Researchers from the University of Cambridge have developed a revolutionary method to produce very low emission concrete at scale, utilizing electrically-powered arc furnaces typically used for steel recycling to recycle cement. Concrete is the second-most-used material on the planet and is responsible for a significant percentage of total anthropogenic CO2 emissions. Finding a way to reduce concrete emissions while meeting global demand is crucial for decarbonization efforts. The researchers discovered that used cement could effectively substitute lime flux in steel recycling, resulting in the production of recycled cement that can be used to make new concrete.
The cement recycling method developed by the Cambridge researchers does not add any significant costs to concrete or steel production, and it reduces emissions from both industries due to the reduced need for lime flux. Recent tests conducted by the Materials Processing Institute confirmed that recycled cement can be produced at scale in an electric arc furnace, marking a significant advancement. The ultimate goal is to produce zero emission cement by powering the EAF with renewable energy. This breakthrough innovation has the potential to transform the construction industry while contributing to global decarbonization efforts.
Traditional cement production involves a process called clinkering, which releases large amounts of CO2 as limestone decarbonates into lime. Scientists have been exploring alternatives to cement over the past decade, with some success in replacing a portion of the cement with alternative materials like fly ash. However, these alternatives still require chemical activation by the remaining cement to harden. With global cement demand at approximately four billion tonnes per year, there is a need to think innovatively to achieve zero emissions in the industry. The Cambridge Electric Cement process offers a promising solution to this challenge by recycling used cement to create new concrete.
The researchers identified that the clinkering process involves heat and a specific combination of oxides, which can be found in used cement but need to be reactivated. By processing a range of slags with added lime, alumina, and silica in the EAF, the researchers were able to create reactivated cement without adding any cost to the steelmaking process. The resulting cement contains higher levels of iron oxide, but this has minimal impact on performance. This innovative approach has the potential to significantly reduce emissions in the concrete and steel industries.
The Cambridge Electric Cement process is rapidly scaling, with the goal of producing one billion tonnes per year by 2050. The researchers emphasize the need to not only produce zero emissions cement but also reduce the overall usage of concrete. They suggest that political will and support are crucial to implementing changes in the construction industry to achieve sustainability goals. The researchers have filed a patent on the process to support its commercialization, and the research was supported by organizations like Innovate UK and EPSRC. This groundbreaking innovation could pave the way for a more sustainable future in construction and contribute to global efforts to achieve net zero emissions.
In conclusion, the research conducted by the University of Cambridge highlights a significant breakthrough in the production of low emission concrete by recycling cement in electric arc furnaces. This method offers a scalable and cost-effective solution to reducing emissions in the concrete and steel industries, contributing to global decarbonization efforts. By reactivating used cement through innovative processes, the researchers have demonstrated the potential for zero emission cement production at scale. This innovation not only benefits the construction industry but also underscores the importance of thinking outside the box to address climate change challenges. With continued support and collaboration, the Cambridge Electric Cement process could be a game-changer in the transition to a sustainable future.
