708 KEYWORDS Thermodynamic modelling, critical raw materials, industrial residue valorization, titanium recovery, sustainable innovation, World Mining Congress 1. INTRODUCTION Titanium (Ti) is classified by the EU as both a Critical Raw Material and a Strategic Material, essential for aerospace, medical, and energy industries (Yagmurlu, 2023). Europe is nearly 100% reliant on Ti ore and metal imports (European Commission, 2023), which has spurred interest in extracting Ti from unconventional domestic sources. At the same time, industrial processes generate vast waste streams enriched in valuable elements. Bauxite residue (red mud) is a highly alkaline by-product of alumina production; about 1-2 tons of bauxite residues (BR) are generated per ton of alumina, amounting to >150 million tons annually worldwide (Rai et al., 2020). BR contains iron (30-60% Fe₂O₃) and titanium (~5-15% TiO₂) along with alumina, silica, and alkali oxides (Stopic et al., 2024). However, due to its chemical complexity and causticity, most of the BR is neutralized and stockpiled at high costs and environmental risks (Winkler et al., 2018). Titanium residues production slag (e.g. from TiO₂ pigment processing) is another product rich in Ti (up to 70% TiO₂) but containing impurities (Ca, Mg, Fe, etc.) that make it a challenge to reintroduce into conventional Ti production (Hayes, 2016; Friedrich et al., 2017; Stopic et al., 2024). Together, these two “waste products” represent an untapped resource of critical-strategical metals. The EURO-TITAN project was conceived to turn these metallurgical residues into a sustainable source of titanium-based materials and iron metal. Its core objective is to develop a decarbonized titanium recovery process that uses green hydrogen in place of carbon-based reductants, thereby drastically reducing CO₂ emissions (EURO-TITAN web page). The envisioned process (schematically illustrated in Figure 1) integrates pyrometallurgical reduction of the residue to separate iron and concentrate titanium, with hydrometallurgical extraction of Ti from the resulting slag, followed by production of Ti metal powder via advanced techniques (e.g. ultrasonic spray pyrolysis and hydrogen reduction of Ti compounds). By using secondary raw materials, EURO-TITAN addresses both waste valorization and supply security of Ti, potentially meeting up to 30% of global Ti demand from these sources (EURO-Titan web page). Moreover, the process aims for 90% lower CO₂ footprint than the traditional Kroll process for Ti (which relies on carbon-intensive chlorination and magnesium reduction) (www.euro-titan.eu). Figure 1 - Schematic view of the EURO-TITAN process.
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