Studies on solvent extraction of Dy(III) and separation possibilities of rare earths using PC-88A from phosphoric acid solutions

Radhika, Surampally; Batchu, Nagaphani Kumar; Mannepalli, Lakshmi Kantam; Bontha, Ramachandra Reddy

doi:10.1016/j.jtice.2012.04.009

Cited by 22 publications

(9 citation statements)

References 26 publications

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“…Likewise to the extraction study, stripping is equally significant for regeneration of adopted extractant in the process and so as the enrichment of extracted metal into the stripped solution for achieving its clean separation. There are several in organic-acids, alkalis and salts are employed for stripping of REEs from the loaded-organic phase 36 – 40 , but these regents have less stripping ability even at higher concentration level. To overcome such issue and to attain quick regeneration of extractant organic green reagents like oxalic acid is preferred as suitable reagent.…”

Section: Resultsmentioning

confidence: 99%

Environmentally friendly comprehensive hydrometallurgical method development for neodymium recovery from mixed rare earth aqueous solutions using organo-phosphorus derivatives

Ruiz

Kuchi

Parhi

et al. 2020

Sci Rep

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Rare earth elements (REEs) have obtained a greatest significant in human lives owing to their important roles in various high technology applications. The present method development was deal technology important REEs such as neodymium, terbium and dysprosium, selective extraction with possible separation and recovery studies, successfully. The chloride mediated mixed aqueous solution containing 1500 mg/L each of REEs such as Nd, Tb and Dy was subjected at selective separation of Nd from other associated REEs. Three organo-phosphorous based commercial extracting agents such as Cyanex 272, PC 88A and D2EHPA, were employed for the extraction, possible separation and recovery of rare earth elements. A comparative extraction behavior of all these three extractants as function of time, pH influence, extractant concentration, temperature and diluents were systematically investigated. The extraction tendency of organo-phosphorus reagents towards the extraction of either of the REEs follows of the sequence as: D2EHPA > PC 88A > Cyanex 272. The thermodynamic behavior of either of the extractants on liquid–liquid extraction processing of REEs was investigated and thermodynamic calculations were calculated and presented. Substantial recovery of neodymium oxalate followed by its calcined product as neodymium oxide was ascertained from XRD study and SEM–EDS analysis.

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Section: Resultsmentioning

confidence: 99%

Environmentally friendly comprehensive hydrometallurgical method development for neodymium recovery from mixed rare earth aqueous solutions using organo-phosphorus derivatives

Ruiz

Kuchi

Parhi

et al. 2020

Sci Rep

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“…For this reason, the search for new sources of rare-earth elements is necessary to serve the growing market. For this reason, several studies have focused on sources of new rare-earth elements to supply the market [4][5][6][7].…”

Section: Introductionmentioning

confidence: 99%

Extraction of Rare-Earth Elements from Silicate-Based Ore through Hydrometallurgical Route

Botelho

Espinosa

Vaughan

et al. 2022

Metals

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The European Union and several countries/regions classified the rare-earth elements (REEs), such as lanthanum, cerium, neodymium, and scandium, as critical due to the risk of supply interruption. For this reason, the growing demand for REEs has resulted in forgotten reserves receiving economic interest. So, the search for new sources and the development of chemical process is important, such as silicate-based ore. Since there is almost no literature on the extraction of REEs from this source, a new approach was developed in the present study. Direct leaching and acid baking were studied using sulfuric acid. The effect of the acid concentration, temperature, solid-liquid ratio, oxidizing/reducing medium, and acid dosage were studied. Results showed that the extraction of REEs achieved up to 80% at 90 °C in oxidizing medium, and scandium and iron achieved 13.5% and 65.0%, respectively. For the acid baking experiments, the results were better than direct leaching for REEs at over 85%. The scandium leaching rate was lower than direct leaching. On the other hand, the extraction of iron was lower in acid baking than direct leaching. The iron and scandium extraction rates were higher in lower temperatures (<200 °C) and acid dosages, achieving 50% and 6.3%, respectively. Future studies should explore thermal treatment before acid leaching.

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“…Solvent extraction is the key step in the aforementioned sequence of steps, requiring the use of a suitable solvent and extractant combination to separate the REEs from each other efficiently. Various extractants such as D2EHPA, − Cyanex 272, Cyanex 921, PC88A, − tributyl phosphate and calixarene derivatives have been used for the extraction and separation of Dy and Nd from a mixture of these REEs. Singh et al proposed a two-stage extraction process to recover nuclear grade Dy 2 O 3 from a crude concentrate of rare earth metals, for application in advance heavy water reactor.…”

Section: Introductionmentioning

confidence: 99%

Differential Stabilization of the Metal–Ligand Complexes between Organic and Aqueous Phases Drives the Selectivity of Phosphoric Acid Ligands toward Heavier Rare Earth Elements

Dwadasi

Gupta

Daware

et al. 2018

Ind. Eng. Chem. Res.

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Rare earth elements (REEs) are widely used in several electrical and electronic devices and emerging technologies. With increase in demand of REEs, their recovery from electronic wastes, through hydrometallurgical routes, is a promising alternate source of these elements over conventional mining processes. In a number of experiments, organophosphoric acid ligands such as bis-2-ethylhexyl phosphoric acid (D2EHPA) and 2-ethylhexylphosphonic acid mono-2-ethylhexyl ester (EHEHPA) have shown high selectivity toward heavier REEs. While the general extraction equilibrium is well established, an atomistically detailed understanding of the origin of this selectivity is still lacking. We use molecular dynamics simulations to elucidate the structure of the Nd-and Dy-D2EPHA complexes in vacuum, aqueous, and organic phases and show that the selectivity of D2EHPA for Dy arises from the favorable differential stabilization of the complex in the solvent phases, caused by the structural features of the Dy-D2EHPA complex. To complement our simulations, solvent extraction experiments were carried out on a 4:1 mixture of Nd and Dy ions in chloride media, representative of their ratios found in NdFeB magnets, with n-heptane as the diluent. Though the concentration of Dy is four times smaller, we show that the selectivity of D2EHPA toward Dy can be exploited to obtain enhanced separation in a two step process by first extracting Dy at low pH and starving doses of D2EHPA, followed by the extraction of Nd at higher pH. Our work gives important insights into the atomistic origins of the selectivity of phosphoric acid ligands, which is essential in the design of newer ligands or ligand combinations to obtain enhanced separation of REEs from e-wastes and eventual commercialization of the process.

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Studies on solvent extraction of Dy(III) and separation possibilities of rare earths using PC-88A from phosphoric acid solutions

Cited by 22 publications

References 26 publications

Environmentally friendly comprehensive hydrometallurgical method development for neodymium recovery from mixed rare earth aqueous solutions using organo-phosphorus derivatives

Environmentally friendly comprehensive hydrometallurgical method development for neodymium recovery from mixed rare earth aqueous solutions using organo-phosphorus derivatives

Extraction of Rare-Earth Elements from Silicate-Based Ore through Hydrometallurgical Route

Differential Stabilization of the Metal–Ligand Complexes between Organic and Aqueous Phases Drives the Selectivity of Phosphoric Acid Ligands toward Heavier Rare Earth Elements

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