A group in Norway ran a pilot plant producing iron from sulfide ores back in the 1950's. Their paper quotes achieving 85% efficiency and around 4.7kwh/kg. It feels like with eletrowinning you can get the cost down to a few hundred dollars a metric ton. Scrap is around $200/ton. So not grossly uneconomic.
I think the devil is really in pre-processing ore. Whatever process can do that most cheaply is likely to win out. If you can figure out how to use waste like red mud so much that better.
I think the devil is really in pre-processing ore. Whatever process can do that most cheaply is likely to win out. If you can figure out how to use waste like red mud so much that better.