Abstract: A pilot-scale fluidized magnetization roasting reactor was introduced and used to study the effects of roasting temperature， flow rates of reducing gas CO and fluidizing gas N₂ on magnetization roasting performance of the pre-concentrate from Donganshan iron ore. The results show that a high-grade ground magnetic concentrate of 66.1% iron with an iron recovery of 91.2% can be obtained from the pre-concentrate after roasting at 540℃ with a gas mixture of CO 4m³/h and N₂ 2m³/h. The iron chemical phase， optical microstructure， and Mossbauer spectrum analyses indicate that weakly magnetic siderite and hematite can be converted to ferromagnetic magnetite successfully. The coarse hematite particles(＞100μm) partly transformed into magnetite， while such particles with a Fe₂O₃@Fe₃O₄ core-shell structure can also be effectively recovered by subsequent magnetic separation after liberating from gangue minerals due to their strong magnetism.

Key words: carbonate-bearing iron ore, fluidized magnetization roasting, phase conversion, magnetic separation