Volatilisation of selenium from coals by heating at different temperature: application of sequential extraction scheme on ash

Abstract

ABSTRACT An important issue to the earth’s atmosphere is the volatilisation of elements such as selenium, from the burning of coal at different temperatures. In the current work, the volatilisation of selenium (Se) during combustion of coal samples at different control temperature range in an electrically controlled furnace was carried out. The coal samples were obtained from various coal fields of Sindh, Pakistan. The duplicate coal samples were combusted in controlled furnace by applying three temperature rounds (200°C, 400°C and 900°C). The ash formed following each temperature round was examined to know the volatilisation contents of Se after burning of coal samples at different temperature. The fractionation of Se in coal ash gained after combustion at 900°C was subjected to three-stage sequential extraction scheme (SES). The obtained data indicated that the total contents of Se in coal samples of block II of Thar coal field (TCF), and Site I and Site II of Lakhra coal field (LCF) were observed in the range of 7.72–14.3, 9.02–16.3 and 8.92–14.2 mg/kg, respectively. It was observed that after the burning of coal samples at 900°C, about 75–81.8% of the total Se was volatised out into atmosphere.