A study of rotary tribo-electrostatic separation of South African fine coal

S. O. Bada, D. Tao, R. Q. Honaker, L. M. Falcon, R. M.S. Falcon

Research output: Contribution to journalArticlepeer-review

28 Scopus citations


This article presents an experimental study of rotary tribo-electrostatic separation (RTS) as an alternative approach for beneficiating steam coal mainly used in South African power plants. An RTS with an octagonal charger developed at the University of Kentucky, USA has been used in beneficiating two types of South African coals containing nearly 37% and 32% ash, respectively. System parameters, such as applied charger potential, separation chamber voltage, rotation speed of the copper-plated rotor, and splitter distances were investigated for their effects on the separation performance. It was found that better separation was observed at 5000rpm rotation speed, no applied potential to the charger, and 25KV separation voltage. The RTS process reduced the ash content of the -177m coal fraction by nearly 14.9% for the Klipfontein coal and 12.2% for the Liketh Townlands coal, with corresponding combustible recovery values of 10.7% and 8.9%, respectively. Total sulphur content was also reduced from 2.1% to 0.9% for the Klipfontein coal and from 2.8% to 0.4% for the Liketh Townlands coal at corresponding combustible recovery values of 5.7% and 8.9%, respectively. The x-ray diffraction analysis of the cleaned-coal samples confirmed a reduction in the mineral content with an improvement in the organic composition for both coal samples.

Original languageEnglish
Pages (from-to)154-172
Number of pages19
JournalInternational Journal of Coal Preparation and Utilization
Issue number2-5
StatePublished - Mar 2010

Bibliographical note

Funding Information:
The authors gratefully acknowledge the financial support of the South African National Energy Research Institute (SANERI). We thank to University of Kentucky Mining Department for providing the Tribo-Electrostatic Separator, Mr. Ed Thompson and the Kentucky Geological Survey Laboratory for granting us the permission to perform the XRD analyses.


  • Coal
  • Dry beneficiation
  • Particle charging
  • Tribo-electrostatic technique

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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