Ca7ZrAl6O18 acting as a hydraulic and ceramic bonding in the MgO–CaZrO3 dense refractory composite

In this paper, the results of an experimental study concerning the dehydration behavior of the hydrated MgO–CaZrO3–Ca7ZrAl6O18 green compacted sample are presented. Hydrated MgO–CaZrO3–Ca7ZrAl6O18 mixture products were studied by XRD, DTA-TG and FT-IR after 24 h of curing and hydration at room temperature. According to the XRD examination it has been found that brucite, Mg(OH)2, was only identified as a crystalline hydrated phase. The presence of the metastable hexagonal hydrates (CAH10, C2AH8) in the hydrated sample were identified by FT-IR and DTA-TG studies. The MgO–CaZrO3–aluminates dense refractory composite material was investigated by XRD, SEM/EDS and mercury porosimetry. The XRD and SEM/EDS results showed that the compound with chemical composition of Ca12Al14O33 occurred in the MgO–CaZrO3–Ca7ZrAl6O18 matrix. By applying the mercury intrusion porosimetry technique, the heterogeneous pore size distribution of the composite was determined.