Separation of heavier-than-water plastic mixtures had been investigated via the fluidization of their packed beds
induced by an upward flow of water. The samples examined were resin pellets and crushed plastic products including
PVC, PET and PBT. On the onset of a flow, a mixed bed was swelled to the state of fluidization and separated into
layers of respective resins depending on their density. The effects of the flow rate, an amount of the samples and their
density difference were examined on the separation of resin pellets. Under an appropriate condition, the process was
completed within a few minutes, and satisfactory separation was attained when the density difference of the samples
exceeded 0.05 g cm3
. By using a column equipped with several sample outlets sorted resins could be recovered with
their purity intact by withdrawing each layer successively from above through a suitable outlet. Multi-stage separation
was also found to be effective in treating close-density samples. Compared with uniform-sized resin pellets, size distribution
of crushed plastic samples deteriorated the separation to some extent.
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