Flotation of Indian Iron Ore - Few Case Studies

The depletion of high grade iron ore, increased generation of fines during mining and handling and demand for high grade iron ore fines / concentrate has necessitated the processing of low to medium grade fines. The presence of alumina (>2%) as fine clay and adherent material and in some cases interspersed in the ore body, poses serious problems in beneficiation. The adverse alumina to silica ratio (ideally, should be <1) is detrimental to blast furnace as well as sinter plant productivity. Lowering alumina content is, therefore, a prerequisite for efficient iron making in India. The physical separation methods were found to be inadequate to process fine sized ore. Under such circumstances, froth flotation is highly useful. Flotation in general and Column Flotation in particular proved to be promising in addressing this problem. The R&D efforts undertaken in this direction over the last two decades at CSIR – National Metallurgical Laboratory (NML) Madras Centre, India have been highlighted. Case studies on flotation / column flotation of iron ore fines of varying silica and alumina content and from different regions of India were discussed. The results clearly indicate the feasibility and significance of flotation process in treating the fines to obtain marketable concentrates.