Fluorite and rare-metals mineralization in greisenized granite of Um Naggat area, Egypt constrained by physical separation and beneficiation assessment

Abstract

Abstract Fluorite and rare-metals mineralization hosted within the greisenized granites of Um Naggat area, Central Eastern Desert, Egypt, represents a potential source of critical raw materials. The studied sample is dominated by quartz and feldspar, with a minor heavy-mineral fraction enriched in fluorite and accessory rare-metal phases, including zircon, columbite, ilmenite, cassiterite, uranothorite, monazite, aegirine, almandine garnet, iron oxides, and biotite. Comprehensive mineralogical, geochemical, and beneficiation investigations were conducted to assess the recovery potential of fluorite and associated rare-metals mineralization. Particle-size analysis and mineralogical characterization indicated favorable liberation of the target minerals, enabling efficient separation from the silicate gangue. Gravity concentration using a Wilfley shaking table upgraded the total heavy-mineral (THM) content from 1.95 wt% in the feed to 6.11 wt% in the combined concentrate, achieving an overall THM recovery of ~ 80%. Subsequent high-intensity magnetic separation effectively partitioned the concentrate into fluorite-rich diamagnetic and rare-metals-bearing magnetic fractions. XRD and SEM-EDS analyses indicate that fluorite is the dominant phase in the diamagnetic product, accompanied by accessory zircon and galena, while columbite, thorite, garnet, and other rare-metals-bearing minerals are concentrated in the magnetic fraction. The results demonstrate the effectiveness of a combined gravity–magnetic beneficiation flowsheet for upgrading fluorite and associated rare-metals mineralization from the studied greisenized granite under laboratory-scale conditions. These findings provide a basis for further process optimization and detailed technical and economic evaluation of Um Naggat mineralization.