of the bricks improve.

Compared To Standard Fireclay Insulating Bricks, High Alumina Bricks Offer:

• Higher temperature capability – Can withstand temperatures up to 1700°C.
• Greater chemical resistance – Resist corrosion from acids, bases and slags better.
• Longer service life – Higher density and strength helps them last longer.

High alumina insulating bricks are commonly used for lining furnaces, reheating boxes, soaking pits, incinerators and other industrial heating equipment. Their combination of superior heat resistance, thermal insulation and chemical durability make them ideal for these high temperature applications.

Insulating Fire Bricks

Insulating fire bricks are a traditional refractory material composed mainly of fireclay, and sometimes kaolin and grog (recycled crushed firebrick). Due to their lower alumina content, typically between 33% to 55%, they can only withstand temperatures up to approximately 1,200°C/2,190°F.

Compared To High Alumina Insulating Brick, Fireclay Insulating Bricks Offer:

• Lower cost – Due to more abundant raw materials and simple manufacturing process.
• Higher porosity – More air pockets provide better insulation at lower temperatures.
• Easier machining – Can be cut and shaped with standard shop tools.

While insulating fire bricks work well for applications under 1200°C, high alumina insulating bricks are required for more demanding processes that exceed this temperature and need greater chemical resistance. The choice between these two refractory options depends on your temperature and durability requirements.