Characterization and Processing of Iron Ore Slimes for Recovery of Iron Values

Intensive characterization studies of iron ore slime carried out by X-ray diffraction spectroscope (XRD), scanning electron microscope (SEM-EDS), field emission scanning electron microscope (FESEM), and quantitative mineralogical evaluation by scanning electron microscope (QEMSCAN) are discussed. In slimes, mineral phases like hematite, goethite, gibbsite, kaolinite, and quartz are present in a complex and intricate way. SEM-EDS and QEMSCAN studies indicate that significant amounts of aluminum are associated with both ochreous and vitreous goethite. Hematite and goethite phases are contaminated with some amount of alumina and silica. The liberation of hematite in the coarser fraction (+500 µm) is only 20.6% compared to 40% in the finer fraction (?500 µm) size. A flow sheet, comprising of hydrocyclone and magnetic separation techniques, has been developed to produce an iron concentrate containing ～63% Fe with 70.7% weight recovery from a feed sample containing 56.8% Fe, 5.1% SiO₂, and 6.4% Al₂O₃.