Discrete element modeling of the microstructure of fine particle agglomerates in sheared dilute suspension

The fragmentation and restructuring under shear of agglomerates of fine mineral particles are studied with the Distinct Element Method. The model used takes into account contact forces, van der Waals forces, and hydrodynamic forces computed with the free-draining approximation. A loose initial agglomerate is submitted to a constant shear rate until reaching a quasi-stationary state, where the number, size and structure of fragment of agglomerates can be considered as constant. The influence of shear stress and size of particles on the characteristics of agglomerates at equilibrium is studied. Fragmentation is controlled by a non-dimensional number, depending on the radius of the particles, shear rate and maximal adhesion force.