Electrochemical Recovery of Rare Earth Elements from Magnets: Conversion of Rare Earth Based Metals into Rare Earth Fluorides in Molten Salts

Abstract

In the present work, selective extraction of rare earth (RE) metals from NdFeB magnets is investigated by studying the effects of various uxes, viz. AlF 3 , ZnF 2 , FeF 3 and Na 3 AlF 6 in the LiF-NdFeB system. The aim is to convert RE from RE magnet into the uoride salt melt. The results show the complete selective separation of neodymium (also dysprosium) from the magnet and formation of rare earth uoride, leaving iron and boron unreacted. The formed rare earth uoride can subsequently be processed in the same reactor through an electrolysis route so that RE can be deposited as a cathode product. The results of XRD and EPMA analysis of the reacted samples indicate that AlF 3 , ZnF 2 and FeF 3 can act as strong uorinating agents for extraction of rare earth from NdFeB magnet, converting the RE to REF 3 .The results con rm the feasibility of the rare earth metals recovery from scrap NdFeB magnet as raw material. The uoride conversion-electrolysis route suggested in the present work enables the extraction of rare earth metals in a single step using the above-mentioned uxes.

Electrochemical Recovery and Behaviors of Rare Earth (La, Ce, Pr, Nd, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, and Yb) Ions on Ni Sheets

“…For this treatment, electrochemistry is an indispensable technique, and the understanding electrochemical behaviors (e.g., electrochemical reduction-oxidation reactions) of the ions over electrodes is very important. For the recovery of RE elements from used industry materials [ 12 , 13 ], the electrochemical recovery method has been a useful method to selectively recover a desired element in an electrolyte with mixed RE ions [ 12 , 13 , 14 ]. To achieve these goals, electrochemical behaviors of RE ions in an electrolyte have fundamentally been studied by electrochemistry [ 15 , 16 , 17 , 18 , 19 ].…”

An Ex-ante LCA Study of Rare Earth Extraction from NdFeB Magnet Scrap Using Molten Salt Electrolysis

“…After completion of the electrolysis, the samples were analyzed by X-ray diffraction (XRD) as well as by Electron Probe Micro Analysis (EPMA) in order to determine the phases that are formed during the experiments and their compositions. The conversion of the neodymium from the magnet into neodymium fluoride was earlier proved in the same lab [26]. The results from XRD and EPMA show the deposition of neodymium and dysprosium on the molybdenum cathode.…”

“…Metal production is an important contributor to global warming [65]. It is therefore important to understand to what extent recycling processes provide an advantage regarding this issue over primary production [26,66]. For this study, the focus is on identifying the environmentally important parameters in process development.…”

Electrochemical Approaches for the Recovery of Metals from Electronic Waste: A Critical Review

“…If one now considers molten salts, the rare earth element neodymium (Nd) can electrochemically be recovered from NdFeB magnets using molten salt electrolysis [102]. During the process, the solid NdFeB material is directly placed in an anodic compartment with molten fluorinating agents (e.g., AlF 3 , ZnF 2 , FeF 3 and Na 3 AlF 6 ), which coverts Nd from a the magnetic alloy into NdF 3 salt melt [103,104]. The Nd 3+ ions from the molten salt can then be electrodeposited at the cathode.…”