Lightweight insulation brick for glass kilns can be classified into 6 categories according to their different raw materials. The most widely used ones are lightweight silica bricks and diatomite bricks. Lightweight insulation bricks have advantages of good thermal insulation performance, but their pressure resistance, slag resistance, and thermal shock resistance are poor, so they cannot directly contact with molten glass or flame.
1. Lightweight silica bricks. Lightweight silica insulation brick is a insulation refractory product made from silica as the main raw material, with a SiO2 content of no less than 91%. The density of lightweight silica insulation brick is 0.9~1.1g/cm3, and its thermal conductivity is only half of that of ordinary silica bricks. It has good thermal shock resistance, and its softening temperature under load can reach 1600 ℃, which is much higher than that of clay insulation bricks. Therefore, the maximum operating temperature of silica insulation bricks can reach 1550 ℃. It does not shrink at high temperatures, and even has slight expansion. Light silica brick is generally produced with crystalline Quartzite as raw material, and combustible substances such as coke, anthracite, sawdust, etc. are added into the raw materials to form porous structure and gas foaming method can also be used to form porous structure.
2. Diatomite bricks: Compared with other lightweight insulation bricks, diatomite bricks have lower thermal conductivity. Its working temperature varies with purity. Its working temperature is generally below 1100 ℃ because the shrinkage of the product is relatively large at high temperatures. The raw materials of diatomite brick need to be fired at a higher temperature, and silicon dioxide can be converted into quartz. Lime can also be added as a binder and mineralizer to promote the conversion of quartz during firing, which is beneficial for improving the heat resistance of the product and reducing shrinkage at high temperatures.
Next issue we will continue to introduce classification of lightweight insulation brick for glass kilns. Please stay tuned!
Post time: Jul-10-2023
