Direct Reduction of Fe₂O₃ nanoparticles by hydrogen gliding arc discharge

Iron and steel industries are responsible for almost 7% of CO₂ global emissions. To achieve net zero carbon emissions, hydrogen-based routes for iron production are under investigation, such as hydrogen plasma reduction. However, this method requires improvement in process efficiency and electrode degradation. Gliding arc discharge is a promising solution to address these challenges. In this study, hematite (Fe₂O₃) nanoparticles were injected into a reactor using a hydrogen flow. An AC gliding arc was initiated at the smallest electrode gap and traveled with the particles and gas, elongating with diverging electrodes. Particles were analyzed, before and after treatment, using X-ray Diffraction Spectroscopy (XRD), Scanning Electron Microscopy (SEM), and Energy Dispersive X-ray Spectroscopy (EDS). The XRD analyses showed that most of the Fe₂O₃ was reduced to metallic iron (Fe), with smaller peaks indicating a small presence of magnetite (Fe₃O₄) and wustite (FeO). SEM images showed that the particles were porous after the process, indicating reduction. It is also possible to visualize that some particles melted and agglomerated. The EDS analysis confirmed the reduction through the O/Fe spectra ratio compared to the untreated particles, while also indicating that no electrode degradation occurred by the absence of copper in the spectra. Future steps will focus on evaluating the effect of particle addition on the plasma by electrical, ICCD imaging, and spectroscopy characterizations.