Effect of particle characteristics on segregation

Abstract

Segregation occurs during most particulate materials-related unit operations including mixing,conveying, discharging, filling, and compaction. A redesigned, second generation primary segregationshear cell was fabricated to simulate and quantify the percolation and sieving mechanisms-basedsegregation. Several binary mixtures were tested to quantify the effect of size ratios, absolute size, anddifferent constituents. In powder handling process, a mixture usually is comprised of differentconstituents. The constituents of binary mixtures studied were spherical shaped glass beads and irregularshaped poultry feed particles. The glass beads were considered as an ideal material whereas mashedpoultry feed was considered as real-world material. Three binary size ratios 4:1, 6:1, and 8:1 were tested.For a given size ratio, three different absolute coarse (710-850, 1000-1200, and 1400-1700 m) to fineparticle sizes were studied. Three key conclusions were drawn based on the PSSC-II test results: 1) Thehigher density and smoother surface of fine component of a binary mixture, the higher is the segregationpotential. 2) The coarse particle shape effect, i.e., the irregular shaped coarse particles or higher porosityof coarse component of a binary mixture lead to higher segregation potential. 3) The fine particleproperties play a major role in determination of the segregation potential of a binary mixture. The fineparticle properties, to a certain extent, determine the particle size-related effects such as absolute sizeand size ratios, i.e., if fine particle properties of a binary mixture change, the size-related effect onsegregation potential would definitely change.