Effect of the water-soluble calcium chloride on volumetric stability and thermal shock resistance of alumina-based castables

Abstract As water-soluble calcium chloride (CaCl2) could be uniformly distributed in the castable compared with commercial CAC particles (25–55 μm), the effect of CaCl2 addition (0–2 wt%) on the distribution of CA6 and the properties of the alumina-based castables (especially thermal shock resistance and permanent linear change) after calcination at 1450 °C were investigated. It was found that the alumina-based castable with 1.5 wt% CaCl2 had the minimum PLC value of 0.18% and the maximum value of residual CMOR ratio (25%). The castable matrix fired at 800–1450 °C was examined by XRD to identify the phase evolution of castable with the addition of CaCl2. The 1450 °C fired castable matrix without and with 1.5 wt% CaCl2 additive was analyzed by SEM to determine the morphology evolution of CA6. The improved volume stability and enhanced thermal-shock resistance of the alumina-based castables containing CaCl2 additive has been illustrated through the formation of CA6 with smaller size and more uniform distribution.