Northern-Ireland based cement producer Cemcor said this week that it has completed trials of a calcined clay cement product called CalcinX. The company started its trials in 2023 and it has been supported by Queen’s University Belfast and funding from Innovate UK. Work with commercial partners has involved precast concrete paving manufacturer Tobermore producing paviours made from 50% CalcinX as a CEM II replacement and Moore Concrete has also manufactured precast units using 50% CalcinX as a CEM I replacement. So far over 3000t of CalcinX has been produced in a number of industrial-scale trials.
David Millar, the managing director of Cemcor, mentioned his company’s plans for calcined clay in June 2022 when he was interviewed by Global Cement Magazine. The company that became Cemcor bought the Cookstown cement plant and a few other assets from Holcim at the start of 2022. It then changed its name to Cemcor in November 2022. At the time of the interview the company was looking to “...develop new value-added products, including low-CO2 options. This will allow us to use the same amount of clinker to produce more cement.” Millar couldn’t give away too many details at the time, however calcined clay was cited specifically. It was also noted that the company had the right material in its quarry and that it was already working with partners on it.
Amongst all the other decarbonisation options available for cement plants, a slow trickle of calcined clay projects keep being announced. In January 2025, for example, thyssenkrupp Polysius said it had secured a front-end engineering design contract from Circlua for the construction of the world’s largest activated clay plant in Brazil. This project in Para state will have a capacity of 3000t/day, will use renewable energy sources and will “improve the CO2 footprint in cement production.” CBMI Construction also officially launched a flash calcination clay project in Tangshan, Hebei province in China. In December 2024, Vicat signed an agreement with the US Department of Energy (DOE) Office of Clean Energy Demonstrations to develop the Lebec Net Zero (LNZ) project at its Lebec cement plant in California. This includes plans to produce calcined clay-based cement. Earlier in the autumn of 2024 Portugal-based Cimpor said it was preparing to convert a kiln at its Souselas plant to produce calcined clays, AVIC International Beijing and KHD said that they had secured a deal to build a 900t/day clay calcination plant for Ciments de l'Afrique (CIMAF) in Burkina Faso, and Holcim Česko said it was going to construct a calcined clay processing line at the Čížkovice cement plant in the Czech Republic.
One news story that stuck out in the autumn was the progress of a collaboration between Aumund and Holcim towards developing an electric linear calcination conveyor (eLCC). The two companies started work on the project in 2020 intending to look at the electrical calcination of clay using an Aumund pan conveyor. Initial tests of the eLCC reportedly demonstrated efficient thermal activation of clay through a combination of radiant heat and material circulation. The eLCC system is fully enclosed, insulated, has a compact design and can operate using electrical-powered renewable sources. The first industrial plant utilising this technology is scheduled for construction in 2025. Calcined clay technology and products by other industrial suppliers are available. The work by Aumund and its competitors show they are watching this market closely.
OneStone Consulting’s Joe Harder has found that only 14 clay calcination plants were operational worldwide in 2023 with a production capacity of just under 3.5Mt/yr. These are based in Latin America, Europe and Africa. In an article previewing a market report in the February 2025 issue of Global Cement Magazine, Harder predicts that by 2035 there will be 79 clay calcination plants with a capacity of just under 21Mt/yr. A steady growth of over 20 new plants annually is also expected subsequently from 2035 to 2050 as cement producers seek cost-effective ways to reduce their clinker factor. He identified installation costs, a lack of knowledge about clay-based cements, trouble obtaining mining rights and policy issues amongst other issues as holding back the use of clay calcination.
The current expectation is that calcined clay usage in the cement industry will be a minority option. Yet the size of global cement production can make a production share of, say, 3 - 8% a viable option for both cement manufacturers and equipment suppliers. The adoption of new cement products and standards can also take a long time and this clouds predictions of how far clay can go in the cement industry. At this point in the calcined clay story it is time to keep track of the new projects being set up.
Joe Harder will present a talk entitled ‘Calcined clay market trends by 2035’ at the Global FutureCem Conference taking place in Istanbul in early February 2025
