Electrochemical catalysis for the production of green cement: towards decarbonizing the cement industry

Abstract

Among the most significant sources of CO₂ emissions, cement manufacturing contributes 8% of such emissions worldwide. The CO₂ emissions are generated from a few key sources: around 60% comes from the decomposition of limestone into calcium oxide, 30% from the combustion of fossil fuels (mainly coal), and roughly 10% from power consumption. To reduce CO₂ emissions during cement manufacturing, alternative fuels, binders, and renewable energy sources could be utilized to achieve carbon neutrality. However, the reduction of CO₂ released from the conversion process of limestone into calcium oxide still presents a significant challenge. This review provides a comprehensive analysis of different electrochemical production approaches of green cement. One of these promising approaches is the decarbonization of CaCO₃ into Ca(OH)₂, while generating pure H₂ at the cathode and O₂/CO₂ gas mixtures at the anode, using several pathways. Ca(OH)₂ is a precursor to cement clinker, whose primary use is to manufacture Portland cement. The produced concentrated gas streams of H₂ and/or O₂ can be used to produce electricity with extremely little pollution through fuel cells or combustion engines. Although hydrogen is the basic fuel for fuel cells, fuel cells require oxygen too. Large portions of hydrogen and oxygen combine to form a harmless by-product, which is water. From an economic point of view, this produced electrical current can be directed to the green cement manufacturing process and can be used to power any electric motor or device.