Abstract:Coal Fly Ash (CFA) is a hazardous waste from coal-fired power plants, but has increasingly become a popular supplementary cementitious material for cement in the construction industry. As a secondary resource of REE, its main advantage lies in its fine particle size that eliminates the need for costly and energy-intensive comminution. In this study, the potential of CFA from the Philippines as a secondary REE resource was investigated by direct leaching of REEs with hydrochloric acid (HCl). The CFA sample came… Show more
“…Products M n+ (aq) + nA − (aq) + yL (org) M(A) (n) •yL (org) − /(M (hyd) •L (y) (n+1) •nA − ) org (5) Furthermore, it is observed that CMPO and DGA have similar behavior in the extraction of Am(III) [52]. ATR-FTIR analysis of the loaded resin shows that the peaks of C=O and P=O have shifted, indicating that they have coordinated with REEs after the adsorption of Y and Ce.…”
Section: Reactantsmentioning
confidence: 99%
“…The Rare-Earth Elements (REEs), a group of 17 elements exhibiting similar chemical properties, have become vital in the last 30 years for the advancement of renewable energy and clean storage technologies owing to their unique magnetic, phosphorescent, and catalytic properties [1][2][3]. In 3 MW wind turbines, for example, 3 tons of REEs are needed [4], while in electric vehicles (EVs), REEs like neodymium (Nd), praseodymium (Pr), samarium (Sm), and dysprosium (Dy) are used in high efficiency and strong permanent magnets [2,5,6]. In 2012, the demand for Dy and Nd for the next 25 years was projected to increase by at least 700% and 2600%, respectively [7].…”
Rare earth elements (REEs) are crucial for green energy applications due to their unique properties, but their extraction poses sustainability challenges because the global supply of REEs is concentrated in a few countries, particularly China, which produces 70% of the world’s REEs. To address this, the study investigated TK221, a modified extraction chromatographic resin featuring diglycolamide (DGA) and carbamoyl methyl phosphine oxide (CMPO), as a promising adsorbent for REE recovery. The elemental composition and functional groups of DGA and CMPO on the polystyrene-divinylbenzene (PS-DVB) support of TK221 were confirmed using scanning electron microscopy with energy dispersive X-ray spectroscopy (SEM-EDX), attenuated total reflectance Fourier transform infrared spectroscopy (ATR-FTIR), and X-ray photoelectron spectroscopy (XPS). The adsorption kinetics of neodymium (Nd), yttrium (Y), cerium (Ce), and erbium (Er) followed the pseudo-second-order kinetic model and Langmuir isotherm, indicating monolayer chemisorption. Furthermore, iron (Fe) adsorption reached apparent equilibrium after 360 min, with consistent Fe adsorption observed at both 360 min and 1440 min. The inclusion of Fe in the study is due to its common presence as an impurity in most REE leachate solutions. The Fe adsorption isotherm results are better fitted with the Langmuir isotherm, implying chemisorption. Maximum adsorption capacities (qmax) of the resin were determined as follows: Nd (45.3 mg/g), Ce (43.1 mg/g), Er (35.1 mg/g), Y (15.6 mg/g), and Fe (12.3 mg/g). ATR-FTIR analysis after adsorption suggested that both C=O and P=O bands shifted from 1679 cm−1 to 1618 cm−1 and 1107 cm−1 to 1142 cm−1 for Y, and from 1679 cm−1 to 1607 cm−1 and 1107 cm−1 to 1135 cm−1 for Ce, implying possible coordination with REEs. These results suggest that TK221 has a huge potential as an alternative adsorbent for REE recovery, thus contributing to sustainable REE supply diversification.
“…Products M n+ (aq) + nA − (aq) + yL (org) M(A) (n) •yL (org) − /(M (hyd) •L (y) (n+1) •nA − ) org (5) Furthermore, it is observed that CMPO and DGA have similar behavior in the extraction of Am(III) [52]. ATR-FTIR analysis of the loaded resin shows that the peaks of C=O and P=O have shifted, indicating that they have coordinated with REEs after the adsorption of Y and Ce.…”
Section: Reactantsmentioning
confidence: 99%
“…The Rare-Earth Elements (REEs), a group of 17 elements exhibiting similar chemical properties, have become vital in the last 30 years for the advancement of renewable energy and clean storage technologies owing to their unique magnetic, phosphorescent, and catalytic properties [1][2][3]. In 3 MW wind turbines, for example, 3 tons of REEs are needed [4], while in electric vehicles (EVs), REEs like neodymium (Nd), praseodymium (Pr), samarium (Sm), and dysprosium (Dy) are used in high efficiency and strong permanent magnets [2,5,6]. In 2012, the demand for Dy and Nd for the next 25 years was projected to increase by at least 700% and 2600%, respectively [7].…”
Rare earth elements (REEs) are crucial for green energy applications due to their unique properties, but their extraction poses sustainability challenges because the global supply of REEs is concentrated in a few countries, particularly China, which produces 70% of the world’s REEs. To address this, the study investigated TK221, a modified extraction chromatographic resin featuring diglycolamide (DGA) and carbamoyl methyl phosphine oxide (CMPO), as a promising adsorbent for REE recovery. The elemental composition and functional groups of DGA and CMPO on the polystyrene-divinylbenzene (PS-DVB) support of TK221 were confirmed using scanning electron microscopy with energy dispersive X-ray spectroscopy (SEM-EDX), attenuated total reflectance Fourier transform infrared spectroscopy (ATR-FTIR), and X-ray photoelectron spectroscopy (XPS). The adsorption kinetics of neodymium (Nd), yttrium (Y), cerium (Ce), and erbium (Er) followed the pseudo-second-order kinetic model and Langmuir isotherm, indicating monolayer chemisorption. Furthermore, iron (Fe) adsorption reached apparent equilibrium after 360 min, with consistent Fe adsorption observed at both 360 min and 1440 min. The inclusion of Fe in the study is due to its common presence as an impurity in most REE leachate solutions. The Fe adsorption isotherm results are better fitted with the Langmuir isotherm, implying chemisorption. Maximum adsorption capacities (qmax) of the resin were determined as follows: Nd (45.3 mg/g), Ce (43.1 mg/g), Er (35.1 mg/g), Y (15.6 mg/g), and Fe (12.3 mg/g). ATR-FTIR analysis after adsorption suggested that both C=O and P=O bands shifted from 1679 cm−1 to 1618 cm−1 and 1107 cm−1 to 1142 cm−1 for Y, and from 1679 cm−1 to 1607 cm−1 and 1107 cm−1 to 1135 cm−1 for Ce, implying possible coordination with REEs. These results suggest that TK221 has a huge potential as an alternative adsorbent for REE recovery, thus contributing to sustainable REE supply diversification.
“…The most notorious and widely reported impacts of coal utilization is related to the air. Coal combustion causes serious environmental issues like the generation of fly and bottom ashes containing soluble B and Se, release of particulate matter (PM), and emissions of hazardous pollutants like Hg, As, CO 2 , SO x , and NO x to the air [ [13] , [14] , [15] ]. Boron and Se are essential micronutrients but toxic at high concentrations to animals and humans [ 16 , 17 ].…”
Section: Introductionmentioning
confidence: 99%
“…In some countries, these ashes are disposed of in special landfills handling hazardous wastes. However, recently, both of fly and bottom ashes were utilized for many purposes in cement industries as well as agriculture [ 14 , 22 ]. Fig.…”
“…To technically and economically render global coal ash deposits resourceful for REEs, significant research input in industry and academia on a global basis is essential, and such an initiative will be a stepping stone for greener alternatives to producing REEs , given the environmental pollution associated with conventional mining practices (Zapp et al, 2022;Yin et al, 2021;. Consequently, the scientific literature on the extraction of REEs from coal ash abounds (Seferinoğlu,2003;Dahan, et al, 2022;Prihutami et al, 2021;Pan et al, 2020).While significant breakthrough in research and commercialization of research findings is yet to be realized, intensive research has reported the advantages and shortfalls in light of technical and economic viabilities (Huang et al, 2019;Miranda et al, 2022;Das et al, 2018;Kim et al, 2019). Moreover, the development of suitable chemical and physical extraction process for the extraction of REEs from coal ash draws on knowledge of their occurrence in these ashes.…”
The orbital elactronic structure of Rare Earth Elements (REEs) contains many unpaired electrons which render them capable of storing large amount of magnetic energy in addition to being critical for hitech applications. Geological deposits are their conventional sources, and the current supply chain relies on production from these deposits. However, given their critical roles in the anticipated global energy transition, there is the need to explore other viable sources to supplement current and future supplies chains.
REEs occur in coal as accessory minerals and their concentration in coal ash to levels that rival those of geological deposits has been estab;ished by sophisticated analytical chemical methods. Conmventional hydrometallurgical processes rely on acid leaching, using tioxic mineral acids. Meanwhile, organosulfonic acids have pKa values that rival those of conventional minerals acid and can, therefore, be used in hydrometallurgy but their uses in this regard are not well documented in the literature. In this extensive review, we have covered geological sources of REEs exaustively in addition to showing the potential of organosulfonic acids as environmentally benign lixiviants for REEs extraction from coal ash. We have also shown how process optimization can be achieved using advance technologies while using organisulfonic acids. Moreover, we have shown current and future global market trends regarding the production of select organosulfonic acids, and the anticipated global increase in their production motivates the use of organosulfonic acids as viable lixiviants for REEs extraction from caol ash deposits.
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