Ellingham diagram and carbon reduction of metal oxides (Sadoway electrochemistry program)

Anybody have any questions on some of these externalities? There's lots of externalities. Another environmental externality, it turns out for metallurgy: we know from the stability of the oxides that any oxide in the world can be reduced with carbon. The thermodynamic stability of burning carbon and oxygen together, or carbon in air with oxygen, you'll generate carbon monoxide. As you go to higher and higher temperatures, the stability of the carbon monoxide becomes greater and greater, it gets more negative — that's the free energy of formation, carbon monoxide becomes more and more stable. Whereas the reduction of the oxide to form the metal goes the other way, and so these lines cross at some point if you go to high enough temperatures. The way we make steel in a blast furnace is we get up to 1700 degrees centigrade, and there should be — there's the iron oxide line. Iron oxide, anything above about 400 degrees if everything was pure — but in fact we get better reaction kinetics at 1700, where there's a big free energy difference between carbon monoxide and iron.