Distribution of major and trace elements in the Kovin lignite (Serbia)

Životić, Dragana; Cvetković, Olga; Vulić, Predrag; Gržetić, Ivan; Šimić, Vladimir; Ilijević, Konstantin; Dojčinović, Biljana; Erić, Suzana; Radić, Bogdan; Stojadinović, Sanja; Trifunović, Snežana

doi:10.4154/gc.2019.06

Cited by 10 publications

(7 citation statements)

References 41 publications

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“…Such affinity of Si is widely reported from various coals around the World (i.e. Beaton et al, 1991;Crowley et al, 1997;Warwick et al, 1997;Spears, Zheng, 1999;Liu et al, 2001;Zhao et al, 2017Zhao et al, , 2020Finkelman et al, 2019;Životić et al, 2019). Furthermore, Querol et al (1997aQuerol et al ( , b, 2001a, Ward et al (1999), Karayigit et al (2000aKarayigit et al ( , 2020 and Alastuey et al (2001) accept a priori the exclusive relationship of Si with the clay minerals and use the correlation of the element with the alumino-silicate part of the ash to determine its mode of occurrence.…”

Section: Resultsmentioning

confidence: 95%

Silicon and aluminum in Bulgarian coals

Zdravkov¹

2021

Rev. Bulg. Geol. Soc.

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The presence and distribution of Si and Al in 19 Bulgarian coal basins and deposits, belonging to 8 coal provinces, were studied. Coals are of different rank (lignite to anthracite) and age (Late Carboniferous to Pliocene). The presence of both studied major elements depends strongly on: i) their concentration within the basin’s provenance; ii) the extent of terrigenous supply; iii) environmental acidity during peat formation; and iv) the presence and composition of epigenetic mineralization within the coal seams. Because of the presumed abundant terrigenous supply, the concentrations of both Si and Al are higher than the world average for most of the studied coals. Exceptions are the Maritsa-West, Burgas, Staniantsi, Oranovo, Chukurovo and Pernik Basins, for which reduced terrigenous supply can be suggested. For most of the basins, both Si and Al demonstrate good positive correlation with the ash yields, thus arguing for predominant inorganic affinity. Relatively low Si/Al ratios (typically <2) and good positive correlation between Si and Al (ro>0.6) imply the predominant role of the clay mineral assemblages as the main source of the elements in coal. Quartz is presumed to have dominant role only in Maritsa-West Basin. Poorer or negative correlations with the ash yields in part of the studied basins (i.e. Svoge, Maritsa-West, Sofia, Burgas and Dobrudzha Basins) suggest either mixed or predominantly organic affinity of the elements. Release of Si and Al from the clay minerals during the peat formation/diagenesis and subsequent formation of organo-metallic complexes is considered to responsible for such affinity.

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Section: Resultsmentioning

confidence: 95%

Silicon and aluminum in Bulgarian coals

Zdravkov¹

2021

Rev. Bulg. Geol. Soc.

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“…Mixed organic/inorganic affinity (Beaton et al, 1991;Querol et al, 1997a;Sutcu, Karayiğit, 2015) or predominant inorganic affinity of Fe (Gluskoter et al, 1977;Querol et al, 1997bQuerol et al, , 2001aLiu et al, 2001;Zhao et al, 2017Zhao et al, , 2020Životić et al, 2019;Karayiğit et al, 2020) are much more readily reported. The research of Querol et al (2001b) on the mode of occurrence of selected elements in coal indicates organic affinity of only ~5-12% of iron.…”

Section: Resultsmentioning

confidence: 99%

“…Numerous authors relate Fe in coal solely to the presence of pyrite (Dill, Wehner, 1999;Ward et al, 1999;Karayiğit et al, 2000a, b;Querol et al, 2001a;Widodo et al, 2010). Iron-rich calcite and dolomite, together with siderite (Kortenski, 1992;Ward, 1992;Bai et al, 2015) or oxides (Životić et al, 2019;Karayiğit et al, 2020), however, can also be recognized as major Fe-bearing minerals in some coals. In addition, contact metamorphism and/or circulation of hydrothermal fluids within the coal seams might also result in increased iron concentrations in coal (Dai et al, 2007;.…”

Section: Resultsmentioning

confidence: 99%

Factors controlling the occurrence and distribution of iron in Bulgarian coals

Zdravkov¹

2020

Rev. Bulg. Geol. Soc.

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Coal of varying age (Upper Carboniferous to Pliocene) and coalification rank (lignite to anthracite) from nineteen coal-bearing basins and deposits, belonging to 8 coal-bearing provinces from Bulgaria, were examined for the occurrence and distribution of Fe. For the majority of the coals, the average Fe concentrations vary from 1.1 to 10.2 wt% and are higher than the World’s average. An exception exists only for Karlovo and Dobrudzha Basins, where slight depletion of Fe (<1 wt%) was established. On contrary, carbonaceous shales from the majority of the basins show Fe depletion in comparison to the Clarke values for clays. Based on the negative correlations with the ash yields, organic affinity of the element can be suggested for most of the studied coals. An exception exists for the Burgas Basin, for which predominantly inorganic affinity of the element can be suggested, whereas for Stanyantsi, Samokov, Bobov Dol, Dobrudzha and Svoge Basins mixed organic/inorganic affinity of Fe can be presumed. The element most probably predominantly occurs in the form of organometallic compounds, especially in the coals that formed in preferentially acidic peat-forming environment. Nevertheless, small contribution from biogenic iron cannot be excluded. The mineral form of Fe is probably mainly associated with sulfides, carbonates, and sulfates, although the presence of Fe oxides, silicates and hydroxides is also established. The analysis of Fe occurrence and its organic/inorganic affinity in Bulgarian coals reveal the following controlling factors: i) Fe concentration within the basin’s provenance; ii) the type (i.e. terrigenous or groundwater) of element supply; and iii) environmental conditions during peat-formation.

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“…Laudal, Benson, Palo, and Addleman (2018) report total lanthanide concentrations in the range 40-400 mg/kg, to be compared with the concentration 56 mg/kg used by Bengtsson 2018. Lower concentrations have however also been reported, (Životić et al, 2019;Adamidou et al, 2007).…”

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confidence: 87%

Hypothetical Soil Thresholds for Biological Effects of Rare Earth Elements

Bengtsson¹

2021

JAS

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Objectives: Anthropogenic exposures to rare earth elements are poorly known and there is limited information on their toxicity and ecotoxicity. At the same time, world production of rare earth elements has doubled every 15 years over the last half-century, and high environmental concentrations of gadolinium and lanthanum have already been found. The current review aims to give some estimates of overall exposures and an initial in-depth appraisal of thresholds for effects on agricultural soil. The results are envisaged to be used in initial assessments of agricultural soil where the natural concentrations have been anthropogenically enhanced. Methods: An extensive review has been made of available scientific literature. Criteria have been established for the selection and analysis of eligible research. For instance, only effects on soils with vegetation have been included in the assessment of biological effects. A species sensitivity distribution based on 25% inhibition of organism functions has been used to establish thresholds for effects on soil organisms. Results: Around the year 2000, mean anthropogenic contributions of lanthanides in European soil regions were at most a few per cent of the total soil content. Since then, they should have increased considerably. The proposed hypothetical threshold for agricultural soils is 1125 mg total rare earth element per kg of soil. This threshold is about 8 times the natural soil concentration. Conclusions: If this result holds up to scrutiny, it implies that general anthropogenic pollution by rare earth elements will not be a threat to agricultural sustainability for the coming generation. A preliminary assessment suggests that this threshold would also protect humans from adverse effects due to secondary exposure.

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Distribution of major and trace elements in the Kovin lignite (Serbia)

Cited by 10 publications

References 41 publications

Silicon and aluminum in Bulgarian coals

Silicon and aluminum in Bulgarian coals

Factors controlling the occurrence and distribution of iron in Bulgarian coals

Hypothetical Soil Thresholds for Biological Effects of Rare Earth Elements

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