Effects of Al2O3 and “Cr2O3” on phase equilibria of the system “FeO”−MgO−SiO2 at iron saturation

Abstract

“FeO”, MgO and SiO2 are the major components of the nickel laterite smelting slags. Significant amounts of Al2O3 and “Cr2O3” may be present in the slag that come from laterite, coal ash and refractory. Effects of Al2O3 and “Cr2O3” on liquidus temperatures and solid solutions have been determined in the olivine and spinel primary phase fields in equilibrium with metallic iron. The results are presented in the form of MgO−‘‘FeO’’−SiO2 pseudo-ternary section at fixed 7 wt% Al2O3 and 2 wt% “Cr2O3”. A series of pseudo-binary phase diagrams have been constructed to demonstrate the application of phase diagram on smelting reduction of laterite. The liquidus temperatures and the compositions of solid solutions are compared between experimental data and FactSage thermodynamic modelling. The possible reasons for the different results have been discussed which will help FactSage to optimize the relevant databases.