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 o f minor elements between copper matte and SiO2-saturated FeOx-SiO2-MgO-base d slag containing 5 to 10 wt pet MgO have been investigated at 1573 K under the SO2 partial pressures of 10.1, 50.7, and 101.3 kPa. The copper and sul fur solubilities in the slag were found to be independent of p(SO2) when th e matte grade was specified, and this behavior was ascribed to the constanc y of (p(O2)/p(S2)) against P-SO2 at a given matte grade. When the distribut ion ratio of a minor element (X) between the slag and matte phases was defi ned as L-x(s/m) = (wt pet X in slag)/{wt pet X in matter}, L-x(s/m) for ars enic, antimony, and bismuth at a given matte grade increased with increasin g p(SO2). On the other hand, the distribution ratio of silver at a given ma tte grade was almost constant against p(SO2).