Migration Behavior of the MgO and its Influence on the Reduction of Fe₃O₄–MgO Sinter

摘要

To investigate the migration behavior of MgO in oxidization-reduction of the vanadium titano-magnetite (VTM) ore and the influence of its content on the reduction, the solid solution was prepared by annealing MgO and Fe_(3)O_(4) and its oxidized products were isothermally reduced under H_(2)–N_(2) atmosphere. It was found that the sinter with high MgO content showed faster reduction rate due to the formation of pores and the increase of active sites caused by the diffusion of Mg~(2+) into Fe_(3)O_(4). In contrast, the as-oxidized sinter with high MgO content showed the slowest reduction rate due to the formation of high content of (MgO)_(x)·(FeO)_(1?x) (x=0.239–0.77) in the reduction process. MgO migrated from the solid solution and combined with partial Fe_(2)O_(3) to form MgFe_(2)O_(4) in the oxidization stage. In the reduction stage, MgO migrated outward as the oxidized sinter was reduced to Fe_(3)O_(4) and FeO, while migrated inwards in the stage of Fe formation. MgO content in per mole formed FeO decreased as the sinter was reduced to FeO, while increased in solid solution during the Fe generation stage.