Brief introduction to corundum self-flowing castable

1. What is Corundum Self-Flowing Castable?

It is a type of castable refractory made primarily of high-purity corundum, combined with micro-powder, binders, and dispersants, through optimized particle size distribution design. Developed from low-cement and ultra-low-cement castables, it is a new type of castable that flows and degasses without vibration. Its innovative feature is that it can flow and fill complex mold spaces solely under gravity, forming a dense and uniform structure, without the application of external force. Compared to vibratory castables, self-leveling castables require more water, have a slightly lower bulk density after drying, a slightly higher porosity, and a slightly lower compressive strength. Corundum self-leveling material degasses and levels itself without vibration, achieving densification. This self-leveling characteristic significantly improves construction efficiency, making it particularly suitable for irregularly shaped areas or areas with dense reinforcement.

2. Composition of Corundum Self-flowing Castable

Its Al₂O₃ content is typically above 90%, its bulk density after drying at 110℃ is typically 2.85-3.05 g/cm³, its room temperature compressive strength is typically around 30 MPa, its room temperature flexural strength is around 4 MPa, its room temperature abrasion value is below 5 cm³, and its self-flow value is typically 170-210 mm (self-flowing method) or 200-220 mm (table-skimming method).

3. Construction Precautions

Uniformity is a key indicator during mixing. Specialized equipment must be used for thorough mixing to ensure consistent dispersion of components and avoid clumping or segregation. The mixed dry material, after packaging, is the finished product and can be used by adding water and mixing on-site. It is important to note that the amount of water added must be precisely controlled: too much water will reduce strength, while too little will affect fluidity. The water-to-material ratio usually needs to be fine-tuned according to the ambient temperature and humidity.

During construction, the base surface must first be cleaned, anchors and templates installed, and then the mixed castable refractory poured into the mold, allowing it to level under its own weight and remove air bubbles. After construction, it needs to undergo natural curing and baking processes to gradually remove moisture and allow the material to sinter and solidify. A reasonable baking regime is crucial to the final performance; heating should be done slowly according to the temperature rise curve to avoid cracking caused by rapid moisture evaporation. The ambient temperature during construction should be controlled within a reasonable range; excessively high or low temperatures will affect the construction quality.

4. Application Area

Due to its self-flowing characteristics, corundum self-flowing refractory castables are widely used in circulating fluidized beds, ladle bottoms, boiler protection pipes, heating furnaces, blast furnace tapping troughs, and other areas where construction is often difficult. Corundum castables are also suitable for use as repair materials around ladle bottoms and bedding bricks, and as grouting materials for electric furnace tops. Corundum self-flowing refractory castables can improve construction efficiency while ensuring the working conditions after construction.