(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.