The majority is hematite, but iron exposed to air will not form hematite, or even magnetite, but hydrated oxides. That iron will also be spread out over large a

The majority is hematite, but iron exposed to air will not form hematite, or even magnetite, but hydrated oxides. That iron will also be spread out over large areas in low concentrations, not richly concentrated ores of oxides. It would be economically and energetically unfeasible to gather hydrated oxides from rusted metal and then try to make workable iron from it. It’s certainly possible, but it would be a kind of insane process with low yields. The other problem is that you need to use coke as a reducing agent, so we’re back to fossile fuels.