Ultrasound-assisted leaching of rare earths from the weathered crust elution-deposited ore using magnesium sulfate without ammonia-nitrogen pollution

Yin, Shaohua; Pei, Jiannan; Feng, Jiang; Li, Shiwei; Peng, Jinhui; Zhang, Libo; Ju, Shaohua; Srinivasakannan, C.

doi:10.1016/j.ultsonch.2017.09.028

Cited by 45 publications

(14 citation statements)

References 22 publications

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“…4. This analysis helped to establish the adequate leaching conditions: pH values between 4 and 6, room temperature (25°C), assisted by ultrasound to improve the dissolution process [25,33].…”

Section: Resultsmentioning

confidence: 99%

Facile method for the selective recovery of Gd and Pr from LCD screen wastes using ultrasound-assisted leaching

Toache-Pérez

Bolarín-Miró

Jesús

et al. 2020

Sustain Environ Res

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Rare earth elements (REE) are essential for the production of technological devices. However, their high demand and low availability, together with an increase in electronic waste generation, compel the development of efficient, economic and green methods for recovering these elements from electronic waste. In this work, a facile method for selective recovering of REE from Liquid Crystal Display (LCD) screen wastes, employing ultrasound assisted leaching is presented. The screen wastes were milled and sieved to pass through a − 325 mesh sieve (44 μm). The milled powder was subjected to ultrasound-assisted leaching in an aqueous medium, at room temperature (25 °C) and pH 6 for 60 min. Subsequently, a magnetic separation was applied to the leach residue. Inductively coupled plasma was employed to quantitatively analyze the composition of the LCD powders and determine the effectiveness of the extraction process. Scanning Electron Microscopy/Energy Dispersive X-Ray Spectroscopy allowed qualitative chemical analysis of the solid materials. The results show that the LCD screen wastes are formed, mainly, by amorphous oxides of Si, Fe, In, Sn and REE. The amount of Gadolinium (Gd) and Praseodymium (Pr) in the wastes were 93 and 24 mg kg− 1, respectively, which justifies their recovery. X-ray diffraction analysis of the magnetic portion of the leached residue, confirmed the presence of an amorphous phase together with crystalline metallic iron alloy. The magnetic behavior, obtained by Vibration Sample Magnetometry, helped to understand the nature of the residues. The formation of this metallic alloy is attributed to the effect of high power ultrasonic during the leach. It was confirmed that the magnetic residue concentrates and recovers 87 wt% of Gd and 85 wt% of Pr contained in the original material. Therefore, ultrasound-assisted leaching is a selective and facile method for recovering Gd and Pr from waste LCD.

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Section: Resultsmentioning

confidence: 99%

Facile method for the selective recovery of Gd and Pr from LCD screen wastes using ultrasound-assisted leaching

Toache-Pérez

Bolarín-Miró

Jesús

et al. 2020

Sustain Environ Res

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“…According to different leaching studies, , the application of ultrasound (US) during the leaching process yields auxiliary energy for the accelerating leaching process. , Furthermore, it increases the leaching efficiency since US energy can cause particle fracture, with a consequent increase in the surface area available for reaction. , This process can produce freshly exposed, high temperature, and contrasting surfaces during the ultrasonic irradiation of powder suspensions in liquid; the cavitation and shock waves created can accelerate solid particles to high speeds, allowing collisions between particles capable of inducing dramatic changes in surface morphology, composition, and reactivity . In order to confirm the positive effect of US in this waste, the morphology and extraction percentages of Er, In, and Gd are shown in Figure after leaching with and without US for 1 h under experimental conditions of (PPi) = 0.05 M, H 2 O 2 (3 v/v %) and pH 6.…”

Section: Resultsmentioning

confidence: 99%

Selective Leaching and Recovery of Er, Gd, Sn, and In from Liquid Crystal Display Screen Waste by Sono-Leaching Assisted by Magnetic Separation

et al. 2022

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We report a facile, economic, and ecofriendly method for selective recovery of Er, Gd, Sn, and In from liquid crystal display (LCD) screen wastes by ultrasound-assisted leaching, followed by magnetic separation. Thermodynamic analysis showed that the pyrophosphate ion is an excellent leaching agent for Er, Gd, and In at pH values below 8. Dissolved screen waste powder was subjected to leaching at room temperature using aqueous solutions of 0.05 M of sodium pyrophosphate (Na 4 P 2 O 7 ) as the leaching agent; hydrogen peroxide (H 2 O 2 ) (3 v/v %) was added as an auxiliary reducing agent, and an ultrasonic source was used in the process. Once completed, magnetic separation was applied to the leached residue. The average contents of Er, In, Sn, and Gd in the LCD screen were found to be 477, 2422, 835, and 93 mg·kg –1 , respectively, of which 93, 97, 72, and 99% were selectively recovered from the waste material by this method at pH 3 after 2 h of leaching. The proposed method emerges as an easy and selective process for leaching Er from LCD screen wastes and concentrating In, Sn, and Gd in a separable magnetic solid.

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“…However, praseodymium ion (Pr(III)) has not reported its value of k, but considering that the log k values for the REE close to Pr are similar (Nd 3+ = 20, Sm 3+ = 20.2, Eu 3+ = 20.3, Gd 3+ =20.5) [32], it is possible to infer that the behavior of this element with PPi is similar. This analysis helped to establish the adequate leaching conditions: pH values between 4 and 6, room temperature (25 °C), assisted with ultrasound in order to improve the dissolution process [25,33].…”

Section: Resultsmentioning

confidence: 99%

Facile method for the selective recover of Gd and Pr from LCD screen wastes using ultrasound-assisted leaching

Toache-Pérez

Bolarín-Miró

Jesús

et al. 2020

Preprint

View full text Add to dashboard Cite

Rare earth elements (REE) are essential for the production of technological devices. However, their high demand and low availability, together with an increase in electronic waste generation, compel the development of efficient, economic and green methods for recovering these elements from electronic waste. In this work, a facile method for selective recovering of REE from Liquid Crystal Display (LCD) screen wastes, employing ultrasound assisted leaching is presented. The screen wastes were milled and sieved to pass through − 325 mesh sieve. The milled powder was summited to ultrasound-assisted leaching in aqueous medium, at room temperature (25 °C) and pH 6 for 60 minutes. Subsequently, a magnetic separation was applied into the leach residue. ICP was employed to quantitatively analyze the composition of the LCD powders and the effectiveness of the extraction process. SEM-EDS allowed qualitatively analyzing the chemical composition of the solid materials. The results shown that the LCD screen wastes are formed, mainly, by amorphous oxides of Si, Fe, In, Sn and REE. The amount of Gd and Pr in the wastes were 93 mg/kg and 24 mg/kg, respectively; It represents enough reason to recover it. X-ray diffraction analysis of the magnetic portion of the leaching residue, confirmed the presence of an amorphous phase together with crystalline metallic iron alloy. The magnetic behavior, obtained by Vibration Sample Magnetometry, helped to understand the nature of the residues. The formation of this metallic alloy is attributed to the effect of high power ultrasonic during the leaching. It was confirmed that the magnetic residues concentrates and recovers 87 wt. % of Gd and 85 wt. % of Pr of the total content of these REE in the magnetic residue. Therefore, ultrasound-assisted leaching is a selective and facile method for recovering Gd and Pr from a screen wastes.

show abstract

Ultrasound-assisted leaching of rare earths from the weathered crust elution-deposited ore using magnesium sulfate without ammonia-nitrogen pollution

Cited by 45 publications

References 22 publications

Facile method for the selective recovery of Gd and Pr from LCD screen wastes using ultrasound-assisted leaching

Facile method for the selective recovery of Gd and Pr from LCD screen wastes using ultrasound-assisted leaching

Selective Leaching and Recovery of Er, Gd, Sn, and In from Liquid Crystal Display Screen Waste by Sono-Leaching Assisted by Magnetic Separation

Facile method for the selective recover of Gd and Pr from LCD screen wastes using ultrasound-assisted leaching

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