Experimental Study of Gas-Slag-Matte-Tridymite Equilibria in the Cu-Fe-O-S-Si-Al System at 1573 K (1300 °C) and P(SO2) = 0.25 atm

Abstract

Fundamental experimental investigations have been conducted to study the effect of Al2O3 on the equilibria between the gas phase (CO-CO2-SO2-Ar) and slag-matte-tridymite phases in the Cu-Fe-O-S-Si-Al system at 1573 K (1300 °C) and P(SO2) = 0.25 atm. The experimental technique used is based on equilibration, rapid quenching and electron probe x-ray microanalysis. New experimental data have been obtained for the four-phase gas-slag-matte-tridymite equilibria system for a range of alumina concentrations up to 20.4 mass% in the slag phase as a function of matte grade, including the concentrations of dissolved sulphur and copper in slag, and Fe/SiO2 ratios in slag. The results obtained for 1573 K (1300 °C) are also used to analyse the effect of temperature on phase equilibria in the range of conditions investigated to that of reported for 1473 K (1200 °C) in the literature. The results obtained show that the concentrations of sulphur, copper and “FeO” in slag decrease with increase of Al2O3 concentration in slag while it has no detectable effect on concentration of sulphur in matte for a given matte grade. The new data provided in the present study are of direct relevance to the pyrometallurgical processing of copper and will be used as an input for optimisation of the FactSage thermodynamic database for the copper-containing, multi-component multi-phase system.