Grain size distribution of Işalnita power plant lignite ash and elemental composition of size classes

Abstract

Grain size analysis of 48 samples of Işalni(a power plant lignite ash revealed a mixture of three populations, each of them showing best fit to Weibull distribution with smallest size ( x 0) 40, 350 and 740 μm, mean size ( x m) 163, 506 and 1068 μm, exponent ( α) 1.42, 2.31 and 0.84, and participation to the whole mass with ( p) 49, 23 and 28%, respectively. The fine population originates, according to the “two phase model of coal”, from the mineral, the coarse, from the maceral pseudo-phase, while the middle fraction is presumably formed from extraneous minerals. Other three samples taken from the same power plant twenty years later could be resolved alike in three populations, with x 0 and x m shifted to smaller sizes. Concentrations of Na and Ca are evenly distributed among size classes, concentrations of K, Mg, Al, Fe, Ti and P are decreasing with particle size, while the concentration of S and C increases from the smallest to the largest size class 5 and 10 times, respectively, due to the mainly organic origin of these elements.