Evaluation of Dry Processing Technologies for Treating Low Grade Lateritic Iron Ore Fines
V. Nunna, Sarath Hapugoda, Sreedhar Gaekwad Eswarappa, Shiva Kumar Raparla, Mark I. Pownceby, Graham J. Sparrow
Abstract
Dry processing options, involving the use of a circulating air classifier and thermal roasting (advanced microwave-assisted magnetizing roasting), followed by magnetic separation using an Induced Roll Magnetic Separator (IRMS), were evaluated for upgrading low-grade hematite-goethite iron ore fines. The novel magnetizing roast was conducted under reducing conditions using CO/CO2 gas mixtures which converted the initial goethite-rich ore into a magnetite-rich ore. From a feed sample containing 54.5% Fe, 2.10% SiO2, 7.97% Al2O3, 0.97% TiO2 and 0.13% P with a density of 3.87 g/cm3 and 80 wt% passing 675 µm, a high-grade IRMS magnetic product of 62.0 wt% Fe was obtained with a yield of 71.6 wt% and around 82 wt% recovery of iron units.