From the Nordics to the Mediterranean, European countries lead the field in reduced-clinker cement production using supplementary cementitious materials (SCMs). While consumers, faced with ever-greater choice, continue to opt for sustainability, projects to improve existing SCMs and develop new ones have won government backing and have become a matter of serious investment for other heavy industries beside cement. European cement producers’ decisions are steering the course to a world beyond CEM I. Yet, even in Europe, great untapped potential remains.
Companies generated a good deal of marketing buzz around their latest reduced-CO2 cement ranges in 2021 and the first quarter of 2022: Buzzi Unicem’s CGreen in Germany and Italy, Holcim’s EcoPlanet in six markets from Romania to Spain, Cementir Holding’s Futurecem in Denmark and Benelux, and Cemex’s Vertua in Spain and several other countries. All boast reduced clinker factors through the use of alternative raw materials. This, however, is really a rebranding of a long-established norm in Europe.
Since 2010, cements other than CEM I have constituted over 75% of average annual cement deliveries across Cembureau member countries (all cement-producing EU member states, plus Norway, Serbia, Switzerland, Turkey, the UK and Ukraine). This statistic breaks down differently from country to country. CEM II is the norm in Austria, Finland, Portugal and Switzerland, with deliveries in the region of 90%. Portland limestone cement (PLC) makes up a majority of deliveries in all four. It has been central to Switzerland’s transition to 89% (3.72Mt) of CEM II deliveries out of a total 4.18Mt of cement despatched in 2021. There, the main types of cement were CEM II/B-M (T-LL) Portland composite cement, with 1.38Mt (33%), and two different classifications of PLC: CEM II/A-LL PLC, with 1.28Mt (31%), and CEM II/B-LL PLC, with 888,000t (21%).
A second approach is that of the Netherlands, where CEM III blast furnace slag cement with a clinker factor below 65% predominates, favoured for its sulphate resistance and the protection it offers against chloride-initiated corrosion of steel reinforcement in marine settings. By contrast, the UK has traditionally maintained a higher reliance on CEM I cement. This can be partly explained by the preference of builders there for adding fly ash or ground granulated blast furnace slag (GGBFS) at the mixing stage. Nonetheless, CEM II Portland fly ash cement held a 14% (1.43Mt) market share in the UK’s 10.2Mt of cement consumption in 2021.
The UK Mineral Products Association (MPA) has identified limestone as an underutilised resource in the country’s cement production. Together with HeidelbergCement subsidiary Hanson Cement, it has applied for a change to National Application standards to allow the production of Portland composite cement from fly ash and limestone or GGBFS and limestone. The association has forecast that Portland composite cement could easily rise to 30 – 40% of UK cement consumption, and that this has the potential to eliminate 8% of the sector’s 7.8Mt/yr-worth of CO2 emissions.
Metallurgical waste streams have long flowed into European cement production, primarily as GGBFS, but also as bauxite residue. In 2021, alumina production in the EU alone generated 7Mt of bauxite residue, of which the bloc recycled just 100,000t (1.4%) that year. Two projects – the Holcim Innovation Center-led ReActiv project and Titan Cement and others’ REDMUD project – aim to produce new alternative cementitious materials from bauxite residue.
By collaborating with other industries, cement producers’ investments can most effectively reduce the overall cost of using these materials in cement production. In Germany, HeidelbergCement and ThyssenKrupp’s Save CO2 project aims to develop new improved latent hydraulic binders or alternative pozzolan from GGBFS by producing slag from directly reduced iron (DRI). The Save CO2 team believes that GGBFS substitution for clinker has the capacity to eliminite 200Mt/yr of CO2 emissions from global cement production.
Meanwhile in the world of mining, ThyssenKrupp and others’ NEMO project is investigating the recovery of a useable mineral fraction for cement production from the extractive waste of the Luikonlahti and Sotkamo mines in Finland and the Tara mine in Ireland, through bioleaching and cleaned mineral residue upcycling. This may give cement producers full access to Europe’s 28Bnt stockpiles of sulphidic mining waste, of which mines generate an additional 600Mt each year.
Denmark-based CemGreen, which produces the calcined clay supplementary cementitious material CemShale, is developing a shale granule heat-treating technology called CemTower. This consists of three pieces of equipment vertically integrated into cement plants’ preheaters, kilns and coolers, and brings the processing of waste materials – here oil shale – to the cement plant.
Lastly, cement producers are exploring the possible uses of waste made of cement itself. In Wallonia, HeidelbergCement subsidiary CBR’s CosmoCem project is investigating the production of alternative cement additives from large available flows of local demolition, soil remediation and industrial waste. Similarly, the Greece-based C2inCO2 project seeks to mineralise fines from concrete recycling for HeidelbergCement to use in the production of novel cements in its Greek operations.
In Switzerland, ZND Portland composite cement (produced using fine mixed granulate from building demolitions) is the third largest cement type, with 178,000t (4.3%) of total deliveries – narrowly behind CEM I with 239,000t (5.7%).Holcim Schweiz developed its Susteno 4 ZND Portland composite cement with Switzerland’s lack of any ash or slag supply in mind, demonstrating the potential flexibility of a circular economic approach to cement production.
On 21 March 2022, the University of Trier reported that it is in the process of mapping mineral resources, waste deposits and usable residues ‘on a cross-border scale,’ in an effort to produce new materials for use in cement production. Industry participants include France-based Vicat, CBR, Buzzi Unicem subsidiary Cimalux and CRH subsidiary Eqiom. Vicat is preparing a kiln at its 1Mt/yr Xeuilley cement plant in Meurthe-et-Moselle to use in testing new alternative raw materials developed under the project.
For Cembureau and its members, work continues, with the goal of Net Zero by 2050 constantly in sight. This goal includes a reduction in members’ clinker-to-cement ratios to well below 65%. In this, the association and its members are working towards a world not just beyond CEM I, but beyond CEM II, too. What exactly this will mean remains to be seen.
Sources
CemSuisse, ‘Lieferstatistik,’ 11 January 2022, https://www.cemsuisse.ch/app/uploads/2022/01/Lieferstatistik-4.-Quartal-2021.pdf
WSA, ‘December 2021 crude steel production and 2021 global crude steel production totals,’ 25 January 2022, https://worldsteel.org/media-centre/press-releases/2022/december-2021-crude-steel-production-and-2021-global-totals/
MPA, ‘Low carbon multi-component cements for UK concrete applications,’ July 2018, https://prod-drupal-files.storage.googleapis.com/documents/resource/public/Low%20carbon%20multi-component%20cements%20for%20UK%20concrete%20applications%20PDF.pdf
European Commission, ‘European Training Network for Zero-waste Valorisation of Bauxite Residue (Red Mud),’ 16 July 2020, https://cordis.europa.eu/project/id/636876
European Commission, ‘Industrial Residue Activation for sustainable cement production,’ 16 February 2022, https://cordis.europa.eu/project/id/958208
Recycling Portal, Zement der Zukunft – Forschungsprojekt „SAVE CO2“ gestartet, 28 May 2021, https://recyclingportal.eu/Archive/65677
h2020-NEMO, ‘Project,’ https://h2020-nemo.eu/project-2/
European Commission, ‘Green cement of the future: CemShale + CemTower,’ 14 April 2021, https://cordis.europa.eu/project/id/101009382
CosmoCem, ‘Communiqué de Presse,’ https://cosmocem.org/
CO2 Win, ‘C²inCO2: Calcium Carbonation for industrial use of CO2,’ https://co2-utilization.net/en/projects/co2-mineralization/c2inco2/
Les Echos, ‘Rendre le ciment moins gourmand en CO2,’ 21 March 2022, https://www.lesechos.fr/pme-regions/innovateurs/des-substituts-au-clinker-rendent-le-ciment-moins-gourmand-en-co2-1395002