Transforming demolition waste into sustainable resources: Lafarge’s recycling innovation combined with Metso crushing plant

The process is based on an innovative grinding technology applied for the first time in Europe for recycling. The new plant combines a variable pressure grinding system (Metso HRC8 crusher) with an air flow system (Metso Air Classifier AC30), making it possible to separate and recover the cement paste during the crushing operation without grinding the original aggregate. Isolating very fine materials with a high concentration of cement in demolition concrete provides carbon-free additions to the manufacturing of new cements.

The plant was built in Saint-Laurent-de-Mure in France and taken into operation in September 2023. The plant will serve as a pilot to deploy this equipment in France from 2024.

Full solution from Metso

Metso has executed a complete scope for Lafarge, including flow sheet definition, mechanical and electrical engineering, all equipment and miscellaneous items manufacturing, site assembly supervision, electrical and automation hardware and software, as well as all documentation.

The plant consists of two independent lines: the first line takes the concrete demolition waste feed, 8/30mm, into the HRC8 that separates the aggregates from the cement paste and creates the final products. The second line is fed with the produced feed, creating the final products.

In addition to the supply of high-quality recycled aggregates for the manufacturing of new low-carbon concrete, the new installation also meets another essential transformation need for ecological construction: production of cement that is both recycled and decarbonized.

Cement’s fines, which in a classic crushing process remain attached to the sand, are becoming a sought-after alternative source material to supplement clinker, thus making it possible to reduce their share in the final composition of the cement and therefore reduce its carbon weight.

Commitment to circular economy                                                      

Firmly committed to circular construction, Lafarge continues to innovate to expand the use of demolition materials so that new materials can be manufactured out of it. The application of ECOCycle technology in the Saint-Laurent-de-Mure recycling installation will make it possible to both increase the quality of recycled aggregates to promote their reuse in concrete, and to recover demolition materials that can be re-injected into the cement manufacturing process with a reduced carbon footprint.

According to the Recybeton organization, 80% of deconstruction concrete is already reused in France today, primarily in various road applications like pavement underlays. By choosing upcycling and reintroducing these demolition concretes into the cement and concrete manufacturing chain, Lafarge is able to increase demolition material value and advance its circular ambition.

“The development of circulars is a major pillar of our strategy. This new Lafarge granulates production unit is a decisive step in developing the reuse of demolition materials by utilizing all the value they have to offer,” says François Petry, Managing Director, Lafarge France. “Recovering the fines from crushed concrete to reuse them as a carbon-free addition to the cement process is a first in Europe and a giant step forward in the ecological project of building the city of tomorrow with the materials of the city of yesterday.”

Complete plant design and construction by Metso in five months

After a commercial agreement signed with the sales team in March 2023, Metso's Aggregate Systems group managed to meet the challenge of completing the installation in five months, meeting Lafarge's target date of a start-up before August 4^th, 2023.

This is the result of an excellent project set up with an optimization of engineering resources, a network of highly efficient suppliers and an experienced site team.

“Metso's experts completed this project in record time, smoothly and seamlessly. Good collaboration between the teams made this challenge possible,” concludes Olivier Marbec, Head of Aggregates Operation, Lafarge France.

Read about Metso's PrimeSite™ - tailored crushing and screening plants.