Fire clay bricks belong to acid refractory products, and the acidity of fire clay brick increases with the increase of silica content. The fire clay bricks have a certain anti erosion ability for acid slag, but the resistance to alkaline slag erosion is weak, so the fire clay bricks are suitable for the lining of acid furnace. Fire clay bricks are also used in blast furnace, hot blast stove, glass kiln, carbon baking furnace and other high temperature equipment.