Spent neodymium-iron-boron (NdFeB) magnets represent a valuable secondary source of rare earth elements (REEs). This study presents an innovative process for recovering Neodymium (Nd) from spent NdFeB magnets using inorganic salt solution composed of aluminium nitrate nonahydrate (Al(NO3)3·9H2O) and water referred to as a ‘green Brønsted solvent’. Hammett acidity measurements confirm that concentrated solutions of Al(NO3)3·9H2O and H2O exhibit strong Brønsted acidity, enabling the selective leaching of Nd from NdFeB magnet sample roasted at 660°C. A high separation factor of 4150 for Nd over iron (Fe) was achieved. This salt solution offers significant advantages, including non-volatility, safety, high solubility, and excellent selectivity for REEs. Under optimal conditions (80°C, solid-to-liquid ratio of 1:20, and leaching time of 150 min), 96.9 per cent of Nd was leached, while Fe leaching was limited to just 0.9 per cent. The dissolved Nd3+ was subsequently recovered from the leachate by precipitation with oxalic acid, followed by oxidative roasting, yielding Nd2O3 with a purity greater than 99 per cent. This high selectivity and product purity demonstrate the feasibility of this process for producing high-quality Nd2O3 suitable for reuse in NdFeB magnet manufacturing. Moreover, the approach minimises impurity incorporation and downstream processing requirements, offering an environmentally friendly strategy for REE recovery from secondary resources.