CHEMICAL SCIENCE

New achievements of Nankai scholars are expected to help “decarbonize” the cement industry


Recently, Luo Jingshan’s research group, professor of the Institute of Optoelectronic Thin Film Devices and Technology, School of Electronic Information and Optical Engineering, Nankai University, proposed a method based on electrochemical limestone conversion to produce slaked lime and valuable carbonaceous products based on electrochemical limestone conversion in view of the problem of large carbon emissions in the cement production process, combined with the research basis of the research group in electrochemical water decomposition and carbon dioxide reduction reaction.

Different from the traditional cement production and preparation process, limestone high temperature heat interpretation of carbon dioxide while obtaining quicklime method, this method does not emit carbon dioxide, but converts the carbon element in limestone into valuable carbonaceous products, which can be used as fuel and chemical production, and is expected to be used in the cement industry to decarbonize in the future and help achieve the “dual carbon” goal.

The study has been published online in the international academic journal iScience.

Among many industrial processes, the production of cement, a building material, is one of the largest sources of CO2 emissions. In 2020, carbon emissions from the cement industry accounted for 13.5% of China’s total carbon emissions, and the green and low-carbon development of the cement industry is crucial for China to achieve the “dual carbon” goal. The statistical report shows that the production of 1 ton of cement emits about 0.6 tons of carbon dioxide, of which about 60% of the emissions come from the thermal decomposition of limestone, and the remaining 40% of the emissions come from the use of fossil fuels and electricity consumption of related equipment during the heating process. CO2 emissions from fossil fuel use and electricity consumption can be reduced through the use of renewable fuels and renewable energy, but eliminating CO2 emissions from the thermal decomposition of limestone to produce quicklime still faces significant challenges.

In view of this problem, Luo Jingshan’s research group proposed a method for converting limestone based on electrochemical system to produce slaked lime and valuable carbonaceous products. Different from the limestone high-temperature pyrolysis method, this method does not emit carbon dioxide, but directly converts the carbon element in limestone into valuable carbonaceous products, which can be used as fuel and chemicals, providing a new idea for carbon emission reduction in the cement industry.

Firstly, this work treats and converts limestone based on a neutral water splitting reaction system. This process uses the hydrogen ions generated in the oxygen evolution reaction in the neutral water splitting reaction to react with quicklime to generate calcium ions and carbon dioxide, and calcium ions are combined with the hydroxide generated in the system to form slaked lime, which can be directly used in cement production. Secondly, by switching the applied voltage, the carbon dioxide generated in the system is converted into valuable carbonaceous products such as carbon monoxide, methane, olefins, etc., and the reaction products can be regulated by switching catalysts.

(a) Schematic diagram of the electrochemical conversion of limestone to slaked lime and carbonaceous products in an electrolytic cell system; (B) quicklime, (C) slaked lime scanning electron microscopy images and (D) X-ray diffraction spectra; (e) Faraday efficiency of different metal electrodes in the formation of valuable carbonaceous products in quicklime-neutral electrolyte systems. Photo courtesy of Nankai University

The related technology of this thesis has been jointly applied for a national invention patent by Nankai University and Conch Group. This technology proposes a new concept of cement production based on electrochemical method to achieve cement industry decarbonization, which is still in the stage of laboratory scientific research, and further research is needed in the future practical application, and Luo Jingshan’s team is optimizing the design of the reaction system and reaction device in order to achieve the goal of industrial application. (Source: China Science News, Xie Qixian, Chen Bin)

Related paper information:https://doi.org/10.1016/j.isci.2023.106015



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