What Chemical Reactions Does Refractory Brick Have When It Encounters High Temperature

When refractory bricks are subjected to high temperatures, within a reasonable temperature range, no obvious chemical reaction will occur, because they have excellent high-temperature resistance and chemical corrosion resistance. However, when the temperature continues to rise, the refractory bricks will change thermal expansion, thermal shock resistance, compressive strength, flexural strength, and bulk density. Generally, when refractory bricks encounter high temperatures, their chemical reactions and properties mainly depend on their chemical composition and mineral composition.

Refractory bricks will undergo thermal expansion and contraction when they encounter high temperatures. At a reasonable temperature for refractory bricks, they can resist such thermal expansion and contraction. However, as the temperature rises and reaches the limit temperature of refractory bricks, refractory bricks may suffer stress due to rapid thermal expansion and contraction, resulting in cracking and damage of refractory bricks.

Some refractory bricks will react with oxygen at high temperatures to form oxides. For example, chromium-aluminum refractory bricks may undergo oxidation reactions with oxygen at high temperatures to generate oxides such as Cr₂O₃ and Al₂O₃.

In addition, the bulk density, apparent porosity, load softening temperature, thermal shock resistance, compressive strength, and flexural strength of refractory bricks will change under high temperatures, especially the load softening temperature, which is generally lower than the refractory temperature. When this temperature is exceeded, refractory bricks are prone to deformation under constant pressure load, which leads to deformation of the overall structure of the kiln.

At present, there are many types of refractory bricks, such as silicon-aluminum refractory bricks, carbon-containing refractory bricks, zirconium-containing refractory bricks, alkaline refractory bricks, and insulating refractory bricks. Their chemical reactions and performance changes under high temperatures may be different, and the specific ones should be referred to according to their physical and chemical indicators.