Concentration of iron ore with high dolomite content via reverse flotation

Quadrilátero Ferrífero is an important mineral province located in Minas Gerais state, responsible for the greatest part of iron production in Brazil. Among the concentration methods of iron ore used by the companies with activities in this region, the most important is the reverse cationic flotation. In this method, gelatinized starch is used as depressant for hematite and etheramine as collector for quartz. Dolomite iron formations, with the presence of hematite, quartz and dolomite, are present in several mining areas and, with the deepening of the iron ore deposits, this type of ore with low iron content and more complex mineralogy is increasingly recurring. Mineral characterization and bench flotation tests were performed with the objective of achieving a selective condition to concentrate hematite from quartz and dolomite gangue minerals. Using the collectors FLOTIGAM 16424 to float quartz and FLOTINOR 16551 to float dolomite it was possible to reduce the grades of SiO₂, MgO and CaO in the final concentrate, maximizing the iron grade for up to 66%. (author)