Untersuchung des Einsatzes oxidischer Legierungselemente im Wasserstoffplasma-Schmelzreduktionsprozess (HPSR)

The steel industry is responsible for approximately 7–9% of global CO₂ emissions, primarily due to its reliance on carbon-based reduction processes. Achieving climate neutrality requires alternative production routes that avoid direct CO₂ emissions. The Hydrogen Plasma Smelting Reduction (HPSR) process represents a promising, carbon-free technology, utilizing hydrogen plasma as both a heat source and a reducing agent for the direct reduction of iron ore to steel as a single-step process.
This master’s thesis investigates the potential of the HPSR process not only for iron oxide, but also for the simultaneous reduction of oxidic alloying elements such as NiO, MoO₃, and WO₃, enabling the direct production of alloyed steel. Thermodynamic calculations were performed using FactSage© were performed to assess the reducibility of different oxides with hydrogen, followed by experimental trials in the laboratory-scale HPSR reactor at the Chair of Ferrous Metallurgy, Montanuniversität Leoben. The reduction behaviour, temperature evolution and process parameters were analysed, complemented by gas composition measurements and investigations of the chemical composition of the products using a scanning electron microscope.
The results confirm the high reduction potential of hydrogen plasma and demonstrate the simultaneous and effective reduction of several alloying oxides under suitable operating conditions. These findings highlight the feasibility of producing pre-alloyed steels directly from oxide mixtures in a single-step, CO₂-neutral HPSR process — offering a significant contribution toward sustainable and climate-friendly steelmaking.