Flotation studies on low grade graphite ore from Eastern India

A low grade graphite ore from eastern India was studied for its amenability to beneficiation by flotation technique. The ore mainly consists of quartz and graphite assaying 87.80% ash and 8.59% fixed carbon. It was crushed in stages followed by primary coarse wet grinding. Rougher flotation was carried out in conventional flotation cell to eliminate the gangue to the maximum extent possible as primary tailings. Diesel & pine oil were used as collector and frother respectively. Regrinding of rougher concentrate was opted for further liberation of graphite. The reground rougher concentrate was subjected to cleaning by laboratory flotation column. This combined process of relatively coarse primary grinding and rougher flotation in conventional cell followed by regrinding of rougher float and its cleaning in column was found to result in optimum yield and grade of the final product. Instead of the usual practice of single stage grinding for grind optimization, two - stage grinding was carried out to recover the flake graphite at the coarsest possible grind initially, thereby minimizing grinding energy costs. A conceptual flow sheet which is cost effective was developed based on this methodology.