Experimental determination of the liquidus surface (1473 K) in Cu-ZnO-SiO2-O system at various oxygen partial pressures

Thermodynamic information of the Cu-ZnO-SiO2-O system has significant importance for high temperature industries. By employing the equilibration/quenching/EPMA technique, phase relation and liquidus surface of the Cu-ZnO-SiO2-O system at 1473 K has been systematically studied at various oxygen partial pressures (pure argon and 0.21 atm). No ternary compound was found. A pseudo-ternary phase diagram (Cu2O-ZnO-SiO2) was used to represent the liquidus of Cu-ZnO-SiO2-O system in equilibrium with air (PO2 = 0.21 atm). Two univariant equilibria (SiO2 + Zn2SiO4 + Oxide liquid, and Zn2SiO4 + ZnO + Oxide liquid) were found in the experiments. The phase equilibria of the Cu-ZnO-SiO2-O system in equilibrium with copper has also been studied at a fixed mole ration between SiO2 and SiO2 + ZnO. With increasing SiO2 content in initial pellets, the concentration of Cu in liquid oxide phase decreases rapidly. Solubility data of Cu in solid phases of Zn2SiO4, ZnO and SiO2 is also reported. © 2016 by The Minerals, Metals & Materials Society.