Low-emission cement clinker precursor production, enabled by electrolytic extraction of calcium from waste cement.
basic_science · Level V
Where this comes from
- Record sourced from PubMed, PMID 41120382.
- Also identified by DOI 10.1038/s41467-025-64339-5 and PMC identifier 12541047.
- Licence recorded as CC BY-NC-ND.
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Abstract
We report here the electrochemical production of cement clinker precursor, containing calcium derived from the electrolytic decomposition of waste cement. Our "cement recycler" contains a cement electrolyzer, coupled to a cement digestion vessel, and a Ca(OH)<sub>2</sub> isolation vessel. The cement electrolyzer creates acid and base equivalents, and converts waste cement into Ca(OH)<sub>2</sub> and SiO<sub>2</sub>. The electrolyzer was demonstrated at current densities up to 300 mA cm<sup>-2</sup> to produce yields higher than 80% for Ca(OH)<sub>2</sub>. We experimentally verified a 99.8% reduction in CO<sub>2</sub> emissions when using fresh waste cement, and an 80% reduction when using aged cement (enriched in CO<sub>2</sub> due to atmospheric carbonation) from a demolition site. Our cement recycler bypasses the need for virgin limestone and could cut global CO<sub>2</sub> emissions by nearly 1 Gt annually, while also helping divert substantial waste cement from landfills.