The Petrography, Mineralogy and Geochemistry of Some Cu- and Pb-Enriched Coals from Jungar Coalfield, Northwestern China

Abstract

Abstract:The petrological, geochemical, and mineralogical composition of the Carboniferous-Permian coal deposit in the Jungar coalfield of inner Mongolia, Northwestern China, were investigated using optical microscopy and field emission scanning electron microscopy in conjunction with an energy-dispersive X-ray spectrometer (SEM-EDX), as well as X-ray powder diffraction, X-ray fluorescence, and inductively coupled plasma mass spectrometry. The Jungar coal is of high volatile C/B bituminous quality with 0.58% vitrinite reflectance and has a low sulfur content of 0.70% on average. Inertinite (mineral-free basis) generally dominates in coal from the lower part of the Shanxi formation, and vitrinite is the major maceral assemblage in the coal from the Taiyuan formation, which exhibits forms suggesting variation in the sedimentary environment. The Jungar coal is characterized by higher concentrations of copper (Cu) in No. 6 coal, at 55 µg/g, and lead (Pb) in No. 4 coal at 42 µg/g. Relative to the upper continental crust, the rare earth elements (REE) in the coal are characterized by light and medium-heavy REE enrichment. The minerals in the Jungar coal are mainly kaolinite, dickite, pyrite, calcite, siderite, quartz, and, to a lesser extent, gypsum and K-feldspar. The enrichment and occurrence of the trace elements, and of the minerals in the coal, are attributed to the fragmental parent rock during diagenesis and coalification. The main elements with high enrichment factors, Cu and Pb, overall exhibit a notably inorganic sulfide affinity and a weak organic affinity. Primary and epigenetic sedimentary environment and the lithology of the terrigenous parent rock are the key factors that influence the occurrence and formation of Cu and Pb in coal. The depositional environment is more influential in the formation of Cu than Pb in coal. Lead is more easily affected by the terrigenous factors than Cu when they are under a similar depositional environment.

Rare Earth Element Characteristics in Coal Ash from the Jungar Energy Gangue Power Plant, Inner Mongolia, China

“…At this power plant, a DG480/13.73-II11 CFB combustion boiler (Dongfang Boiler Company, Sichuan, China) is used, and the fuel is coal from the No. 6 coal seam of the Taiyuan Formation [48,49] in the Heidaigou open-pit mine (Figure 1), with an ash yield of approximately 20%. Further, the combustion temperature in this boiler is between 850 and 900 • C.…”

The Characterization and SCR Performance of Mn-Containing α-Fe2O3 Derived from the Decomposition of Siderite

“…On the other hand, siderite is abundant in China with a low utilization rate [25,26]. Calcined siderite can form Fe 2 O 3 and Fe 3 O 4 [27].…”