Dunkirk, future demonstrator of Ecocem for its new “low carbon” cement

“Today, we recover blast furnace slag: what is left over from the manufacture of cast iron. We buy this co-product of cast iron from steelmakers, we grind it, and we partially replace clinker, explains Conor O’Riain, the dashing general manager of Ecocem France and Europe. It increases the durability of concrete, its strength, and makes it much whiter. However, there is not enough slag in the world, and production is set to reduce, hence the development of a technology that can be implemented with several materials»,

A new hydraulic binder

Act, which is a cement, or a hydraulic binder according to the established term, which required 40 million euros of investment in R&D over the past decade. Objective: to reduce the clinker rate from 75% to less than 30% compared to an average cement sold in France. “Clinker is the first lever for decarbonizing cement in concrete”hammer Conor O’Riain.

“What slowed down the development of the electric car was the lack of infrastructure, so we wanted to use the same concrete plants and the same mixer trucks. The Act cement will see its composition vary according to the cement plants”continues the manager. Ecocem relies in particular on limestone fillers (crushed limestone) and mineral additions, such as clays, fly ash, fines (editor’s note: fine elements) from recycled concrete or pozzolanic rock.

Act was developed internally, within the Ecocem R&D center, based in Champlan (Essonne), in partnership with ENS Paris-Saclay and INSA Toulouse. “Most PhD students and doctors do not come from the concrete industry, allowing us to move forward without preconceptions“, the group’s managers are pleased. In order to meet its stated desire to contribute to a 50% reduction in global CO2 emissions linked to the cement industry by 2050, Act will be marketed in the form of licenses or technology transfers. It follows a standardization process with a request for a European technical assessment monitored by the Scientific and Technical Center for Building.

A reconfiguration of the production mix

To demonstrate Act, Ecocem will therefore rely on its Dunkirk site, opened in 2018, where the Ecocem France entity operates as a joint venture with ArcelorMittal (present at 49%). The steelmaker, located 800 meters away, supplies the plant with slag (550,000 tons this year, supplemented by external purchases). This is one of the group’s four production sites (one in Ireland, one in the Netherlands, one in Fos-sur-Mer in the Bouches-du-Rhône). The new facilities will be built on existing land.

Currently 80% focused on grinding blast furnace slag and 20% on manufacturing composite cements, the Dunkirk site should see its production rebalance between the two activities at the end of the works, estimated at 18 months on an occupied site. The start of the latter is conditional on the granting of French and European aid – hence Ecocem’s refusal to mention a new investment figure.

Ecocem will bring in a new partner, CB Green, a limestone supplier, in the form of a new joint venture. The project consists of the construction of a filler mill, with an estimated capacity of 600 kt per year. The CB group, a French company specializing in ore processing, already delivers materials to the port of Dunkirk from its Leulinghen-Bernes site (Pas-de-Calais). Other changes planned in Dunkirk include increasing the capacity for storage, mixing and loading of materials, as well as adapting existing infrastructure. 300,000 tonnes of Act cement are expected to be produced each year in Dunkirk.