From Unavoidable CO₂ Source to CO₂ Sink? A Cement Industry Based on CO₂ Mineralization

Area of Science:

• Materials Science
• Environmental Science
• Chemical Engineering

Background:

• The cement industry is a major source of anthropogenic greenhouse gas (GHG) emissions, contributing 7% globally.
• Cement production inherently releases CO2 through limestone calcination, posing a significant challenge for emission reduction.

Purpose of the Study:

• To investigate carbon dioxide (CO2) mineralization as a strategy for achieving a carbon-neutral cement industry.
• To assess the feasibility of CO2 mineralization for both capturing CO2 and reducing clinker usage in cement production.

Main Methods:

• Life cycle assessment (LCA) was employed to analyze the carbon footprint of combined CO2 mineralization and cement production.
• Evaluation of two primary mechanisms: CO2 capture and storage, and substitution of cement with mineralization byproducts.

Main Results:

• Combined CO2 mineralization and cement production can reduce the industry's carbon footprint by 44% with current energy mixes, potentially reaching 85% theoretically.
• The integration of low-carbon energy sources or increased blending of mineralization products can lead to carbon-neutral blended cement.
• Utilizing direct air capture with this process could result in carbon-negative blended cement production.

Conclusions:

• CO2 mineralization presents a viable pathway to transform the cement industry from a significant CO2 source into a potential CO2 sink.
• Developing integrated processes and products for CO2 mineralization is crucial for decarbonizing cement production.
• This approach offers a dual benefit of CO2 mitigation and sustainable material development for the construction sector.