Fluorine in Coal: The Modes of Occurrence and its Removability by Froth Flotation

Based on the results of tests on feed coal from the Lublin Coal and Upper Silesian Coal Basin and its fly ash and slag carried out using X-ray diffraction and X-ray fluorescence analysis, atomic emission spectroscopy, and scanning electron microscopy, it was found that in feeds, coal Th is associated with phosphates and U with mineral matter. The highest Th content was found in anhedral grains of monazite and in Al-Si porous particles of fly ash of <0.05 mm size; whereas in the slag, Th is concentrated in the massive Al-Si grains and in ferrospheres. U is mainly concentrated in the Al-Si surface of porous grains, which form a part of fly ash of <0.05 mm size. In the slag, U is to be found in the Al-Si massive grains or in a dispersed form in non-magnetic and magnetic grains. Groups of mineral phase particles have been identified that have the greatest impact on the content of Th and U in whole fly ash and slag. The research results contained in this article may be important for predicting the efficiency of Th and U leaching from furnace waste storage sites and from falling dusts to soils and waters.

Section: Introductionmentioning

confidence: 99%

The Role of Mineral Matter in Concentrating Uranium and Thorium in Coal and Combustion Residues from Power Plants in Poland

Parzentny

Róg

2019

“…A coal sample from Guizhou Province, China 357 Fluorine mainly occurred in residual-associated form and carbonate-and Fe/Mn-associated form. [15] <200 µg/g Most of these coals are low fluorine (<200 µg/g); however, the fluorine content of clay is as high as 1027.6 µg/g. [16] 715.20 (average) The inorganic occurrence is the primary mode of occurrence of fluorine in coals from Guizhou province.…”

Section: Coal Samplementioning

confidence: 99%

“…Thus, the commonly used coal preparation methods can be useful for the removal of fluorine from coal, such as gravity separation (physical method) and flotation (physicochemical method). Zhou et al [15] reported that a total of 76.05% of the total fluorine was removed by froth flotation under an optimum condition. Lin et al [20] demonstrated that froth flotation can reduce the amount of fluorine significantly.…”

Section: Coal Samplementioning

confidence: 99%

Characterization and Removal Potential of Fluorine in Lignite from a Mine in Shaanxi Province, China: A Case Study

Zhou

et al. 2022

Fluorine appears in coal and is released into the atmosphere upon combustion, resulting in harmful impacts on the environment and life, which needs to be removed from coal before utilization. Coal can be processed by flotation and gravity separation to reduce its fluorine content. In this study, a lignite sample from a mine in Shaanxi Province, China, was characterized using the float–sink test, sieving test, X-ray diffraction (XRD), and polarized light microscopy. Mineralogical analysis indicated that the fluorine in coal is mainly contained in Muscovite and polylithionite, and partly in pyrite. The washability and floatability analyses were employed to evaluate the extent of fluorine removal from >0.5 and <0.5 mm size fractions of lignite, respectively. Compared to the raw sample that contained 347.74 μg/g fluorine content, the proposed combination of gravity-flotation separation process decreased the fluorine content to 90.14 μg/g, which meets the requisites of coal standards.

“…The analyses of the content and the binding mode of the elements in coal are important, to know where and why they are concentrated in coal deposits; this would also provide more informed forecasts of the volume of elements released into the environment as a result of the combustion, weathering, and leaching of coal in deposits or storage yards [9,[17][18][19][20][21][22][23]. The analyses also facilitate forecasting the effectiveness of various procedures of purifying coal of interlaying mineral matter and heavy metals [9,22,[24][25][26][27]. Radioactive elements and heavy metals [5,[28][29][30], referred to as ecotoxic elements by Duffus [31], are considered to be the most toxic for the environment.…”

Section: Introductionmentioning

confidence: 99%

Spatial Macroscale Variability of the Role of Mineral Matter in Concentrating Some Trace Elements in Bituminous Coal in a Coal Basin—A Case Study from the Upper Silesian Coal Basin in Poland

Parzentny

2020

As there are numerous claims that the mode of occurrence of trace elements in coal influences the quality of the substrates as well as the course and results of the coal preparation processes, it is necessary to analyse the differences in the mode of occurrence of the elements in coal within a coal basin or a coal deposit. With the use of concentration distribution functions and the Pearson correlation coefficient, it was concluded that (1) mineral matter plays a significant and nearly constant or constant role in concentrating V, Cr, Co, As, Rb, Sr, Ba, and Pb in coal; (2) organic matter plays a stable role in concentrating Sn; and (3) there are significant differences in the role of organic and mineral matter in concentrating Mn, Ni, Cu, Zn, Mo, Cd, and Sb in coal throughout the USCB (Upper Silesian Coal Basin). Moreover, there was observed a difference in the mode of occurrence of Cr, Mn, Co, Ni, Cu, Zn, Mo, Cd, Sn, and Sb in coal in the vertical profile of the USCB. At the same time, there were observed no differences and a stable significant role of mineral matter in concentrating V, As, Rb, Sr, Ba, and Pb in coal, while the role of the petrographic groups of the coal components in concentrating the elements in raw coal was differentiated. It is believed that the difference in the mode of occurrence of the trace elements in coal within coal seams and coal deposits is a geochemical regularity.