Sulphur in Jharia and Raniganj coalfields: Chemical fractionation and its environmental implications

Abstract

In coal, total sulphur content is not the only important factor for the industry, but also the forms of sulphur and their distributions should be considered before utilizing any coal for a particular use. In Jharia and Raniganj coalfields, sulphur is present in the forms of organic sulphur (OS), pyritic sulphur (PS), and sulphate sulphur (SS). In this perspective, the present study aims to know the different forms of sulphur in coking and non-coking coals of Jharia and Raniganj coalfields. Twenty samples were collected from both the mining areas. The total sulphur content in coking coals varied from 0.28% to 0.55% and in non-coking coals it varied from 0.33% to 0.54%. The distribution pattern of sulphur showed that PS and OS are dominating in both the coalfields. The OS in Jharia field varied from 0.13% to 0.47%, and in Raniganj coalfield it varied from 0.19% to 0.41%. This depicts that both the coalfields were formed under freshwater condition. Similarly, PS varied from 0.01% to 0.21% and from 0.06% to 0.29%, and SS varied from 0.0052% to 0.01% and 0.005%–0.02% in the above fields, respectively. It is noticed that the content of sulphate sulphur is less than 0.1 wt%, which is lower than other forms of sulphur. In the past two decades, sulphur emission has increased with the increase of thermal power plants due to more demand for power, which is one of the causes of global warming. During coal combustion, H2S and SOx, are produced and that can react with O2 and H2O to form H2SO3, H2SO4 or H2S. Thus, sulphur release can respond within the ecosystem in the form of acidic precipitation that may acidify and affect lakes and streams, sub-surface water and historical monuments. In India, coal consumption and ecological contaminations are increasing day by day due to the rapid energy consumption. Therefore, special attention should be given to adopt clean coal technologies though the coal contains less sulphur.