Preparation of Hematite by Drip Thermal Oxidation Using a Fluidized Bed for Conversion to Electromagnetic-Wave-Absorptive Magnetite

Electromagnetic wave absorbing properties in GHz region were investigated for magnetite prepared by hydrogen reduction of hematite, which was synthesized via drip thermal oxidation using a fluidized bed. The magnetite powder product showed better absorption ability when the precursor hematite was prepared at a higher bed temperature, which also induced an improvement in morphology. This morphological enhancement is believed to result from the rapid thermal oxidation treatment of the hematite powder in the bed along with an accelerated evaporation of aqueous FeCl2 solution.