ORIGINAL ARTICLE
Low-Temperature Electrowinning of Iron from Hematite Suspension in Sodium Hydroxide Solution: Toward Sustainable Ironmaking
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1
Materials Science and Engineering, King Fahd University of Petroleum and Minerals, Saudi Arabia
2
IRC for Advanced Materials, King Fahd University of Petroleum and Minerals, Saudi Arabia
Submission date: 2025-11-29
Final revision date: 2026-01-07
Acceptance date: 2026-03-06
Publication date: 2026-03-31
Journal of Undergraduate Research International 2026;2(1):119-126
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ABSTRACT
This study examines the low-temperature electrochemical reduction of iron from a hematite suspension in concentrated sodium hydroxide as a mechanistic step toward low-carbon ironmaking. Experiments were conducted at 95–110 °C using a three-electrode configuration with a graphite working electrode, a platinum counter electrode, and an Ag/AgCl reference. Cyclic voltammetry indicated the onset of iron oxide reduction near −1.10 V vs. Ag/AgCl, with voltametric features consistent with limited electrochemical reversibility under the tested conditions. Potentiostatic electrolysis performed at −1.33 V produced a porous iron-rich deposit containing residual oxide. X-ray diffraction combined with Rietveld refinement identified a two-phase product comprising approximately 63 wt.% Fe₃O₄ and 37 wt.% α-Fe, with crystallite sizes in the range of 40–45 nm. SEM and EDS analyses revealed a nanostructured, porous morphology dominated by metallic iron with localized oxygen-rich regions associated with retained magnetite. Charge analysis showed that the 47.4 C supplied corresponded to only a small fraction of the theoretical charge required for complete reduction of the 5 g hematite feed, explaining the observed partial deoxygenation. The results demonstrate the initiation and governing features of alkaline electrowinning at reduced temperature, while highlighting the constraints imposed by limited charge input, hydrogen evolution, and mass transport under static slurry conditions.