LAUSR

Abstract The liquidus of the ternary system ZnO–“FeO1.5”–SiO2 in air has been experimentally investigated in the tridymite and cristobalite, spinel, and zincite primary phase fields in the temperature range 1623–1923 K (1350–1650°C). Slags containing up to 65 mol.% “FeO1.5” have been studied for the first time. The slag–spinel–zincite eutectic in the binary ZnO–“FeO1.5” system in air has been estimated by extrapolation of the low-SiO2 part of the ternary system to x(SiO2) = 0. High-temperature equilibration on primary phase (silica) or inert metal (platinum) substrates, followed by quenching and direct measurement of Zn, Fe and Si concentrations in the equilibrium phases with electron probe X-ray microanalysis has been used to accurately characterize the system in equilibrium with air. The discrepancies of the previous experimental work in this system have been resolved. The obtained data have been used to reoptimise the existing thermodynamic model.