Characterization of Sangan low-grade iron ore and its processing by dry low-intensity magnetic separation

Abstract

Nearly two million tons of low-grade iron ore has been extracted, deposited, and left intact in the Sangan mining site. On the other hand, the mining site is located in a semi-arid region, and wet processing has been restricted due to water shortage. In this research, the enrichment of Sangan low-grade iron ore from Mine B was performed using the dry low-intensity magnetic separation (DLIMS) technique to solve both problems of unprocessed low-grade iron ores and water scarcity. The X-Ray diffraction analysis showed that the ore minerals are magnetite and to less extent, hematite, and the main gangue minerals are quartz and calcite. The Fe, FeO, and sulfur contents of some collected samples were determined to be 36.86%, 8.1%, and 0.12%, respectively. The scanning electron microscopy equipped with energy dispersive X-ray analysis showed that the full liberation of the iron minerals is achieved in the particle size less than 30 μm. The Davis Tube tests in three different magnetic field intensities of 1420, 2340 and 3800 Gauss confirmed the good amenability of the low-grade iron ore to low-intensity magnetic separation. A concentrate of 47.15% Fe, with a yield of 68.56% was produced using DLIMS technique. The process development for the enrichment of the Sangan low-grade iron ore was conducted through the DLIMS approach, for which a flowsheet was proposed. The results showed that after two steps of DLIMS, it would be possible to produce a concentrate with iron grade more than 50%, which can be traded as high-grade iron ore or fed to the on-site processing plants.