(b)(c)Fig – 3: Dependence of current efficiency for Nd on the
cathode current density at temperature of process t =
750oC (a) Electrolyte NdF3 – LiF –
BaF (b) Electrolyte BaCl2 – LiCl –
NdF3 – LiF, (c) Electrolyte
BaF2-NdF3-LiF [15].
During the electrolysis of these melts at the electrodes the following
reactions are taking place: at the graphite anode. [16]
2F-1 – 2e F2 (gas)
C + 2F2 CF4 (gas)
2Cl-1 – 2e Cl2 (gas)
at the iron cathode:
Nd+3 + 3e Nd
Nd + Fe Nd2Fe + αNd – low-melting eutectic (Tm = 640 С)
Production of Nd-Fe foundry alloy by the electrolysis of
neodymium oxide
During the electrolysis of neodymium oxide in fluoride melts at the
electrodes the following reactions are taking place at the graphite
anode [16]
2O-2 – 4e O2
C + O2 CO2 (gas)
2C + O2 2CO (gas)
at the iron cathode:
Nd+3 + 3e Nd
Nd + Fe Nd2Fe + αNd - low-melting eutectic (Tm = 640 C)
Coefficients
Following coefficients are important, must be considered and calculated
for effective electrometallurgical operations. Activity coefficients,
diffusion coefficients, equilibrium separation coefficients, effective
separation coefficients.