Carbon-Negative Cement Manufacturing from Seawater-Derived Magnesium Feedstocks


Badjatya P., Akca A. H. , Fraga Alvarez D., Chang B., Ma S., Pang X., ...More

ChemRxiv, vol.1, pp.1-39, 2021 (Non-Refreed Journal)

  • Publication Type: Article / Article
  • Volume: 1
  • Publication Date: 2021
  • Doi Number: 10.33774/chemrxiv-2021-5dznt
  • Journal Name: ChemRxiv
  • Page Numbers: pp.1-39

Abstract

This study describes and demonstrates 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 (Mg2+) in seawater into magnesium hydroxide (Mg(OH)2) precursors for the production of Mg-based cement. After a low-temperature carbonation curing step converts Mg(OH)2 into magnesium carbonates through reaction with carbon dioxide (CO2), the resulting Mg-based binders can exhibit compressive strength comparable to that achieved by Portland cement after curing for only two days. Although the proposed “cement-from-seawater” process requires similar energy use per ton of cement as existing processes, its potential to achieve a carbon-negative footprint makes it highly attractive to decarbonize one of the most carbon intensive industries.