Utilisation of low grade graphite ores occurring in the Precambrian Eastern Ghats complex of Orissa

Abstract

Low grade ores at Rajunagfena, Bolangir district, Orissa occur as disseminations as well as schists. Graphite schists occur at the margins of pegmatite in migmatised khodnalite and is dominantly controlled by foliation. The fixed carbon (F.C.) content of the samples varies from 12.16 to 13.12%. Mineralogical association and fabric features of graphite and their implications in beneficiation are described in the paper. The fabric features suggest remobilisation of graphite after its Formation. Optimum liberation size of graphite is determined to be below 210 mu m. Beneficiation studies were carried our to optimise the effect of collector and particle size. The results of beneficiation indicated that a concentrate having 79% F.C. and 80% recovery can be obtained in conventional cell in six stages. Almost similar performance was achieved by column in two stages. The concentrate can be further improved to around 95% F.C. by a combination of chemical treatment and flotation.