I ran into a fascinating paper published in the 1950's by a Norwegian group who ran a pilot plant to electrowin iron from iron-sulfide waste from a copper mine

I ran into a fascinating paper published in the 1950's by a Norwegian group who ran a pilot plant to electrowin iron from iron-sulfide waste from a copper mine. They claimed something like 4-5 kwh per kg. Unlike electrowining aluminum it's a room temp aqueous process. My thought is, it's probably economic if you have access to intermittent sources of really cheap electricity.