"To introduce multifunctionalities to concrete using graphene,...

"To introduce multifunctionalities to concrete using graphene, we first prepared suspensions of graphene in water by high-shear liquid phase exfoliation of graphite powder using the surfactant sodium cholate (see Figure 1A), resulting in surfactant FG. Figure 1B shows the high-shear mixer used in this work. The exfoliation process occurs inside the square hole head, shown in the inset of Figure 1B, where the rotor blade shears platelets at very high speed (up to 8000 rpm) against the square hole head. When graphite flakes are trapped in the narrow space between the rotor and the head, shear forces developed in the liquid separate the weakly (van der Waals) coupled graphene layers of graphite."

8000 rpm is not really fast at all. Basically this paper describes making use of a high shear mixer ($8000 a machine apparently?) to shear graphite flakes into graphene flakes 4-8 layers in thickness. The paper alludes to how cost-effective it is with regard to input materials and industrial scaleability.

Is it cost effective for graphite recycling purposes? I dont know. Doesn't seem outlandish to me though, if you could recover suitably pure graphite. As an aside I would love to one day order talga-graphene'd cement to build something.

from: Ultrahigh Performance Nanoengineered Graphene–Concrete Composites for Multifunctional Applications
source: https://onlinelibrary.wiley.com/doi/full/10.1002/adfm.201705183