Mineralogy and pre-concentration of the chromite overburden of the Sukinda Ultramafic Belt, Orissa, India

CIM Bulletin, Vol. 93, No. 1038, 2000

J.K. Mohanty, Regional Research Laboratory, Orissa, India D.S. Rao, National Metallurgical Laboratory, Jamshedpur, India B. Das and R.B. Rao, Regional Research Laboratory, Orissa, India

Physical, mineralogical and geochemical characterization, along with some beneficiation approach to pre-concentrate the Ni content of the chromite overburden material of the Sukinda Valley, India, have been carried out in detail. Mineralogically, the overburden consists of geothite, quartz, hematite, magnetite and secondary silicates in varying proportions. A specific Ni mineral phase is absent in this material with the Ni and Fe being mostly enriched in finer fractions. Distribution of Ni and Fe in various size fractions and increase of Ni with increase in Fe (goethite content) indicate that goethite is the major Ni-bearing mineral phase. Quantitative estimation of goethite from chemical analysis and weight loss data indicates that the goethite quantity varies from 40% to 90%. Electron microprobe analysis (EPMA) indicates that Ni-rich and Ni-poor goethite are present in the overburden material. A sequential dissolution study indicates that more than 50% of the Ni are present within the goethite lattice as a lattice substitution. The results of pre-concentration studies (size classification, gra

Keywords: Chromite overburden, Mineralogy, Pre-concentration.