This story is not about carbon-free steel but the production of steel without releasing carbon in the atmosphere. The most carbon dioxide intensive step of ste

This story is not about carbon-free steel but the production of steel without releasing carbon in the atmosphere. The most carbon dioxide intensive step of steel production is in the production of iron sponge, from which both steel and wrought iron is produced. It is where the blast furnace is involved. But hydrogen can be used instead. It is a lot more complicated than one would think because not only is carbon very efficient at picking up oxygen, it is also an exothermic process which makes it very practical. This energy have to be added some other way when using direct reduction. https://en.wikipedia.org/wiki/Direct_reduced_iron https://en.wikipedia.org/wiki/Direct_reduced_iron