20.500.12556/DiRROS-32149 Characterisation of selected bauxite profiles in Slovenia with emphasis on REE distribution Bauxites are the primary mineral resource for alumina and aluminium production. Recently, there has been growing interest in the chemical characterisation of bauxite, as it is listed as a critical raw material (CRM) by the European Union and can contain elevated content of rare earth elements (REE), which are also listed as CRM. This research focuses on the REE content and distribution across profiles of four Slovenian bauxite occurrences of different ages (Triassic T32+3, Jurassic J31,2, Cretaceous K22,3 and Oligocene Ol2) and their implications for potential genesis. General mineral composition analysed by XRD showed a prevalence of böhmite and kaolinite in all samples except Ol2, where diaspore is the main Al-hydroxide. Minor minerals include hematite, quartz, and anatase. Geochemical ICP-MS analysis showed the lowest REE content in Cretaceous bauxites (average 218 mg/kg) and the highest in Jurassic bauxites (average 711 mg/kg). SEM/EDS inspection revealed different carriers of REE. The main carriers of REEs in all profiles are mostly detrital, with some individual secondary authigenic xenotime, secondary authigenic cerianite (Ce) (T32+3, J31,2), calcioancylite (Nd) or cerianite (Ce) without Th (J31,2, Ol2), lanthanite (Ce) and (Nd). Relatively low P2O5 indicates dispersion of REEs throughout a profile and their adsorption onto Al/Fe oxides and hydroxides and clay minerals. The T32+3, J31,2 and K22,3 bauxites show a changing Eh-pH environment, which supports their categorisation as vadose bauxites, while the Ol2 profile is phreatic bauxite where redox conditions prevailed. bauxites mineral resources ore deposits rare earth elements true false true Angleški jezik Ni določen Neznano 2026-08-28 10:51:31 2026-08-28 10:51:31 2026-08-29 04:22:23 0000-00-00 00:00:00 2026 0 0 21 str. vol. 197, [article no.] 107523 2026 0000-00-00 Zaloznikova Objavljeno NiDoloceno 0000-00-00 0000-00-00 2026-08-24 553 1872-7360 10.1016/j.oregeorev.2026.107523 289117443 1-s2.0-S0169136826004233-main.pdf 1-s2.0-S0169136826004233-main.pdf 1 BBB2C2F91C4D2A0394DD5151FA568D31 a6198c9f3da1cf8910c5d9e5cf6c3e250c538984d5a6d0559a178782746869c9 ed3f12bb-a2be-11f1-b645-001a4af901a5 https://dirros.openscience.si/Dokument.php?lang=slv&id=50140 1-s2.0-S0169136826004233-mmc1.docx 1-s2.0-S0169136826004233-mmc1.docx 1 C76552E3298D6B20B070A016B0D04C75 861536922ac492eb31d4b12537ac534e9affae1dfac5ef401fff8a3a37672303 877269f5-a2be-11f1-b645-001a4af901a5 https://dirros.openscience.si/Dokument.php?lang=slv&id=50139 Geološki zavod Slovenije 0 0 0