Sources: Fives FCB, Villeneuve d’Ascq, France; CO staff
Identifying optimal grinding kinetics and compressive force trajectories for up to 5-in. demolition concrete feeds, global mineral process equipment specialist Fives FCB attains economical separation of cement paste from sand and gravel or rock. In one to three cycles or material passes, the FCB Rhodax 4D inertial vibrating cone grinder nets cement paste powder at a purity level sufficient to use as a significant replacement for virgin raw materials in cement kiln raw mix (subject mostly to chemistry) or Portland cement in concrete mix designs. The grinder also delivers fine and coarse aggregates with cubicity and water demand characteristics suiting new concrete mixes.
IN BED COMPRESSIVE GRINDING PRINCIPLE
Conventional Crushing
FCB Rhodax 4D Crushing, Grinding
The Construction & Demolition Recycling Association’s 2025 C&D World Conference and Exhibition in Texas saw a North American market debut of the FCB Rhodax 4D-based process. Fives FCB team members showed how the equipment literally liberates three recyclable concrete components by applying an in bed constant compressive force to generate fractures at the most fragile points along the interface between hydrated cement and fine or coarse aggregate. In conventional demolition concrete crushing, by contrast, the cracks are typically generated at the point of impact – resulting only in feed material size reduction.
The FCB Rhodax 4D crusher is composed of a grinding chamber that is set in motion and a central cone free in rotation. The material is compressed in between, while the gap between the chamber and the cone allows an adjustment of the maximal outlet particle size. The 4D nomenclature refers to four motorized, unbalanced masses that bring constant compressive force by driving the chamber horizontally in circular motion. The chamber’s eccentric orientation facilitates compression on one side and material segregation or downward movement on the other.
Fives FCB brought the demolition concrete recycling concept to the mid-March C&D World event following four FCB Rhodax 4D delivery commitments in Europe and Taiwan during 2024 and 2025, the first to a Heidelberg Materials site in Poland. Fives FCB is based in northern France and operates as the Cement & Minerals Division of Fives Group, with headquarters in Paris. Overseeing the FCB Rhodax 4D process launch in North America is Cement & Minerals Area Sales Manager Daniele Cardone, [email protected].
