France: Heidelberg Materials has announced plans for its CIRCO₂BETON concrete recycling project. It intends to build an industrial-scale selective separation unit at its Achères quarry near Paris. Here it will recycle demolished concrete by crushing it and separating it into its components: sand, aggregates, and recycled concrete paste (RCP). The recycled sand and aggregates will be reincorporated into new concrete.

The RCP will be transported to the Ranville cement plant in the Normandy region. There, a reactor for enforced carbonation will be installed to carbonate the RCP by exposing it to CO₂-containing exhaust gases from the kiln. The carbonated RCP acts as a carbon sink and will replace clinker in new low-carbon cement types. The project has the potential to reduce the CO₂ emissions of the Ranville cement plant by 20%.

CIRCO₂BETON is supported by the ‘Investment for the Future’ Program coordinated by the Ecological Transition Agency (ADEME). In addition, the Île-de-France region supports the selective separation plant at Achères through its zero-waste and circular economy plan. Subject to the funding, construction of both industrial pilots is scheduled to start in 2024 with production of RCP starting in 2025. The carbonation reactor is planned to be operational by 2026.

Nicola Kimm, the chief sustainability officer at Heidelberg Materials, said ”We are investing in a pioneering large-scale project based on innovative process technologies. Selective separation and CO₂ mineralisation are important levers to reduce the carbon footprint of our products. By closing the materials loop, we prove that concrete has the potential to be the most sustainable building product over its entire life cycle from production to recycling.”

Read more about RCP in the Decemeber 2022 issue of Global Cement Magazine