Investigation of phase equilibria in the Cu-Fe-Si-Mg-O system at low MgO concentrations in equilibrium with copper metal

In pyrometallurgical processes where high temperatures and/or corrosive slag systems are used, excessive deterioration of the refractory lining is often a problem. An increasingly popular alternative is freeze lining. Previously, the interface between the bath and freeze lining was mostly assumed to be the primary phase at the liquidus temperature. Recent research, though, has demonstrated that this is not always the case. The present research focuses on the determination of the effect of several slag and process parameters on this bath-freeze lining interface. Further study will be undertaken with a Cu-Fe-Si-O slag in an MgO crucible. This slag system is important in copper smelting, particularly in the 'direct to blister' process. The MgO crucible was chosen to minimise the uncertainties introduced by the high solubility in slag of Al2O3 crucibles used in previous studies. The liquidus in the multi-component Cu-Fe-Si-Mg-O system has not yet been investigated. The focus of the present stage of the study is to characterise the liquidus in this system at low MgO concentrations in equilibrium with copper at temperatures between 1100 and 1300°C