Potentially toxic elements in lignite and its combustion residues from a power plant

• Published in: Environmental monitoring and assessment 2015-01, Vol.187 (1), p.4148-14, Article 4148
• Main Authors: Ram, L. C., Masto, R. E., Srivastava, N. K., George, J., Selvi, V. A., Das, T. B., Pal, S. K., Maity, S., Mohanty, D.
• Format: Article
• Language: English
• Subjects: Ashes; Atmospheric Protection/Air Quality Control/Air Pollution; By products; Cadmium; Coal; Coal - analysis; Coal Ash - analysis; Coal Ash - chemistry; Coal Ash - toxicity; Combustion; Copper; Earth and Environmental Science; Earth crust; Ecology; Ecotoxicology; Energy; Environment; Environmental Management; Environmental Monitoring; Fly ash; Gypsum; India; Kaolinite; Leaching; Lead; Lead (metal); Lignite; Lithium; Mercury; Minerals - analysis; Minerals - chemistry; Minerals - toxicity; Monitoring/Environmental Analysis; Particle size; Power Plants; Pyrite; Quartz; Silver; Toxicity; Trace elements; Trace Elements - analysis; Trace Elements - toxicity
• ISSN: 0167-6369; 1573-2959
• DOI: 10.1007/s10661-014-4148-0

The presence of potentially toxic elements in lignite and coal is a matter of global concern during energy extraction from them. Accordingly, Barsingsar lignite from Rajasthan (India), a newly identified and currently exploited commercial source of energy, was evaluated for the presence of these elements and their fate during its combustion. Mobility of these elements in Barsingsar lignite and its ashes from a power plant (Bikaner-Nagaur region of Thar Desert, India) is presented in this paper. Kaolinite, quartz, and gypsum are the main minerals in lignite. Both the fly ash and bottom ash of lignite belong to class-F with SiO 2  > Al 2 O 3  > CaO > MgO. Both the ashes contain quartz, mullite, anhydrite, and albite. As, In, and Sr have higher concentration in the feed than the ashes. Compared to the feed lignite, Ba, Co, U, Cu, Cd, and Ni are enriched (10–5 times) in fly ash and Co, Pb, Li, Ga, Cd, and U in bottom ash (9–5 times). Earth crust–normalization pattern showed enrichment of Ga, U, B, Ag, Cd, and Se in the lignite; Li, Ba, Ga, B, Cu, Ag, Cd, Hg, Pb, and Se, in fly ash; and Li, Sr, Ga, U, B, Cu, Ag, Cd, Pb, and Se in bottom ash. Hg, Ag, Zn, Ni, Ba, and Se are possibly associated with pyrite. Leaching test by toxicity characteristic leaching procedure (TCLP) showed that except B all the elements are within the safe limits prescribed by Indian Standards.