Yttrium partitioning and associations in coal-combustion ashes prior to and after their leaching in HCl

Bartoňová, Lucie; Serenčíšová, Jana; Čech, Bohumír

doi:10.1016/j.fuproc.2018.01.011

Cited by 16 publications

(5 citation statements)

References 43 publications

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“…71 Accordingly, previous studies have investigated both direct leaching, where no pre-treatment of the CCBs is performed, and indirect leaching, where the CCBs are chemically or physically treated prior to acid leaching, as well as the impacts of different acids, lixiviants, alkaline treatments, and/or experimental conditions on leaching efficiency. 36,71,78,79 Leaching results presented here include the percent LREE, HREE, and TREE released from each CCB following leaching by 3 M HCl (Fig. 2), as well as the major and trace metals (Fig.…”

Section: Acid Leachingmentioning

confidence: 99%

Insights into the rare earth element potential of coal combustion by-products from western Canada

Bishop

Shivakumar

Alessi

et al. 2023

Environ. Sci.: Adv.

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Section: Acid Leachingmentioning

confidence: 99%

Insights into the rare earth element potential of coal combustion by-products from western Canada

Bishop

Shivakumar

Alessi

et al. 2023

Environ. Sci.: Adv.

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“…The existence of nano-sized REE-bearing particles in carbon was reported in fly ashes derived from bituminous coals [20,114,115]. Even so, most of the studies show that the REEs in coal combustion ashes are mainly associated with aluminosilicate glass (e.g., [9,15,24,27,96,107,[116][117][118][119]). This association could be the result of the incorporation of the REE-bearing phases, or, less probably, to the REE diffusion into the glass phase [41].…”

Section: Geochemical Associationsmentioning

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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“…Coal has long been a reliable energy source and currently, it is also intensively studied as the source of critical elements, such as REE and Y [1,2]; Ge and Ga [3][4][5]; Li [6]; Nb [5,7]; U, Se, and Re [6]; or Ta, Zr, and Hf [7]. However, due to the presence of minor and trace elements, it can be responsible for serious pollution problems [8][9][10][11].…”

Section: Introductionmentioning

confidence: 99%

Distribution of As within Magnetic and Non-Magnetic Fractions of Fluidized-Bed Coal Combustion Ash

Kovár

Bartoňová

2021

Minerals

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Separation of coal ash into magnetic and non-magnetic fractions facilitates their utilization when processed separately. Due to desulphurization additives added to coal during the fluidised-bed combustion, non-magnetic fractions often contain elevated CaO levels (while magnetic concentrates are typically rich in Fe2O3). Both CaO and Fe2O3 are known for their ability to bind As during the combustion, whose distribution is a crucial parameter in terms of proper utilization of these fractions. Therefore, the study deals with the As partitioning within magnetic and non-magnetic fractions of fluidized-bed coal combustion ashes. Two different (successive) procedures of dry magnetic separation were used to separate each ash into strongly magnetic, less magnetic, and a non-magnetic fraction. Due to their optimal utilization, the concentrations of As and other target elements in these fractions were evaluated and compared. Magnetic concentrates from the first separation step (in vibrofluidized state) contained 60–70% Fe2O3, magnetic concentrates separated manually out of the residues after the first separation contained 26–41% Fe2O3, and the non-magnetic residues contained 2.4–3.5% Fe2O3. Arsenic levels were the highest in the non-magnetic residues and gradually decreased with the increasing Fe2O3 content in the magnetic fractions. The dominant As association in the studied samples was to CaO (r = +0.909) and with SO3 (r = +0.906) whereas its joint occurrence with Fe2O3 was improbable (r = −0.834).

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Yttrium partitioning and associations in coal-combustion ashes prior to and after their leaching in HCl

Cited by 16 publications

References 43 publications

Insights into the rare earth element potential of coal combustion by-products from western Canada

Insights into the rare earth element potential of coal combustion by-products from western Canada

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

Distribution of As within Magnetic and Non-Magnetic Fractions of Fluidized-Bed Coal Combustion Ash

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