Production of sponge iron powder by reduction of rolling mill scale

Rolling mill scale is a solid byproduct of the steelmaking industry that contains metallic iron and three types of iron oxides: wüstite, haematite and magnetite. It also contains traces of non-ferrous metals, alkaline compounds and oils from the rolling process. A study was made of the reduction of mill scale to sponge iron using coke at different temperatures and times. The reduced samples were studied by X-ray diffraction and scanning electron microscopy. Oxygen analysis was carried out by combustion in a LECO oven. Sponge iron was successfully produced for reuse in electric furnaces as part of the metallic charge or as a raw material in the production of iron-based powder metallurgy parts.