Effect of MgO on liquidus temperatures in the system ZnO-“FeO”-Al2O3-CaO-SiO2-MgO in equilibrium with metallic iron

The phase equilibria in the ZnO-"FeO"-AlO -CaO-SiO-MgO system have been determined experimentally in equilibrium with metallic iron. Synthetic slags were equilibrated at a high temperature, quenched, and then the compositions of the phases in equilibrium were measured using electron probe X-ray microanalysis. Pseudoternary sections of the form ZnO-"FeO"-(AlO + CaO + SiO ) for CaO/SiO = 0.71, (CaO + SiO)/Al O = 5 and fixed MgO concentrations of 2, 4, and 6 wt pct have been constructed. Wustite (Fe,Mg,Zn)O and spinel (Fe ,Mg,Zn)O•(Al,Fe)O are the major primary phases in the temperature and composition ranges investigated. The liquidus temperatures are increased by 140 K in the wustite primary phase field and by 70 K in the spinel primary phase field with the addition of 6 wt pct MgO in the slag. The partitioning of MgO and ZnO between the solid and liquid phases has been discussed