Geochemistry of arsenic and selenium in a Ge-poor coal from the Wulantuga coal-hosted Ge ore deposit, Inner Mongolia, North China

Abstract

This paper reports new data for arsenic (As) and selenium (Se) in a total of twelve bench samples of Ge-rich and Ge-poor coals in the No. 6 coal seam from the Wulantuga ore deposit, Inner Mongolia, Northeastern China. The Ge-poor coals are characterized by low-ash (with a weighted average ash yield 10.59 %). The coal samples were digested using an UltraClave microwave high pressure reactor (milestone) and trace elements were detected by inductively coupled plasma mass spectrometry—collision/reaction cell technology, a reliable method for As and Se determination in coal samples. The contents of As and Se in the Ge-poor (with a weighted average content of 9.14 and 0.30 μg/g, respectively) and Ge-rich coal samples in the present study (varies from 16.88 to 17,776 μg/g and from 0.26 to 14.39 μg/g, respectively) are in a sharp contrast. The As in the Ge-poor coals is of both organic- and pyrite-associations, and its enrichment is attributed to the sediment source, and to a lesser extent, to hydrothermal fluids. Se is predominantly connected with organic matter in the Wulantuga Ge-poor coals.