Controlling Particle Segregation: Implications of Particle Cohesion, Properties, and Flow Perturbations

Joseph McCarthy, University of PittsburghSegregation, or un-mixing, of particles can be a costly problem and a source of frustration for industries ranging from pharmaceuticals to ceramics to agriculture. When particles differ in almost any mechanical property—size, density, shape, etc.—they become very difficult to keep homogeneous and this problem can even plague "uniform" materials if their is a size or shape distribution within the sample. In this talk, we highlight recent advances in controlling segregation. Specifically, we examine two techniques for segregation control. The first involves using interparticle cohesion, both due to van der Waals forces and/or liquid bridges, either to cause or prevent segregation. The second technique, inspired by fluid mixing, allows us to exploit flow perturbations to limit or even eliminate segregation in free-flowing systems, while at the same time yielding a predictive test-bed for past and future model of segregation kinetics.