High-Efficiency and Economical Recovery of Cerium, Lanthanum, and Neodymium from Iron Ore Apatite Waste via Optimized Hydrochloric Acid Leaching

This study investigates the leaching behavior of three rare earth elements (REEs), cerium (Ce), lanthanum (La), and neodymium (Nd) from apatite concentrate derived from iron ore waste using hydrochloric acid. The effects of key parameters, including acid concentration, solid-to-liquid (S/L) ratio, leaching time, and temperature, were systematically evaluated using response surface methodology (RSM). Statistical analysis revealed that acid concentration and temperature had the most significant influence on REE extraction, whereas leaching time had a comparatively minor effect. Under optimized conditions (37% HCl, 1 : 9 S/L ratio, 60 min, and 65°C), maximum recoveries were achieved: 94.19% for Ce, 86.33% for La, and 76.34% for Nd. These findings confirm the viability of hydrochloric acid leaching as an effective technique for REE extraction from apatite-rich waste. Moreover, the optimization process provides a cost-effective approach, striking a balance between high recovery efficiency and moderate chemical and energy inputs.