Assessment of the content, occurrence, and leachability of arsenic, lead, and thallium in wastes from coal cleaning processes

Abstract

The aim of the study was to evaluate the content, occurrence, and leachability of arsenic (As), lead (Pb), and thallium (Tl) in wastes from coal cleaning processes with respect to the safe management of this waste. The study focused on wastes resulting from the wet gravitation and flotation processes employed for the purposes of coking coal cleaning in four coal mines situated in the Upper Silesian Coal Basin (Poland). The scope of the study included (i) determination of the content of these elements in the investigated wastes using atomic absorption spectrometry, (ii) evaluation of their mode of occurrence using electron microprobe analysis, and (iii) preliminary assessment of their leachability in deionized water. The content of the analyzed elements in the examined samples of coal waste was twice as high as the average content of these elements in the Earth’s crust. The contents of As and Pb, however, did not exceed their permissible contents in inert waste in accordance with Polish legal regulations based on EU directives. The limit on the content of Tl is not specified by these regulations, but its amount in the examined samples was similar to that occurring in the soils. Moreover, leaching tests have shown that these elements are hardly eluted from the analyzed material. Their content in the water leachates was generally lower than the detection limit of the analytical method, complying with the standards for good and very good water quality. Low leachability of these elements most probably results from their mode of occurrence in the investigated wastes. The chemical analysis using an electron microprobe and the analysis of the correlation between these elements, e.g., total and pyritic sulfur, have shown that Pb, As, and Tl are mainly found in sulfide minerals which are characterized by negligible solubility. In conclusion, the investigated hard coal processing waste does not constitute a threat to the environment and can be commercially used or safely neutralized, e.g., by landfilling.

Arsenic quantification techniques and ISO/IEC 17025 accreditation in Brazil

“…The ET AAS showed a LOQ between 0.05 and 10.00 μg L -1 in liquid samples and between 50.0 and 1,000 μg kg -1 in solids (Table 2). Studies using the same technique also present similar results in liquids ranging from 0.006 μg L -1 (Hassanpoor et al, 2015) and 4.60 µg L -1 (Makowska et al, 2018). In solid samples (soils), Nielsen et al (2011) obtained a considerably lower value (7.40 μg kg -1 ) than the present data survey.…”

Assessment of mercury emissions into the atmosphere from the combustion of hard coal in a home heating boiler

“…Furthermore, it was found that other ecotoxic elements are also adsorbed in large quantities on the surface of chimney soot, e.g. As, Pb, Cu, Zn, Ni, Cr (Chyc and Burzała 2012 ), which are commonly present in hard coal (Makowska et al 2019 ).…”

Archives of Mining Sciences

“…These elements, generally, can be removed from coal sufficiently (up to 80%), through applying gravity separation and/or flotation (Liu et al, 2019;Makowska et al, 2014;Mohanty et al, 1998;Parzentny, 1995). However, quite often the content of the elements in processed coal is still higher than the average content of the elements in hard coals from around the world (Chen et al, 2017;Duan et al, 2018aDuan et al, , 2018bDai et al, 2020b;Liu et al, 2019;Makowska et al, 2018;. Removing these elements from macerals and submicroscopic minerals of the elements from coal, through gravity separation and flotation, is considered to be ineffective and improbable.…”