Ambient air from the room is pumped into a tank containing the algae; this supplies the CO2. The algae are then harvested and transferred to a second tank that stimulates calcium carbonate production. This process is complete when all the algae sink to the bottom of the tank, where they’re then collected, dehydrated, and mixed with other natural binding agents. The result is a bio-cement; it’s then ready to be mixed with aggregates to create concrete
https://www.archpaper.com/2023/09/cement-production-emissions-problem-companies-addressing-it/