Microstructures of coal containing iron ore concentrates reduced by
microwave heating are classified as the metal iron
Microstructure,
the wustite
microstructure and the slag phase microstructure. The self-reduction process of iron ore concentrates containing coal heated by microwave was that magnetite grains were initially reduced around coal grains to form metal iron granular structure, then jointed together to form metal iron semi-annular structure, annular structure and cincture structure. Being accompanied by development of reduction reaction, the reduced metal irons increased between coal grains and magnetite grains, which obstructed the interface of direct reduction reaction. The core of FeO was sequentially reduced by CO and C diffusion in the metal iron, eventually the vermiform iron-jointed crystal texture was formed. Wustite possessed the absorbency of microwave to a certain degree and might be broken up itself in microwave field, which was helpful to carbothermic reduction. Slag also possessed the absorbency of microwave because its component is very complicated,and propitious to the reduction of its complex iron oxide.