Critical assessment and thermodynamic modeling of the Cu–O and Cu–O–S systems

Critical evaluation, thermodynamic modeling and optimization of the Cu–O and Cu–O–S systems are presented. The liquid phase over the whole composition range from metallic liquid to sulfide melt to oxide melt is described by a single model developed within the framework of the quasichemical formalism. The model reflects the existence of strong short-range ordering in oxide, sulfide and oxysulfide liquid. Two ranges of maximum short-range ordering in the Cu–O system at approximately the Cu2O and CuO compositions are taken into account. Parameters of thermodynamic models are optimized to reproduce all available thermodynamic and phase equilibrium data within experimental error limits. The optimization of the Cu–O and Cu–O–S systems performed in the present study is of particular importance for the description of the solubility of oxygen in matte and liquid copper. The obtained self-consistent set of model parameters can be used as a basis for development of a thermodynamic database for simulation of copper smelting and converting.