,- AGH University of Krakow, Faculty of Geology, Geophysics and Environmental Protection, Department of Mineralogy, Petrography and Geochemistry, Poland (czeremuga@agh.edu.pl)
Electric Arc Furnace Dust (EAFD) is a byproduct of steel production in electric arc furnaces (EAF). With an annual production of approximately 5-10 million tons, EAFD represents a significant challenge for both the steel industry and the environment. Currently, only ~30% of EAFD is utilized for recovery of metals (mainly Zn), while the remaining 70% is landfilled. The reuse of EAFD is essential for greener and more sustainable steel production. One potential application of EAFD is to be used as an adsorbent for phosphate removal due to its high Fe content.
The focus of this study was the characterization of EAFD magnetic fraction enriched in iron-related phases and depleted in other heavy metals using a range of analytical techniques including X-Ray Diffraction (XRD), Mössbauer spectroscopy, Transmission Electron Microscopy (TEM), Fourier Transformed Infrared Spectroscopy (FTIR) and N2 adsorption/desorption analysis. To validate its usage as an adsorbent, we functionalized EAFD to enhance its reactivity towards phosphates. Functionalization was achieved via a dissolution (1 M HCl) followed by recrystallization through precipitation with either 5M NaOH or Ca(OH)2 until pH reached 7, according to the method described by Fu et al. (2018). Functionalized materials were characterized regarding their physicochemical properties and applied in phosphate adsorption experiments.
Phase composition analysis using XRD and Mössbauer spectroscopy revealed a mixture of iron minerals, including magnetite, hematite, franklinite, and nano-maghemite with additional quartz and calcite. In both NaOH (Fr-Na) and Ca(OH)2 (Fr-Ca) precipitated materials, ferrihydrite was detected among the iron phases. Its formation was linked with the disappearance of franklinite and a slight decrease in magnetite content. Additionally, Fr-Na material was depleted of calcite. TEM images confirmed the presence of ferrihydrite coating on the functionalized materials. FTIR spectra of all the samples exhibited intensive bands at 637, 570 and 440 cm-1 corresponding to Fe-O and Fe-OH stretching vibrations. EAFD and Fr-Ca showed additional strong bands at 1445 and 875 cm-1, attributed to C-O stretching vibrations of carbonate anions. The absence of these bands in Fr-Na is consistent with the disappearance of calcite observed in the XRD pattern. Functionalization resulted in a sevenfold increase in specific surface area (10 → 70 m2/g), creating many new adsorption sites.
Adsorption studies confirmed the enhanced reactivity of functionalized materials towards phosphates. The Fr-Ca material exhibited the best performance under all tested conditions, with its adsorption capacity increasing fivefold from 2 to 10 mg/g compared to raw EAFD. Moreover, functionalization led to a longer time required to reach adsorption equilibrium (from approximately 20 minutes to over 2 hours), which is attributed to phosphate diffusion within the nanometric pore system of the ferrihydrite coating.
The simplicity of the functionalization process, combined with the substantial increase in adsorption capacity, highlights EAFD as a promising adsorbent for phosphate immobilization. Its wide availability and magnetic properties further support its applicability, especially compared to the current practice of landfilling.
This work was supported by the National Science Centre (Poland) (grant number 2021/41/B/NZ9/01552).
How to cite: Czeremuga, J., Skalny, M., and Bajda, T.: Electric Arc Furnace Dusts characterization, functionalization and potential applications, EGU General Assembly 2026, Vienna, Austria, 3–8 May 2026, EGU26-13813, https://doi.org/10.5194/egusphere-egu26-13813, 2026.
