Thermodynamic assessment of the CaO–Cu2O–FeO–Fe2O3 system

Abstract

Thermodynamic assessment of the CaO–Cu2O–FeO–Fe2O3 system is presented. Effects of temperature and P(O2) on the phase equilibria involving slag, solubility of copper and the Fe3+/Fe2+ ratio in slag have been modeled using available experimental data. Subsolidus phase equilibria and concentration of iron in liquid copper were evaluated as well. Different ways of representing phase equilibria in a quaternary system are illustrated. The slag model, [Ca2+, Cu+, Fe2+, Fe3+][O2−], was developed using the Modified Quasichemical Model (MQM). Liquid metal phase is modeled using the MQM, but as a separate solution, (CuI, FeII, OII). Spinel phase is modeled using the Compound Energy Formalism (CEF) and takes into account the solubility of copper and calcium. A thermodynamic database produced in the present study can be used for predictions in pyrometallurgical processing of copper involving calcium ferrite slags. The database is internally consistent with the binary and ternary sub-systems published earlier, as well as with higher-order systems. It works in the environment of FactSage, ChemApp, ChemSheet and SimuSage software packages.