Solid phase sulphatizing of zinc ferrite spinel with iron sulphates

The study explores the solid phase sulphatization of zinc ferrite spinel using iron sulphates as an environmentally friendly method for zinc recovery. The objective is to decompose the scarcely reactive zinc ferrite into soluble ZnSO4 and insoluble Fe2O3 polymorphs through the application of iron(II or III) sulphates at a temperature of 650°C for 4 hours. The methodology employed includes various characterization techniques such as XRD, TG/DTA-MS, Mössbauer, Raman, and IR-spectroscopy to monitor the sulphatization process. Results indicate that the gaseous SO3 generated during the thermal oxidation of iron(II) sulphate serves as the active agent in the reaction. The process results in the formation of Fe2O3 polymorphs, which can subsequently be processed into iron(III) sulphate via sulphuric acid, allowing for regeneration of the reagent used. Therefore, the study suggests that these selective sulphatization reactions represent a viable approach for the decomposition of zinc ferrite into ZnSO4 and Fe2O3 with minimal reagent consumption, highlighting its potential as an environmentally sustainable method for zinc recovery.