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.
The production of carbonate minerals involves two major steps:
(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
QNRF project code
Partners: IMDEA Energia, Qatar National Cement Company, Qatar Electricity and Water Company, QatarQatari Diar, SMEET W.L.L, Umm Al Houl Power