United Kingdom – For their invention of the world’s first zero-emissions cement, three Cambridge engineers have filed a patent and received new research funding.
One of the most difficult challenges on the road to a safe climate with zero emissions is replacing today’s cement. There are a variety of ways to make cement with lower emissions, the most common of which is to combine new reactive cement with other supplementary materials. However, making the reactive component of cement without emissions has not been possible until now. For the first time, the new invention accomplishes this within the constraints of existing industrial processes.
When inventor Cyrille Dunant noticed that the chemistry of used cement is nearly identical to that of lime-flux used in traditional steel recycling processes, he was inspired to create Cambridge Electric Cement. As a result, the new cement is made in a virtuous recycling loop that not only eliminates cement production emissions, but also saves raw materials and even reduces emissions from lime-flux production.
Concrete waste
Concrete waste from the demolition of old buildings is the starting point for the new process. This is crushed to separate the stones and sand that make up concrete from the cement powder and water mixture that holds it all together. In steel recycling, the old cement powder is used instead of lime-flux. The flux forms a slag that floats on top of the liquid steel as it melts, protecting it from oxygen in the air. After the recycled steel has been tapped off, the liquid slag is quickly cooled in air and ground into a powder that is nearly identical to the clinker that forms the foundation of new Portland cement. The Cambridge team demonstrated this combined recycling process in pilot-scale trials, and the results show that it has the chemical composition of clinker made with today’s process.
The new cement was developed as part of Professor Allwood’s large multi-university UK FIRES program, which aims to enable a rapid transition to zero emissions by repurposing existing technologies rather than waiting for new energy technologies such as hydrogen and carbon storage. The inventors of the cement have been awarded a £1.7 million EPSRC research grant to work with Dr Zushu Li at Warwick University and Dr Rupert Myers at Imperial College to reveal the underlying science behind the new process.
The new grant will support an additional research team to investigate the range of concrete wastes that can be processed into Cambridge Electric Cement, evaluate how the process interacts with steel production, and confirm the material’s performance.
