Cation Exchange in Smectites as a New Approach to Mineral Carbonation

Mineral carbonation of alkaline mine residues is a carbon dioxide removal (CDR) strategy that can be employed by the mining industry. Here, we describe mineralogy and reactivity processed kimberlites kimberlite ore from Venetia (South Africa) Gahcho Kué (Canada) diamond mines, which are smectite-rich (2.3–44.1 wt.%). Whereas, serpentines, olivines, hydrotalcites brucite have been traditionally used for mineral carbonation, little known about smectites to CO 2 . The smectite both mines distributed as fine-matrix saponite, Mx/mm+ Mg 3 (Al x Si 4−x )O 10 (OH) · n H O, where layer charge deficiency balanced labile, hydrated interlayer cations (M m + ). A positive correlation between cation exchange capacity saponite content indicates most reactive phase within these ultramafic rocks it source labile 2+ Ca reactions. Our work shows provide fast in absence highly [Mg(OH) ]. It opens up possibility using other, previously inaccessible rock types including tailings sediment-hosted metal deposits oil sands tailings. We present decision tree accelerated at based on this revised understanding mineralogical controls potential.