The Cement 2 Zero (C2Z) project will investigate the technical and commercial aspects of upscaling Cambridge Electric Cement (CEC) production to produce 20 tonnes of cement that will be used in its first commercial application.
Expanding CEC beyond the laboratory is the result of a process developed by the University of Cambridge 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 C2Z project aims to demonstrate that concrete can be recycled to create a Slag Forming addition which could, when cooled rapidly, replace Portland cement.
University of Cambridge researcher Dr Cyrille 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, one of the main ingredients in cement, is produced by firing limestone and other minerals in a kiln at high temperatures (1,450 degrees Celsius), a process which accounts for more than 50 percent 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 by-product 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 eliminates emissions of cement and steel production and saves raw materials.
Professor Julian Allwood, University of Cambridge and Cambridge Electric Cement, said: “By combining steel and cement recycling in a single process powered by renewable electricity, we could supplement the global supply of the basic construction materials to support the infrastructure of a zero emissions world and to enable economic development where it is most needed.”
The C2Z project follows a series of successful pilot-scale melts.
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 in CELSA’s EAF in Cardiff.
The two-year industrial trial will test each stage of the production process and brings together the expertise of the Materials Processing Institute, the University of Cambridge and key supply chain partners – Atkins, Balfour Beatty, CELSA, Day Aggregates and Tarmac – before using the product in an unspecified live UK construction project.
If successful, it could further advance the cement, steel and construction industries as well as influence the recycling, construction and maintenance of the built environment and transport infrastructure.
Dr Philippa Horton, University of Cambridge, who created the project consortium, said: “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.”