Advancing seawater-based mineral carbonation: Exploring novel pathways for enhanced carbonation efficiency and control of carbonate polymorphism and size

Seawater -based mineral carbonation is a treatment method that can simultaneously address the issues of global warming and marine pollution caused by the desalination brine. However, the selection of reactants without considering wastewater, the low reaction rate and selectivity of generated carbonate compounds require improvement. This study aims to more efficiently precipitate magnesium (Mg) and calcium (Ca) in desalination brine and control the characteristics of the precipitated CaCO3 (PCC). The efficiency of Mg carbonation under brine conditions is analyzed, and the precipitation of CaCO3 is controlled by separating the CO2 absorptionprecipitation process. Mass transfer of CO2 improved under atmospheric pressure brine conditions, accelerating the carbonation of Mg. The adjusted [Ca2+]:[CO32-] ratio was a factor influencing polymorphism and size during the precipitation process of CaCO3. Sodium -rich wastewater generated in the process can be integrated with chlor-alkali processes and additional sodium precipitation processes to secure its value as a sustainable technology.