Magnetic concentration route for recovering pellet feed fines stored in a mining dam

Abstract The greatest and noblest challenge of mining engineering for the present and the future of iron ore treatment could be considered as the pursuit of optimizing the use of mineral resources. The use of mining tailings, in the mineral sector itself, or in another industrial branch, meets the needs of circular economy as it increases the useful service life of this material. In order to investigate this scenario, a technological characterization of a sample from a tailings dam was carried out along with magnetic concentration tests in a Wet High-Intensity Magnetic Separator (WHIMS) to propose a possible concentration route. In relation to the characterization itself, the results demonstrated a relative density of 3.04 x 103 Kg/m3and an average superficial specific area of 3.75 cm3/g. The granulometric analysis classified the material as fine, with d90 of 0.110 mm and d50 ≅ 0.049 mm. Quartz, hematite, goethite, kaolinite and manganese oxide were identified in the sample. The test which presented the best results (66.83% Fe and 1.74% SiO2) consisted of the Rougher, Cleaner and Recleaner phases, using a 1.5 mm grooved GAP matrix, a 7,000 Gauss magnetic field, 30% solids, and water pressure at 0.5 kgf/cm2 (49.0 x 103 Pa). Finally, the conclusive results indicate that the studied material can be concentrated through magnetic concentration, keeping in mind the specifications concerning the pellet feed fines commercial product. Besides the financial gain, the activity prolongs the durability of the tailings dam and reduces the environmental impacts associated with these structures.