Phase Transformation and Zinc Extraction from Zinc Ferrite by Calcium Roasting and Ammonia Leaching Process

Zinc ferrite (ZnFe2O4), one of the major forms zinc in electric arc furnace dust and leaching residue, is very difficult to chemically dissolve either acidic or alkaline solutions. It therefore necessary study extraction from achieve full recovery resources. In this paper, CaO was used degrade structure then ammonia method applied recover zinc. The thermodynamic analysis indicated that could react with form oxide dicalcium ferrite. CaO–Fe2O3–ZnO phase diagram shows Ca2Fe2O5 can be equilibrium ZnO rather than ZnFe2O4 at a higher area. experimental results transformation ferrite, reacted CaO, completely achieved addition 2.4:1 (mole ratio). peaks X-ray diffraction (XRD) patterns cannot clearly observed after calcium roasting 1220 °C for 2 h. tests showed rate about 90% under optimal conditions.