What is the glass burning process?
Fanyu
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2018-08-29 15:28:34
| In the case of a certain formula, the relationship between the properties of the material and the calcination process is large, and the foaming process system is carried out in several stages such as preheating, sintering, foaming, foam stabilization and annealing. 1. Preheating: The preheating process mainly removes the chemically bound water, adsorbed water and free water in the batch, and because the thermal conductivity of the blank is poor, direct high temperature heating and sintering will cause oxidation of the surface carbon, so that the foaming is not Evenly. For this reason, between room temperature and 400 ° C, the heating rate is generally 5 ~ 8k / min, and is kept at 400 ° C for 20 ~ 30min. 2. Sintering: The preheated green body is rapidly heated to the sintering temperature (650~750 °C). The purpose of rapid temperature rise is to prevent excessive decomposition of the foaming agent and to increase the gas phase with the temperature rise of the green body. Wrapped in the body without escaping, so that more gas phase can be obtained. In the sintering process, the heating rate is generally 8~10k/min, and the body after foaming and sintering is heated to a foaming temperature at a speed of 10~15k/min for foaming (750~1000°C) at the foaming temperature. Keep it under heat for a period of time (15~50min) to facilitate even foaming. 3. Stabilized foam: When the foaming is finished, the blank is quickly cooled to about 600 °C, and the cooling speed is fast, generally 15~20k/min. The purpose is to quickly fix the resulting pore structure. 4. Annealing: Due to the rapid cooling of the blank, stress will be generated. To eliminate the stress, the temperature is maintained at 600 ° C for 20 to 35 minutes, and then gradually cooled to room temperature. Due to the low thermal conductivity of foam glass, its annealing cooling rate is much slower than that of ordinary glass, and the total annealing cooling time is generally more than 24 hours. |