Tapan Kumar Baidya

Mineralogy and carbothermal reduction behaviour of vanadium-bearing titaniferous magnetite ore in Eastern India

Vanadium-bearing titaniferous magnetite bands hosted by Precambrian gabbro-norite-anorthositic rocks or their metamorphic equivalents were discovered in some parts of Eastern Indian Shield, containing 48%–49% Fe (total), 10%–25% TiO2, and 0.3%–2.20% V2O5 by mass. Mineralogical and petrological study, composition, and characterization of the vanadium-bearing titaniferous magnetite ore were carried out by scanning electron microscopy-energy dispersive X-ray (SEM-EDX), wave length X-ray florescence (WDXRF), inductively coupled plasma-atomic emission spectroscopy (ICP-AES), X-ray diffraction (XRD), etc. Chemical beneficiation for valuable metals, such as Fe, Ti, and V, was performed by reduction roasting. The direct and indirect reduction were investigated by mixing the lump ore with solid activated charcoal in a closed reactor and purging the reducing gas mixture in standard reducibility index apparatus at different temperatures and time intervals. The reduction roasting parameters were optimized. Finally, the reduced samples were crushed and upgraded by magnetic separation. The results show that, the maximum mass fractions of magnetic and nonmagnetic parts achieved are 69.36% and 30.64%, respectively, which contain 10.6% TiO2 and 0.84% V2O5 in the magnetic part and 36.5% TiO2 and 0.22% V2O5 in the nonmagnetic part.

NEUTRON ACTIVATION ANALYSIS OF NOBLE AND PLATINUM GROUP METALS IN THE PROTEROZOIC DALMA ROCKS OF EASTERN INDIA

Abstract The Proterozoic Dalma volcanic belt in the Singhbhum Orogen represents the main zone of axial rifting along which lavas of ultrabasic, basic and acidic compositions, pyroclastics and ashes were extruded spasmodically carrying the mineralizing elements from the subcrustal magmatic chamber. Neutron activation analysis, supported by AAS studies of the metamorphosed volcanic and sedimentary rocks in the Belpahari-Kankrajhor sector (22°37′N, 86°41′E) of the Eastern Dalma belt in the district of Midnapore, West Bengal, India, has revealed the existence of platinum, palladium, silver, gold and iridium at concentrations of 2.1, 3.3, 1.92 ppm, 2.65 and 0.12 ppb respectively. Prior to neutron activation, the noble and platinum group metals have been preconcentrated in lead buttons through fire assay and the activated samples have been studied by gamma-ray spectrometry. The anomaly in the existence of the noble and platinum group metals in the relevant rocks deserves detailed geological and exploratory study.