Electrochemical Properties of Lanthanum on the Liquid Gallium Electrode in LiCl-KCl Eutectic

Abstract

This work presents an electrochemical study of La(III) in the LiCl-KCl-LaCl 3 melt on a liquid gallium electrode. The reduction of the La(III) on a liquid gallium starts at −1.13 V (vs. Ag/AgCl) and is a one step process with three electrons transferred. The activities, activity coefficients and solubilities of La in La-Ga alloys were calculated by open circuit potential technique at the temperature range of 673 to 823 K. Moreover, galvanodynamic methods was also applied on a W electrode to evaluate the apparent standard potential of La(III)/La couple, the Gibbs free energy for the formation of LaCl 3 and the activity coefficient of La(III) in the LiCl-KCl-LaCl 3 melt. The co-reductive cyclic voltammograms of La(III) and Ga(III) present several redox couples which correspond to the formation and dissolution of different La-Ga intermetallic compounds. Finally, potentiostatic electrolysis was employed to deposit La on a liquid Ga electrode and the intermetallic compound LaGa 6 was identified by Scanning Electron Microscopy coupled with Energy Dispersive Spectroscopy (SEM-EDS) and X-ray diffraction (XRD) characterizations.

Electrochemical properties of yttrium on W and Pb electrodes in LiCl–KCl eutectic melts

“…35 where i, i 0 , h have the similar meaning with eqn (8), A and E a present charge-transfer resistances (U), pre-exponential factor (A cm À2 ) and the reaction activation energy for Y(III)/Y(0) (kJ mol À1 ), respectively. Since there is a linear relationship between currents and over-potentials near the equilibrium potential, the chargetransfer resistances (R ct ) at different temperatures can be obtained by eqn (10).…”

“…For example, the electrode area is changeless, and the diffusion of deposited metal into the liquid metal is easier. 6,7 Thus, liquid Ga, [7][8][9][10][11] Bi, [12][13][14][15] Cd, 13,16 Zn, [17][18][19][20][21][22][23][24] Sn 25 were selected as cathode to separate REs from molten salts. The melting point of Pb metal is 600 K and boiling point is 1798 K, it is easy to melt but doesn't evaporate at 723-823 K. Thus, Pb metal seems to be a good candidate as the cathode material in separation and extraction of REs by molten salt electrolysis.…”

Recycling of Spent Indium–Gallium–Zinc Oxide Based on Molten Salt Electrolysis

“…Generally, a metal crucible is preferred due to its high strength. But, it is worth noting that the melting point of gallium is low under standard atmospheric pressure, and liquid gallium can be infiltrated into almost all metals to form alloys. , So, metallic crucibles cannot be used as IGZO containers. On the basis of the above analysis, a nonmetallic graphite crucible was selected as the cathode to collect the electrolytic product in this work due to its good electrical conductivity and low price.…”

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.…”