Characterization of rare earth elements present in coal ash by sequential extraction

Park, Sungyoon; Kim, Min‐Soo; Lim, Yejee; Yu, Jimin; Chen, Siyu; Woo, Sang Woon; Yoon, Sangho; Bae, Sungjun; Kim, Han Soo

doi:10.1016/j.jhazmat.2020.123760

Cited by 60 publications

(28 citation statements)

References 32 publications

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“…The quantity of scandium that can be found in the ashes varies in function of coal origin [35][36][37]. Park et al [38] reported Sc concentration in the Korean fly and bottom ashes to be 63.9 ± 5.5 ppm and 54.4 ± 5.7 ppm, respectively. US fly ashes were reported to contain 1 to 4 times the content of scandium in the upper continental crust, with mean values per basin varying between 24 and 38.5 ppm [37].…”

Section: Coal Ashmentioning

confidence: 99%

“…The same study reported occurrence of Sc-containing xenotime in the coal sample, prior to ashing. Park et al [38] found that most scandium dissolved during the last step of Tessier sequential extraction (using hydrofluoric and nitric acids under high temperature and pressure) and the last step of European Community Bureau of Reference sequential extraction (mixture of hydrochloric acid and nitric acid at elevated temperatures) indicating that scandium in the ashes was strongly bound in crystalline structures. A significant portion of other REEs was also extracted in this last extraction step, which explains the necessity of using strong acids for the recovery of REEs from fly ashes.…”

Section: Coal Ashmentioning

confidence: 99%

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The Future of Scandium Recovery from Wastes

Chernoburova

Chagnes²

2021

International Conference on Raw Materials and Circular Economy

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With growing demand for renewable and clean energy technologies, the need in rare earth metals is increasing. Scandium, which is often considered a rare earth element (REE), is a critical metal mainly used in solid oxide fuel cells (SOFCs) and high strength aluminum alloys used in aerospace and 3D printing applications. Furthermore, scandium supply is limited due to its scarcity and the high cost of its production in Asia and Russia while Europe has no production of scandium. Therefore, scandium extraction from alternative resources such as secondary resources located in Europe is of great concern. Within this context, this work provides a condensed state-of-art review of the issue of scandium recovery from industrial wastes. Priority was given to addressing the technological and economic challenges associated with the recovery of scandium from the said residues, with particular emphasis on the bauxite residue from alumina production, which represents nearly 5 million tons on dry basis per year in Europe.

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Section: Coal Ashmentioning

confidence: 99%

Section: Coal Ashmentioning

confidence: 99%

The Future of Scandium Recovery from Wastes

Chernoburova

Chagnes²

2021

International Conference on Raw Materials and Circular Economy

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“…With the development of modern technologies, the demand for REE (rare-earth elements), 17 chemical elements, which include two elements from the scandium group (scandium and yttrium) and all lanthanides, has also increased. Currently, intensive work is being carried out on the recovery of REE from coal deposits and coal ash [72][73][74][75]. In some coal deposits, mainly in China [76][77][78][79][80], REE concentrations are higher than their Clarke values.…”

Section: For Example Such Elements As Bismuth (Bi) Chromium (Cr) Cuprum (Cu) Germanium (Ge) Hafnium (Hf) Niobium (Nb) Tungsten (W) and Ytmentioning

confidence: 99%

Selected Critical Raw Materials in Waste from Coal Gasification in Poland

Bielowicz

2021

Energies

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In an effort to identify new sources of critical raw materials (CRMs) possibility of recovering selected CRMs from Polish coals, chars, and ashes resulting from the combustion of coals and chars was investigated. The samples were collected from pilot fluidized bed gasification systems. The search for CRMs in coal gasification wastes has not been widely reported before. The study used 2 bituminous coal and 1 lignite sample; the concentration of individual critical raw materials (CRMs) was analyzed using the ICP-MS method. The obtained results were compared with Clarke values in coal ash and in the Earth’s crust, and with the adopted cut-off grade. As shown by the analysis, the highest concentrations of CRMs can be found in fly ash, mainly in samples from the eastern part of the Upper Silesian Coal Basin. This applies mostly to Be, Cs, or Sb due to the fact that their concentrations were found to be higher than the Clarke value in the Earth’s crust; the mentioned fly ashes could be used as potential sources of critical elements if appropriate recovery technologies are developed. In addition, the tested materials have elevated Se, Pb, Ni concentrations, but their recovery is currently not economically viable. Compared to the currently adopted cut-off grade levels, there are no critical elements in the analyzed coal gasification waste that could be recovered.

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“…The growing demand rate (3.7-8.6% per year) and their supply risk led to the classification of REEs as "critical" raw materials and has stimulated the search for alternative sources [6][7][8][9][10][11]. Coal, and especially coal combustion ashes, have been pointed out as promising sources of REEs, and many studies have been conducted concerning the REE contents, the modes of occurrence, and the extraction potential [11][12][13][14][15][16][17][18][19][20][21][22][23][24][25][26][27][28][29][30].…”

Section: Introductionmentioning

confidence: 99%

Integrative Study Assessing Space and Time Variations with Emphasis on Rare Earth Element (REE) Distribution and Their Potential on Ashes from Commercial (Colombian) Coal

et al. 2022

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The increasing demand for rare earth elements (REEs), which is associated with their economic importance and the supply risk, has motivated the research for alternative secondary sources of these elements. Coal and coal combustion ash have been pointed out as promising REE raw materials. This research seeks to understand REE fractionation, from feed coals to ashes, considering seasonal variations, and to assess the trends within the ash fractions that can be used for further beneficiation processes. Colombian commercial feed coals, combustion ashes, and their respective fractions were sampled from a Portuguese power plant and were characterized via petrographical, mineralogical, and chemical analyses. The total REE concentrations in the feed coals studied range between 6.97 and 23.15 ppm, while, in the ashes, they vary from 159.9 to 266.6 ppm. Fly ash (FA) from electrostatic precipitator (ESP) presented higher concentrations than the bottom (BA) and economizer (ECO) ashes. Furthermore, REEs and the LREE/HREE ratio increased slightly towards the back rows of the ESP. In the feed coals, the REEs are significantly correlated with ash, and they occur in micrometric phosphate minerals intermixed with clays. In the ashes, the REEs were mostly detected in micrometric particles, with P and Al-Si as the major components. The results from the fractioned samples show that the REEs were enriched in the fine (<25 µm) and nonmagnetic fractions of the ESP FA. A single trial combining sieving and magnetic separation enabled the attainment of a REE recovery of 53%, and a final enrichment factor of 1.25. Coal combustion ashes and their respective size fractions are promising REE raw materials; however, the REE oxide concentrations are below the economical cutoff of 1000 ppm.

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Characterization of rare earth elements present in coal ash by sequential extraction

Cited by 60 publications

References 32 publications

The Future of Scandium Recovery from Wastes

The Future of Scandium Recovery from Wastes

Selected Critical Raw Materials in Waste from Coal Gasification in Poland

Integrative Study Assessing Space and Time Variations with Emphasis on Rare Earth Element (REE) Distribution and Their Potential on Ashes from Commercial (Colombian) Coal

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