Electrochemical Cement Clinker Precursor Production at Low Voltages
Benjamin A. W. Mowbray, Zishuai Zhang, Colin T. E. Parkyn, Curtis P. Berlinguette
Abstract
Cement production is carbon intensive today because fossil fuels are used to heat high-temperature kilns, and because CO 2 is released as a byproduct of limestone (CaCO 3 ) decomposition. Electrochemical reactors can decarbonize cement production by using electricity instead of heat to convert CaCO 3 into Ca(OH) 2, a cement clinker precusor, while releasing the CO 2 byproduct as a pure stream. Herein, we report a “cement electrolyzer” that electrolytically converts limestone into Ca(OH) 2 at a cell voltage of 1.8 V at 100 mA cm –2 . This new benchmark improves upon the previous record of 4.2 V by oxidizing the H 2 byproduct from the cathode compartment into protons for CaCO 3 decomposition. A techno-economic model shows that this use of H 2 decreases the cost of cement production by $36/t cement compared to the use of H 2 as a kiln fuel. This work describes an energy-efficient cement electrolyzer and advances the feasibility of electrochemical cement production.