Drying and high temperature sintering of glass fiber cloth. Wet formed composite bricks need to be dried and sintered at high temperature. Considering that the polycrystalline mullite composite prefabricated parts may shrink greatly after high temperature treatment, the geometric size of the product should be well controlled. In addition, the product is larger and thicker, which will bring difficulties to drying. Pre-wet cutting should be adopted to increase its evaporation area, and hot air circulation should be used for drying at the same time. During the circulation process, water vapor should be continuously discharged to speed up the drying speed of the product.
After the polycrystalline mullite fiber composite prefabricated brick body is dried, the product still does not have sufficient strength, and the strength will be greatly improved after high-temperature sintering. When sintered at high temperature, the fibers will become dense and cause shrinkage. Therefore, when the composite prefabricated brick of polycrystalline mullite fiber is sintered, the heating process and speed are not allowed to rise slowly as usual, especially when the temperature of glass crystallization must be controlled. Well, limit its periodic process of crystallization at high temperature. This requires a sufficient heating rate and a suitable sintering temperature for the glue used as a sintering agent. Table 1-26 is the physical and chemical indicators of polycrystalline mullite fiber composite prefabricated bricks.