Types of refractory bricks

2024-05-23 10:09:33
Refractory bricks are an important material used for building refractory structures. They are classified in various ways, among which classification by material is a common method. The following will introduce in detail the main types of refractory bricks classified according to their materials, and explain their characteristics and application fields.

1. Silica refractory bricks

Silica refractory bricks are mainly composed of silica (SiO2), with the content usually above 90%. They have good chemical stability and high temperature strength and are the main varieties of acid refractory bricks. Silica refractory bricks are mainly used to build high-temperature equipment such as coke ovens, glass furnaces, acid steel-making furnaces, and as high-temperature load-bearing parts of hot blast stoves. However, silica refractory bricks are not effective when used in thermal equipment with temperatures below 600°C and large temperature fluctuations.

2. Aluminum-silicon series refractory bricks

Aluminum-silicon series refractory bricks use alumina (Al2O3) and silica (SiO2) as the main components. According to the different alumina content, they can be divided into clay refractory bricks and high alumina bricks.

Clay refractory bricks: The alumina content is between 30% and 40%. It is one of the most cost-effective and widely used varieties of refractory bricks. They have good thermal shock resistance and slag resistance and are suitable for various medium and low temperature furnaces. The formula of clay refractory bricks can also be adjusted according to the specific use environment to produce varieties with different performance properties, such as low creep clay bricks, phosphoric acid impregnated clay bricks, low porosity clay bricks and lightweight clay bricks.
High alumina bricks: The alumina content is above 48%, which has higher refractoriness and mechanical strength. High alumina bricks are mainly used in high-temperature kilns, such as electric furnaces, converters, blast furnaces, etc. They can withstand higher temperatures and more complex chemical attacks, ensuring long-term stable operation of equipment.
3. Magnesia refractory bricks

Magnesia refractory bricks use magnesium oxide (MgO) as the main component and have good refractoriness and resistance to alkaline slag erosion. Magnesia refractory bricks are mainly used in industrial sectors such as steelmaking converters, electric furnaces, non-ferrous metal smelting and cement. Among them, magnesia-chromium bricks are refractory products with magnesium oxide and chromium trioxide as the main components. They have higher refractoriness and slag resistance and are suitable for harsher working environments.

4. Carbon refractory bricks

Carbon refractory bricks are mainly composed of carbon elements and have extremely high refractory resistance and thermal conductivity. They are mainly used in high-temperature equipment such as blast furnace bottoms, hearths and hot blast furnaces. Carbon refractory bricks can withstand extremely high temperatures and have good thermal stability and thermal shock resistance. However, due to the low mechanical strength of carbonaceous refractory bricks, they require special attention to protection when used.

5. Special refractory bricks

In addition to the common refractory bricks mentioned above, there are also some special refractory bricks, such as corundum refractory bricks, silicon carbide refractory bricks, zirconia refractory bricks, etc. These refractory bricks have special chemical and physical properties and are suitable for some special high-temperature environments. For example, corundum refractory bricks have extremely high hardness and wear resistance and are suitable for making grinding tools and cutting tools; silicon carbide refractory bricks have extremely high thermal stability and thermal shock resistance and are suitable for making high-temperature furnaces and nozzles. and other components; zirconia refractory bricks have extremely high melting points and corrosion resistance, and are suitable for making molten metal containers and nuclear reactors and other components.

In short, refractory bricks can be divided into several main types according to material classification: siliceous refractory bricks, aluminum-silicon series refractory bricks, magnesia refractory bricks, carbonaceous refractory bricks and special refractory bricks. Each type of refractory brick has its own unique chemical and physical properties and application range. Choosing the right refractory brick is crucial to ensure the normal operation and extended service life of the equipment.
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