Separation of valuable fine phosphate particles from their slimes by column flotation

N. A. Abdel-Khalek, F. Hassan, M. A. Arafa

Research output: Contribution to journalArticlepeer-review

16 Citations (Scopus)


Large quantities of fines are generated as slimes during beneficiation of phosphate ores. These slimes are discarded due to the lack of a suitable method for their treatment. This decreases the total recovery of phosphate. Moreover, the presence of these slimes causes an environmental problem in some localities. This paper studies the possibility of recovering the valuable fine phosphate particles (<45 μm) from their slimes through the application of the column flotation technique. Tests were performed using oleic acid as a collector for the phosphate minerals, and sodium silicate as a depressant for their associated gangues. The main operating parameters affecting the performance of column flotation were investigated. The results indicate that the best operating conditions for column flotation of phosphate slimes are: superficial gas velocity 0.84 cm/s, frother concentration 0.1 kg/ton, column height 230.5 cm, and superficial water velocity 2.2 cm/s. At these conditions a product assaying 25.3% P2O5 (~55.24% BPL, bone phosphate of lime) and 14.64% LR. (insoluble residue) with a P2O5 recovery of about 51.52% was obtained from a feed containing 18.26% P2O5 (~39.87% BPL) and 24.03% LR. Such a grade and recovery were not obtained by applying the conventional froth flotation technique, even after cleaning the rougher concentrate. Recovery of more than 50% of phosphate from disposed slimes will improve the economic viability of the beneficiation process for phosphate ores. It will also help in solving the environmental problems associated with the disposal of these slimes.

Original languageEnglish
Pages (from-to)1077-1086
Number of pages10
JournalSeparation Science and Technology
Issue number7
Publication statusPublished - 2000
Externally publishedYes


  • Bubble size
  • Column flotation
  • Column height
  • Fine particles
  • Frother
  • Phosphate ore
  • Slimes
  • Washwater

ASJC Scopus subject areas

  • General Chemistry
  • General Chemical Engineering
  • Process Chemistry and Technology
  • Filtration and Separation


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