Preparation and processing optimization of magnesium‐calcium refractory aggregates

Abstract Magnesium‐calcium refractory aggregates with a low water absorption rate were prepared by using high‐temperature sintering of light‐burned dolomite, magnesite, with polyvinyl alcohol as the binder. The effects of CaO content, slaking process, and sintering parameters on the microstructure and properties were thoroughly investigated. When the CaO content was 40 wt%, light‐burned dolomite was slaked with the addition of 30 wt% water for 2 h, followed by sintering at 1600°C for 3 h, the overall properties of the magnesium‐calcium refractory aggregates were optimal, achieving a linear shrinkage rate of 20.93%, a bulk density of 3.32 g/cm 3 , an apparent porosity of 5.02%, compressive strength of 213.73 MPa, flexural strength of 86.84 MPa, and a residual strength retention ratio of 92.12% after three thermal shocks. Additionally, the absorption rate was low at 0.52% after treatment for 72 h at constant temperature and humidity (RH = 99%, T = 21°C).