Isothermal Kinetics of Iron in Vacuum Carbothermal Reduction of Ilmenite Concentrate

The kinetics of Fe,in vacuum carbonthermal reduction of(Panzhihua) ilmenite concentrate,was studied.The influence of the reduction temperature/time on the extraction/growth of Fe-clusters via reduction of Fe₃O₄ was investigated with X-ray diffraction,scanning electron microcopy and energy dispersive spectroscopy.The results show that the reduction temperature and time had a major impact.For example,as the reduction temperature and time increased,the reduction rate of Fe₃O₄ increased,accompanied by increasing accumulation and growth of Fe-clusters.Initially reduced at 1100-1250℃ for 30 min,only surface/interfacial reduction happened,with apparent activation energy of 207.92 kJ/mol; but later reduced at 1100-1200℃ for 30 min~90 min,strong bulk reduction dominated,with apparent activation energy of 521.47 kJ/mol,because of thermal diffusion of the contents involved.We suggest that the reduction sequence be FeTiO₃→Fe₂TiO₄→ FeTi₂O₅→Ti₂O₃.