Improvement of dry float-sink separation of smaller sized spheres by reducing the fluidized bed height

Jun Oshitani, Tetsuya Kawahito, Mikio Yoshida, Kuniaki Gotoh, George V. Franks

Research output: Contribution to journalArticlepeer-review

18 Citations (Scopus)


In this study, the influence of the fluidized bed height on the float-sink of different sized spheres in a gas-solid fluidized bed was investigated. Fluidized beds with heights h = 200, 150, 100 and 50 mm were prepared using a cylindrical column of inner diameter = 290 mm and a mixture of zircon sand and iron powder as the fluidized medium. Float-sink experiments were carried out using density adjusted spheres of diameter D sp = 40, 30, 20 and 10 mm. It was found that the float-sink performance at D sp ≥20 mm is not affected by the height of the bed, and the sharpness of separation (the density range where spheres neither float nor sink completely) is less than or equal to 200 kg/m 3. In the case of D sp = 10 mm, the sharpness of separation is a larger value (1100 kg/m 3 at h = 200 mm), whereas it decreases with decreasing h and is 400 kg/m 3 at h = 50 mm. The fluctuation of the surface height of the fluidized bed was visually recorded. The fluctuation is reduced by reducing h. The fluctuation vs. h correlates with the sharpness of separation at D sp = 10 mm vs. h. These results indicate that the dry float-sink separation of smaller sized spheres is improved as the fluctuation of fluidized bed surface is decreased by reducing the fluidized bed height.

Original languageEnglish
Pages (from-to)27-30
Number of pages4
JournalAdvanced Powder Technology
Issue number1
Publication statusPublished - Jan 2012


  • Dry dense medium
  • Fluidized bed
  • Separation
  • Surface fluctuation

ASJC Scopus subject areas

  • Chemical Engineering(all)
  • Mechanics of Materials


Dive into the research topics of 'Improvement of dry float-sink separation of smaller sized spheres by reducing the fluidized bed height'. Together they form a unique fingerprint.

Cite this