Elaboration of iron powder from mill scale

This work refers to the study of the conditions of mill scale reduction, a by-product of iron and steel formed during the hot rolling of steels, with a reducing gas (carbon monoxide) in order to produce iron powder having characteristics required by powder metallurgy. The reduction was carried out at various temperatures (750-1050°C) during different times ranging between 40 and 180 min in an atmosphere of pure CO. The produced iron powder was characterized by chemical analysis, x-rays diffraction, optical microscopy and scanning electron microscopy. These methods of investigation confirm the presence of iron, graphite and iron carbide (Fe3C) as the products of reactions. The maximum iron content (98.40% Fe) in the iron powder was obtained by reduction of mill scale at 1050°C for 180 min. A reduction annealing under hydrogen makes it possible to decrease carbon and oxygen content of the reduced iron powder up to acceptable values.