Investigation of Pore Structure and High-Temperature Fracture Behavior of Lamellar Hydrates Bonded Alumina-Spinel Castables

Lamellar hydrates of CAC were designed with the introduction of Mg -Al hydrotalcite (M -A -H), and the effects on the early setting behavior, demolding strength, pore structures, mechanical properties, and fracture behavior of alumina-spinel castables were investigated. The results showed that Mg -Al hydrotalcite stimulated rapidly the hydration of CAC and the formation of lamellar C2AH8 and C4AcH11 when curing at 25 and 40 degrees C. In comparison, CAH10 and C2AH8 were detected without M -A -H and were transformed completely into C3AH6 at 40 degrees C. The formation of lamellar C2AH8 and C4AcH11 would contribute to a more complicated pore structure, especially in the range of 1-10 mu m. Meanwhile, the incorporation of MgO from M -A -H also regulates the distribution of CA6 and spinel (pre -formed and in -situ). Consequently, the optimized microstructure and complicated pore structure can induce the deflection and bridging of cracks, thus facilitating the consumption of fracture energy when testing at 1400 degrees C.