Mechanism of improved magnetizing roasting of siderite–hematite iron ore using a synergistic CO–H2 mixture  

作　　者：Qiang Zhao Ji-lai Xue Wen Chen 

机构地区：[1]School of Metallurgical and Ecological Engineering,University of Science and Technology Beijing,Beijing 100083,China [2]Changsha Research Institute of Mining and Metallurgy Co.,Ltd.,Changsha 410083,Hunan,China

出　　处：《Journal of Iron and Steel Research International》2020年第1期12-21,共10页

基　　金：The authors would like to express their thanks to the National Natural Science Foundation of China(No.5157041410)for the financial support of this research.

摘　　要：A fluidized-bed magnetizing roasting-magnetic separation process was selected to treat this type of material.Phase transformations and microstructural changes in the product resulting from magnetizing roasting under different reducing gases(CO,H2,CO+H2)were clarified by vibrating sample magnetometry,X-ray diffraction,scanning electron microscopy,and energy-dispersive X-ray spectroscopy.The results indicated that the conversion ratio and saturation magnetization of samples roasted in a mixed gas of CO and H2 were higher than those of samples produced under CO or H2 alone.This indicated that synergy of the combined CO and H2 gas had a positive effect on the fluidized-bed magnetizing roasting process.The mechanism and kinetics of the improved magnetizing roasting of a siderite-hematite iron ore mixture under this synergistic CO-H2 system were investigated under isothermal conditions.The results indicated that the apparent activation energies of the reactions of the iron oxides decreased from 37.7 and 17.9 to 15.9 kJ/moI when the roasting atmosphere was changed from pure H2 or CO to a gas mixture of CO and H2,respectively.The mixed CO-H2 gas promoted the conversion ratio of hematite and siderite to magnetite,thereby improving the conversion ratio in the fluidized-bed magnetizing roasting process.

关 键 词：SIDERITE HEMATITE Mixed iron ore FLUIDIZED-BED MAGNETIZING ROASTING Kinetics MAGNETITE 

分 类 号：TF56[冶金工程—钢铁冶金]