关键词: 铁尾矿, 还原焙烧, 弱磁选, 金属化率, 金属铁粉

Abstract: The mineral composition of Qibaoshan iron ore tailing with Fe grade of 38.74% is complicated,and the main iron mineral is goethite.The experiments were conducted for efficient utilization of iron in tailings,by adopting the process of reduction roasting-low intensity magnetic separation.The results showed that the metallization ratio and the grade of iron powder increased with the increasing of reduction temperature,reduction time and the addition of coal powder.The iron concentrate with total iron content of 88.80% at a recovery rate of 92.28% was obtained under conditions of the reduction temperature at 1 250 ℃,reduction time for 60 min,the addition of coal 15%,the grinding fineness of -325 mesh 58.80% and the magnetic field intensity 88 kA/m.The microscopic structure analysis of roasting product showed that with the reaction time extending,the fine iron particle,which is formed in initial period of the reduction reaction,would grow constantly.When reduction time was more than 60 min,the growth of iron particle was not obvious.With the enhancing of reduction temperature,the growth of iron particle was more obvious.The particle size of iron particle reached 100 μm when the reduction temperature was 1 250 ℃.The fine gangue,wrapped in the iron particle,was a main obstacle for the large increasing of iron concentrate grade.

Key words: Iron ore tailing, Reduction roasting,Low-intensity magnetic separation, Metallization ratio, Metallic iron powder