Recovery of metal-doped zinc ferrite from zinc-containing electric arc furnace dust: Process development and examination of elemental migration

We herein report elemental migration during the hydrothermal treatment of zinc-containing electric arc furnace dust (Zn-containing EAFD). Initially, the Zn-containing EAFD was characterized and the crystalline phases of Zn, lead (Pb), and chromium (Cr) were determined to be mainly in the form of (Zn,Mn)Fe2O4, PbO (PbSO4), and Cr2O3 (CrO3/CrO42 −), respectively. Subsequently, the elemental migration and transformation behavior during the Zn hydrothermal extraction process using ferric chloride hexahydrate (FeCl3·6H2O) was studied in detail. Results indicated that under optimum leaching conditions, Zn, Pb, calcium (Ca), and manganese (Mn) were extracted with high leaching efficiencies of 97.4%, 98.3%, 93.4%, and 97.5%, respectively. Furthermore, suitable adjustment of the leaching solution pH resulted in the simultaneous precipitation of Fe, Zn, Mn, and Pb ions in the form of the stable spinel ferrite MFe2O4 (M: Zn, Mn, and Pb), which was recovered following calcination of the precipitate at 1000 °C for 2 h. Meanwhile, the majority of Fe, total Cr, and silicon (Si) existed as Fe2O3, Cr2O3, and SiO2, respectively, in the leaching residue, which can be recycled in the steel mill.