Separation of Solid Particles by Density Difference in a Liquid–Solid Fluidized Bed

摘要

References(14) Cited-By(6) To examine the separation characteristics of solid materials in the liquid-solid fluidized bed, the motion of one solid material immersed in the fluidized bed was examined. The fluidizing particles were put in the column and fluidized by the liquid flow. To reduce the effects of size and shape of a sample, the liquid velocity was set at a low value, i.e., relatively small particles were used as the fluidizing particles. The glass beads (ρp = 2500 kg/m3) whose diameters were 60, 100, 200 and 500 μm and the zirconia beads (ρp = 6000 kg/m3) whose diameters were 60 and 100 μm were used as the fluidizing particles. Tap water was used as the fluidizing liquid. One sample, whose density was adjusted, was immersed in the bed, and the existing height of the sample in the bed was examined for different liquid velocities, fluidizing particle diameters and densities, experimentally.When the liquid velocity is low and the apparent density of the particle bed is higher than that of the sample, the sample floats on the bed (floating region). As the liquid velocity increases, the apparent density of the bed decreases and the sample becomes to suspend in the bed (suspending region). Further increments of liquid velocity makes the sample settle at the bottom of the bed (settling region). As the liquid velocity increases, the apparent density of the particle bed decreases and the sample sinks in turn. The range of the non-dimensional sample existing height in the suspending region is affected by the diameter of the fluidizing particle, but is not affected by the density of the fluidizing particles.