Experimental investigation of gas-matte-spinel and gas-slag-matte-spinel equilibria in the Cu-Fe-O-S-Si system at 1200°C: effect of SO2 partial pressure

ABSTRACT Experimental measurements have been undertaken of the gas-matte-spinel and gas-slag-matte-spinel equilibria in the Cu–Fe–O–S–Si system at 1200°C and of 0.1 and 0.6 bar. The technique involved high temperature equilibration of sulfide-oxide mixtures on iron spinel support substrates, preservation of the equilibrium phases by rapid quenching, and direct compositional analysis of the phases using microanalysis techniques. The results, combined with previous data obtained at  = 0.25 bar show the effects of sulphur dioxide partial pressure on the gas-matte-spinel and gas-slag-matte-spinel equilibria at fixed temperature and as a function of matte grade. For a given matte grade the concentration of dissolved copper in slag is found to decrease with increasing SO2 partial pressure.