Abstract:Effects of CaO, reduction time and reduction temperature on the Zn migration mechanism and kinetic model were studied. Results show that CaO improves the volatilization rate of Zn by promoting the precipitation and enrichment of the intermediate product ZnO on the surface of the mixture of Fe and CaO. The reduction steps of ZnFe₂O₄ with CaO are ZnFe₂O₄→Ca₂Fe₂O₅→FeO→Fe. The volatilization model of the reduction of ZnFe₂O₄ was changed from a first-order chemical reaction model (without CaO) to a three-dimensional diffusion model (with CaO), and the apparent activation energy was reduced from 313.9 to 91.77 kJ/mol, providing favorable conditions for the efficient reduction and volatilization of zinc.

Key words: zinc-containing dust; zinc ferrite; reaction kinetics; migration mechanism; direct reduction; Zn recovery