Equilibrium of Copper Matte and Silica-Saturated Iron Silicate Slags at 1300 °C and PSO2 of 0.5 atm

Experimental study on the phase equilibria between copper matte with silica-saturated iron silicate slags was conducted at 1300 °C and PSO2 = 0.5 atm. The high-temperature isothermal equilibration in silica crucibles under controlled flowing CO-CO₂-SO₂-Ar was followed by quenching in an ice–water mixture and direct phase composition analyses by an electron probe X-ray microanalyzer. The equilibrium compositions for matte and slag, as well as the distribution coefficients, were displayed as a function of matte grade. The data set obtained at PSO2 = 0.5 atm and the previous study at PSO2 = 0.1 atm by the authors enabled an investigation on the impacts of PSO2 as well as Al₂O₃ and CaO additions on phase equilibria in the multiphase copper matte smelting system. Thermodynamic calculations using MTDATA software were performed to compare the experimental results with modeling. The present results enrich the fundamental thermodynamic information for the matte/slag/tridymite/gas equilibria in the primary copper smelting process at high PSO2.