A Photosynthetic Route to Carbon-Negative Portland Limestone Cement
The University of Colorado Boulder will manufacture and commercialize a net-CO2-storing portland limestone cement using biogenic limestone (CaCO3) produced via photosynthesis that will store more than 275 kgCO2 and cost less than $100 per ton of cement. Most cement-related CO2 emissions are caused by heating CaCO3 to produce calcium oxide (quicklime), which releases CO2 in the process. The proposed technology will produce biogenic CaCO3 using calcifying microalgae that sequester and store CO2 in mineral form through biological direct air capture via photosynthesis and calcification. Using this CaCO3 in biogenic cement production leads to a net carbon neutral carbon cycle.
HESTIA projects will facilitate the use of carbon storing materials in building construction to achieve net carbon negativity by optimizing material chemistries and matrices, manufacturing, and whole-building designs in a cost-effective manner.