Experimental Study of the Combined Effects of Al2O3, CaO and MgO on Gas/Slag/Matte/Spinel Equilibria in the Cu–Fe–O–S–Si–Al–Ca–Mg System at 1473 K (1200ºC) and p(SO2) = 0.25 atm

Abstract

The combined effects of Al2O3, CaO and MgO slagging components on phase equilibria and thermodynamics in the basic Cu–Fe–O–S–Si system have been evaluated at 1473 K (1200 ºC) and p(SO2) = 0.25 atm for a range of oxygen partial pressures and matte compositions. The experimental technique included high-temperature equilibration of the samples on a spinel substrate under controlled gas atmosphere (CO/CO2/SO2/Ar), followed by rapid quenching and subsequent measurement of the equilibrium phase compositions using Electron Probe X-ray Microanalysis (EPMA). The experimental data have been compared with the results of thermodynamic calculations undertaken using FactSage software and an internal thermodynamic database. Both the experimental results and the calculations results revealed that the presence of Al2O3, CaO and MgO reduced both the sulphur and copper concentrations in the slag phase for a given set of process conditions. The data have been used for further optimisation of the parameters of the thermodynamic database describing multicomponent metallurgical systems. The resulting thermodynamic database is capable of predicting, with high accuracy, the phase equilibria and the distribution of all elements between the phases in the Cu–Fe–O–S–Si–(Al, Ca, Mg) system.Graphical