Great efforts have been carried out in order to replace the calcium aluminate cement (CAC) by other types of binders in refractory castables. Contents higher than 2-3 wt% of this binder can be deleterious to the drying behavior and to the system's refractoriness when microsilica is present. The literature relates as an interesting alternative the replacement of CAC for silica sol that provides, among another advantage, a higher drying speed and sinterability of the castable. In this work, the performance of CAC and silica sol as binder agents in refractory castables was compared. Their rheological and drying behavior, mechanical strength, permeability, explosion, porosity and refractoriness under load were evaluated. The results showed that the use of silica sol may be advantageous in comparison with the refractory cement, however in order to master the application of this binder, further research is needed.
refractory castables; binder; silica sol
