Exploring the production process of refractory castables

In the production process of refractory castables, attention must be paid to raw materials and proportions, bulk premixing, product sampling, and curing inspection:

Raw material preparation: Aggregates, powders, binders, and admixtures should all be prepared according to the established proportions, ensuring they are free of impurities and have not been affected by moisture or deterioration. Particle size distribution should be reasonable: coarse particles (>1 mm), medium particles (0-1 mm), and fine powder (<0.088 mm) should be controlled according to the three-gradation principle to obtain the maximum bulk density. Micro-admixtures and ultrafine powders (such as alumina powder and silica powder) must be thoroughly and evenly mixed during bulk production to avoid uneven dispersion caused by direct addition on-site. Whether binders need to be packaged separately is generally determined based on on-site usage.

Bulk premixing equipment generally uses a forced mixer. When changing to a different type of castable, the equipment must be thoroughly cleaned. The production area must be kept clean and dry to prevent the mixing of impurities such as mud, lime, and cement. Regularly inspect, maintain, and replace equipment as needed. For the first batch of each production run, check the weight of the raw materials to ensure consistency with the batching list.

During product sampling and testing, for packaged products, add the binder according to the specified ratio and stir for 20 seconds to ensure the dry material is uniform. Then add water in two stages: first add 80% and stir for 1 minute, then add the remaining 20%, with a total stirring time of 3 minutes. For unpackaged castables, dry-mix for at least 20 seconds before adding water. Strictly follow the product instructions for water addition, adhering to the principle of less is better; pure drinking water with a pH of 7-7.5 is recommended. Observe the workability, flowability, and hardening speed of the mixed castable to ensure they meet the design requirements. The mixed material must be used within the specified time; once it has initially set, it is considered unusable and must not be reused with added water.

Use standard molds for molding. Apply an interface agent or oil to the contact surfaces with the castable. Generally, a vibrating table is used for compaction until the surface is covered with slurry, avoiding segregation due to over-vibration. After vibration molding, the mold is placed in a horizontal, well-ventilated area for 24 hours. Once the initial strength is achieved, the mold is removed and cured for another 24 hours. During the curing period, external forces and vibrations are prohibited. Sample blocks should be tested promptly to ensure their performance meets requirements.

In conclusion, castable refractory production is an extremely demanding system engineering process, requiring precise coordination between personnel operation, equipment operation, and raw material quality. Deviations in any of these aspects will directly affect the final product performance. During production, personnel, machinery, and materials are interconnected and indispensable; any uncertainty in any one of these can lead to fluctuations in product performance. Products are the backbone of an enterprise and the foundation for its market position. Only by continuously ensuring stable and reliable product quality and improving technical standards and processes can an enterprise truly gain a competitive advantage and achieve long-term development.