The £6.5m UKRI-funded project aims to further the decarbonisation of the construction, cement and steel sectors to help meet the UK government’s Net Zero ambitions.
Led by the Materials Processing Institute, supported by Cambridge University (UoC) - and in collaboration with Atkins, Balfour Beatty, CELSA Steel, Day Aggregates and Tarmac - Cement 2 Zero is said to be the first collaborative trial of its kind to address the global construction industry’s biggest challenge of decarbonisation.
In a statement, Chris McDonald, CEO of the Materials Processing Institute, said: “Cement 2 Zero has the potential to make a significant contribution to achieving a zero-carbon society, secure and increase jobs in the UK cement and steel sectors and challenge conventional production processes, creating high-value materials from demolition waste.”
The chemical and thermal combustion processes involved in the production of cement are a significant source of carbon dioxide (CO2) emissions, with over four billion tonnes of cement produced annually, accounting for around seven per cent of global CO2 emissions, according to the Global Cement and Concrete Association (GCCA). In the UK, concrete and cement account for 1.5 per cent of UK carbon dioxide emissions.
The Cement 2 Zero project will investigate the technical and commercial aspects of upscaling Cambridge Electric Cement (CEC) production to produce 20 tonnes of the world’s first zero emissions cement.
Dr Philippa Horton, Department of Engineering, Cambridge University, 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.”
Dr Horton, along with Dr Cyrille Dunant and Professor Julian Allwood, developed CEC, a process that converts construction and demolition waste to cement over molten steel, using an 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 1,450oCelsius, a process which accounts for more than 50 per cent of the cement sectors’ emissions.
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.
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 Electric Arc Furnace (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 before using the product in a live UK construction project.
“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,” said Prof Allwood.