Hybrid Processing of Low-Grade Itabirites: Coupling Dry Magnetic Concentration and Froth Flotation to Produce High-Grade Concentrates and to Eliminate Tailing Dams

This study presents a hybrid mineral processing route designed to produce high-grade concentrates from low-grade deposits of itabirite ore while eliminating disposal of tailings in dams. The proposed route integrates dry grinding, air classification, dry rare-earth magnetic separation and reverse froth flotation. A global mass recovery of 47.7% and a metallurgical recovery of 77.2% were achieved, producing concentrates with 68.6% Fe, 1.17% SiO₂, and 0.31% Al₂O₃—suitable for direct reduction. Final tailings exhibited 17.6% Fe and optimal moisture levels, enabling safe dry stacking. Mixing tests using intensive technologies confirmed excellent homogenization, critical for tailing piles stability. Despite the energy cost of drying, reduced consumption of grinding media and chemicals, and savings on tailings operations demonstrated promising economic feasibility. This work provides a viable, sustainable alternative to wet processing, offering substantial environmental and operational benefits, particularly in scenarios of water management concerns.