Hindered settling of flocculated multi-sized particle suspension, part I: Segregation mechanism of non-flocculated particles

Abstract

Segregation phenomenon is widely observed both in field and in laboratory. The purpose of this research is to examine the flocculation states of particles in suspension and investigate the mechanism of the segregation phenomenon occurring in hindered settling of flocculated multi-sized particle suspensions. In settling environment, force balance analyses are performed for particles with different sizes to investigate the flocculation states of these particles. Particle flocculation state is assessed based on the relative movement of the particle with respect to the network structure in the flocculated suspension. Three flocculation scenarios are discussed for suspensions with different maximum hindrance abilities. The segregation mechanism is explored based on the concept of critical particle size. A size-dependent continuous segregation mechanism is presented to illustrate the segregation sequence of particles with different sizes during the settling process. Applying the size-dependent continuous segregation on hindered settling, segregation-impacted settling modes of flocculated multi-sized particle suspensions are proposed. Interruptive batch settling tests were all carried out on copper tailings to validate this segregation behavior.