Data from high-temperature and high-pressure carbon dioxide sequestration experiments limited to 24 hours, performed on Platinum Group Metals mine tailings from the South African Bushveld Igneous Complex.

Mine tailings derived from mafic-ultramafic rock formations may offer promising potential for mineral carbon dioxide (CO2) sequestration. This dataset evaluates the suitability of South African tailings, produced during Platinum Group Metals (PGM) extraction at the Two Rivers mine, for CO2 mineralisation under supercritical conditions in a batch reactor. These tailings are typically enriched in oxides such as MgO (12 %), Fe2O3 (22 %), and CaO (2 %), which can provide the necessary alkalinity for carbonate formation. They also contain significant amounts of Al2O3 (11 %), SiO2 (18 %), and Cr2O3 (34 %), which may influence reaction pathways. Reactivity with CO2 was investigated under supercritical conditions (200 °C, 160 bar) in a saline aqueous solution for various reaction times ranging from 2 h to 24 h. The geochemical and physicochemical properties of the fresh tailings were determined using X-ray fluorescence (XRF) and X-ray diffraction (XRD). Post-reaction tailings were further analysed using scanning electron microscopy (SEM), Carbon and Sulphur (C&S) analysis, and particle size distribution (PSD) analysis.