Our LCA-based assessment showed that all considered CCU technologies for mineralization can reduce climate impacts over the entire life cycle due to the permanent storage of CO2 and the credit for substituting conventional products.

The cement industry emits 7% of the global anthropogenic greenhouse gas (GHG) emissions. Reducing the GHG emissions of the cement industry is challenging since cement production stoichiometrically generates CO 2 during calcination of limestone. In this work, we propose a pathway towards a carbonneutral cement industry using CO 2 mineralization. CO 2 mineralization converts CO 2 into a thermodynamically stable solid and byproducts that can potentially substitute cement. Hence, CO 2 mineralization could reduce the carbon footprint of the cement industry via two mechanisms: (1) capturing and storing CO 2 from the flue gas of the cement plant, and (2) reducing clinker usage by substituting cement. However, CO 2 mineralization also generates GHG emissions due to the energy required for overcoming the slow reaction kinetics. We, therefore, analyze the carbon footprint of the combined CO 2 mineralization and cement production based on life cycle assessment. Our results show that combined CO 2 mineralization and cement production using today's energy mix could reduce the carbon footprint of the cement industry by 44% or even up to 85% considering the theoretical potential. Lowcarbon energy or higher blending of mineralization products in cement could enable production of carbon-neutral blended cement. With direct air capture, the blended cement could even become carbon-negative. Thus, our results suggest that developing processes and products for combined CO 2 mineralization and cement production could transform the cement industry from an unavoidable CO 2 source to a CO 2 sink.

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Minimum development requirements for electrochemical CO2 reduction (eCO2R) to compete against H2-based power-to-chemical pathways.

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Employing mineral carbonation products as a cementitious substitute could reduce the cement industry’s greenhouse gas (GHG) emissions. However, a transition toward low-emission cement requires financially competitive cement production at standardized product specifications. Aiming to tackle this challenge, we modeled and optimized a direct mineral carbonation process. In detail, we embedded a mechanistic tubular reactor model in a mineral carbonation process and imposed product specifications based on the European cement standard in the optimal design formulation. In the next step, we considered the business case of blended cement consisting of ordinary Portland cement and the mineral carbonation product that could be categorized as CEM II in the European cement standard. We computed the minimum production cost and GHG emissions of the produced blended cement by using Bayesian optimization to find Pareto optimal operating conditions of the mineral carbonation process. Our results showed that the cost of mineral carbonation in the cement industry can be competitive while cutting the GHG emissions by up to 54%.