Beneficiation of low-grade iron ore fines by multi-gravity separator (MGS) using optimization studies

There is an urgent need for development of environmental friendly processes through which iron ore fines can be beneficiated and utilized effectively. For processing of low-grade iron ores, ground to finer size necessitates the use of centrifugal force. This is because the settling rate of the particles in centrifugal force is 500-600 times more than that noticed for the nominal gravitational force. Multi-gravity separator (MGS) is the one such unit used for recovering hematitic fines without addition of chemicals. In the present article, an approach has been made to beneficiate low-grade hematitic iron ore of Jilling mine, Odisha, India, using MGS. The effect of three important variables was studied and their influences were analyzed through statistical approach to optimize grade, recovery, and separation efficiency. Use of response surface methodology (RSM) based on Box-Behnken design has also been adopted for analysis purpose. The results obtained indicate that it is possible to beneficiate low-grade hematitic iron ore from a feed of 50.74% Fe to 65.11% Fe with an acceptable recovery of 71.88%. Optimization of process variables was done for each response, optimized independently irrespective of other responses. Further optimization of the variables was carried out with a multi-objective target.