As the concentration of greenhouse gases in our atmosphere continues to rise, so does the urgency to transform the construction industry, which has thus far been among the highest CO₂ emitters. A key part of the decarbonisation effort is the development of sustainable materials, which can capture CO₂.

For instance, the utilization of CO₂ to produce solid carbonates as construction materials can provide a large-scale sink for CO₂, in terms of long-term storage, while providing a sustainable solution for the industry. The captured CO₂ used in the production process is securely stored within the structure of carbonate precipitates: the total mass of the hardened material consists of more than 30wt% of CO₂. Furthermore, the process utilises desalination reject brines which would otherwise be released into the ocean, causing harm to the aquatic life and general environment.

(i) CO₂ absorption in alkaline solution and (ii) carbonate reaction with Mg²⁺ rich brines.
For the absorption step external source of OH- is supplied by sustainably produced NaOH, or alkaline wastes (such as cement kiln dust or fly ash); for the precipitation reaction desalination brines are used to provide Mg²⁺ ions. The obtained solids are processed at temperatures of 70-130° C and used in the production of slabs and boards suitable for interior construction.

The product has a wide array of applications, some of which are based on its self-cementing properties, e.g.:

• Plasterboard/Drywall manufacture
• Stucco production
• Specialty products, such as lightweight false ceiling panels
• Alternative applications: e.g. direct use as cement additive/filler