Linking mineralogical variability to processing: Strategies for a rare earth carbonatite deposit

The global demand for rare earth elements continues to rise, while newly discovered deposits typically exhibit lower ore grades as most high-grade resources have already been exploited. Their extraction is often constrained by complex mineralogy. Economically important rare earth minerals such as bastnäsite and monazite typically occur in fine-grained, heterogeneous assemblages with carbonates and silicates as gangue minerals. Linking mineralogical variability to beneficiation performance enables the identification of suitable concentration techniques, including gravity, magnetic, electrostatic, and froth flotation methods. This study employs a process mineralogical approach to characterize low-, medium-, and high-grade intervals of a rare earth carbonatite drill core containing monazite, parisite, bastnäsite, and synchysite, and to evaluate their implications for mineral processing. Elemental and mineralogical data are investigated to evaluate beneficiation potential and guide flowsheet development. At the current grind size, each sample grade has the potential to achieve acceptable recovery, each exhibiting distinctive characteristics. Low-grade sample may require specific conditions due to the phosphate nature of the main target mineral (monazite). Medium-grade sample may exhibit limited efficiency in magnetic separation due to higher association degree between magnetite and the target minerals and reduced selectivity during flotation due to its higher apatite content. High-grade sample, containing the highest Fe-bearing carbonates, may require the use of tailored reagents to maintain satisfactory separation. The findings emphasize that grade-specific process design, informed by elemental and mineralogical characterization, is essential to maximize rare earth recovery. This integrated approach provides a framework for optimizing beneficiation strategies in complex REE-bearing carbonatite deposits.