Cost-Effective Carbon Dioxide Removal via CaO-based Mineralization with Concurrent Recovery of Value-Added Calcite Nanoparticles

The rapid increase in atmospheric CO₂ concentrations has intensified the demand for scalable, sustainable, and economically viable carbon sequestration technologies. This study presents a cost-effective calcium oxide (CaO)-based mineralization process that not only achieves efficient CO₂ removal but also enables the simultaneous recovery of high-purity calcite nanoparticles as value-added products. The process consists of hy-drating CaO, followed by controlled carbonation under optimized CO₂ flow rates and temperature conditions, producing nanocrystalline calcite with an average particle size of approximately 100 nm. Comprehensive characterization using X-ray diffraction, transmission electron microscopy, and energy-dispersive X-ray spectroscopy confirmed a polycrystalline nanoparticle structure with exceptional chemical purity (99.9%) and rhombohedral morphology. A techno-economic analysis further revealed that inte-grating CO₂ sequestration with nanoparticle production can significantly enhance profitability, particularly when utilizing CaO-rich industrial residues such as steel slags or lime sludge as feedstock. This hybrid, multi-revenue approach—combining carbon credits, nanoparticle sales, and waste valorization—provides a scalable pathway aligned with circular economy principles, improving both environmental and economic per-formance. The findings highlight the potential of CaO-based mineralization to evolve from a carbon management solution into a platform for advanced materials manufac-turing, thereby contributing to global decarbonization goals.