Review article

https://doi.org/10.4154/gc.2026.10

Croatian Critical Mineral Commodity Letters: Bauxite

Sibila Borojević Šoštarić ; University of Zagreb, Faculty of Mining, Geology and Petroleum Engineering, Zagreb, Croatia *
Nenad Tomašić ; University of Zagreb, Faculty of Science, 10000 Zagreb, Croatia
Vječislav Bohanek ; University of Zagreb, Faculty of Mining, Geology and Petroleum Engineering, Zagreb, Croatia
Erli Kovačević Galović ; Croatian Geological Survey, Zagreb, Croatia
Nikola Gizdavec ; Croatian Geological Survey, Zagreb, Croatia
Slobodan Miko ; Croatian Geological Survey, Zagreb, Croatia

* Corresponding author.

Supplements: GC_79_2_Borojevic Sostaric et al. (2026) suppl.pdf

Abstract

Bauxite is a critical raw material with high importance for the European Union economy. Bauxite has versatile applications in industries: aluminium production (≈ 90%), the chemical industry (aluminium sulphate, chloride, sodium aluminate, trihydrate), cement (high-alumina cement), refractory production, and abrasives (brown- and white-fused alumina). The Republic of Croatia hosts bauxite deposits with variable potential: (1) High-potential deposits include Jurassic bauxites in Istria (total reserves >5 Mt; Al2O3 50–60 wt %, Fe2O3 10–22 wt %, SiO2>16 wt %) suitable for cement and structural clay production, and Upper Eocene Promina bauxites in Dalmatia (total reserves >5 Mt) suitable for cement and/or structural clay production; the REE content in the Promina bauxites reaches up to 3,495 ppm, representing a potential secondary sources of critical elements. (2) Medium-potential deposits are the Upper Triassic clayey bauxites (at Lika, Kordun, north Dalmatia), with individual deposits up to several hundred thousand tons, and total remaining reserves of several million tons. Their low Al2O3 and high SiO2 make them suitable for brick and structural clay production. (3) Low- or no-potential deposits include the Lower Cretaceous, Miocene, Palaeocene, Upper Cretaceous, and Mid Eocene bauxites, with small reserves (10–35 kt) and limited industrial use. A case study of the Upper Eocene Promina bauxite beds (≈ 2.4 Mt remaining reserves) shows lens-shaped or pseudo-layered deposits in karstified limestones (up to 30 m thick). Historical extraction used open-pit and underground mining (Čveljo Dolac ≈ 80% under-ground, Mamutovac 100% surface, Krste Radas 100% underground). Bauxite is mainly suitable for cement and structural clay production; the bulk value of remaining reserves is estimated at ≈42 M€ (market price ≈20 €/t). The deposits are enriched in critical elements: Ti ≈10.4 kt, Cr ≈0.6 kt, V ≈0.5 kt, Ni ≈0.2 kt, and ∑REE ≈1.4 kt, representing potential secondary sources for future industrial and strategic uses.

Keywords

Critical raw materials; bauxite; Croatia; case-study Promina

Hrčak ID:

348067

URI

https://hrcak.srce.hr/348067

Publication date:

17.6.2026.

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