Rare earth element extraction from pretreated bastnäsite in supercritical carbon dioxide

Sinclair, Laura; Baek, Donna L.; Thompson, John F.; Tester, Jefferson W.; Fox, Robert V.

doi:10.1016/j.supflu.2017.01.005

Cited by 35 publications

(21 citation statements)

References 25 publications

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“…16, 26, and 27°and Nd (CO 3 )(OH) at 2θ ca. 23,31,35,44 and 47°(Figure 1b). [35] However, the presence of oxycarbonate -Nd 2 O 2 CO 3 (2θ ca.…”

Section: Resultsmentioning

confidence: 99%

“…23,31,35,44 and 47°(Figure 1b). [35] However, the presence of oxycarbonate -Nd 2 O 2 CO 3 (2θ ca. 11, 23, 26, 31, 34, 46, 48, 56 and 58°), already identified in the Cu- containing samples could not be discarded.…”

Section: Resultsmentioning

confidence: 99%

“…31 and 44° and Nd 2 O 2 CO 3 at 2θ ca. 31, 46 and 56° (Figure a) . Therefore, it seems that neodymium is responsible for the stabilization of carbonates in the sample.…”

Section: Resultsmentioning

confidence: 99%

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Effect of Neodymium on the Physico‐chemical Properties and N₂O Decomposition Activity of Co(Cu)−Al Mixed Oxides

Jabłońska

Nocuń

et al. 2019

ChemCatChem

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Cu−Al and Co−Al (M/Al=0.8/0.2, molar ratio; M=Cu or Co) mixed metal oxides showed a moderate activity in N2O decomposition (deN2O) with full conversion at about 500–550 °C. Addition of Nd modified the physico‐chemical and catalytic properties of both Cu−Al and Co−Al materials, though an optimal Nd loading was required. The addition of Nd in Cu0.8Al0.2 and Co0.8Al0.2 with Nd/Co(Cu)/Al = 0.5/0.8/0.2 molar ratio, improved significantly their catalytic activity. In particular, the temperatures needed for full N2O conversion were 100 °C lower than those of the bare materials. Furthermore, the most active Nd0.5Co0.8Al0.2 catalyst exhibited a stable 60 % N2O conversion at 450 °C for 50 h in presence of NO (200 ppm), O2 (20,000 ppm) and H2O (2500 ppm). The enhancement in the activity of both Cu‐ and Co‐containing materials was related to the formation of CuNd2O4 for Nd0.5Cu0.8Al0.2 and NdCoO3 for Nd0.5Co0.8Al0.2. The presence of CuNd2O4 or NdCoO3 accounted for changes in redox properties, e. g., easier reduction or faster release of oxygen, and in turn an increased catalyst activity in deN2O. The investigation of rare earth‐based catalysts for deN2O is limited in the scientific literature, while a comprehensive understanding of the involved active species may facilitate a knowledge‐based catalyst optimization.

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“…16, 26, and 27°and Nd (CO 3 )(OH) at 2θ ca. 23,31,35,44 and 47°(Figure 1b). [35] However, the presence of oxycarbonate -Nd 2 O 2 CO 3 (2θ ca.…”

Section: Resultsmentioning

confidence: 99%

Section: Resultsmentioning

confidence: 99%

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Effect of Neodymium on the Physico‐chemical Properties and N₂O Decomposition Activity of Co(Cu)−Al Mixed Oxides

Jabłońska

Nocuń

et al. 2019

ChemCatChem

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“…Sinclair et al [37] showed that this adduct can leach rare earth metals on its own while other researchers [38,39,40], also reported its use as a ligand. Subsequently, the influence of the adduct as an extractant was also studied.…”

Section: Table 1 Ligands Selected For Investigation In This Studymentioning

confidence: 99%

Selection of a suitable ligand for the supercritical extraction of gold from a low-grade refractory tailing

Dyk

Mawire

Potgieter

et al. 2022

The Journal of Supercritical Fluids

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Reprocessing tailings for gold recovery is generating new low-grade refractory secondary tailings. Unlocking gold trapped within these secondary tailings potentially holds additional economic value. In this study, the use of supercritical carbon dioxide (scCO2) at 100 bar and 40 °C for gold extraction from such a secondary gold tailings sample (0.27 g/t) was investigated. The research identified and screened the following ligands as suitable extractants for gold in scCO2, i.e. 3-(trifluoromethyl)-phenyl-thiourea (TPT), 1,1,1-trifluoro-2,4pentanedione (TFA), betaine bis(trifluoromethylsulfonyl)imide ([Hbet][TF2N]), 4-methyl-4H-1,2,4-triazole-3-thiol (MHTT) and hexafluoroacetylacetone (HFA). Results from screening experiments showed that extraction of gold for all ligands in the presence of a tri-n-butyl phosphate-nitric acid adduct (TBP-HNO3) as oxidant exceeded 50% after 18 h, with the highest extraction offered by [Hbet][TF2N] (82% after 24 h). A comparative study, where no scCO2 was present, showed that the presence of scCO2 offered a distinct advantage in extraction.

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“…Carefully choosing a sufficiently soluble extractant that rapidly forms ligand-cerium complexes with a high extraction capacity is crucial. The most commonly used complex for Ce extraction in SC-CO 2 is TBP-HNO 3 [6][7][8][9][10], but the ore has to be pretreated to achieve good extraction capacities (< 5% without vs ~100% with pretreatment) [6][7][8][9]. In another study investigating Ce extraction from an acidic solution (6 M HNO 3 and 3 M LiNO 3 ) using SC-CO 2 (333 K, 35 MPa), adding a second molecule (thenoyltrifluoroacetone) was found to enhance the extraction yield from 60% to 72% [10].…”

Section: Introductionmentioning

confidence: 99%

Amidophosphonate ligands as cerium extractants in supercritical CO2

Bouali

Leybros

Toquer

et al. 2019

The Journal of Supercritical Fluids

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Industrial-scale rare earth extraction is typically performed by liquid-liquid extraction with large amounts of solvents, acids and organophosphorus ligands. An alternative is to use these extractants in supercritical CO 2 (SC-CO 2), where the crucial operating parameter is their solubility. Different molecules with amidophosphonate backbones have been synthesized and investigated in view of improving their solubility in SC-CO 2 and thereby their cerium extraction capacity. The CO 2-philicity of these extractants was adjusted by attaching branched or linear alkyl chains with four, six and eight carbons. Using a dynamic gravimetric setup, the solubility and cerium extraction capacity of these molecules were measured to vary from 1.56 to 2.47 mmol/mol and 0.25 to 0.46 mmol/mol, respectively. The two properties were correlated and in both cases the highest values were obtained with a diisobutylamine chain. The solubility of the corresponding amidophosphonate extractant was found to be optimal at 320 K and 28 MPa.

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Rare earth element extraction from pretreated bastnäsite in supercritical carbon dioxide

Cited by 35 publications

References 25 publications

Effect of Neodymium on the Physico‐chemical Properties and N₂O Decomposition Activity of Co(Cu)−Al Mixed Oxides

Effect of Neodymium on the Physico‐chemical Properties and N₂O Decomposition Activity of Co(Cu)−Al Mixed Oxides

Selection of a suitable ligand for the supercritical extraction of gold from a low-grade refractory tailing

Amidophosphonate ligands as cerium extractants in supercritical CO2

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Rare earth element extraction from pretreated bastnäsite in supercritical carbon dioxide

Cited by 35 publications

References 25 publications

Effect of Neodymium on the Physico‐chemical Properties and N2O Decomposition Activity of Co(Cu)−Al Mixed Oxides

Effect of Neodymium on the Physico‐chemical Properties and N2O Decomposition Activity of Co(Cu)−Al Mixed Oxides

Selection of a suitable ligand for the supercritical extraction of gold from a low-grade refractory tailing

Amidophosphonate ligands as cerium extractants in supercritical CO2

Contact Info

Product

Resources

About

Effect of Neodymium on the Physico‐chemical Properties and N₂O Decomposition Activity of Co(Cu)−Al Mixed Oxides

Effect of Neodymium on the Physico‐chemical Properties and N₂O Decomposition Activity of Co(Cu)−Al Mixed Oxides