A liquid fluidized bed was used to elutriate and hence separate particles on the basis of sizeand also density, with the ratio of the superficial fluidization velocity, U, to particle terminalvelocity, u_t, (terminal velocity at g=9.8 ms~(-2)) exceeding 1000 fold. This ratio is extraordinarybecause the centrifugal acceleration involved was much lower at 73g. The fluidized bedsystem incorporated a system of parallel channels inclined at an angle of 20° to the directionof the centrifugal force. Inclined channels have been deployed previously in a centrifugalfield. However, this is the first study to also introduce fluidization, allowing efficientseparation to be achieved. Moreover, it was shown that the combination of the inclinedchannels and the centrifugal force helped to almost fully suppress the effects of particle sizeover a wide size range.The processing of ultrafine particles less than 0.1 mm is often limited by their exceedinglylow terminal settling velocity. This is especially true when the particles need to remaindispersed in order to facilitate their classification, either by size or by density. Centrifugalforces, with an acceleration G times the normal gravitational value, offer one approach forincreasing the particle settling velocity by a significant factor, up to a maximum of G. Theparticle Reynolds number then increases significantly, ultimately leading to a change in thesettling regime from the Stokes’ to Intermediate, and hence dependence of the terminalvelocity on the particle diameter, from d~2 to d~1. This reduction in the dependence on the
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