During the construction of refractory castables for circulating fluidized bed boilers, curing work shall be carried out after the completion of castable pouring. The general curing period is 48 hours. After the castables are completely hardened, they can be demoulded and put into use.
Corundum castables are generally selected for use on the fire-facing surfaces or wear-resistant parts of circulating fluidized bed boilers. Like other castables, corundum castables also require pouring and curing before application. Then how should the demoulding time of corundum castables be controlled?
When pouring and forming corundum castables, first of all, it is necessary to clean the working surface thoroughly, then set up the formwork, pour the mixed corundum castables into the formwork and carry out fixed forming. After forming, the surface of the castables shall be leveled to make it smooth. The formed castables shall not be exposed to water for the second time to avoid dry cracks on the surface of the green body.
It should be noted that there will be excess mud on the edges of the formed corundum castables, which needs to be cleaned up to prevent uneven edges of the green body after demoulding, thus affecting the appearance quality or causing excessive dimensional deviation.
The formed corundum castables, together with the formwork, shall be placed in a place with suitable temperature, avoiding areas with excessively high or low temperatures. During storage, if the weather is too dry, the surface of the formed corundum castable green body can be covered with wet sacks to prevent the quality of the green body from being reduced due to too fast evaporation of water in the green body.
In cold weather, heating facilities shall be added to ensure the indoor temperature, which shall not be lower than 6℃. Production shall be stopped when the temperature is lower than this value.
The following points shall be noted when demoulding corundum castables:
  1. The hardening time of the corundum castable green body shall not be less than 8 hours, and appropriate adjustments shall be made according to the weather conditions. The demoulded corundum castables shall be placed in a place with suitable temperature for natural curing. The general curing time is 48 hours, while the curing time of large-sized corundum castables shall be determined according to the actual situation.
  2. During demoulding, a leather hammer shall be used first to knock and separate the formwork from the green body, then loosen the formwork and take out the green body. If any parts need to be repaired after demoulding, the same materials shall be used for timely repair.
  3. If the green body is found to be distorted or deformed after demoulding, the formwork must be corrected in a timely manner to avoid affecting its use effect.
  4. Specific problems shall be analyzed in detail. If you have any questions, please feel free to contact us at any time.