Researchers at the Max-Planck-Institut für Eisenforschung have developed a method to make sustainable steel by reducing solid iron oxides with hydrogen released from ammonia. An open-access paper on their work is published in the journal Advanced Science.

In their study, the researchers show that ammonia-based reduction of iron oxide proceeds through an autocatalytic reaction, is kinetically as effective as hydrogen-based direct reduction, yields the same metallization, and can be industrially realized with existing technologies.

A pathway toward sustainable steel production via ammonia-based direct reduction. a) Comparison of the predicted costs required for hydrogen and ammonia produced by renewable electricity in 2030, assuming that it is produced in Australia and then transported to Japan (reproduced based on data from the International Energy Agency). b) Future steel industry with deploying intermittent renewable energy mediated by green ammonia. c) Autocatalytic reduction of iron oxide by hydrogen released from ammonia cracking during the direct reduction process. Ma et al.

The produced iron/iron nitride mixture can be subsequently melted in an electric arc furnace (or co-charged into a converter) to adjust the chemical composition to the target steel grades.

A novel approach is thus presented to deploying intermittent renewable energy, mediated by green ammonia, for a disruptive technology transition toward sustainable iron making.

—Ma et al.

Resources

• Ma, Y., Bae, J. W., Kim, S.-H., Jovičević-Klug, M., Li, K., Vogel, D., Ponge, D., Rohwerder, M., Gault, B., Raabe, D. (2023) “Reducing Iron Oxide with Ammonia: A Sustainable Path to Green Steel.” Adv. Sci. doi: 10.1002/advs.202300111