The raw materials used for light refractory bricks can be divided into clay, silica, aluminum and mullite. The reason why light bricks can be insulated is that there are a large number of pores (including closed pores and open pores) in the brick body. The methods of causing porosity include adding combustible method, foam method and chemical method. Light refractory bricks have low compressive strength, poor slag resistance and poor thermal vibration resistance, and can not be in direct contact with liquid glass or flame.

① Light clay insulation brick

Light clay thermal insulation brick is a thermal insulation refractory product with Al2O3 content of 30% - 48% made of refractory clay as the main raw material. The production process uses burning and adding method and foam method. The product with bulk density of 0.3 ~ 1.5g/cm3 is prepared by taking refractory clay, floating beads and refractory clay clinker as raw materials, adding binder and sawdust, batching, mixing, forming, drying and firing '. The output of light clay insulating brick accounts for more than half of the total output of insulating refractory brick.

② Light silica insulating brick

Light silica thermal insulation brick is a thermal insulation refractory product with SiO2 content not less than 91% made of silica as the main raw material. The bulk density of light silica thermal insulation brick is 0.9 ~ 1.1g/cm3, the thermal conductivity is only half of that of ordinary silica brick, and the thermal vibration resistance is good. Its load softening starting temperature can reach 1600 ℃, which is much higher than that of clay thermal insulation brick. Therefore, the maximum service temperature of silicon insulation brick can reach 1550 ℃. It does not shrink or even expand slightly at high temperature.

③ Light alumina insulating brick

Light alumina heat insulation brick is a heat insulation refractory product made of fused corundum, sintered alumina and industrial alumina. The production process consists of two methods: foaming method and burning adding method.

④ Light mullite insulation brick

Light mullite thermal insulation brick is a thermal insulation and refractory product made of mullite as the main raw material. Mullite insulating brick has the advantages of high temperature resistance, high strength, low thermal conductivity and direct contact with flame. It is suitable for the lining of various industrial kilns.