Phase equilibrium and minor element distribution between FeOx-SiO2-MgO-based slag and Cu2S-FeS matte at 1573 K under high partial pressures of SO2

As part of a fundamental study of copper smelting processes using oxygen or oxygen-enriched air as a blowing gas, phase equilibrium and distribution of minor elements between copper matte and SiO-saturated FeO-SiO-MgO-based slag containing 5 to 10 wt pct MgO have been investigated at 1573 K under the SO partial pressures of 10.1, 50.7, and 101.3 kPa. The copper and sulfur solubilities in the slag were found to be independent of p when the matte grade was specified, and this behavior was ascribed to the constancy of (p/p) against p at a given matte grade. When the distribution ratio of a minor element (X) between the slag and matte phases was defined as L = (wt pct X in slag)/{wt pct X in matter}, L for arsenic, antimony, and bismuth at a given matte grade increased with increasing p. On the other hand, the distribution ratio of silver at a given matte grade was almost constant against p