The increased demand for rare earth elements in advanced technological applications and supply shortages call for metal recovery from secondary sources. Permanent magnet (Nd2Fe14B or NdFeB) may serve as a potential secondary source due to its high rare earth (Nd+Pr+Dy: ~30%) content and its vast application. The present study utilizes a chloridizing roasting (CaCl2.2H2O) pre-treatment process followed by water leaching, acid leaching (0.5M HCl, S/L =1/10g/ml, 90 °C, 3h), oxalic acid precipitation and calcination (850 °C, 2h) to obtain mixed rare earth oxides. The process was optimized based on temperature (400-700 °C), dosage (CaCl2.2H2O: NdFeB=0.5:1-2.5:1), and time (30-120min) on the rare earth dissolution. The theoretical activation energy for the chloridizing roasting process is estimated as 22.3 (OFW) and 16.7kJ/mol (KAS), while the experimental activation energy for Nd and Dy dissolution was determined to ~29.3 and ~17.7kJ/mol, respectively depicting product layer diffusion-controlled kinetics. Higher dosages of CaCl2.2H2O (1.5:1 and 2:1) favored NdOCl formation, thereby, higher dissolution; however, further higher dosage (2.5:1) leads to reduced Nd dissolution due to higher CaO formation and acid consumption by Ca during leaching. Incomplete oxidation at lower temperatures (400 °C) and iron dissolution impair the Nd dissolution and selectivity. Excessive oxidation at >700 °C favors the formation of NdFeO3, decreasing Nd dissolution. The maximum dissolution of Nd was ~89%, while for Dy, it was ~88% at optimum conditions of 600 °C, 90min, 2:1. Water leaching post-roasting leads to ~87% Ca removal and the precipitation efficiency of rare earth oxalates was 99%. The overall extraction for rare earth elements was ~89%, and 1kg of NdFeB powder can yield ~285g of rare earth oxides (~239g Nd2O3, ~14g Dy2O3) with 96% purity. Further, this study demonstrates that using CaCl2.2H2O as a solid chlorinating agent in chlorination roasting enhances recovery rates of mixed rare earth oxides while providing a safer and more environment-friendly alternative for industrial applications.