Phase Equilibria in the CaO–SiO<sub>2</sub>–Al<sub>2</sub>O<sub>3</sub>–MgO System with CaO/SiO<sub>2</sub> Ratio of 1.3 Relevant to Iron Blast Furnace Slags

Abstract

Phase equilibria and liquidus temperatures in the CaO–SiO2–Al2O3–MgO system with CaO/SiO2 weight ratio of 1.30 have been experimentally determined by means of high temperature equilibration and quenching technique followed by electron probe X-ray microanalysis. Isotherms between 1723 and 1773 K were determined in the primary phase fields of melilite, dicalcium silicate, spinel, merwinite and periclase that are relevant to ironmaking slags. Effects of Al2O3, MgO and CaO/SiO2 ratio on the liquidus temperatures have been discussed. Compositions of the solid phases corresponding to the liquidus have been accurately measured that will be used for development of the thermodynamic database.