For a recycling procedure for rare earths from spent hydrogen absorbing alloys by rare earths electrodeposition in a molten salt, the electrolytic bath and the cathode accessories have been optimized by evaluating the appropriate secondary current distribution using finite element method (FEM) computer
simulation. The desirable cathode dish as an accessory was designed to prevent drops of less adherent electrodeposits, which improved the current density distribution compared with an a priori
determined one. In the bath optimization, a reciprocal proportionality of the difference between the maximum and minimum current densities vs. the ratio of volume to surface area (or electrolyte volume) was found. It was found by FEM that if a resistive floating mass is assumed on the electrolyte
surface, the observed necking in the electrodeposit near the electrolyte surface can be analyzed.