The mechanism and kinetics of zinc ferrite formation in steelmaking processes—A review

Abstract

This review focuses on the mechanism and kinetics of zinc ferrite (ZnFe₂O₄) formation, which has a critical implication on a recently proposed process for removing and recovering Zn from steelmaking processes, named In-Process Separation technology for Electric Arc Furnace Off-Gas Cleaning Systems. While the solid–solid reaction between ZnO and Fe₂O₃ has been much studied for different applications, in this review, the authors examined the significance of the interaction between Zn vapor and iron oxides through a gas–solid reaction with CO₂ and CO present in the Electric Arc Furnace Off Gas Cleaning System. X-ray diffraction, scanning electron microscopy with energy dispersive x-ray spectroscopy, and particle size distribution analysis have been used in investigations reported in the literature to study the reaction mechanism and kinetics of ZnFe₂O₄ formation using Fe₂O₃ pellet in a gas–solid reaction and using Fe₂O₃ powder and pellet through a solid–solid reaction. These techniques enable monitoring of the evolving solid phases (Fe₂O₃, Fe₃O₄, ZnO, Zn, and ZnFe₂O₄) to determine their morphology, particle size, and the extent of ZnFe₂O₄ formation for kinetics analysis. The industrial operating conditions, thermodynamic feasibility, and kinetics data of the gas–solid pathway are critical for implementing the In-Process Separation and to minimize undesired ZnFe₂O₄ formation towards sustainable and efficient steel production.