Carbon dioxide (CO2) mineralization also known as carbonation, i.e., the process of transforming gas-phase CO2 into a solid carbonate (often calcite: CaCO3 or magnesite: MgCO3) offers opportunities for the synthesis of building materials including cementation agents, and mineral aggregates. While a thermodynamically favorable reaction, carbonation on account of its acid-base neutralization basis requires causticity to be maintained. Considering the case of portlandite (Ca(OH)2) as an archetypical base that can be produced from geologically sourced precursors, first, this talk will highlight pathways for the carbonation of portlandite at ambient pressure and sub-boiling temperatures using dilute streams of gas-phase CO2 to form cementation agents, e.g., to bind mineral aggregates in concrete. Special focus is placed on highlighting the attributes of portlandite’s carbonation which support its selection as a precursor for such reactions. Second, due to the significant CO2 intensity associated with traditional portlandite synthesis, a new low-temperature precipitation strategy is demonstrated while emphasizing the (re)use of alkaline solid-wastes in the production process. Finally, based on the lessons learned from the outcomes above the possibility for the near-surface disposal of solid carbonates formed via precipitation using surface water sources and atmospheric CO2 is discussed in terms of its feasibility as a global carbon management strategy.

Carbon dioxide mineralization: Strategy for the provision of building materials, and for carbon management globally

2019 Fall National Meeting

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