Decarbonizing the cement industry

Cement, the essential binder of concrete—the most used material worldwide, only second to water—is produced at over four gigatonnes per year and contributes to 8% of global carbon dioxide (CO₂) emissions. With the annual global demand for cement projected to increase by 50% by 2050, there is an urgent need to incorporate carbon capture, utilization, and storage technologies to control and mitigate the carbon footprint of cement manufacturing.

In a paper published in Energy & Environmental Science, LLNL researchers and collaborators have demonstrated a novel approach to decarbonize the decomposition of limestone—the primary cement feedstock (raw material used in manufacturing). This research was supported by LLNL’s Laboratory Directed Research and Development program (21-ERD-050).

Their process utilizes water electrolysis (a non-greenhouse-gas-emitting form of electricity and renewable energy production) to electrochemically generate carbon-negative calcium carbonate (CaCO₃), which substitutes limestone as the primary cement manufacturing feedstock, neutralizing the 200-year-old liming routine without modifying the conventional cement manufacturing process. To produce the CaCO₃, the team combined carbon-negative calcium silicates from abundant, industrial/construction/mine wastes and rocks with captured atmospheric CO₂.

A life cycle assessment and techno-economic analysis indicate this process can maintain profitability while being carbon neutral/negative. This approach could enable gigaton-scale annual decarbonization of the cement industry, meeting regulatory compliance with minimal capital investment. Research is currently underway to upscale the present laboratory gram-scale experiments into industrial-style systems.

[X. Kun Lu, W. Zhang, B.N. Ruggiero, L.C. Seitz, J. Li, Scalable electrified cementitious materials production and recycling, Energy & Environmental Science (2024), doi: 10.1039/D4EE03529A.]

–Physical and Life Sciences Communications Team