Experimental Determination of the Liquidus in the High-Basicity Region in the Al2O3(25 mass pct)-CaO-MgO-SiO2 and Al2O3(35 mass pct)-CaO-MgO-SiO2 Systems

Liquidus in the Al2O3(25 mass pct)-CaO-MgO-SiO2(<20 mass pct) and Al2O3(35 mass pct)-CaO-MgO-SiO2(<20 mass pct) systems were determined experimentally in the high-CaO-containing region at 1873 K (1600 degrees C). For the Al2O3(35 mass pct)-CaO-MgO-SiO2(<20 mass pct) system, liquidus data were also determined for 1773 K (1500 degrees C). The equilibrating and quenching technique with subsequent electron probe microanalyzer (EPMA) microanalysis were employed. Based on the data, liquidus lines were constructed for the 25 and 35 mass pct alumina planes at silica contents generally below 20 mass pct. The current results showed a slightly lower solubility of CaO and a higher solubility of MgO at 1873 K (1600 degrees C) for the 25 mass pct Al2O3 section compared with the existing phase diagram. At 1773 K (1500 degrees C), the result showed a slightly lower solubility of both CaO and MgO in the 35 mass pct Al2O3 section compared with the existing phase diagram. In addition, the activities of MgO, CaO, and Al2O3 were estimated at 1773 K and 1873 K (1500 degrees C and 1600 degrees C) using the phase diagram information. DOI: 10.1007/s11663-011-9530-5 (C) The Minerals, Metals & Materials Society and ASM International 2011