Avaliação do uso de flotação em coluna para processamento de lamas de minério de ferro

Abstract

Iron mining, an essential activity for the global economy, generates large volumes of fine and ultrafine tailings, whose disposal poses both environmental and operational challenges. In this context, this study aimed to evaluate the feasibility of column flotation for the reuse of iron ore tailings, by varying operational parameters focusing on maximizing iron recovery and grade, as well as reducing the amount of silica in the concentrate. The research was conducted with samples from the Quadrilátero Ferrífero, which underwent physical and chemical characterization. Initially, tests were carried out in a mechanical cell to define some experimental parameters. Subsequently, a pilot-scale flotation column was used to analyze the effects of reagent dosage, solids percentage, and superficial velocities of air and water. The tests were performed at CETEM (Center for Mineral Technology), located in Rio de Janeiro/RJ. The bench-scale tests defined the optimal operational parameters, highlighting the dosage of 300 g/t of the collector Flotinor 16939 at pH 10.5, which resulted in a metallurgical recovery of up to 76.4% and an iron grade of 56.2% in the concentrate. These parameters were later applied in column flotation, where the best results were obtained with the highest air superficial velocity (Jg) evaluated, 1.5 cm/s, and the lowest water velocity (Jw), 0.1 cm/s, reaching an iron grade of 54.8% and metallurgical recovery of 96%. Variation in the percentage of solids, in turn, did not show a significant impact on the results. The results demonstrated the efficiency of column flotation for recovering iron from tailings, with high performance even under variable conditions. The results confirm the potential of the technology as a technically and environmentally viable alternative for the utilization of ultrafine iron ore tailings in mineral processing operations.