Experimental and Theoretical Contribution to the Phase Equilibria in the Ternary CaO-Al2O3-B2O3 System

The phase equilibria in the lime rich part of the CaO-Al2O3-B2O3 ternary system were investigated by thermodynamic modeling and key experiments. Three ternary compounds, CaAl2B2O7 (CAB), Ca2Al2B2O8 (C(2)AB) and Ca2Al2B6O14 (C(2)AB(3)), are reported in the literature and their thermodynamic properties were calculated using Density Functional Theory and lattice dynamics theory. Partial isothermal sections of the lime rich part of the CaO-Al2O3-B2O3 ternary system were investigated at 950 and 1020 degrees C using solid state reactions and x-ray diffraction on 14 selected samples. The observed results confirm the available experimental data from the literature. Based on thermal analysis using differential scanning calorimetry, the Ca3Al2O6-CaB2O4 and CaAl2O4-CaB2O4 T-x sections as well as a tentative partial liquid surface of the lime rich part were constructed.