Picobubble column flotation of fine coal

Daniel Tao, Samuel Yu, Xiaohua Zhou, R. Q. Honaker, B. K. Parekh

Research output: Contribution to journalArticlepeer-review

36 Scopus citations


Froth flotation is widely used in the coal industry to clean -28mesh (0.6mm) or -100mesh (0.15mm) fine coal. A successful recovery of particles by flotation depends on efficient particle-bubble collision and attachment with minimal subsequent particle detachment from bubble. Flotation is effective in a narrow size range, nominally 10-100μm, beyond which the flotation efficiency drops sharply. A fundamental analysis has shown that use of picobubbles can significantly improve the flotation recovery of particles by increasing the probability of collision and attachment and reducing the probability of detachment. A specially designed column with a picobubble generator has been developed for enhanced recovery of fine coal particles. Picobubbles were produced based on the hydrodynamic cavitation principle. Experimental results have shown that the use of picobubbles in a 5-cm diameter column flotation increased the combustible recovery of a highly floatable coal by up to 10% and that of a poorly floatable coal by up to 40%, depending on the feed rate, collector dosage, and other flotation conditions.

Original languageEnglish
Pages (from-to)1-14
Number of pages14
JournalInternational Journal of Coal Preparation and Utilization
Issue number1
StatePublished - Jan 2008


  • Bubble size
  • Coal
  • Flotation
  • Picobubble
  • Separation efficiency

ASJC Scopus subject areas

  • General Chemical Engineering
  • Mechanical Engineering
  • Energy Engineering and Power Technology
  • Geotechnical Engineering and Engineering Geology
  • Fuel Technology


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