Materials Processing Institute leads £6.5m cement and steel project

National research and innovation centre The Materials Processing Institute has announced a £6.5m ‘Cement 2 Zero’ project to develop the world’s first zero emission cement on an industrial scale.

concreteThe project aims to create cement clinker using Electric Arc Furnaces (EAF). This is different to traditional methods of steelmaking, which see cement clinker produced by firing limestone and other minerals in a kiln, requiring energy and heat, and leading to approximately 6.5 metric tons of CO2 emissions per year.

The Materials Processing Institute says that EAF produces steel from recycled scrap metal and lime (EAF flux), using ‘the recovered cementitious matrix from recycled concrete as the Electric Arc Furnace flux instead of lime’. This should allow steelmakers to transition to the use of renewable energy in their EAFs and see the emissions relating to cement manufacture significantly reduced.

Dr Cyrille Dunant of the University of Cambridge, a partner of the project, found that the chemistry of recovered cement paste made it suitable for use as flux in the EAF process.
After identifying the suitability of the high temperature reached by EAF’s for the ‘reclinkering of the paste’, Dunant identified that cement could be recycled under these conditions.

Simultaneously, the process could avoid emissions from both the decarbonisation of limestone for cement making and the production of the lime flux normally used in the EAF.

According to tests initially conducted by the Materials Processing Institute, recovered cement can function as an effective EAF flux. Using an EAF which is used to recycle scrap steel, the Cambridge researchers have invented a process that converts construction and demolition waste into recycled cement.

The Teesside-based Institute will operate its own EAF as part of the project. The ‘green steelmaking’ project will also develop the UK’s first prototype crusher for recovering cement paste from construction demolition waste, and the creation of ‘a prototype EAF slag cooling system’ to transform steel slag into cement clinker.

Through this process, the steel and cement industries will be brought together – a move that could support material and energy security while reducing the carbon emissions associated with conventional clinker production, the Processing Institute says.

Currently, the concrete and cement sector is a key part of a combined mineral products industry, which contributed around £16bn to the UK’s GDP in 2018 and directly employs 81,000 people, supporting a further 3.5m jobs.

The Processing Institute also found that steel recycling in the UK could expand to £11 million tonnes per year by recycling all scrap – estimated to be worth £2.8bn per year – with ‘forecasts that the global market for steel recycling may treble over the next 30 years’.

Estimated to run for two years, the Cement 2 Zero project could create new markets within the circular economy, including the valorisation of construction and demolition waste.

The project has been conducted in partnership with the University of Cambridge, Tarmac, Atkins, Cardiff-based steel firm Celsa Manufacturing UK, Balfour Beatty, Livingston-based Brewster Brothers, which specialises in construction, demolition, and waste recycling, and Day Group, a leading supplier of construction materials.

Chris McDonald, Chief Executive of the Materials Processing Institute, said: “We are delighted to be leading a project that has the potential to make a major 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.”

Dr Philippa Horton, Cambridge Electric Cement/University of Cambridge, added: “If Cambridge Electric Cement lives up to the promise it has shown in early laboratory trials, it could be a turning point in the journey to a zero-emissions society. We are delighted to collaborate with companies across the sector to expand the project from the laboratory, and into the wider supply chain.”

Kwasi Kwarteng, Secretary of State for Business, Energy and Industrial Strategy of United Kingdom, also commented: “Driving down emissions from the production of cement is one of the key challenges facing British manufacturers and construction companies. Achieving it will have hugely beneficial knock-on effects for the competitiveness of businesses right across UK supply chains.

“Backed by UK Government funds, this world first project shows how the UK’s universities, businesses and government are working in tandem to deliver the technologies that can make a real, transformational difference to the decarbonisation of key industrial sectors.”