Rare Earth Element Potential from Bauxite to Red Mud: Economic Insights from the Al Ba’itha Mine, Saudi Arabia

Abstract

The Saudi Arabian mining sector is expanding rapidly. Among the strategic resources under investigation are bauxite ore and its industrial byproduct, red mud, both of which have potential as secondary sources of REEs. This study characterizes the mineralogical and geochemical properties of bauxite and red mud to evaluate REE distribution and behavior. Two groups of bauxite in the Al Ba’itha mine have been petrologically identified: (i) a high-Al group and (ii) a high-Fe ferruginous group. The bauxite was predominantly composed of gibbsite and boehmite, followed by kaolinite, with lesser amounts of hematite, anatase, minor goethite, quartz and calcite. In contrast, red mud generated via the Bayer process predominantly contained hematite and goethite, along with sodalite and cancrinite, and minor residual gibbsite and boehmite, as well as calcite, rutile, anatase, and quartz. The analyzed bauxite averages ~60 wt.% Al2O3, primarily from gibbsite and boehmite, affirming its value as an aluminum ore. The red mud was ~27 wt.% Fe2O3 and ~22 wt.% Al2O3, reflecting its mineralogical complexity and enrichment in iron and aluminosilicate phases. ICP-MS analysis revealed notable REE concentrations: bauxite contained Ce (142.5 ppm), La (63.2 ppm), and Nd (40.0 ppm), while the red mud exhibited higher concentrations of Ce (256 ppm), La (112 ppm), and Nd (77.2 ppm), with total REE contents exceeding 500 ppm. REEs were primarily associated with Al-bearing phases in bauxite, while Dy and Eu could also be associated with Fe-bearing phases. In contrast, HREEs showed a strong positive correlation with Fe2O3 in red mud. These findings highlight Saudi red mud as a strategic secondary REE resource within the rapidly expanding Saudi mining sector. They demonstrate strong economic potential and align with global trends seeking sustainable, residue-based pathways for REE recovery.