Beneficiation studies of some Indian Iron ores

Abstract

Comprehensive investigations were carried out on a pilot plant scale with representative samples of iron ore drawn from the various mines of India primarily with a view to finding a solution for the serious ore handling and screening problems encountered practically in all the iron ore mines in India during monsoon season, besides exploring their amenability to beneficiation. Iron ore containing laterite as the principal gangue constitutes the bulk of Indian reserves of iron ores and studies on this type of iron ore proved that all the ore handling and screening problems can be overcome by washing the run-of-mine ore after crushing to a suitable size followed by jigging of the resulting classifier fines, producing (1) a clean sized lumpy ore suitable for smelting in a blast furnace, (2) a free-flowing upgraded fines free from slime s suitable for iron making after agglomeration and (3) a reject able slime containing 30-60 %silica, 15-30% alumina and about 15-20% of the iron present in the test sample. Iron ore fines of lateritic variety received from Goa and Maharashtra normally do not require any beneficiation but it is desirable to pass them through washing and cyclone set up, to take care of any unforeseen contamination of the Sample with lateritic gangue. Siliceous iron ores of Rajasthan and Assam Could be best upgraded by spiral concentration followed by tabling of the spiral tails, producing a good iron concentrate suitable for export after agglomeration. Low-grade magnetite samples from Salem (Madras) and Kudremukh (Mysore) could be concentrated by wet magnetic separation followed by either tabling or flotation. Based on the nature of the gangue minerals associated with the iron-bearing minerals, on which the beneficiation treatment depends, Indian iron ores can be classified broadly into (1) lateritic iron ores, and (2) siliceous iron ores and (3) magnetite iron ores.