Carbon-negative cement manufacturing from seawater-derived magnesium feedstocks.
basic_science · Level V
Where this comes from
- Record sourced from PubMed, PMID 35972958.
- Also identified by DOI 10.1073/pnas.2114680119 and PMC identifier 9407650.
- Licence recorded as CC BY-NC-ND.
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Abstract
This study describes and demonstrates key steps in a carbon-negative process for manufacturing cement from widely abundant seawater-derived magnesium (Mg) feedstocks. In contrast to conventional Portland cement, which starts with carbon-containing limestone as the source material, the proposed process uses membrane-free electrolyzers to facilitate the conversion of carbon-free magnesium ions (Mg<sup>2+</sup>) in seawater into magnesium hydroxide [Mg(OH)<sub>2</sub>] precursors for the production of Mg-based cement. After a low-temperature carbonation curing step converts Mg(OH)<sub>2</sub> into magnesium carbonates through reaction with carbon dioxide (CO<sub>2</sub>), the resulting Mg-based binders can exhibit compressive strength comparable to that achieved by Portland cement after curing for only 2 days. Although the proposed "cement-from-seawater" process requires similar energy use per ton of cement as existing processes and is not currently suitable for use in conventional reinforced concrete, its potential to achieve a carbon-negative footprint makes it highly attractive to help decarbonize one of the most carbon-intensive industries.