Green steel thanks to ammonia

The steel industry is one of the world’s biggest CO2 emitters. This is mainly due to the smelting process, which takes place in blast furnaces. In this process, coal is used as a reducing agent to extract iron from iron ore. A German research team from the Max-Planck-Institut für Eisenforschung sees ammonia as a promising alternative to fossil reducing agents. When companies want to make steel production greener, they mostly rely on hydrogen instead of coal. However, green hydrogen is scarce, and its transport is costly and energy-intensive. Ammonia, on the other hand, is cheaper and more energy-efficient to transport, and can also be produced in a green manner. It was previously thought that ammonia had to be split into hydrogen and nitrogen before being used in a blast furnace. However, tests now show that when ammonia is fed directly into a blast furnace, around 98 percent of the iron ore is converted into metallic iron. This is possible because the hydrogen in the molecule splits off by itself at the temperatures used for smelting steel. The hydrogen is then freely available to reduce the heated iron ore. This cuts costs by 18 percent. Using ammonia as a hydrogen carrier could make it easier to start producing steel in a more climate-friendly way.

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