@snacks @mangeurdenuage And you also use carbon to get the various carbon oxides out. End result is that a lot of CO2 is produced. The blast furnace fuel is also almost always coke. And you can't make that ecological because there's no way around that, that someone figured out.
In raw ore there is from ~48% to ~72% of iron and pig iron that comes out from the blast furnace (where you process raw iron ore) has 3% to 5% of carbon. To be classified as steel, you need =<2.14% of total carbon content while the usual low-grade-ish steel is below 1.5%. Everything above 2.14% is cast iron.
So you burn carbon, to get rid of oxygen to create carbon oxides to then make CO2 and what's left of the other byproducts. And how do you get rid of the carbon from pig iron? You guessed it. By creating more CO and CO2 using oxygen.
TL;DR You cannot make steel making ecological, which is why EU decided it would be a great idea to kill almost all ironworks in the EU.
blast furnace