Electroreduction of Dy(III) assisted by Zn and its co‐deposition with Zn(II) in LiCl–KCl molten salt

Abstract

To recover dysprosium (Dy) from LiCl–KCl molten salt, the electrochemical mechanism of Dy(III) on liquid Zn electrode and co‐deposition of Dy(III) and Zn(II) on W electrode were studied using electrochemical methods. Cyclic voltammetry results demonstrated that the redox process of Dy on liquid Zn electrode is reversible and controlled by diffusion. Reverse chronopotentiograms showed that the transition time ratio of reduction and oxidation is ~3:1, revealing the redox of Dy on liquid Zn electrode is a kind of soluble–soluble system: Dy(III) + 3e− = (Dy–Zn)solution. The half‐wave potential of Dy(III) was almost constant with the increase in scanning rate. The electrochemical separation of metallic Dy from the molten salt was performed using constant potential electrolysis, and the product characterized using X‐ray diffraction and scanning electron microscopy–energy‐dispersive X‐ray spectroscopy was the thermodynamic unstable compound DyZn5. Also, the co‐deposition mechanism of Dy(III) and Zn(II) was explored, indicating that Dy(III) could deposit on pre‐deposited Zn and form Dy–Zn compounds: Zn(II) + 2e− = Zn and xDy(III) + yZn + 3xe− = DyxZny. Moreover, the effect of Dy(III) concentration on the formation of Dy–Zn compounds was investigated. The redox peak currents corresponding to different Dy–Zn compounds changed with the increase in Dy(III) concentration. The co‐deposition of Dy(III) and Zn(II) was performed using constant current electrolysis at diverse Dy(III) concentrations. The different Dy–Zn compounds were produced by controlling Dy(III) concentration.

Electrochemical and Spectroscopic Properties of Europium in AlCl3-NaCl Melts

“…The transition times of II c and II a are similar also implies that the reduction product of II c is insoluble. 31 When the oxidation time of Eu(II) increased and more Eu(III) was generated, the transition time of II c also increased. This phenomenon indicates that II c is attributed to the reduction of Eu(III).…”

Electrode reaction of Pr on Sn electrode and its electrochemical recovery fromLiCl‐KClmolten salt

“…Therefore, it is critical to recover and separate lanthanides from molten salt for nuclear fuel cycle and the purification of waste salts 29 . In recent years, the electrorecovery lanthanides from molten salt were explored on various electrodes, 30‐51 for example, Mg, 30 Al, 31‐34 Ni, 35,36 Cu, 37‐39 Bi, 40‐43 Zn, 38,39,44,45 Cd, 46,47 Sn, 48 Pb, 49‐51 and Ga 52 . Since there are some advantages to use low melting point metal as a liquid working electrode, many researchers paid more attentions to the electrochemical extraction using a liquid electrode.…”

Electrochemical Coreduction of Gd(III) with Pb(II) and Recovery of Gd from LiCl-KCl Eutectic Assisted by Pb Metal

“…14 Thus, liquid cathode is paid more attention because of its complete physical separation between the metal product and electrolyte, constant electrode area, and easy diffusion of deposited metal into liquid metal. Low melting metal and alloy, for example, Bi, [30][31][32] Sn, 33,34 Cd, 35,36 Pb, [37][38][39] Ga, 40,41 Zn 14,[42][43][44] metals and Al-Ga alloy [45][46][47] were explored as a liquid cathode. The feasibility of liquid metals (Sb, Bi, Pb, Sn, Ga) as cathode was systematically investigated in molten fluorides, Gibilaro et al found that the electroactivity domains and reactivity of liquid metals are Bi > Pb > Sn > Sb > Ga. 48 Lebedev 49 evaluated the separation factor between actinides and lanthanides on various cathodes in molten chlorides, and found that the separation order is Al > Ga > Pb > Zn > Bi > Sn > In > Cd > Tl.…”