Thermodynamic optimization of the Cu–As–S system

A literature review, critical assessment and thermodynamic modeling of matte, metal (speiss) and solid phases in the Cu–As–S system are presented. The literature data include enthalpies and entropies of formation, activity measurements using vapor pressure, phase equilibrium and element distribution data. The model for the liquid phase was developed within the framework of the Modified Quasichemical Model (MQM) in pair approximation. Liquid metal and matte phases were described using the single solution with a miscibility gap. Previously published model parameters for the liquid phase in the Cu–S system were modified to achieve agreement with the data for the Cu–As–S system. The resulting set of model parameters was incorporated into a large multicomponent thermodynamic database intended for predictions of phase equilibria, heat balance and distribution of arsenic in the course of pyrometallurgical processing of copper- and lead-containing materials.