Leveraging Flow-Assisted Electrochemistry to Decarbonize Calcium Hydroxide Production in Cement Manufacturing

To decarbonize the global economy by 50% by 2030 and achieve net-zero emissions by 2050, electrifying industrial processes, particularly in cement manufacturing, is crucial. Cement production accounts for ~8% of global CO2 emissions, primarily due to the thermal decomposition of calcium carbonate in Portland clinker. This study presents a novel electrochemical strategy for converting calcium carbonate to calcium hydroxide, a key clinker precursor, using a fossil-free, flow-assisted electrolysis process. A scalable three-channel flow electrolyzer is employed, comprising an acidic anolyte, basic catholyte, and a neutral chemical flush, separated by a cation exchange membrane (CEM) and an anion exchange membrane (AEM). The performance of the system was assessed under varied operating conditions to elucidate electrochemical behavior and practical limitations. To the best of our knowledge, this is the first reported demonstration of a bench-scale three-channel flow electrolyzer achieving ~40% faradaic efficiency at 50 mA/cm2 using calcium carbonate as the input. Results indicate significant opportunities for performance gains through optimization of electrolyte composition and membrane stability. This work offers a promising step toward decarbonizing cement production while contributing to the broader advancement of flow-based electrolysis technologies for sustainable chemical manufacturing.