Quantification of the modes of occurrence of 42 elements in coal

Finkelman, Robert B.; Palmer, Colin A.; Wang, Peipei

doi:10.1016/j.coal.2017.09.005

Cited by 288 publications

(158 citation statements)

References 54 publications

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“…), but more Ba, Br, Be, Co, Se, Sr, W, V and REE are of organic association and/or other phases. The result of this study is largely in accordance with those previous studies, with some difference probably due to different coal ranks [28] and place of origin. The sum of all rare earth elements (∑REE) as a whole largely has a positive correlation with ash yield with a R 2 value of 0.876 (Figure 6), suggesting that inorganic matter in the ROM coal holds more REE than that of the organic part [28,29].…”

Section: Organic Affinities Of Trace Elementssupporting

confidence: 92%

“…The result of this study is largely in accordance with those previous studies, with some difference probably due to different coal ranks [28] and place of origin. The sum of all rare earth elements (∑REE) as a whole largely has a positive correlation with ash yield with a R 2 value of 0.876 (Figure 6), suggesting that inorganic matter in the ROM coal holds more REE than that of the organic part [28,29]. Actually, REE includes 15 lanthanide elements and Y and Sc, which can be divided into two groups as the Light rare earth elements (LREE: La, Ce, Pr, Nd, Sm and Eu) and the Heavy rare earth elements (HREE: Gd, Tb, Dy, Y, Ho, Er, Tm, Yb and Lu).…”

Section: Organic Affinities Of Trace Elementssupporting

confidence: 92%

“…Cheng et al [13] investigated the Late Permian coal from the same region and also suggested that Mo, Ni, and Cd have relatively strong organic affinity. Finkelman et al [28] studied the modes of occurrence of 42 trace elements in coal by using sequential leaching and found that most of the elements in high rank coal are of inorganic modes of occurrence (such as clays, carbonates, sulfides, oxides, phosphates, silicates, etc. ), but more Ba, Br, Be, Co, Se, Sr, W, V and REE are of organic association and/or other phases.…”

Section: Organic Affinities Of Trace Elementsmentioning

confidence: 99%

“…For the coal in this research, the correlation coefficients between individual REE and ash yields were found to decline gradually from La to Lu (Figure 7), and the LREE/HREE is lower in light fractions (average at 3.29 for density from <1.60 g/cm 3 ) while much higher in heavy fractions (average at 4.29 for density >1.60 g/cm 3 ) ( Table 3), showing that LREE are more likely to be associated with inorganic matters. In other words, HREE have a stronger organic affinity than that of LREE [28,30,31]. Eskenazy [32,33] proposed that the formation of organometallic compounds by sorption on the coagulating humic and fulvic might be the bound mechanism for REE and organic matters in coal.…”

Section: Organic Affinities Of Trace Elementsmentioning

confidence: 99%

“…Some indicate that LREE have stronger organic affinity than HREE [13,37]; some found HREE have stronger organic affinity than LREE [28,29]; some suggest ignorable difference between LREE and HREE [33]; while Yang [38] found that REE's organic affinity increases from La to Eu, but decreases from Gd to Lu. Finkelman (2018) [28] suggested that HREE have stronger organic affinity than LREE. The study also found that the difference in organic affinity between LREE and HREE is even bigger in high rank coal than that in low rank coal, which means coal rank influences the REE's modes of occurrence.…”

Section: Organic Affinities Of Trace Elementsmentioning

confidence: 99%

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Washability and Distribution Behaviors of Trace Elements of a High-Sulfur Coal, SW Guizhou, China

et al. 2018

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Abstract:The float-sink test is a commonly used technology for the study of coal washability, which determines optimal separation density for coal washing based on the desired sulfur and ash yield of the cleaned coal. In this study, the float-sink test is adopted for a high-sulfur Late Permian coal from Hongfa coalmine (No.26), southwestern Guizhou, China, to investigate its washability, and to analyze the organic affinities and distribution behaviors of some toxic and valuable trace elements. Results show that the coal is difficult to separate in terms of desulfurization. A cleaned coal could theoretically be obtained with a yield of 75.50%, sulfur 2.50%, and ash yield 11.33% when the separation density is 1.57 g/cm 3 . Trace elements' distribution behaviors during the gravity separation were evaluated by correlation analysis and calculation. It was found that Cs, Ga, Ta, Th, Rb, Sb, Nb, Hf, Ba, Pb, In, Cu, and Zr are of significant inorganic affinity; while Sn, Co, Re, U, Mo, V, Cr, Ni, and Be are of relatively strong organic affinity. LREE (Light rare earth elements), however, seem to have weaker organic affinity than HREE (Heavy rare earth elements), which can probably be attributed to lanthanide contraction. When the separation density is 1.60 g/cm 3 , a large proportion of Sn, Be, Cr, U, V, Mo, Ni, Cd, Pb, and Cu migrate to the cleaned coal, but most of Mn, Sb and Th stay in the gangue. Coal preparation provides alternativity for either toxic elements removal or valuable elements preconcentration in addition to desulfurization and deashing. The enrichment of trace elements in the cleaned coal depends on the predetermined separation density which will influence the yields and ash yields of the cleaned coal.

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Section: Organic Affinities Of Trace Elementssupporting

confidence: 92%

Section: Organic Affinities Of Trace Elementssupporting

confidence: 92%

Section: Organic Affinities Of Trace Elementsmentioning

confidence: 99%

Section: Organic Affinities Of Trace Elementsmentioning

confidence: 99%

Section: Organic Affinities Of Trace Elementsmentioning

confidence: 99%

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Washability and Distribution Behaviors of Trace Elements of a High-Sulfur Coal, SW Guizhou, China

et al. 2018

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Research on how acidification affects the coal's microscopic pore structure in the Guizhou mining region

He,

Li,

Xue

et al. 2023

Energy Science & Engineering

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By eliminating their minerals, acidification technology makes coal seams more permeable. Acidification technology were conducted in the Farr and Qinglong mining areas using a mixed acid solution to study the impact of acidification technology on increasing the permeability of primary structural coals in the Guizhou region, China. The microphysical and chemical structure of the coal samples before and after acidification transformation was compared using X‐ray diffraction, scanning electron microscope, mercury intrusion porosimetry, and Fourier transform infrared spectrometry experiments. The results show that after acidification, the volatile matter content is reduced by 4.2% and 16.25%, the carbon content is increased, the degree of coalification is deepened, the gas content of the coal seam is elevated, and the gas source is more abundant. The minerals on the surface are dissolved to different degrees, and the pores and cracks are dredged, so that the surface of the coal samples shows better connectivity, which is conducive to the diffusion and transport of coalbed methane. The volume and pore diameter of the macropore and mesopore in the Farr coal samples were improved after acidification, and the fractal structure was more prominent, the pore connectivity was good, and the pore diameter of the Qinglong coal samples was greatly increased. The content of oxygen‐containing functional groups increased by 11.2% and 2.1%, respectively, which is conducive to the desorption of coalbed methane after acidification, and with the increasing degree of metamorphism of the coal samples, the higher the content of oxygen‐containing functional groups was and the less pronounced the effect of acidification. Acidification technology can effectively remove the minerals in the coal body and has a good effect on penetration enhancement, and the results of the study can provide certain theoretical references for the penetration enhancement of coal seams in Guizhou mining areas.

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