exhibits a broad stability field across the investigated temperature and oxygen fugacity range. This behaviour promotes the concentration of titanium into a stable and potentially recoverable titanate phase. Aluminium is primarily accommodated in spinel-group minerals (including hercynite and Mg-rich spinel), as well as in gehlenite and corundum, which remain stable throughout the investigated reduction conditions. Calcium is predominantly incorporated into gehlenite, lime, and perovskite, reflecting its role as a structural stabilizer in silicate and titanate phases. Importantly, the experimental temperature range lies within the stability fields of metallic iron, spinel-group minerals, gehlenite, and perovskite, confirming that hydrogen reduction at these conditions is thermodynamically favourable for iron metallization and titanium concentration into perovskite. These predictions are consistent with XRD results, which identified metallic iron and perovskite as major phases in the reduced material. Stability fields, and modal abundance (%vol.) have been calculated for each one of the relevant phases. By querying the equilibrium results as a function of temperature and oxygen fugacity, Perple_X enabled the generation of detailed phase stability maps plotted with PyWerami (Figure 3), allowing direct identification of the conditions under which key phases such as metallic iron, perovskite, spinel, and silicate phases are thermodynamically stable. Figure 3 - Perple_X-calculated stability fields with modal abundance (%vol.) of the major mineral phases as a function of oxygen fugacity (Log fO₂) and temperature (T), based on the bulk composition of the BR
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