A castable classed by lime content from its cement: conventional types carry more than 2.5 percent CaO, low-cement 1.0 to 2.5 percent, ultra-low-cement 0.2 to 1.0 percent and no-cement up to 0.2 percent. Replacing cement with reactive micro-fines and dispersants cuts water to roughly 4 to 6 percent, giving high density, hot strength and slag resistance. The trade-off is low permeability, so these castables need slow, careful dry-out.
Erosion lining is a low-cement castable, so the dry-out holds are longer than the old conventional stuff.
Low-cement castables are unforgiving of water. An extra half percent costs a big share of hot strength and raises the spalling risk.
Also heard as
- LCC
- low cement
Related terms
Castable
Dry refractory mix of aggregate, fines and binder that is mixed with water and poured or pumped like concrete.
Calcium aluminate cement
Hydraulic cement that binds most refractory castables, sold in grades of roughly 40 to 80 percent alumina.
Explosive spalling
Violent failure of a castable during first heat-up when trapped steam pressure blows the lining apart.
Fines
Smallest particle fraction of a refractory mix, which fills the gaps between coarse grains and forms the bond.