Optimization of mechanochemical activation of basalt fines in aqueous environments for CO ₂ mineralization and pozzolanic reactivity: discovery of a Pareto optimal front

Mechanochemical activation of abundant basalt offers a promising route to supplementary cementitious material (SCM) production, yet systematic frameworks for linking milling parameters to pozzolanic reactivity and energy consumption remain undeveloped. A definitive screening design coupled with DEM modeling revealed that ball-to-powder ratio (B:P) dominates reactivity over rotational speed (RPM), with an energy-optimal strategy of minimizing RPM just above the granular settling threshold (∼130 RPM) while maximizing B:P. Multiobjective optimization revealed a Pareto-optimal front, where maximizing pozzolanic reactivity required high B:P at the minimum viable RPM, while carbonate formation (0.08–0.90 wt%) correlated solely with the liquid-to-solid ratio. Specific energy, additionally, correlates highly to reactivity but its variance can be explained by individual processing conditions, with the Pareto-optimal front achieving a significant reduction in milling energy to achieve 229 J/gSCM from 8050 to 2600 kWh/mt.