Chemical and mineralogical composition of Kathara Coal, East Bokaro Coalfield, India

Abstract

Utilisation of any coal primarily depends on its organic constituents. However, the inorganic constituents i.e., mineral matter present in the coal can decide its end uses. Therefore, the study of mineral matter in coal is an inevitable and such type of studies in India is very scanty. In this paper, we present the characters of a relatively low-ash non-coking coal from Kathara mines, East Bokaro coalfield, India with emphasis on its inorganic constituents and mineral matter. The coal is characterised by 22.56wt% ash (dry basis), 28.78wt% volatile matter (dry basis), and 48.66wt% fixed carbon (dry basis). Modal analysis by optical microscopy revealed 53.6vol% vitrinite, 38.3vol% inertinite, 8.1vol% liptinite on the mineral matter free basis (mmf), and 25.1vol% mineral matter. The minerals present in this coal are dominantly clay, quartz and siderite with a minor quantity of hematite, magnetite, goethite and pyrite. Electron micro-probe studies revealed trace presence of sphalerite, baddeleyite, and some altered magnesium silicate. The total sulphur content of this coal is found to be 1.16wt% on dry ash free basis (daf). Since the majority of the minerals, although fine in size, occur as independent phases with distinct and weak grain boundaries with the macerals, the coal shall be susceptible for beneficiation and the cleaner product can find applications in metallurgical industries for partial substitution in coke making because the mean vitrinite reflectance of this coal is 0.70%.