| Abstract Scope |
Production of high-purity total rare earth oxides (TREO) from low-grade resources is essential to meet growing demand for rare earth elements (REEs) in advanced technologies. In this study, a low-grade apatite ore from the Khotgor deposit, Mongolia (2–2.5 wt.% TREO), was beneficiated by flotation to a concentrate containing 30.88 wt.% TREO. XRD analysis identified apatite, pyrite, quartz, hematite, and aegirine-augite as the major mineral phases. REEs were recovered by sulfuric acid leaching followed by sequential hydroxide and oxalate precipitation. The effects of acid concentration, temperature, agitation speed, and leaching time were systematically optimized, while leaching kinetics were evaluated using the Shrinking Core Model. Under optimum conditions (6 M H2SO4, 70°C, 400 rpm, and 180 min), REE extraction reached 96%, yielding a final product containing 95.03 wt.% TREO. XRD analysis revealed gypsum formation and residual CeO2, indicating Ce3+ oxidation during leaching. These results demonstrate feasible high-purity TREO production from Khotgor. |