Improved sequential extraction method for determination of alkali and alkaline earth metals in Zhundong coals

Yang, Yanmei; Wu, Yuxin; Hai, Zhang; Zhang, Man; Liu, Qing; Yang, Hee‐Man; Lü, Junfu

doi:10.1016/j.fuel.2016.05.014

Cited by 61 publications

(39 citation statements)

References 12 publications

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“…As shown in Figure , Ca and Mg species are mainly HCl soluble. Yang et al reported that these metals originate mainly from carbonates including some sulfates. Therefore, to summarize the results, insoluble AAEMs are dominated by sodium, potassium, and calcium species, HCl‐soluble AAEMs are dominated by calcium and magnesium species, water‐soluble AAEMs are dominated by sodium species, and the content of ion‐exchangeable AAEMs is less than the contents of other forms and dominated by sodium and calcium species.…”

Section: Resultsmentioning

confidence: 99%

“…However, Matsuoka et al investigated the extraction solutions used in the experiment and found that not only nonmineral Ca but also a portion of the Ca contained in mineral, such as CaCO 3 , was removed by leaching with ammonium acetate and that the leaching method leads to overestimation of the amount of nonmineral Ca. To solve this problem, an improved sequential extraction method was proposed by Yang et al In the proposed method, NH 4 Cl is recommended instead of NH 4 OAc for exchangeable AAEMs determination to avoid overdetermination of exchangeable Ca and Mg due to the high solubility of carbonates and sulfates in the conventionally used neutral NH 4 OAc, but the method of using centrifugal separation is an easy method for returning the solid residue to the liquid in the solid–liquid separation stage.…”

Section: Introductionmentioning

confidence: 99%

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Catalytic effect of alkali and alkaline earth metals in different occurrence modes in Zhundong coals

Liang

Xie

Zhou

et al. 2018

Asia-Pacific J Chem Eng

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Two Zhundong coals, Nanlutian coal and Wucaiwan coal, were pretreated by a sequential extraction; alkali and alkaline earth metals (AAEMs) in different occurrence modes were separated from the coal samples. The contents and compositions of AAEMs in coal were investigated, and then a kinetic model was used to quantify their catalytic behavior. Experimental results show that the content of water-soluble AAEMs is high and that these AAEMs are composed mainly of NaCl and other sodium species. After removing these AAEMs from the Nanlutian coal and the Wucaiwan coal, the activation energy required for gasification increases by 7.679 and 4.035 kJ mol −1 , respectively. Some of the sodium, potassium, calcium, and magnesium species exist in ion-exchangeable form, but the content is low. When the ion-exchangeable AAEMs were removed, the activation energy increases by 5.117 and 1.400 kJ mol −1 , respectively. The content of acid-soluble AAEMs is high and composed mainly of calcium and magnesium salts. After removing these AAEMs, the activation energy was increased by 2.002 and 0.537 kJ mol −1 , respectively.Finally, the content of insoluble AAEMs is very high, and this fraction is composed mainly of silicates and aluminosilicates. As these AAEMs are stable, their catalytic effect could be ignored.

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Section: Resultsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Catalytic effect of alkali and alkaline earth metals in different occurrence modes in Zhundong coals

Liang

Xie

Zhou

et al. 2018

Asia-Pacific J Chem Eng

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“…This implies that the basic oxides (AAEMs) have a catalytic role rather than acid oxides on the gasification. Yang et al [27] have studied occurrence modes and contents of AAEMs in three kinds of Zhundong coals. It was found that Na was mainly water soluble (Naw/Natotal = 50-85%), which was halite or in the form of surface bound Na + .…”

Section: Effect Of Aaems During Gasificationmentioning

confidence: 99%

CO<sub>2</sub> Gasification Reactivity of Chars Derived From Zhundong Coal

Guan

Zhang

2017

Preprint

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“…Alkali metals and alkaline earth metals (these elements play a decisive role in the formation of ultrafine-mode PM) have a high proportion in the minerals of Zhundong coal, and their occurrence forms are various [38]. These characteristics make Zhundong coal a suitable medium for studying the influence of the mineral occurrence forms on the PM 10 emissions.…”

Section: Introductionmentioning

confidence: 99%

Contribution of Minerals in Different Occurrence Forms to PM10 Emissions during the Combustion of Pulverized Zhundong Coal

Zhao

Gao

et al. 2019

Energies

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The comprehensive and quantitative assessment of the contribution of minerals with different occurrence forms to particulate matter with an aerodynamic diameter of less than 10 μm (PM10) emitted from the combustion of Zhundong coal is of great significance for its clean utilization and for the development of particulate matter formation mechanisms. Samples with simplified occurrence forms of inorganic species were prepared by water-, salt-, and acid-washing of Zhundong coal. The samples were combusted in a drop-tube furnace under 20 vol % oxygen at 1250 °C, and the emitted PM10 was collected. The effects of the minerals in different forms on the PM10 emissions were analyzed by comparing the mass concentration distributions, yields, and elemental compositions of PM10. The results showed that water-soluble, ion-exchangeable, acid-soluble, and acid-insoluble minerals contributed 8.3%, 37.8%, 29.7%, and 24.2% of the PM10 emissions, respectively. The distributions of the Na, Mg, Ca, and Fe contents in PM10 were bimodal, as follows: 63.6% of Na and 54.5% of Fe were deported to the ultrafine mode PM, while 63.6% of Mg and 86.6% of Ca were deported to the coarse mode PM. The distributions of the Si and Al contents were unimodal, namely: 92.9% of Si and 90.5% of Al were deported to the coarse mode PM. Water-soluble Na; ion-exchanged Mg, Ca, and Fe; and acid-insoluble Si and Al played decisive roles in the distribution of minerals in PM10.

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Improved sequential extraction method for determination of alkali and alkaline earth metals in Zhundong coals

Cited by 61 publications

References 12 publications

Catalytic effect of alkali and alkaline earth metals in different occurrence modes in Zhundong coals

Catalytic effect of alkali and alkaline earth metals in different occurrence modes in Zhundong coals

CO<sub>2</sub> Gasification Reactivity of Chars Derived From Zhundong Coal

Contribution of Minerals in Different Occurrence Forms to PM10 Emissions during the Combustion of Pulverized Zhundong Coal

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