global carbon emissions. If the global cement industry were a country, it would be the third largest carbon emitter after China and the United States. Zheng Jianhui, chief analyst of
China Cement Network Cement Big Data Research Institute, has said that in 2022, global cement carbon emissions will be about 2.7 billion tons, accounting for 7.5% of global energy-related carbon emissions. The top 12 major cement producers account for 77% of global cement production, and the task of reducing cement carbon emissions is heavy.
Cement industry carbon emissions are divided into direct emissions and indirect emissions. Direct emissions include fuel combustion emissions and production process (carbonate decomposition) emissions. Indirect emissions include carbon dioxide emissions converted from power consumption in cement production links and energy consumption in non-production links such as power generation, heat supply and transportation. Carbon dioxide emissions from
cement industry mainly come from the clinker production process, in which the carbon dioxide emissions from carbonate decomposition account for about 60% of the total carbon emissions, and the carbon dioxide emissions from fuel combustion account for about 35% of the total carbon emissions; Carbon dioxide indirectly produced by electricity consumption accounts for about 5% of total emissions.
From the above point of view, if we want to reduce the carbon emissions of the cement industry, we should look for a low-carbon or carbon-free cement manufacturing method or key elements. Just recently, after years of efforts, Jiang Yeming, a famous professor of materials science at the MIT of the United States, and Leah Ellis, a 33-year-old female chemist in Canada, developed a method of making cement from various abundant calcium sources at room temperature by replacing the most energy-consuming kiln with an electrolyzer, thus avoiding the use of fossil fuels. And release of carbon dioxide from limestone. The production principle of the
method is as follows: calcium sources such as limestone, gypsum, calcium alginate and the like which are easy to obtain are put into water without pretreatment or crushing, and then electrolysis is carried out by electrifying, so that calcium ions are separated out from the solution and deposited on an electrode. The calcium is then mixed with other ingredients to form a cement material that can be used as a direct substitute for existing concrete formulations. This material has the same or better strength, slump and durability than today's Portland cement. Compared with traditional cement manufacturing methods,
this process has four advantages:
First, it can significantly reduce the carbon emissions of cement manufacturing, which is the first cement production process that eliminates both limestone emissions and fossil fuel emissions in the process of high temperature combustion.
Second, low-cost renewable energy, such as wind or solar energy, can be used to drive electrochemical reactions, which can not only reduce energy consumption and costs, but also improve energy efficiency and utilization.
Thirdly, it can improve the quality and performance of cement, because it can use various calcium sources without the limitation of raw materials, and the cement produced is compatible with traditional cement without changing the existing concrete formula or equipment.
Fourthly, this material can be directly used in the fields of construction and infrastructure without any modification of concrete mixer or conveying equipment.
Although electrochemical cement is still controversial, if it can be mass-produced, it will undoubtedly completely subvert the traditional cement production methods, promote the development and application of clean technology, thus having a positive impact on the whole world and contributing to a better, greener and more sustainable world. On July 6-7,
2023, China Cement Network will hold the " 2023 China Cement Energy Conservation and New Energy Development Conference " in Chongqing, starting from energy-saving transformation, photovoltaic, energy storage and other technology applications, green power, alternative fuels to replace tradi tional energy transformation, and so on. Explore new ways of energy saving and consumption reduction in cement industry.
After the meeting, we will visit Dongfang Hope Chongqing Cement Preheater "Level 5 to Level 6" Energy-saving Demonstration Line and Steam-driven Fan Energy-saving Project.
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