Physical and chemical indicators of alumina bricks

Alumina bricks are a type of refractory brick made from aluminum oxide (Al2O3) and other additives. They are widely used in high-temperature industrial applications due to their excellent thermal and chemical resistance properties. The physical and chemical indicators of alumina bricks include:
【Physical Indicators】
1.Apparent porosity
Generally, the apparent porosity of alumina bricks is less than 10%, which indicates good density and low permeability.
2.Bulk density
The bulk density of alumina bricks ranges from 2.5 to 3.0 g/cm3, with higher densities indicating more compacted and stronger bricks.
3.Compressive strength
The compressive strength of alumina bricks can range from 50 MPa to 200 MPa, depending on the manufacturing process and additives used.
4.Thermal conductivity
The thermal conductivity of alumina bricks is low, typically ranging from 1 to 3 W/(m·K), which makes them ideal for use in high-temperature insulation applications.

【Chemical Indicators】
1.Al2O3 content
The Al2O3 content of alumina bricks is generally greater than 48%, with higher levels indicating greater thermal stability and chemical resistance.
2.SiO2 content
The SiO2 content of alumina bricks is typically less than 50%, as excessive silica can reduce the thermal shock resistance of the bricks.
3.Fe2O3 content
The Fe2O3 content of alumina bricks should be minimized, as iron oxides can reduce the thermal stability and corrosion resistance of the bricks.
4.Impurities
Other impurities such as alkalis, alkaline earths, and transition metal oxides should also be minimized, as they can have negative effects on the performance and durability of alumina bricks.
Overall, these physical and chemical indicators are important measures of the quality and suitability of alumina bricks for specific high-temperature applications.