Gibbs Energy Modeling of the Cu-S Liquid Phase: Completion of the Thermodynamic Calculation of the Cu-S System

Abstract

AbstractA thorough review and critical evaluation of all experimental sulfur potential and phase diagram data available from the literature has been made for optimizing the Gibbs energy of the copper-sulfur liquid phase at 1 bar total pressure. The extended modified quasichemical model serves as a basis for the mathematical expression of the Gibbs energy of binary Cu-S solutions over the complete composition range. A structurally versatile molten phase ranging from highly metallic via sulfur-rich to pure sulfuric is described simultaneously by a single Gibbs energy function. In combination with the recently published Gibbs energies of all Cu-S solid phases, the complete T–x phase diagram as well as for the first time the $$ {\text{log(}}p_{{{\text{S}}2}} /{\text{bar)}} - 1 /T $$log(pS2/bar)-1/T diagram is calculated. A limited set of obtained model parameters reproduces a large body of data within experimental uncertainties.