Non-isothermal Reduction Behavior and Mechanism of Hongge Vanadium Titanomagnetite Pellet with Simulated Shaft Furnace Gases

Abstract

As an integral part of developing a novel clean smelting process for the comprehensive utilization of Hongge vanadium titanomagnetite (HVTM), the non-isothermal reduction behavior and mechanism of HVTM pellet (HVTMP) were investigated using simulated shaft furnace gases of dry pulverized coal gasification (DPCG), water-coal slurry gasification (WCSG), Midrex, and HYL-III in the current study. The results showed that the reduction degree significantly increased with the decrease of heating rate. The reduction degree was found to increase in the order of DPCG<WCSG<Midrex<HYL-III. An approximately reversed linear relation could be concluded that the compressive strength of reduced HVTMP decreased as the reduction swelling index increased. The phase transformations of valuable elements under non-isothermal reduction conditions could be described as follows: Fe2O3→Fe3O4→FeO→Fe; Fe9TiO15→Fe2.75Ti0.25O4→Fe2TiO4; (Fe0.6Cr0.4)2O3, Fe0.7Cr1.3O3→FeCr2O4; (Cr0.15V0.85)2O3→Fe2VO4. However, under non-isothermal reduction conditions, SEM results indicated that the reduced metallic iron could not be connected together to form a uniform continuous area even at 1100°C. These results could provide both theoretical and technical basis for the comprehensive utilization of HVTM.