Solvent Extraction of Light Rare Earth Ions Using D2EHPA from Nitric Acid and Sulphuric Acid Solutions

Khaironie, Mohamed Takip; Markom, Masturah; Sulaiman, Meor Yusoff Meor; Ashifa, Salim Nazaratul

doi:10.4028/www.scientific.net/amr.970.209

Cited by 13 publications

(3 citation statements)

References 13 publications

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“…The effect of the pH on iron, zinc, manganese and cobalt extraction is given in the Figure 5. The relative position of each performance curve of a metal cation in Figure 5 is justified by the selectivity of D2EHPA towards each of the components and follows the sequence: Fe>Zn>Mn>Co (Kopper Chemical Industry, 2019a; Niinae et al, 1991;Khaironie et al, 2014;Qiu et al, 2016).…”

Section: Ph Effectmentioning

confidence: 99%

Purification of cobalt solutions in several solvent extraction steps: Using MEXTRAL and D2EHPA as extractants

Constantin¹,

eritier²,

Moramess³

et al. 2021

J. Chem. Eng. Mater. Sci.

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A sulphate solution of cobalt (18.93 g/L Co 2+ ) containing major impurities such as copper (1.35 g/L Cu 2+ ), iron (0.28 g/L Fe tot ), zinc (0.70 g/L Zn 2+ ) and manganese (4.83 g/L Mn 2+ ) was purified through the solvent extraction method using two extractants; MEXTRAL and D2EHPA for the removal of copper and for the removal in two stages of a zinc-iron-manganese complex respectively. The effects of the solution's pH, O/A ratio, extraction time and stirring intensity were investigated. The purification extent was enhanced by optimizing these four parameters through Taguchi's L16 (4^4) experimental. The final solution obtained through sequential extractions showed a reduction in Cu, Fe, Zn and Mn content of 98.7, 97.5, 98.2, and 80.5% respectively. This study showcased the possibility of obtaining high purity cobalt as a precursor for Lithium ion battery applications, representing 49% of its current global use. The coextraction value of cobalt was estimated at 6.2%.

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Section: Ph Effectmentioning

confidence: 99%

Purification of cobalt solutions in several solvent extraction steps: Using MEXTRAL and D2EHPA as extractants

Constantin¹,

eritier²,

Moramess³

et al. 2021

J. Chem. Eng. Mater. Sci.

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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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“…Moreover, it has also been observed on attainment of low separation factors with most of the adopted solvent reagents. In some studies, more than one similar group reagents and their synergistic approach are also adopted to improve separation behavior of REEs with either of the solvents [12][13][14][15] .…”

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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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Solvent Extraction of Light Rare Earth Ions Using D2EHPA from Nitric Acid and Sulphuric Acid Solutions

Cited by 13 publications

References 13 publications

Purification of cobalt solutions in several solvent extraction steps: Using MEXTRAL and D2EHPA as extractants

Purification of cobalt solutions in several solvent extraction steps: Using MEXTRAL and D2EHPA as extractants

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

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

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