Leachability of environmentally hazardous elements from ashes produced after lignite combustion in Agios Dimitrios power plant, Northern Greece

Abstract

A bottom ash and a fly ash sample from Unit 1 of the Agios Dimitrios Power Plant, Northern Greece, were subjected to a one stage leaching procedure (Synthetic Groundwater Leaching Procedure – SGLP). The lignite burned in it derives from the Southern Field Mine from the Lignite Centre of Western Macedonia. The Relative Mass Leached (RML) for ten major (Al, P, Ca, Mg, K, Fe, Na, Si, S and Ti) and forty eight trace elements (Li, Be, B, V, Cr, Mn, Co, Ni, Cu, Zn, Ga, Ge, As, Se, Rb, Sr, Y, Zr, Nb, Mo, Ag, Cd, Sn, Sb, Te, Cs, Ba, La, Ce, Pr, Nd, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb, Lu, Hf, Ta, W, Pb, Bi, Th, and U)were determined by use of ICP-OES and ICP-MS. Calcium is the mostabundant element in both ashes, as well as in their respective leachates, related tothe high calcium minerals content of the bottom ash and fly ash. The resultsindicate that the majority of the elements show a very low to moderate mobility.The only elements that could be mentioned as exceptions are S and Sr. Sulphurhas RML values that are greater than 70% for both leachates, while Sr is totallyreleased in the fly ash leachate. Consequently, the majority of the elementsrepresent a low to moderate potential hazard to the environment.