Assessment of fracture behavior of mono-carbonate (C₄AcH₁₁) bonded alumina-spinel castables by wedge splitting test

In this study, nano CaCO3 was added to CAC to prepare mono-carbonate hydrate (C4AcH11). The mechanical properties, pore structure, and fracture behavior at high temperatures of mono-carbonate bonded alumina-spinel castables were assessed. The results showed that the plate-like mono-carbonate promotes early setting behaviors and higher demolding strength. The sintering effects of nano CaCO3 compensate for the strength decay at intermediate temperatures. Moreover, well-distributed CaO sources are essential to forming smaller and elongated CA(6) interlocking laminar structures and contribute to the refinement of pore structures (<10 m) after firing at 1600 degrees C. The fracture behavior of CAC-bonded alumina-spinel castables evaluated at 1400 degrees C shows that the deformation of fine grains/matrices and pores leads to typical nonbrittle fracture.