What is the required curing condition for heat-setting plastic refractories?

Heat-setting plastic refractories require specific curing conditions to ensure proper strength and performance. Allowing them to air dry at specific temperatures is crucial because it facilitates the curing process in a controlled manner. This method helps the materials achieve the desired chemical and physical properties, enabling them to handle the thermal and mechanical stresses they will face in high-temperature applications.

During the air-drying process, maintaining a consistent temperature aids in the evaporation of solvents and the proper development of the refractory matrix. This process helps in minimizing shrinkage and cracking, which can occur if the drying happens too quickly or unevenly. Therefore, adhering to specified temperature guidelines is essential for optimal curing and to attain the necessary mechanical strength of the plastic refractories.

The other options do not align with the best practices for curing heat-setting plastic refractories. For instance, avoiding contact with water is critical, but it is not the complete answer, as some moisture control is necessary during the curing stage. Direct sunlight may cause uneven drying and potentially damage the material. Sealing refractories in airtight containers can hinder the curing process, as it would trap moisture and prevent proper drying. Each of these factors plays a role in the overall curing conditions, but allowing air drying at specific temperatures is the