Response of process parameters for processing of iron ore slime using column flotation

• Superficial air velocity and froth height have a vital role on recovery and grade in column flotation.
• Low froth height and high superficial air drastically reduces the grade.
• Ultrafines in feed are difficult to control even at high froth height and low superficial velocity.
• Increased residence time demands more collector dosage for high recovery and Fe grade in concentrate.

Iron ore slimes of India contain high alumina and silica that reduce the grade and pose difficulty in processing. This investigation addresses the interactive effect of process parameters on the processing of Indian iron ore slimes by using column flotation. The iron ore slime containing 58.7% Fe, 5.2% SiO2 and 4.9% Al2O3 was used for this investigation. The subsequent size analysis, chemical characterisation, desliming and column flotation tests were performed targeting the effect of process parameters on the flotation behaviour of the slimes. A factorial design of experimental approach was followed using three variables at two levels namely froth height, superficial air velocity, and collector dosage. The dosages of frother and depressant were held constant. Froth height plays a significant role on recovery and Fe-grade in the concentrate. The interaction effects of the variable factors on recovery and Fe grade of concentrate were studied. The relationship between the residence time of air in froth zone and recovery was also established. Increased residence time demands more collector dosage for high recovery of the concentrate. Recovery of the concentrate could be improved to 63% (54.6% overall recovery) with a grade of 64.3% Fe, 1.9% silica and 2.2% alumina.

Figure optionsDownload as PowerPoint slide