Leaching characteristics of rare earth elements from coal ash using organosulphonic acids

Banerjee, Riya; Chakladar, Saswati; Mohanty, Ashok; Chattopadhyay, Shyamal Kumar; Chakravarty, Sanchita

doi:10.1016/j.mineng.2022.107664

Cited by 14 publications

(8 citation statements)

References 29 publications

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“…The distribution of REEs along with their modes of occurrence has been thoroughly investigated for unaltered thermal coals aiming at improving the efficiency of extraction of valuables (Fu 2022;Banerjee et al 2021Banerjee et al , 2022Das et al 2023;Pan et al 2019). Sequential leaching has been widely acknowledged as an important tool to delineate the elemental distribution in coal (Mittermüller et al 2016;Pan et al 2021).…”

Section: Introductionmentioning

confidence: 99%

Petrology and association of rare earth elements in magmatically altered high-ash coal of Indian origin

Banerjee,

Chakladar,

Kumar

et al. 2024

Int J Coal Sci Technol

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The extraction of valuables from waste has gained momentum. Thermal influence alters both the organic and inorganic components of coal. Insufficient knowledge on the association of rare earth elements (REEs) with the parent matrix of thermally altered high-ash coals (63% ash) limits the potential for such coals being utilized for isolation of valuables. In this study, we analyzed the distribution and occurrence modes of REEs within a magmatically altered high-ash coal via nine-step sequential extraction, combining Tessier and BCR methods. The total concentration of REEs in the coal sample, on whole coal basis, was found to be 820 ppm, which is significantly higher than the world average. Major mineral oxides were deduced to be those of Si, Fe, Al, Ca, Mg, and Ti. Sequential extraction confirmed that about 66% of HREE and 25% of LREE were included in the residual fraction. LREEs were concluded to be primarily in ionic form, whereas HREEs were speculated to be associated with the TiO2 phase. XRD analyses showed that thermal alteration affected the dolomite phase specifically, which selectively got removed where carbonate-bound elements were assessed. Petrographic analysis supported the magmatic influence and demonstrated the presence of mosaic structures and pores containing unfused vitrinite, with a reflectance value of 3.6. To summarize, the present study pertaining to delineation of association of valuables in high-ash heat-altered coals from an Eastern coalfield in India can potentially open up new avenues for utilizing such coals, which are otherwise considered waste.

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Section: Introductionmentioning

confidence: 99%

Petrology and association of rare earth elements in magmatically altered high-ash coal of Indian origin

Banerjee,

Chakladar,

Kumar

et al. 2024

Int J Coal Sci Technol

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“…Researchers have previously conducted investigations on the leaching characteristics of raw bituminous coal from different sources [5][6][7][8][9]. Zhang and Honaker leached the heavier density fractions of Pocahontas No.…”

Section: Introductionmentioning

confidence: 99%

Pilot Scale Testing of Lignite Adsorption Capability and the Benefits for the Recovery of Rare Earth Elements from Dilute Leach Solutions

Nawab

Honaker

2023

Minerals

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Naturally occurring organic materials containing humic acids show a strong affinity towards rare earth elements (REE) and other critical elements. Leaching experiments on lignite coal waste produced from construction sand production revealed that the contained REEs were associated with the organic matter. Furthermore, adsorption studies revealed that the lignite waste was capable of extracting REEs from a model solution and increased the REE content of the lignite waste by more than 100%. As such, this study aimed to utilize the lignite waste to adsorb REEs from pregnant leach solutions and acid mine drainage sources having low REE concentrations and subsequently leach the lignite material to produce pregnant leach solutions containing relatively high amounts of REEs, which benefits the performance and economic viability of downstream separation and purification processes. An integrated flowsheet was developed based on this concept and tested at a pilot scale. The pregnant leachate solution (PLS) was generated from a heap leach pad containing 2000 tons of Baker seam coarse refuse. The pilot scale circuit was comprised of aluminum precipitation, adsorption using the waste lignite, and rare earth-critical metal (RE-CM) precipitation stages in succession. The results indicated that the aluminum precipitation stage removed over 88% and 99% of the Al and Fe, respectively. The adsorption stage increased the REE content associated with the waste lignite from 457 ppm to 1065 ppm on a whole mass basis. Furthermore, the heavy REE (HREE) content in the feedstock increased by approximately 250%, which raised the percentage of HREE in the REE distribution by 19 absolute percentage points. In addition to the REEs, concentrations of other critical elements such as Mn, Ni, and Zn also improved by 75%, 37%, and 250%, respectively. Bench-scale tests revealed that increasing the solids concentration in the waste lignite and PLS mix from 1% to 20% by weight enhanced the adsorption efficiency from 32.0% to 99.5%, respectively. As such, a new flowsheet was proposed which provides significantly higher REE concentrations in the PLS that can be fed directly to solvent extraction and/or oxalic acid precipitation and, thereby, enhancing process efficiency and economics.

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“…Reducing the consumption of non-renewable natural resources and replacing them with industrial waste is one of the most important aspects of a sustainable development strategy. Fly ash is recognized as a potential source of rare earth elements [2,4,12,15]; however, the efficient extraction and isolation of valuable lanthanides remain elusive to date. In known cases, the described processes are too energy-and labor-intensive and involve the introduction of additional chemicals into the environment.…”

Section: Introductionmentioning

confidence: 99%

“…Chemical analysis, especially the determination of elements important for their strategic significance and human and environmental safety, is a vital part of scientific research as well as commercial analysis. There are several instrumental methods routinely utilized in determining the minor (0.1-1%) and trace (<0.1%) elements of CCRs: inductively coupled plasma mass spectrometry, ICP-MS; inductively coupled plasma optical emission spectroscopy, ICP-OES; X-ray fluorescence, XRF; and the less commonly used single-element atomic absorption spectroscopy, AAS [9][10][11][12][13][14][15][16][17].…”

Section: Introductionmentioning

confidence: 99%

Comparison of the Analytical Performance of Inductively Coupled Plasma Mass Spectrometry and Instrumental Neutron Activation Analysis Techniques in the Elemental Analysis of Coal Fly Ash

Chajduk,

Kalbarczyk

2023

Minerals

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Inductively coupled plasma mass spectrometry (ICP-MS) and instrumental neutron activation analysis (INAA) were applied to study the elemental content of coal combustion residues. Both methods’ analytical applicability and suitability for this type of material were described in detail. A certified reference material, fine fly ash (CTA-FFA-1), was used to examine the capabilities and validation of both methods. A comparison study allowed for the modification of the procedures for these materials (previously elaborated in the Institute of Nuclear Chemistry and Technology), resulting in more accurate data with lower uncertainty. We highlighted that INAA and ICPs complemented each other in the analysis of coal and coal combustion residues. The digestion procedure was an integral part of the measurement and affected the environmental analysis results. Both methods were applied to the chemical characteristics of coal ashes from household furnaces. The hard coal was from Polish, Columbian, and Kazakh mines. The majority of elements had similar concentrations, independently of coal origin. Because ash from domestic coal combustion is used as a fertilizer or an anti-icing agent, we assessed the potential environmental impact via leaching experiments (according to PN-EN 12457-2). The potential risk of soil contamination due to ash dumping around the house and its surroundings was determined as insignificant (for the elements investigated).

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Leaching characteristics of rare earth elements from coal ash using organosulphonic acids

Cited by 14 publications

References 29 publications

Petrology and association of rare earth elements in magmatically altered high-ash coal of Indian origin

Petrology and association of rare earth elements in magmatically altered high-ash coal of Indian origin

Pilot Scale Testing of Lignite Adsorption Capability and the Benefits for the Recovery of Rare Earth Elements from Dilute Leach Solutions

Comparison of the Analytical Performance of Inductively Coupled Plasma Mass Spectrometry and Instrumental Neutron Activation Analysis Techniques in the Elemental Analysis of Coal Fly Ash

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