Spectroscopic Study of Hydrogen Plasma Smelting Reduction in Rotating Gliding Arc Discharge*

To achieve net-zero carbon emissions, it is crucial to prioritize the decarbonization of the iron and steel industry, which currently contributes to nearly 7% of global carbon dioxide emissions. Hydrogen Plasma Smelting Reduction shows promise as a carbon-free method for iron production, offering improved reactivity. To make informed decisions about scaling up this technology, it is essential to understand the interactions between plasma and particles. This study investigates the impact of in-flight reduction and melting of hematite (Fe₂O₃) on hydrogen rotating gliding arc discharge characteristics. Employing Optical Emission Spectroscopy (OES) and Boltzmann calculations of the hydrogen emission lines, we estimate the rotational, vibration, and electronic temperatures of the plasma with and without particle addition at different electric powers. Additionally, the excitation temperature of iron atomic lines is determined based on its emission. The average particle temperature is calculated by fitting a blackbody radiation model to the measured spectra. Hydroxyl radical is measured and analyzed using SPECAIR for a comprehensive assessment. We will also present and discuss the effect of particles addition on the electron density derived from H_β lines. Finally, the treated particles are analyzed using X-ray Diffraction Analysis (XRD), followed by post-processing using Rietveld Refinement.