Lucheva B.Iliev P.Kazakova N.Stefanova V.Ivanov H.2026-01-202026-01-202026-01-202026-01-202026-01-010543-584610.64486/m.65.1.6SCOPUS_ID:105020814220https://rlib.uctm.edu/handle/123456789/1912Zinc ferrite residue, a by-product from the hydrometallurgical processing of zinc calcine, contains significant amounts of zinc, iron, lead, copper, and silver, often locked in complex oxide and spinel phases. This study aims to characterize zinc ferrite residue using ICP-OES analysis, XRD, and SEM/EDS, and to evaluate its behavior during sulfuric acid leaching under controlled laboratory conditions. Thermodynamic modeling with HSC Chemistry software was used to construct Eh–pH diagrams and predict phase stability across different temperatures and redox conditions. The experimental results confirmed efficient leaching of zinc, copper and iron, while lead and silver were largely retained in the insoluble residue. These findings highlight the potential for selective zinc extraction and concentration of lead and silver in the solid phase, offering a promising route for sustainable ZFR processing.enReview