Z. Naturforsch. 68a, 48 – 58
Optimization of a Molten Salt Electrolytic Bath Geometry for Rare Earth Metal Recovery using a Finite Element Method
1 Graduate School of Metallurgy and Ceramics Science, Tokyo Institute of Technology, 2-12-1-S8-7, Ookayama, Meguro-ku, Tokyo 1528552, Japan
2 Research Laboratory for Nuclear Reactors, Tokyo Institute of Technology, 2-12-1-N1-10, Ookayama, Meguro-ku, Tokyo 1528550, Japan
Received October 16, 2012 / published online February 15, 2013
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.
Key words: Computer Simulation; Finite Element Method; Secondary Current Distribution; Rare Earth; Molten Salt; Electrolytic Bath.