BENEFICIATION OF ALUMINA-RICH INDIAN IRON-ORE SLIMES

The current practice of washing iron ores in India results in three products namely lumps, (directly charged to blast furnace), fines (used in sinter plant) and slimes (-150 microns) currently discarded as waste. The generation of slimes is estimated to be 10-25% of the total weight of iron ore mined. Slimes disposal is one of the most serious problems for the iron ore industry. Results of various R&D efforts to beneficiate these slimes in order to reduce alumina from present 6-10% to less than 2%, so as to make them acceptable for sinter making are critically reviewed in this paper. Amongst the various techniques employed including WHIMS, multi-gravity separation appears to be most promising. The need to develop reagents for hematite-gibbsite separation (an important observation ignored thus far in R&D efforts) is also highlighted.