Effect of CaO on the liquid/spinel/matte/gas equilibria in the Si–Fe–O–Cu–S system at controlled P(SO2) 0.3 and 0.6 atm

Herein the phase equilibria in the Si–Fe–Ca–O–S–Cu system in equilibrium with matte at controlled P(SO2) of 0.3 and 0.6 atm and fixed matte grade of 72 wt % Cu were experimentally investigated in the spinel primary phase field. The high-temperature equilibrations were realized in spinel substrate and the sample after quenching were characterized using Electron Probe Micro-analysis (EPMA). The effect of CaO on the liquidus temperature of slags was quantified with varying CaO content from 0 to 6 wt %. It was found that, the presence of CaO increased the liquidus temperature of slags and moreover, the increment effect got enhanced with increasing CaO content in the present range. The influence of P(SO2) was further clarified and it was found that, the equilibrium SiO2 content in the liquid phase, at the same temperature, remarkably increased with increasing P(SO2). The present study will not only deepen the understanding of the equilibration in the present liquid/spinel/matte/gas system, but also provide useful guidance for the industrial operations.