The Mineral Products Association (MPA) has been appointed lead partner for research into how recycled clay can be used to both recycle waste from other industries, such as brick making, and create low carbon cements.
Funded by Innovate UK, the two-year project will use waste-derived clays to assess the potential to reduce waste by 1.4 million tonnes and cut the embodied CO2 of cement by between 20% and 40% compared to market leading CEM I cements.
The sources of waste clays in this project include waste from brick manufacturing and overburden clays at quarry sites.
MPA director, Diana Casey, said: “Trialling the use of waste clay from brick manufacturing as a cementitious material is a huge step forward for our industry as we continue to decarbonise and move towards a circular economy.
“This will not only lower carbon and reduce waste, but has the potential to create a whole new market if waste clays become widely used in the construction industry, helping to retain economic value in the UK, secure jobs and attract investment.”
Using clay also requires less, or in some cases no heating (for example when using waste brick) when compared to cement clinker production.
Clay is a naturally abundant material in the UK, which the MPA believes can offer an alternative to other industrial by-products including ground granulated blast-furnace slag (GGBS) and fly-ash (a by-product from coal-fired power stations), which are already used to lower embodied carbon within cement.
Two heating methods are being trialled to prepare the clay for use in cement and concrete: a rotary kiln, which is a commonly used technique, and the less common flash heating technique.
The project is supported by industry partners Tarmac, Hanson, Imerys and Forterra, with research partners from the University of London and the University of Dundee.
Once the research project is completed, the MPA will share the results to drive adoption of this technology by cement manufacturers across the UK.
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