The effect of MgO on liquidus temperatures of fayalite slags

The effects of minor MgO additions on the liquidus temperatures of fayalite slag have been investigated experimentally in equilibrium with metallic iron. The synthetic slags were equilibrated, quenched, and subsequently examined by using optical microscopy and electron probe X-ray microanalysis. Liquidus isotherms in the fayalite primary field and boundary lines were determined in the multicomponent systems MgO-“FeO”-CaO-SiO₂ and Al₂O₃-MgO-“FeO”-CaO-SiO₂ in equilibrium with metallic iron. The experimental results show that the magnesia addition expands the fayalite primary phase field in size and increases the liquidus temperatures in the fayalite primary phase field. It has been found that the effects of alumina and magnesia additions on the liquidus temperatures in the fayalite primary phase field are independent of each other.