Mullite brick: What it is & Where it’s Used

  • Time:Aug 25, 2023
  • Views: 15
Mullite brick refers to a high alumina refractory material with mullite as the main crystal phase. Generally, the alumina content is between 65% and 75%. Mineral composition In addition to mullite, those with lower alumina content also contain a small amount of glass phase and cristobalite; those with higher alumina content also contain a small amount of corundum. It is mainly used for hot blast stove top, blast furnace body and bottom, glass melting furnace regenerator, ceramic sintering kiln, dead corner furnace lining of petroleum cracking system, etc.

【1】 What is mullite brick?

  Mullite brick is a type of refractory brick made from mullite, a synthetic material that is formed from alumina and silica. It has excellent high-temperature resistance, thermal shock resistance, and chemical stability, making it ideal for use in various high-temperature applications.

  Mullite brick is commonly used in the construction of furnace linings, kiln linings, and other high-temperature equipment in industries such as ceramics, metallurgy, and petrochemicals. The following are some key properties of mullite brick:

  1. High-temperature resistance: Mullite brick can withstand high temperatures up to 1800°C without losing its mechanical strength or shape.

  2. Thermal shock resistance: Mullite brick has good thermal shock resistance, meaning it can withstand rapid temperature changes without cracking or breaking.

  3. Chemical stability: Mullite brick has excellent chemical stability, making it resistant to acid corrosion and oxidation.

  4. Low thermal conductivity: Mullite brick has a low thermal conductivity, which provides good insulation and helps to reduce heat lossmore

【2】 Mullite bricks properties

  1.High-temperature stability

  Mullite bricks can withstand temperatures up to 1800°C without significant deformation or degradation. This makes them suitable for use in furnaces, kilns, and other high-temperature equipment.

  2.Low thermal conductivity

  Mullite bricks have a low thermal conductivity, which means they are good insulators and can help to reduce heat loss in high-temperature systems.

  3.Good thermal shock resistance

  Mullite bricks have good thermal shock resistance, which means they can withstand rapid changes in temperature without cracking or breaking. This makes them suitable for use in processes where rapid heating and cooling cycles occur.

  4.Chemical resistance

  Mullite bricks are highly resistant to acidic and basic environments, making them suitable for use in harsh chemical and industrial applications.

  5.High mechanical strength

  Mullite bricks have a high compressive and flexural strength, which allows them to withstand the weight of heavy loads and resist mechanical wear.

  6.Low creep

  Mullite bricks have a very low creep rate, meaning they resist deformation under load even at elevated temperaturesmore

【3】 Mullite brick physical and chemical indicators

  Mullite brick is a type of refractory brick made from high-purity mullite and other materials with excellent thermal shock resistance and mechanical strength. Below are some typical physical and chemical indicators for mullite brick:

  1.Apparent Porosity: ≤18%

  2.Bulk Density: ≥2.65 g/cm³

  3.Cold crushing strength: ≥80 MPa

  4.Refractoriness Under Load (0.2 MPa, 0.6%): ≥1650°C

  5.Thermal Shock Resistance (1100°C water quenching, cycle times): ≥20

  6.Thermal Conductivity (1000°C): ≤1.5W/(m·K)

  7.Chemical Composition: Al₂O₃ content: ≥70%, SiO₂ content: ≥25%

Mullite brick physical and chemical indicators

【4】 Mullite bricks price

  The price of mullite bricks depends on several factors such as the size, shape, and quantity needed, as well as the supplier and market conditions. Generally, mullite bricks are considered to be a premium refractory material, so they tend to be more expensive than other types of bricks.

  As of my knowledge cutoff date (September 1, 2021), the price range for mullite bricks was around USD 800-1200 per ton, although this may vary depending on the specific supplier and market conditions. It's important to note that prices are subject to change over time and can vary depending on many factors, including supply and demand, raw material costs, and shipping costs.

  It's always recommended to obtain quotes from multiple suppliers to compare prices and ensure that you are getting a fair price for the mullite bricks you need.

Mullite bricks price


【5】 What is the density of mullite bricks?

      The density of mullite bricks can vary depending on several factors, including the specific composition, manufacturing process, and porosity. Generally, the density of mullite bricks falls within the range of 2.6 to 3.0 grams per cubic centimeter (g/cm³) or 2600 to 3000 kilograms per cubic meter (kg/m³).

  It's important to note that the density of mullite bricks can be influenced by the presence of other additives, such as alumina or silica, which may affect the overall density of the material. Additionally, the level of porosity in the bricks also contributes to their density. Higher porosity generally leads to lower density.

  Specific manufacturers or suppliers may provide more precise information about the density of their mullite brick products, as different formulations and production processes can result in slightly different densities. Therefore, it is advisable to consult with the manufacturer or refer to the product specifications for accurate density measurements for a particular type of mullite brick.

What is the density of mullite bricks?

【6】 What is the composition of mullite bricks?

  The typical composition ranges for mullite bricks are as follows:

  1. Mullite (3Al2O3·2SiO2): Mullite is the main component and typically constitutes the majority of the brick's composition. It provides the desirable thermal and mechanical properties of mullite bricks.

  2. Alumina (Al2O3): In addition to being a constituent of mullite, alumina is often included as a separate phase in mullite bricks. Alumina enhances the high-temperature resistance and chemical stability of the bricks.

  3. Silica (SiO2): Besides being a constituent of mullite, silica may also be present as a separate phase in small amounts. Silica contributes to the thermal shock resistance and refractoriness of the bricks.

  4. Other additives: Various additives or binders might be added to the raw materials during the manufacturing process to improve the performance of mullite bricks. These can include clay, kaolin, magnesia, zirconia, or other refractory materials that enhance specific properties like strength, thermal conductivity, or corrosion resistance【more

What is the composition of mullite bricks?

© Zhengzhou Zhenjin Refractory Materials Co.,Ltd.