Effects of Heating Rate on the Thermal and Mechanical Properties of the Bauxite-Based Low-Cement Refractory Castables

Abstract

This study was conducted to investigate the effects of sintering conditions on the phase composition, microstructure, and physico-mechanical properties of the bauxite-based low-cement refractory castables. For this purpose, the specimens were sintered at various temperatures (1350-1450 °C) and heating rates (3-10 °C/min). Results showed that the sintering conditions have a remarkable effect on the physico-mechanical properties of the refractory castables. The mechanical strength was considerably increased by increasing the heating rate from 3 to 10 °C/min which was attributed to lower amounts of porosity and higher amount of the platy crystals of CA6 phase. The lower porosity of the specimens sintered at lower temperature with 10 °C/min of heating rate also resulted in the higher mechanical strength. The results obtained in this study showed a negative linear relationship between the cold crushing strength and porosity of the specimens with a high degree of measurement conformity.