Development of Hydrometallurgical Process for Recovery of Rare Earth Metals (Nd, Pr, and Dy) from Nd-Fe-B Magnets

Non-availability of rich primary resources rare earth metals (REMs) and the generation huge amounts discarded magnets containing REMs, compelled researchers to explore possibilities for recovery REMs from magnets. Therefore, present paper reports (Nd, Pr, Dy) Nd-Fe-B The process consists demagnetization, pre-treatment, hydrometallurgical processing recover as salt. Leaching studies indicate that 95.5% Nd, 99.9% Dy were found be dissolved at optimized experimental condition i.e., acid concentration 2 M H2SO4, temperature 75 °C, pulp density 100 g/L, mixing time 60 min. Solvent extraction technique was tried selective extraction/separation Fe. result indicates 99.1% (24.42 g/L) Nd along with 90% (1.08 Pr total Fe co-extracted using 35% Cyanex 272 organic aqueous (O/A) ratio 1/1, eq. pH 3.5 in 10 min time. It requires multistage separation therefore, not feasible view economics. Thus, direct precipitation salt iron oxide pigment studied two stages different pH. obtained precipitate hydroxides dried separately remove moisture further treated elevated get pure red oxide.