A comprehensive literature on H2-based DRI reduction and degradation has been completed by DC1.
In situ carburization in the furnace’s cooling zone is being explored by DC2 to enhance DRI compatibility with current steelmaking practices—improving energy balance, slag foaming, and melting efficiency. Thermodynamic analyses have suggested optimal conditions for carburization based on gas composition, temperature, and pellet grade. Experimental validation using single pellets is underway.
The melting behavior of H-DRI has been studied by DC3 through lab-scale melting experiments and thermal property measurements. A model that predicts the thermal properties of HDRI from the composition over a wide range of HDRI samples has been developed, with regression and machine learning components trained. The predictions show good agreement with thermodynamic results and differential scanning calorimetry (DSC) data.
The influence of carbon content on P and N removal in the primary steelmaking process step has been assessed by DC4 via thermodynamic simulations, considering temperature, slag composition, and pO2. These insights guide the design of high-temperature experiments and the development of a predictive model.
Lab-scale experiments by DC5 and DC6 have explored the hydrogen plasma smelting reduction of pure Cr2O₃ and Cr-containing mixtures, assessing the influence of process parameters and oxide compositions. DC5 and DC6 have tailored their system compositions to reflect chromite ores and AOD slags, respectively. Initial results confirm the feasibility of Cr2O₃ reduction, though further optimization is needed to achieve higher reduction degrees. Thermodynamic calculations are used to support the experimental design and interpretation.
Industrial dust from stainless steel production has been thoroughly characterized by DC7 to identify phase composition and elemental distribution. Based on these insights, two flowsheets have been developed to recover Fe, Cu, Ni, Cr, and Mo: one using solid-state hydrogen reduction with selective leaching, and the other combining molten-state hydrogen reduction with hydrogen plasma smelting. Both flowsheets are currently under investigation to evaluate their recovery efficiency for the targeted elements.
DC8 is evaluating technologies for continuous hydrogen content and temperature monitoring during EAF and HPSR operations. Several options have been identified, and both lab- and pilot-scale tests are underway to assess their performance.
DC9 applied Optical Emission Spectroscopy (OES) for in-situ plasma monitoring during the hydrogen plasma smelting reduction (HPSR) of ilmenite, pure and fluxed chromium oxides Cr2O₃ reduction. Data analysis revealed the temporal evolution of plasma elements and enabled plasma temperature estimation, offering real-time insights into the reduction process. The analysis of chromium oxide trials is ongoing and will provide valuable information for the process conditions during HPSR.
For sustainability assessment, DC10 selected NG-DRI-EAF as the benchmark and compiled relevant literature data. This serves as a reference for comparing the hydrogen-based processes developed by other DCs. Life cycle costing is being studied, and economic data are being gathered. A consequential life cycle assessment will be conducted to evaluate potential market shifts due to hydrogen-based steelmaking.
