Selective recovery of zinc from steelmaking dust via sulfation and hydrometallurgical processing: a purification strategy for high-quality zinc sulfate production

Electric arc furnace dust (EAFD) is a hazardous steelmaking by-product rich in valuable metals such as Zn, Fe, Mn, Cu, and Pb. This study proposes a selective zinc recovery route based on thermal sulfation followed by hydrometallurgical leaching, purification, and crystallization. Sulfation at moderate temperatures converted metal oxides into soluble or insoluble sulfates, enabling selective Zn dissolution. Leaching conducted at 60 °C and pH 2–3 achieved Zn extraction of 96.3 ± 2.3%. Sequential removal of Fe and Cu impurities enabled the crystallization of high-purity zinc sulfate (ZnSO₄·xH₂O) with 32.49 wt% Zn and <0.005 wt% impurities. Insoluble lead and iron compounds (PbSO₄ and Fe₂O₃) were recovered as secondary products. The process offers an efficient, low-acid consumption route for EAFD valorization, generating high-quality ZnSO₄ and minimizing environmental impact.