Characterization and concentration by selective flocculation/magnetic separation of iron ore slimes from a dam of Quadrilátero Ferrífero – Brazil

In this paper the results of size, chemical and mineralogical characterizations as well as the concentration tests performed with a slimes sample of iron ore from a dam at the Quadrilátero Ferrífero in the state of Minas Gerais, Brazil are presented. The sample was constituted by 75 % of slimes (particles –10 μm). The main minerals identified by X-ray diffractometry and thermal analysis were: goethite, hematite, quartz and kaolinite. The sample grades were: Fe (∼51.4 wt.%.), SiO2 (∼15.1 wt.%), Al2O3 (∼3.4 wt.%), P (0.097 wt.%) and LOI (∼7 wt.%). During the optimized bench testing condition of selective flocculation/magnetic separation (pH = 10.5, sodium silicate and corn starch =50 g/ton, magnetic strength =3575 G) by experimental statistical planning design, the mass recovery was of 48.4 %. There was an increase of 8 % in Fe grade and a decrease of 50 % in both SiO2 and Al2O3 grades when compared with the feed. Agglomeration studies with the obtained concentrate will be performed in future.