The growing technological demand combined with the increase application of refractory castable, has promoted further studies on the rheology of this material. As the rheological behavior is intrinsically linked to the particle size distribution, several analysis have been made aiming to determine the relationship between rheology and the particle size distribution. Usually, such analyses are based on distributions where the particle size range is constant and the maximum particle diameter is close to 4750 µm. However, in order to obtain specific properties, different applications may require changes of this diameter. Due to such needs, the objective of this paper was to evaluate the impact of the range and particle size distribution on the rheology of zero-cement (100% Al2O3) refractory castable. Castables compositions were formulated according to the Andreasen model, varying the distribution coefficients (q = 0,21; 0,26 and 0,31) and the particles maximum diameters (D L = 2800, 4750 and 8000 µm). The evaluations were performed using a rheometer developed for refractory castable. The results revealed a high sensibility of these materials to variations on the particle size distributions studied, mainly when tested under conditions that simulated its pumpability.
refractory castables; particle size distribution; rheology; pumping; maximum diameter
