Major and Some Trace Elements Concentrations of Miocene-Aged Alpu Coals, Eski?ehir, Turkey

Abstract

Elemental contents, organic matter, and relation with Miocene-aged coal samples were analyzed in Alpu, Eskişehir, Turkey. The coal samples were identified as upper and lower seams in the m2 series. This series includes the following from the bottom to the top: claystone–marl, coal lower seam, sandstone, siltstone–claystone, upper coal seam, and claystone–sandstone–gravelstone. A total of 17 coal samples (eight and nine from the upper and the lower seam) were collected from five boreholes. Proximate and element analyses of the samples were performed and evaluated. In an air-dried basis, the upper and the lower seam have low average moisture contents (about 8% and 6%), average moderate ash yields (about 31% and 28%), and high total average calorific values (about 3215 and 2934 kcal/kg). The major elements found in Miocene-aged coal in this area are Na, Mg, Al, Si, P, K, Ca, Ti, Mn, Fe, and S. Compared with the average world coal content, major elemental contents of the two seams have highly enriched levels. Some trace elemental contents (e.g., V, Cr, Ni, Cu, Zn, Rb, Sr, Ba, Pb, Zr, and As) of the studied coal samples indicate similarity between the two coal seams, which are highly depleted with respect to the world average. The Al and Si contents of both coal seams have positive correlations with the ash yield, whereas those of Mg, Na, Ca, and Fe have negative correlations. The concentrations of Ni and Ba in these seams are positively correlated with the ash yield, and that of Sr and Zr have negative correlations.