Environmental implications of material leached from coal

Abstract

Samples of coal were collected from different seams at a South African coal mine and comparative leaching experiments were carried out under various pH conditions and times to investigate the leaching behavior and potential environmental impact of possibly hazardous elements such as As, Cd, Co, Cr, Mn, Ni, Pb, Th and U. The calculated leaching intensities, sequential extraction results and cumulative percentages demonstrate that the leaching behavior of the elements is strongly influenced by the pH, the leaching time and the properties and occurrences of the elements. The leached concentrations of As, Cd, Co, Cr, Mn, Ni and Pb exceeded the maximum concentrations recommended by the Environmental Protection Agency (EPA) for surface water.

Longitudinal and contemporaneous manganese exposure in apartheid-era South Africa: Implications for the past and future

“…The three elements are constituents of South African coal and fly ash from coal-fired power plants (Ayanda et al, 2012;Kalenga et al, 2011). It is logical that they may be correlated if the source of Mn exposure in our sampled remains is coal, which can release particulate matter into the atmosphere via combustion or contaminate water via acid mine (AMD) drainage near coal mines (McCarthy, 2011;Moyo et al, 2011). Highveld coal in particular is highly enriched in Mn compared to other South African coals and compared to the global average for Mn in coal (Wagner and Hlatshwayo, 2005).…”

Physico-chemical and elemental investigation of aqueous leaching of high sulfur coal and mine overburden from Ledo coalfield of Northeast India

“…ion in leachates with leaching time is attributed to the production of orthosilicic acid (Li et al 2017). Figures 11, 12, 13 and 14 show an increase in F -, Cland SO 4 2ion concentrations in aqueous leachates of Ledo coal and OB with leaching time which is due to the fact that leaching time is an important factor which determine the amount of elements leached from the raw coal (Moyo et al 2011). The leaching of SO 4 2ion from coal and overburden was increased with leaching temperature from 25 to 65°C and time (in Figs.…”

“…The mobility of pollutants contained in the waste is expressed as the potentiality of them to leach in water (Kalembkiewicz and Palczak 2015). Leaching methods are classified into two types depending upon whether the leaching liquid is added at a single instance (static) or it is renewed (dynamic) (Moyo et al 2011). The potential to produce acidity of drainage from mine water and mine wastes can be predicted by both geochemical methods in static and kinetic leaching processes (Ferguson and Erickson 1998).…”

Leaching of Trace Elements from Indian Coal

“…The behavior of these elements during leaching is mainly controlled by pH and mineralogy (Yue and Zhao, 2008). The leaching of coal indicates the likely potential release of elements in mine drainage, and it is widely accepted technique for prediction of mobilization of elements (Moyo et al, 2011;Baruah and Khare, 2010).…”