This paper addresses the characterization of fines stocked in a pond as tailings from an iron ore concentrator. The characterization consisted of size analyses by wet screening, chemical analyses by ICP, and mineralogical analyses by X-ray diffraction. The next stage consisted of technological tests. Two concentration routes were evaluated at bench scale: the first (route I) consisting of classification (0.15mm), magnetic separation (-1.0+0.15mm), desliming and flotation (-0.15mm); and the second (route II) consisting of magnetic separation (-1.0mm global), aiming at achieving a concentrate adequate for use in the metallurgical industry. The size distribution of the iron ore fines indicated 8.21% above 0.150mm and 58.81% passing 0.045mm. The calculated average chemical composition of the sample is 48.08% Fe, 20.58% SiO2, and 3.16% Al2O3. The iron minerals identified by X-ray diffraction were: hematite, martite, magnetite, and goethite; and the detected gangue minerals were: quartz, gibbsite, and kaolinite. The best performance came from route II, magnetic separation only: weight recovery 68.00%, metallurgical recovery 90.81%, 67.54% Fe, 1.50% SiO2, 0.49% Al2O3.
Flotation; silicon-carbonate ore; carbonates; apatite; phosphoric acid
