Abstract:The electrochemical formation of RE-Cu (RE=Dy, Nd) alloys were investigated in a molten LiCl-KCl-RECl 3 (0.50 mol% added) at 723 K. Open-circuit potentiometry was carried out with a Cu electrode after depositing Dy metal by potentiostatic electrolysis at 0.40 V (vs. Li + / Li) for 120 s in a molten LiCl-KCl-DyCl 3 (0.50 mol%) at 723 K. There were four potential plateaus at (a) 0.50 V, (b) 0.68 V, (c) 0.88 V and (d) 0.95 V. An alloy sample was prepared at 0.55 V for 4 h. From the XRD pattern of the sample, the … Show more
“…This result was caused by not controlling the potential at the entry side in this experiment. If the potential was controlled, the Dy/Nd ratio would be expected to be high from the previous study (Konishi et al 2012, 2013). 10 The relationship between the amount of permeated Dy and Nd and the amount of electricity during electrolysis at 723 K…”
Section: Resultsmentioning
confidence: 89%
“…This result was caused by not controlling the potential at the entry side in this experiment. If the potential was controlled, the Dy/Nd ratio would be expected to be high from the previous study (Konishi et al 2012(Konishi et al , 2013.…”
Section: Dy Permeation Experimentsmentioning
confidence: 93%
“…This new process was first applied to chloride melts, and the separation of Dy and Nd was investigated using Ni and Cu cathodes in a molten LiCl-KCl-DyCl 3 -NdCl 3 system (Konishi, Ono, Nohira and Oishi 2011;Konishi, Ono, Nohira and Oishi 2012;Konishi, Ono, Nohira and Oishi 2013). The highest mass ratio of Dy/Nd in the Dy-Nd-Ni alloy sample was found to be 72 by ICP-AES.…”
We proposed a new separation and recovery process for RE metals from Nd magnet scraps using molten salt electrolysis. The present study focused on the electrochemical formation of RE–Ni (RE = Dy, Nd, Pr) alloys in a molten LiCl–KCl system at 723 K. Cyclic voltammetry was conducted using a Ni electrode in molten LiCl–KCl–RECl3 systems at 723 K. In the negative scan for the DyCl3 added system, a large cathodic current was observed from 0.70 V (vs. Li+/Li) as a result of the formation of Dy–Ni alloys. In contrast, large cathodic currents as results of the formation of Nd–Ni and Pr–Ni alloys were observed from 0.60 V. On the basis of these results, an alloy sample was prepared by potentiostatic electrolysis at 0.65 V for 1 h using a Ni plate cathode in a molten LiCl–KCl–DyCl3–NdCl3–PrCl3 system. The mass ratio of Dy/Nd+Pr in the alloy sample was found to be 50 by ICP-AES. Finally, a Dy permeation experiment was conducted with a new electrolytic cell.
“…This result was caused by not controlling the potential at the entry side in this experiment. If the potential was controlled, the Dy/Nd ratio would be expected to be high from the previous study (Konishi et al 2012, 2013). 10 The relationship between the amount of permeated Dy and Nd and the amount of electricity during electrolysis at 723 K…”
Section: Resultsmentioning
confidence: 89%
“…This result was caused by not controlling the potential at the entry side in this experiment. If the potential was controlled, the Dy/Nd ratio would be expected to be high from the previous study (Konishi et al 2012(Konishi et al , 2013.…”
Section: Dy Permeation Experimentsmentioning
confidence: 93%
“…This new process was first applied to chloride melts, and the separation of Dy and Nd was investigated using Ni and Cu cathodes in a molten LiCl-KCl-DyCl 3 -NdCl 3 system (Konishi, Ono, Nohira and Oishi 2011;Konishi, Ono, Nohira and Oishi 2012;Konishi, Ono, Nohira and Oishi 2013). The highest mass ratio of Dy/Nd in the Dy-Nd-Ni alloy sample was found to be 72 by ICP-AES.…”
We proposed a new separation and recovery process for RE metals from Nd magnet scraps using molten salt electrolysis. The present study focused on the electrochemical formation of RE–Ni (RE = Dy, Nd, Pr) alloys in a molten LiCl–KCl system at 723 K. Cyclic voltammetry was conducted using a Ni electrode in molten LiCl–KCl–RECl3 systems at 723 K. In the negative scan for the DyCl3 added system, a large cathodic current was observed from 0.70 V (vs. Li+/Li) as a result of the formation of Dy–Ni alloys. In contrast, large cathodic currents as results of the formation of Nd–Ni and Pr–Ni alloys were observed from 0.60 V. On the basis of these results, an alloy sample was prepared by potentiostatic electrolysis at 0.65 V for 1 h using a Ni plate cathode in a molten LiCl–KCl–DyCl3–NdCl3–PrCl3 system. The mass ratio of Dy/Nd+Pr in the alloy sample was found to be 50 by ICP-AES. Finally, a Dy permeation experiment was conducted with a new electrolytic cell.
“…Thus, it is necessary to develop an inexpensive and effective recovery/separation process of Dy from scraps of the Dy-added Nd-Fe-B magnet. From this background, we have been investigating a new recovery process of Dy and Nd from the magnet scraps using molten salt electrolysis and alloy diaphragms (1)(2)(3)(4)(5)(6)(7)(8)(9)(10)(11)(12)(13)(14). The key step in this process is the alloying and de-alloying of rare earth (RE) elements on both sides of the diaphragm in order to effectively separate them in the molten salt.…”
The electrochemical formation of Dy-Ni alloys was investigated in a molten CsCl-DyCl3 system at 973 K under a dry Ar gas atmosphere. Open-circuit potentiometry was performed with a Ni electrode after depositing Dy metal at 0.13 V(vs. Cs+/Cs) for 60 s. Five potential plateaus were observed at 0.34 V, 0.44 V, 0.54 V, 0.79 V and 0.91 V, which were considered to correspond to the potentials of two-phase coexisting states of different Dy–Ni alloys. Potentiostatic electrolysis was conducted at 0.31 V for 4 h and 0.41 V for 1 h using Ni plate electrodes, and XRD analysis indicated the formation of DyNi and DyNi2, respectively. After the formation of DyNi2 on the Ni plate electrodes, potentiostatic electrolysis were also conducted at 075 V and 0.85 V for 1 h. The formed DyNi2 was transformed to Dy2Ni7 and DyNi5 at 0.75 V, while DyNi5 was formed at 0.85 V.
“…29 Recently, besides the Ni substrate, we have investigated the RE-alloying behaviors of many other materials. [30][31][32][33][34] In previous studies, we achieved high separation ratios in chloride melts and high alloy formation rates at high operation temperatures. To achieve high values for both, the separation ratio and the alloy formation rate, a high temperature operation of a chloride melt with low vapor pressure is a reasonable approach.…”
The electrochemical formation of Dy–Ni alloys was investigated in molten CaCl2–DyCl3 (1.0 mol%) at 1123 K. Cyclic voltammetry indicated the formation of Dy–Ni alloys at more negative than 1.0 V vs. Ca2+/Ca. Higher cathodic currents were observed from approximately 0.6 V, which indicated the formation of Dy–Ni alloys having higher Dy concentration. An open-circuit potentiometry was carried out with Mo and Ni electrodes before and after the addition of DyCl3. After the potentiostatic electrolysis of Mo electrode at −0.50 V for 30 s in molten CaCl2–DyCl3, only one potential plateau appeared at 0.33 V, which was interpreted as the equilibrium potential of Dy3+/Dy. In contrast, four potential plateaus were observed at 0.49, 0.62, 0.87, and 1.04 V for Ni electrode after the potentiostatic electrolysis at 0.25 V for 15 min. According to energy-dispersive X-ray spectroscopy and X-ray diffraction of the electrolyzed samples, the four potential plateaus correspond to the two-phase coexisting states of (DyNi + DyNi2), (DyNi2 + DyNi3), (DyNi3 + DyNi5), and (DyNi5 + Ni). Standard Gibbs energies of formation were calculated for Dy–Ni alloys.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.
