Environmental trade-offs of CO2 mineralization cell by life cycle assessment

CO 2 mineralization cell (CMC) is a promising approach for permanent carbon mitigation, enabling CO 2 mineralization using carbide slag to produce high-purity carbonate products while converting mineralization-derived energy into electricity. However, its environmental performance lacks insufficiently quantified because of the complexity of its system boundary. In particular, as CO 2 is emitted during carbide production but consumed during subsequent mineralization, such systems may be intuitively regarded as nearly “zero-sum” or simply classified as a “CaCO 3 cycle”. Meanwhile, the contributions of CO 2 capture, transportation, and process energy consumption have not been consistently accounted for. In this study, a comprehensive and rigorous life cycle assessment (LCA) was conducted to quantify the environmental trade-offs and resource requirements of the CMC system. Mineralizing 1 t CO 2 via the CMC achieves a reduction of -1096.82 kg CO 2 eq, driven by the combined effects of CO 2 mineralization and substitution credits from high purity CaCO 3 production and electricity generation. This demonstrates that the value of the CMC lies not only in CO 2 consumption, but also in its ability to displace more carbon-intensive conventional pathways, revealing an often-overlooked net mitigation effect. Favorable performance is also observed across multiple impact categories, including human carcinogenic toxicity and ecotoxicity. Sensitivity and scenario analyses further reveal that system configuration influences environmental performance, while carbon reduction is maintained under varying CO 2 sources, energy structures, and deployment conditions, reaching up to -1374.75 kg CO 2 eq within the defined boundary. This work provides a transparent, system-level evaluation of the environmental implications of the CMC system and supports more informed assessment and future development of CO 2 mineralization cell.