Comparative studies of reverse cationic/anionic flotation of Vale iron ore

The comparative studies of reverse cationic/anionic flotation routes were conducted using Vale iron ore in batch scale flotation tests. The effect of slimes on the performance of the two flotation routes was also studied. After desliming, the overall Fe recovery in reverse anionic flotation is significantly higher than reverse cationic flotation at the same concentrate grade. For ultrafine particles (< 10 μm), the metal loss in reverse cationic flotation is over 92% due to the entrainment of hematite ultrafine particles. However, in reverse anionic flotation, metal loss is as low as 42% in the particle size range of 5 to 10 μm, while rejecting almost all the quartz ultrafine particles at the same time. In the coarse particle size range (> 210 μm), the performance of reverse cationic flotation is slightly better than reverse anionic flotation, with more quartz coarse particles rejected. The major advantage of reverse anionic flotation over reverse cationic flotation was found to be its excellent capability to selectively separate ultrafine particles of quartz and hematite.