Technological and mineralogical characterization of quartz-dolomitic and dolomitic itabirite with low iron content and use of magnetic separation as a method of concentration

There is a growing need for the use of iron ore with lower iron contents, for which studies of technological and mineralogical characterization are crucial to have a better understanding of the material. In this case study two samples of dolomitic itabirite with low Fe contents were analyzed to verify the viability of the magnetic separation as a concentration method. The quartz-dolomitic itabirite sample has 28.68% Fe, with a large amount of CaO (6.15%) and SiO₂ (42.29%). The mineralogy is composed mainly of magnetite, quartz and dolomite. The results for the rougher stage of magnetic separation showed an increase of Fe content to 56.43%, with a recovery of 88.24%, requiring a cleaner stage to purify the concentrate. The sample of dolomitic itabirite has in its composition a low amount of SiO₂ (0.91%) and Fe content of 35.27%, with the presence of hematite. The result of the rougher stage of magnetic separation showed an increase of Fe content to 65.46%, already being characterized as final product. The scavenger stage recovered most of the Fe (72.63%) lost in the rougher stage. In general, magnetic separation proved to be an efficient method for the concentration of dolomitic and quartz dolomite itabirite. (author)