Integrated experimental and thermodynamic modeling study of phase equilibria in the “CuO0.5”–CaO–AlO1.5 system

The phase equilibria in the “CuO_0.5”–CaO–AlO_1.5 system in equilibrium with Cu metal were investigated as part of the integrated experimental and thermodynamic modeling study of phase equilibria in the Cu–Pb–Zn–Fe–Ca–Si–Al–Mg–O–S–(As, Sn, Sb, Bi, Ag, Au, Ni, Cr, Co, and Na) gas/oxide liquid/matte/speiss/metal/solids system in support of the development and optimization of pyrometallurgical processes. The equilibration and quenching technique, followed by the electron probe X-ray microanalysis (EPMA) was used in the present study. The liquidus of the “CuO_0.5”–CaO–AlO_1.5 system in equilibrium with Cu, including primary phase fields of Ca₃Al₂O₆, Ca₁₂Al₁₄O₃₃, CaAl₂O₄, CaAl₄O₇, CaAl₁₂O₁₉, corundum (Al₂O₃), delafossite (CuAlO₂), and lime (CaO), as well as the immiscibility gap in the liquidi of these phases were characterized. The thermodynamic model parameters for the CaO–AlO_1.5 binary system and the “CuO_0.5”–CaO–AlO_1.5 ternary systems in equilibrium with Cu metal were reoptimized based on the experimental data obtained. New experimental results, combined with phase equilibria and thermodynamic literature data, were used to derive a self-consistent set of parameters of the thermodynamic model of all phases in the “CuO_0.5”–CaO–AlO_1.5 system in equilibrium with Cu metal, in agreement with the major 20-component system. The predicted phase diagram of the CaO–AlO_1.5 and “CuO_0.5”–CaO–AlO_1.5 systems were presented for the first time.