Cement production stands as a significant contributor to global carbon emissions, accounting for 7.5% of total greenhouse gas emissions. Traditional methods involve heating raw materials to high temperatures, primarily to produce clinker, which constitutes 90% of cement’s carbon footprint due to both heat requirements and chemical reactions.
A breakthrough research led by Julian Allwood at the University of Cambridge introduces a promising alternative. By reusing cement paste from demolished buildings as a substitute for lime flux in steel recycling, the team has developed a process to create clinker-free cement. This paste, when incorporated into the steel recycling process, forms a slag that, once ground into powder, mirrors the properties of clinker. This method, when powered by renewable or nuclear energy in an electric furnace, virtually eliminates emissions.
Initial laboratory trials have successfully demonstrated the feasibility of this approach. It is scalable using existing equipment, potentially saving up to 3 gigatonnes of carbon dioxide annually if widely adopted. The next phase involves industrial trials through Cambridge Electric Cement, a spin-out company collaborating with construction firms like Balfour Beatty and Tarmac. These trials aim to produce up to 30 tonnes per hour, marking a significant step towards commercialization.
However, challenges remain, including the need for higher furnace temperatures compared to traditional methods, which may increase energy costs. Establishing robust supply chains for waste cement, securing capital investments, and overcoming industry skepticism are also critical hurdles. Despite these challenges, the potential environmental benefits make this innovation a promising pathway towards sustainable cement production, aligning with global efforts to mitigate climate change. Continued research and industry collaboration will be crucial in realizing its full potential.
