Exploiting iron values from iron ore source rock: Opportunities

Removal or leaching of gangue phase from the source rock and successive precipitation of iron by hydrothermal fluid possibly resulted in high grade iron ore formation. The source rock of the iron ore ranges of Jharkhand and Orissa is the Banded iron Formation which represents one of the most distinctive rock types that occur wide spread in the space and time. This source rock also contains mineral phases along with the complexly interlocked gangue phases. In India commercially viable and strategically accepted cutoff grade of iron ore is >55% Fe (t). The alumina is of major concern in Indian ores for their effective utilization in iron making in particular through sinter. However, the beneficiation process has been established to treat up to 58% Fe level. In contrary to this the source rock is having a very low Fe(t). In order to meet the projected ∼100 million tons of steel production in India the demand of iron ore will increase in the order of ∼3 times than the present day demand. Since the volume of high grade ore is being gradually depleting focus is being made on the material where iron content has been less than that cutoff grade. So the source rock of iron ore is now also been considered to be a potential resource for the extraction of iron ore of desired quality for sintering. In this context, this study deals with the results of characterization and beneficiation studies undertaken on iron ore source rock samples with a view to develop high grade concentrate which can be used for sinter making.