UK launches Cement 2 Zero project

Cement 2 Zero, a UK-based project trialling the world’s first zero-emissions cement on an industrial scale, was officially launched this week having successfully conducted the first in a series of pilot-scale melts. The project, which secured GBP6.5m (US$7.9m) of government funding, aims to further advance the construction, cement and steel sectors’ decarbonisation journey to net zero industries of the future, and help meet the UK government’s commitment of achieving net zero by 2050.

Led by the Materials Processing Institute, supported by the University of Cambridge (UoC), and in collaboration with key players in the supply chain, Cement 2 Zero is the first collaborative trial of its kind, to address the global construction industry’s biggest challenge of decarbonisation, in response to the climate emergency. The project will investigate both the technical and commercial aspects of upscaling Cambridge Electric Cement (CEC) production to produce 20t of the world’s first zero emissions cement.

CEC is the brainchild of three researchers at the UoC – Dr Cyrille Dunant, Professor Julian Allwood and Dr Philippa Horton – who invented a process that converts construction and demolition waste to cement over molten steel, using an electric arc furnace (EAF), which is used to recycle scrap steel. The Cement 2 Zero project aims to demonstrate that concrete can be recycled to create a slag forming addition which could, when cooled rapidly, replace Portland cement.

Dr Dunant discovered that the chemical composition of used cement is virtually identical to that of the lime-flux used in the conventional EAF steel recycling process. Traditional Portland clinker is produced by firing limestone and other minerals in a kiln at extremely high temperatures (1450˚C), a process which accounts for more than 50 per cent of the cement sectors’ emissions. By contrast, Cement 2 Zero will use recycled cement as the flux in the electric steel recycling process (EAF powered by renewables), the byproduct of which, when cooled and ground, produces Portland cement clinker, which is then blended to make zero-emissions cement. Therefore, CEC could be made in a virtuous recycling loop, that not only eliminates the significant emissions of cement and steel production, but also saves raw materials.

The first phase of trial melts is being carried out by the Materials Processing Institute, initially in a 250kg induction furnace, before being scaled up to 6t in an EAF. Once the process has been substantially trialled, developed and de-risked effectively, industrial scale melts will follow. The two-year industrial trial will test each stage of the production process and brings together the expertise of the Materials Processing Institute, the UoC and supply chain partners – Atkins, Balfour Beatty, CELSA, Day Aggregates and Tarmac – before using the innovative product in a live UK construction project.

“If Cambridge Electric Cement lives up to the promise it has shown in early laboratory trials, when combined with other innovative technologies, it could be a pivotal point in the journey to a zero-emissions society. The Cement 2 Zero project is an invaluable opportunity to collaborate across the entire construction supply chain, to expand CEC from the laboratory to its first commercial application,” said Dr Horton.