Geochemical Behavior and Enrichment Mechanisms of Arsenic in Low‐Rank Coal, Baiyinhua Depression, Erlian Basin

Abstract In this study, the abundance of trace elements in Baiyinhua Depression coal and its relationship with the coal depositional environment was examined. (1) The content of arsenic in Baiyinhua Depression coal is that of a typically high arsenic coal from the late Mesozoic of China. The average arsenic content of Baiyinhua coal is 24.93 times, the highest being 132.71 times, that of Chinese coal. Coal rank is not a controlling factor affecting arsenic enrichment in coal. (2) Arsenic is primarily enriched in the syngenetic and diagenetic stages, the enrichment being most obvious in the syngenetic stage, with the intrusion of a magmatic‐hydrothermal solution in the epigenetic stage also providing rich sources of arsenic. (3) The Baiyinhua Coal‐forming plant material is mainly woody plants. The coal seam was covered with deep water, the oxygen supply was very weak, the bacteria very few, the sedimentary environment of the swamp relatively calm and the degree of damage to the woody plants is very low. The minerals in the coal are mainly quartz and clay minerals. The coal ash yield of Baiyinhua is small, with SiO 2 , Al 2 O 3 , MgO, K 2 O, TiO 2 , MnO and P 2 O 5 mainly being combined in the inorganic minerals of the coal.