Obsah stopovych prvku v uhelne hmote spodni a svrchni lavky hlavni sloje Mostecke panve

The objective of the present study was to determine the trace element contents in the lower and upper benches of the main coal seam (Holešice Member) in the Most Basin. The contents of all analyzed elements were compared to Clarke values for coals. Fifty coal samples from the lower bench and ten samples from the upper bench were collected in the Bílina open cast mine in the Most Basin. Contents of the following trace elements: As, V, Ni, Cu, Zn, Pb were determined in collected samples using the X-ray fluorescence method (XRF). The chemical and technological parameters such as ash yield and calorific value, total sulphur, total carbon, nitrogen, hydrogen, were measured. All results are presented in relevant figures as a median.
Results of technological parameters proved the coal seam of the upper bench to be classified as a low-rank coal according to the International Classification ECE-UN (1998). Based on the ash content, calorific value, and the content of major organic elements (S, N, H, C), the samples of the upper bench are classified as lignite, while samples from the lower bench as coaly claystone according to the ash yield up to 50 wt.% (Fig. 1). The coal claystone contained an increased amount of all observed trace elements, vanadium in particular. Clarke values for brown coal and all coals determined by Ketris and Yudovich (2009) are significantly lower compared to the median of element contents given for the upper and lower benches of the main coal seam. The results further show clearly that contents of As, V, Ni, Cu, Zn, and Pb are higher in the lower bench compared to the upper bench. The high variability in concentrations of the analyzed elements prevents to establish their actual contents. There was no significant correlation between total carbon and vanadium content found in analyzed samples (Fig. 2). A marked correlation between As and S^d was observed only in the lower bench (Fig. 3).

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