Microsilica can improve particle packing and flow in refractory castables and may participate in bonding reactions depending on the system. Refractory formulations, however, can be sensitive to carbon, alkalis, moisture and particle agglomeration.
Buyers should distinguish refractory requirements from ordinary concrete grades. The acceptable SiO2 range, impurity limits and dispersant compatibility should come from the castable formulation and firing conditions. Stable batch-to-batch behavior may be more important than selecting the highest nominal SiO2 alone.
Specification points
- SiO2, carbon, LOI and alkali limits
- Moisture and retained oversize
- Bulk density and densification state
- Flow response with the selected dispersant
- Packaging and storage against moisture
Use the typical grade comparison as an inquiry starting point and validate the material in the actual castable.