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

This review focuses on the mechanism and kinetics of zinc ferrite (ZnFe 2 O 4 ) 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 Fe 2 O 3 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 CO 2 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 ZnFe 2 O 4 formation using Fe 2 O 3 pellet in a gas–solid reaction and using Fe 2 O 3 powder and pellet through a solid–solid reaction. These techniques enable monitoring of the evolving solid phases (Fe 2 O 3 , Fe 3 O 4 , ZnO, Zn, and ZnFe 2 O 4 ) to determine their morphology, particle size, and the extent of ZnFe 2 O 4 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 ZnFe 2 O 4 formation towards sustainable and efficient steel production.