| Abstract Scope |
The rising demand for rare earth elements, driven by advanced technological applications and supply shortages, necessitates the recovery of these metals from secondary sources. Permanent magnets (Nd2Fe14B or NdFeB), with their high rare earth content (~28-30%) and widespread applications, can serve as a valuable secondary source for these metals. This study employs copper nitrate (Cu(NO3)2.3H2O) assisted leaching pre-treatment, followed by oxalic acid precipitation, and calcination (850 °C, 2 h) to produce mixed rare earth oxides. During Cu-nitrate leaching, nitrate ions oxidize rare earths to soluble REE3+ under acidic oxidative conditions. The process is optimized by varying the temperature (30-90 °C), Cu(NO3)2.3H2O to NdFeB feed dosage (0.25:1-2:1), duration (0.5-5 h), and S/L (20-50) to enhance rare earth dissolution. The extraction for rare earth elements (Nd+Dy+Pr) was ~94-96% at optimum conditions of 0.75:1 dosage, 90 °C, 5 h, and S/L of 50. The purity of the recovered rare earth oxides was ~96-98%. |