scholarly journals Electrochemical Removal of Rare Earth Element in LiCl-KCl Molten Salt

2020 ◽  
Vol 2020 ◽  
pp. 1-5
Author(s):  
Gha-Young Kim ◽  
Junhyuk Jang ◽  
Seungwoo Paek ◽  
Sung-Jai Lee

This study was carried out to examine the removal of rare earth (RE) elements by electrodeposition for the purification and reuse of LiCl-KCl salt after electrorefining and electrowinning. The electrochemical behavior of RE elements (Dy and Gd) in LiCl-KCl-DyCl3-GdCl3 at 500°C was investigated using the cyclic voltammetry (CV) technique using Mo and Mg electrodes. It was observed that the reduction potential of the RE elements shifted at the Mg electrode owing to the alloy formation with Mg (RE-Mg alloy). Subsequently, a series of potentiostatic electrolysis tests were conducted to remove the RE elements in the salt and check the formation of deposits at the Mg and Mo electrodes. The scanning electron microscopy-energy dispersive X-ray spectroscopy (SEM/EDS) technique was used to confirm that the reduced RE metals were deposited on the surface of the Mg electrode. However, no significant deposit on the Mo electrode was observed, and a mud-like deposit was found on the bottom of the electrochemical cell. The salt analysis performed by employing the inductively coupled plasma-optical emission spectrometry (ICP-OES) indicated that the removal efficiency of Dy3+ and Gd3+ through electrodeposition was 83.5∼95.2 and 91.6∼95.2%, respectively.

2013 ◽  
Vol 69 (2) ◽  
pp. 312-319 ◽  
Author(s):  
Cennet Karadaş ◽  
Derya Kara

A new method has been developed for the determination of rare earth elements (REEs) (Ce, Pr, Nd, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb and Lu) in water samples based on preconcentration with a mini-column packed with 6-(2-thienyl)-2-pyridinecarboxaldehyde functionalized Amberlite XAD-4 resin prior to their determination using inductively coupled plasma optical emission spectrometry (ICP-OES). The optimum experimental parameters for preconcentration of REEs, such as pH of the sample, sample and eluent flow rates and sample volume, were investigated. The optimum pH values for quantitative (90–110%) sorption of the REE ions were between 6.0 and 8.0. The elution process was carried out using 2 mL of 1.0 mol L–1 HNO3 solution. Under the optimum conditions, detection limits between 0.032 and 0.963 μg L−1 for a 10 mL sample volume and 0.006 and 0.193 μg L−1 for a 50 mL sample volume were determined. The proposed method was successfully applied to the determination of REEs in water samples with recoveries in the range of 90.1–110.5%.


2017 ◽  
Vol 2 (1) ◽  
Author(s):  
Man He ◽  
Bin Hu ◽  
Beibei Chen ◽  
Zucheng Jiang

Abstract Inductively coupled plasma optical emission spectrometry (ICP-OES) merits multielements capability, high sensitivity, good reproducibility, low matrix effect and wide dynamic linear range for rare earth elements (REEs) analysis. But the spectral interference in trace REEs analysis by ICP-OES is a serious problem due to the complicated emission spectra of REEs, which demands some correction technology including interference factor method, derivative spectrum, Kalman filtering algorithm and partial least-squares (PLS) method. Matrix-matching calibration, internal standard, correction factor and sample dilution are usually employed to overcome or decrease the matrix effect. Coupled with various sample introduction techniques, the analytical performance of ICP-OES for REEs analysis would be improved. Compared with conventional pneumatic nebulization (PN), acid effect and matrix effect are decreased to some extent in flow injection ICP-OES, with higher tolerable matrix concentration and better reproducibility. By using electrothermal vaporization as sample introduction system, direct analysis of solid samples by ICP-OES is achieved and the vaporization behavior of refractory REEs with high boiling point, which can easily form involatile carbides in the graphite tube, could be improved by using chemical modifier, such as polytetrafluoroethylene and 1-phenyl-3-methyl-4-benzoyl-5-pyrazone. Laser ablation-ICP-OES is suitable for the analysis of both conductive and nonconductive solid samples, with the absolute detection limit of ng-pg level and extremely low sample consumption (0.2 % of that in conventional PN introduction). ICP-OES has been extensively employed for trace REEs analysis in high-purity materials, and environmental and biological samples.


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