Neodymium iron is widely used in the synthesis of permanent magnets and are recovered from their EoL magnets using dissolution of the scrap by alkali hydroxides to precipitate into neodymium salts that are further refined to form their oxides. Selective recovery of REEs from these magnets that is composed of several other metals focuses on factors influencing the codissolution of ion and boron that coexists in the magnets. The differences in the standard reduction potential are used to selectively recover the rare metals through selective dissolution and thereby collecting the REEs at the cathode. The dissolution of neodymium or for many REEs, acidic solutions are mostly favored for its dissolution due to the passive layer it forms on the scraps (Lee et al., 2014; Prakash et al., 2015; Vander Hoogerstraete et al., 2014). Codissolution of iron and cobalt, that are also part of the system scraps, is a common phenomenon when attempting to recover neodymium. Sulfamic acids and a certain high current density applied could make the iron smelt at the bottom leaving the neodymium salts present in the leachate whose pH is made to drop to acidic conditions to precipitate to obtain the recovered REEs. The scrap magnets are used as an anode in a simple two-electrode electrochemical system with the REEs gets concentrated in the leachate that can be further recovered and extracted via precipitation by double salt or with hydrogen fluoride (Prakash et al., 2015).

Neodymium is a chemical element with the symbol Nd and atomic number 60. It is the fourth member of the lanthanide series and is considered to be one of the rare-earth metals. It is a hard, slightly malleable, silvery metal that quickly tarnishes in air and moisture.

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