Mineralogical characteristics and sources of alkali metals in the No. 6 coal seam from the Fukang mining area of the Zhunnan coalfield, Xinjiang province, Northwest China

Abstract

Minerals in coal are of great significance in determining coal properties, washing, combustion, gasification, and liquefaction. The content of alkali metals in coal is an important factor determining corrosion and/or erosion in combustion boilers. Eleven coal samples were taken from the No. 6 coal seam of the Fukang mining area, Zhunnan coalfield, Xinjiang province, China. X-ray fluorescence, inductively coupled plasma-mass spectrometry, low-temperature ashing-X-ray diffraction, and electron probe microanalyzer were used for analyzing the minerals, major elements, and trace elements of the coal. The results indicated that the minerals mainly consist of dawsonite, dolomite, albite, calcite, kaolinite, quartz. The average content of Na2O in the ash of the No. 6 coal seam samples was 10.91%. Na mainly occurs in the form of organic compounds in the No. 6 coal seam, then in the form of inorganic minerals, such as dawsonite and albite. Na in surface and underlying strata was brought into the coal by water and combined with organic matter, resulting in relatively high Na contents in the upper and bottom parts of the coal seam and relatively low Na contents in the middle part.

Geochemical characteristics of Jurassic high-sodium coal in Tatuo Coal Mine, Qinghai Province, China

“…However, the content is much lower in the parting samples; it is all below 0.20% (Table 3). The coal with Na 2 O content greater than 2% in the ash is called high-sodium coal (Li et al, 2018; Xu et al, 2019). According to this standard, Tatuo coal belongs to high-sodium coal.…”

“…However, some Jurassic coal is also characterized by an extremely high content of sodium. The Na 2 O contents are much higher than 2% in coal, which is belonged to high-sodium coal (Xu et al, 2019). Sodium will cause serious problems in reactors because of its stronger solubility and volatility when burned (Bryers, 1996; Li et al, 2015; Yang et al, 2014).…”

Geomineralogical, Physiochemical, Thermal and Kinetic Characterisation of Selected Coals From the Benue Trough and Anambra Basins in Nigeria

“…Ti, Mn, and Fe along with the minerals present in elemental and fused forms are also considered major determinants of surface morphology, thermochemical properties, and quality of the coal (Xu et al 2019). To examine this, the elemental composition of CHK, LFB, and OKB was examined by EDX spectroscopy as presented in the next section of the paper.…”

“…Furthermore, the chemical species found in coal are also considered an indication of chemical weathering (Akinyemi et al 2019;Akinyemi et al 2020b). It is also a measure of the degree of coalification, rank, and the source coal of mineral matter Dai et al 2015;Xu et al 2019).…”

Geochemical characteristics of elements in coal seams 41 and 42 of Heshan Coalfield, South China

“…According to the Ministry of Ecology and Environment of the People's Republic of China, coal consumption in China accounted for 59.0% of the total energy consumption in 2018. Both hazardous and valuable elements have been reported in various types of Chinese coal (Seredin et al, 2013;Wang et al, 2013Wang et al, , 2019bXu et al, 2019;Zheng et al, 1999). One such type is referred to as superhigh-organic-sulfur (SHOS) coals owing to its organic sulfur content in the coal is more than 4% (Chou, 2012); such a high sulfur content makes SHOS coals more hazardous to the environment.…”