Cohesive particle mixing and segregation under shear

Mixing and segregation is important to industries ranging from food to pharmaceuticals to ceramics. Despite the fact that there have been significant advances recently in the understanding of both free-flowing and cohesive particles, the effects of cohesion on particulate mixing and segregation in even the simplest devices is not well understood. In this paper, we theoretically and experimentally examine the cohesive (here, liquid-bridge induced) mixing and segregation in an annular shear cell. We extend previous theoretical arguments for pseudo-static particle systems to sheared beds and use our theory to develop phase diagrams that correctly predict cohesive particle mixing/segregation. Interestingly, under certain conditions mixing is stronger for small shear rates (i.e., slower stirring) than for high shear rates (i.e., faster stirring). (c) 2006 Elsevier B.V. All rights reserved.