The developed green process achieved selective REE recovery from spent NdFeB magnets under acid-free and room-temperature conditions. In addition, the effects of the electrolyte solution concentration, current density, and temperature on NdFeB electrolysis and Fe 2+ oxidation efficiency were further investigated. Fe(OH) 3 and Nd(OH) 3 were calcined to obtain Nd 2O 3 products and Fe 2O 3 by-products. Then, the NaOH solution was used to dissolve small amounts of Zn and obtain Nd(OH) 3. Subsequently, Na 2SO 4 was added to form an RENd(SO 4) 2 precipitatewhile achieving the recycling of the ZnCl 2 electrolyte. After ≥97.10% of Fe 2+ was oxidized at the inert anode, it was hydrolyzed to Fe(OH) 3 in situ to separate it from the REEs. NdFeB magnets served as active anodes to produce REE ions and Fe 2+. In this study, room-temperature electrolysis was used to selectively recover REEs,while ZnCl 2 solution was used as the electrolyte and a double anode system was introduced. However, their conventional recovery processes require high-temperature roasting and acid leaching, which cause high consumption of energy and chemical inputs, and generate massive salt wastewater pollution issues. Spent NdFeB magnets are valuable secondary resources of rare earth elements (REEs).
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