Scientists at Stanford have discovered that small nanoparticles in iron ore are the main hurdle in creating more efficient hydrogen-based steel production. Understanding this could lead to the development of green steel reactors, potentially revolutionizing the steel industry and reducing its environmental impact.
Steel production is a major source of greenhouse gas emissions, accounting for 8% of all such emissions globally. Typically, the production process uses coal to convert iron ore into molten iron. However, hydrogen fuel, which produces only water as its byproduct, offers a cleaner alternative. Technical challenges have slowed the adoption of hydrogen in steel manufacturing, but new findings could change that.
Leora Dresselhaus-Marais, an assistant professor of materials science and engineering at Stanford, and her team have identified that the smallest nanoscale particles in iron ore are the root cause of the technical challenges facing hydrogen-based steel production. Their research, published in the Proceedings of the National Academy of Sciences (PNAS), points to the role these nanoparticles play in reducing the efficiency of reactors over time.
In the high heat of hydrogen reaction inside the reactors, nanoparticles in iron ore self-assemble to form whisker-like structures. These structures clog the reactors and diminish their efficiency, which has kept hydrogen-based steel production on the sidelines. Understanding this "whiskering" problem has been a crucial part of the research.
Dresselhaus-Marais and her team noted the role of "fines," tiny particles prevalent in iron ore dust produced during ore processing. These fines are significantly smaller than the millimeter-scale pellets commonly used in ironmaking. The research suggests that these fines are essential to understanding how and why reactors become clogged over time.
The ironmaking process requires multiple steps to refine the iron ore into pure iron suitable for steelmaking. The transition from an intermediate material known as wüstite to pure iron is particularly challenging. The team's findings could lead to a more streamlined and efficient process by focusing on how nanoparticles behave during this transition.
The newfound knowledge has significant implications for the future of green steel production. The reaction pathways for nanoparticles are fundamentally different from those for larger particles, which could lead to alternative approaches in steel manufacturing. As Dresselhaus-Marais suggests, the industry could potentially skip certain phases in the process to make it more efficient and sustainable.
The research at Stanford has opened a door to make hydrogen-based steel production more efficient and feasible. By understanding the role of nanoparticles in the process, we are a step closer to realizing the dream of greener and more sustainable steel manufacturing.