As various regions around the world implement carbon taxes, we assert that the competitiveness of steel products in the marketplace will shift according to individual manufacturers’ ability to reduce CO₂ emissions as measured by cradle-to-gate Life Cycle Analysis (LCA). This study was performed by using LCA and cost estimate research to compare the CO₂ emissions and the additional cost applied to the production of various decarbonized materials used in sheet for automotive industry applications using the bending stiffness-based weight reduction factor. The pre-pandemic year 2019 was used as a baseline for cost estimates. This paper discusses the future cost scenarios based on carbon taxes and hydrogen cost. The pathways to decarbonize steel and alternative materials such as aluminum and reinforced polymer composites were evaluated. Normalized global warming potential (nGWP) estimates were calculated assuming inputs from the current USA electricity grid, and a hypothetical renewables-based grid. For a current electricity grid mix in the US (with 61% fossil fuels, 19% nuclear, 20% renewables), the lowest nGWP was found to be secondary aluminum and 100% recycled scrap melting of steel. This is followed by the natural gas Direct Reduced Iron–Electric Arc Furnace (DRI-EAF) route with carbon capture and the Blast Furnace-Basic Oxygen Furnace (BF-BOF) route with carbon capture. From the cost point of view, the current cheapest decarbonized production route is natural gas DRI-EAF with Carbon Capture and Storage (CCS). For a renewable electricity grid (50% solar photovoltaic and 50% wind), the lowest GWP was found to be 100% recycled scrap melting of steel and secondary aluminum. This is followed by the hydrogen-based DRI-EAF route and natural gas DRI-EAF with carbon capture. The results indicate that, when applying technologies available today, decarbonized steel will remain competitive, at least in the context of automotive sheet selection compared to aluminum and composites.

Iron ore pellet reduction experiments were performed with pure hydrogen (H₂) and mixtures with carbon monoxide (CO) at different ratios. For direct reduction processes that switch dynamically between reformed natural gas and hydrogen as the reductant, it is important to understand the effects of the transition on the oxide reduction kinetics to optimize the residence time of iron ore pellets in a shaft reactor. Hence, the reduction rates were studied by varying experimental parameters such as the temperature (800, 850 & 900 °C), reactant gas flow rate (100, 150 & 200 cm³/min), pellet size and composition of the reactant gas mixture. The rate of reduction was observed to increase with an increase in temperature and reactant gas flow rate, but it decreased with an increase in pellet size. SEM greyscale analysis was performed to analyze the porosity and phase composition of partially reduced pellets. The porosity of the pellets was observed to increase from 0.3 for unreacted pellet to 0.42 for a completely reduced pellet. Energy-dispersive X-ray spectroscopy (EDAX) analysis was performed to identify the phases observed in the SEM images. The fraction of iron phase was observed to increase from the shell region of the pellet to the core region with an increase in the degree of reduction. A 2D-axisymmetric numerical model was developed on COMSOL Multiphysics, and it was validated using the conversion (X) vs. time curves obtained from each experiment. The model was able to accurately predict the total time needed for the complete conversion of a single iron ore pellet for multiple experiments. Effects of changes in the porosity and tortuosity of the pellet on the model were also studied and the rate of reduction was observed to be sensitive to changes in both porosity and tortuosity. The SEM analysis and the model results show that tortuosity is higher for pellets reduced with H₂ than for pellets reduced with H₂-CO gas mixtures.

Direct reduction of hematite pellets with hydrogen (H₂) was used to produce directly reduced iron (DRI) in a pilot scale reactor at a pellet feed rate of 21.4 kg/h. At a steady state, operational parameters of the pilot plant (gas recycling rate and inlet temperature) along with key reactor output parameters, the pellet metallization, and the internal temperature profile of the reactor were reported for two scenarios with high recycle and low recycle rate of H₂. Scenario 1, with a high recycle rate of 400 L/min H₂ along with external heating of 870 °C, gave an average metallization of 91.8%, while Scenario 2, with low recycle rate of 100 L/min H₂ and external heating of 850 °C gave a metallization of 67.8% due to the higher moles of H₂ available for reduction and the external energy required for the endothermic reduction reaction in Scenario 1 as compared with Scenario 2. Finite element analysis was used to build a model of the shaft reactor, which was validated against the metallization and internal temperature profile data. The average metallization values predicted by the model were very close to the metallization values obtained from the pilot plant samples, with 90.9% average metallization for Scenario 1 and 65.6% average metallization for Scenario 2. The internal temperature profiles in the lower region of the reactor obtained from the model were very close to these pilot plant data, with a maximum difference of 52.7 °C and 67.6 °C for Scenarios 1 and 2, respectively. The pilot plant reactor model was used extensively in the commissioning of the pilot plant and to predict the startup outcomes for a given set of operating parameters.

During the steelmaking process, a great amount of slag is generated as a by-product. Vanadium-bearing steelmaking slags are classified as hazardous and require special handling and storage due to the toxicity of vanadium pentoxides. At the same time, such slags are valuable sources for the recovery of vanadium. The present work reviews the investigations on vanadium recovery from CaO-SiO₂-FeO-V₂O₅ thin film slags under the neutral and oxidizing conditions in the temperature range 1653 K to 1693 K (1380 °C to 1420 °C) using Single Hot Thermocouple Technique (SHTT). The slag samples were analyzed by SEM/EDX. The results indicated that vanadium pentoxide evaporation can be up to 17.73% under an oxidizing atmosphere, while spinel formation under an argon atmosphere was detected in the conditions of thin film slags.

We present our discovery of switchable high explosives (HEs) as a new class of energetic material that cannot detonate unless filled with a fluid. The performance of fluid-filled additive-manufactured HE lattices is herein evaluated by analysis of detonation velocity and Gurney energy. The Gurney energy of the unfilled lattice was 98% lower than that of the equivalent water-filled lattice and changing the fluid mechanical properties allowed tuning of the Gurney energy and detonation velocity by 8.5% and 13.4%, respectively. These results provide, for the first time since the development of HEs, a method to completely remove the hazard of unplanned detonations during storage and transport.

The interaction behavior between iron oxide‐bearing slags and carbon‐bonded MgO refractory (MgO‐C) containing calcium magnesium aluminate (CMA) was investigated at 1400°C, 1500°C, and 1600°C. After the iron oxide was reduced by the carbon from the MgO‐C refractory, a significant amount of MgO and metallic iron was observed to precipitate and disperse in the bulk of slag. During the iron oxide reduction process, the penetrative ability varied throughout the whole process, attributed to the effect of iron oxide on the thermophysical properties of the molten slag. No reduced iron was detected on the side of MgO‐C, which implies the slag penetration was primarily conducted after the iron oxide was reduced in the slag. Spinel was found to be predominantly formed during the interaction between MgO‐C refractory bearing CMA additive and slags, which strongly hindered further refractory corrosion. Additionally, the Ca ₃ Al ₄ MgO ₁₀ phase is predicted via ThermoCalc and XRD.