Why do different refractory bricks have different levels of fire resistance?

Different refractory bricks have different fire resistance levels due to differences in raw materials and firing temperatures.

In the production of refractory materials, in recent years, fire resistance tests have basically not been conducted because the mature manufacturing process can achieve results in fire resistance. Furthermore, the fire resistance is not as important as other physical and chemical indicators in the quality consideration of refractory bricks.

The materials of refractory bricks are divided into acidic, alkaline, and neutral, and their fire resistance varies from 1600 to 2000 ℃. For example, clay bricks have low aluminum content and liquid phase, and their usage temperature and fire resistance are relatively low. High alumina bricks have a high aluminum content, high load softening temperature, and an increase in fire resistance.

The low fire resistance is due to the low liquid phase of oxides in the product, which leads to a decrease in fire resistance and is closely related to the substrate of the raw materials and the firing temperature. For example, the magnesium series in alkaline refractory bricks have high bulk density, high firing temperature, and increased refractory strength. There are also silica bricks in the acidic series of products, although they have a high coefficient of expansion, their fire resistance is relatively higher than that of clay bricks.

The higher the fire resistance, the higher the operating temperature. For example, neutral series high alumina bricks have a fire resistance of over 1700 ℃ and a usage temperature of 1350 ℃. Corundum bricks have a fire resistance of over 1800 ℃ and a usage temperature of over 1400 ℃. Alkaline series refractory bricks have a fire resistance of over 2000 ℃ and a usage temperature of 1700 ℃.

The slag resistance of refractory bricks increases with the increase of the main content. The higher the main indicator, the lower the impurities, which is more conducive to improving corrosion resistance.

Products with a usage temperature above 1300 ℃ for refractory bricks have corrosion resistance function. The main indicator of refractory brick's refractory content varies, and it also changes with the softening temperature under load.