Towards H2 implementation in the iron- and steelmaking industry: State of the art, requirements, and challenges for refractory materials

The iron- and steelmaking sector accounts for 7–9% of global anthropogenic CO2 emissions. Industrywide efforts are currently underway to bring those figures down, and hydrogen has emerged as a key part of the solution. Hydrogen is projected to take over the role of reducing agent for iron oxides in direct reduction processes, and it can also be used as an alternative, more sustainable fuel in industrial furnaces. Importantly, the implementation of H2 in different installations will affect the refractory lining, but wear mechanisms are not fully understood. This review addresses this question, placing emphasis on chemical aspects – especially the effect of exposure to reducing hydrogen atmospheres, or to the water vapor that will be generated when H2 is used. The present state of knowledge, as well as the main challenges and open questions, is outlined with a view to guiding researchers and engineers in both academia and industry.