This study combined X-ray fluorescence spectroscopy (XRF), inductively coupled plasma optical emission spectrometry (ICP-OES), X-ray diffraction (XRD), mineral liberation analysis (MLA), scanning electron microscopy-energy-dispersive X-ray spectroscopy (SEM-EDS), and density functional theory (DFT) to characterize zinc-bearing constituents in electric arc furnace (EAF) dust from a steel plant in Hebei, China, across multiple length scales. ICP-OES gave Zn and Fe contents of 33.48 and 19.05 wt.%, respectively, in general agreement with the XRF results. Screening semi-quantification by XRD-RIR indicated that the relative contents of the Zn-bearing Fe-based spinel-type oxide group, ZnO, and KCl among the identified crystalline phases were 81.3%, 15.2%, and 3.5%, respectively. Because the diffraction peaks of several spinel endmembers overlap, the first value does not represent the abundance of pure ZnFe₂O₄. MLA assigned a calculated mass fraction of 67.96 wt.% to the spinel-type Zn-Fe oxide class and 76.57% of Zn to this operational class. SEM-EDS of selected regions showed that the spinel-type Zn-Fe oxide class was dominated by Zn and Fe, whereas the Mg-bearing Zn-rich composite oxide class contained Zn, Mg, Ca, and Fe; both classes showed non-stoichiometric, multicomponent characteristics. Fine-particle attachment and agglomeration observed by SEM indicate that some coarse MLA objects may correspond to fine-grained intergrowths or agglomerates. DFT comparison of ideal ZnFe₂O₄ and ZnO structural endmembers showed that the Fe-O network contributes substantially to framework stability in the spinel model and that the two structures differ in their local atomic-force responses to vacancy perturbations. The resulting framework integrates bulk phase confirmation, particle-scale occurrence, and atomic-scale structural comparison, providing a structural basis for future activation and selective recovery of zinc-bearing phases.
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