Ceramic Sand can be used as a key component in the production of ladle filler sand (usually used for pouring and drainage in metallurgical scenarios such as ladles and tundishes) due to its spherical particles, high refractoriness, low thermal expansion coefficient and chemical stability, to optimize the performance of traditional quartz sand or chromite sand. The following are its specific application methods and process points:
1. The role of Ceramic Beads in drainage sand
Improve fluidity
Spherical particles reduce friction, making the drainage sand fill more tightly and evenly at the ladle water inlet to avoid blockage.
Enhance high temperature resistance
Refractory ≥1700℃, better than quartz sand (easy to melt), suitable for high temperature molten steel environment.
Stable pouring performance
Low thermal expansion coefficient (≈6×10⁻⁶/℃) reduces the risk of thermal cracking and ensures smooth flow of molten steel.
Reduce impurity pollution
Chemical inertness (main components are Al₂O₃ or ZrO₂) avoids reaction with molten steel and reduces the risk of inclusions.
2. Formula design and mixing process
Typical formula ratio
Ceramic sand-based ladle filler sand: Ceramic sand (50%~70%) + chromite sand (20%~30%) + resin binder (3%~5%) + antioxidant (such as silicon powder, 1%~2%).
Replacement of traditional materials: It can partially or completely replace quartz sand, and the proportion needs to be adjusted according to the type of steel (such as ordinary carbon steel, stainless steel).
Particle size matching
Ceramic sand main particle size: 0.5~1.0mm (to ensure fluidity);
Fine powder (<0.1mm) accounts for ≤15%, which is used to fill gaps.
Bonding system
Phenolic resin or silica sol is a binder, which needs to be cured at high temperature (150~200℃) to enhance strength.
3. Production process
Raw material pretreatment: drying of baozhu sand (water content ≤ 0.5%), magnetic separation of chromite sand to remove iron.
Mixing: dry-mix baozhu sand, chromite sand, etc. in proportion, then add liquid binder and stir until uniform.
Granulation: form 1~3mm particles by extrusion or rolling into balls (strength must be controlled ≥ 5MPa).
Curing: heat treatment in a curing furnace to fully cross-link the resin.
Sieving and packaging: remove fine powder and oversized particles, and seal and store in a moisture-proof manner.
4. Performance Advantage Comparison
Performance Index Baozhu Sand Drainage Sand Quartz Sand Drainage Sand Chromite Sand Drainage Sand
Refractory (℃) ≥1700 ~1600 ≥1800
Thermal Expansion Low High (Easy to Crack) Medium
Flowability Excellent (Spherical) Poor (Angular) Medium
Risk of Molten Steel Pollution Very Low Low (SiO₂ Volatilization) Medium (Containing Cr)
5. Application Notes
Steel Type Compatibility
High-oxygen steel (such as stainless steel) needs to be matched with antioxidants (such as Al powder) to prevent Baozhu Sand from oxidizing.
Sprue Structure Matching
Ceramic Sand has high fluidity, and the nozzle taper (usually 15°~25°) needs to be optimized to prevent self-flow.
Cost Control
Ceramic Sand is expensive, and the cost can be reduced by mixing with chromite sand or recycling (performance attenuation needs to be detected).
6. Alternative solutions and innovation directions
Complexification: Mix with hollow microspheres (such as floating beads) to further reduce density and thermal conductivity.
Environmentally friendly binders: Develop formaldehyde-free resins or inorganic binders (such as phosphates).
Intelligent filling: Combined with pneumatic conveying technology, automatic and accurate filling of drainage sand is achieved.
