Production of Iron Powder by Solid-Phase Reduction of Fine Magnetite

It is shown that the effectiveness of fluidized-bed reactors is limited by the low reaction rate at low temperatures rather than by the small size of particles. Low-temperature hydrogen reduction is associated with low gas utilization and high energy consumption of the gas treatment system. Temperature cannot be increased since coalescence of iron particles causes destruction of the fluidized bed, but mechanical activation allows accelerating the reaction without increase in the process temperature. Since sulfur and phosphorus bond with iron in the reduction of iron oxides, iron and magnetite can be separated from iron sulfides and phosphides using difference in the Curie points for different iron compounds and magnetic separation at ~500 °C. The possibility to create high-temperature magnetic separators for fine materials is pointed out.