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The Study of Effective Parameters on Thorium Extraction by Cyanex 272 in an Emulsion Liquid Membrane System

Ehyaie, Darya | 2024

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  1. Type of Document: M.Sc. Thesis
  2. Language: Farsi
  3. Document No: 57646 (46)
  4. University: Sharif University of Technology
  5. Department: Energy Engineering
  6. Advisor(s): Samadfam, Mohammad; Zaheri, Parisa; Zahakifar, Fazel
  7. Abstract:
  8. This study used the emulsion liquid membrane method to investigate the extraction and separation of thorium from nitrate solution. According to the results obtained from the studies, Cyanex 272 was a suitable option for selectively extracting thorium. For simultaneous extraction and stripping of thorium from dilute aqueous solutions, an emulsion liquid membrane system consisting of Cyanex 272 as an extractant, Span 80 as a surfactant and sulfuric acid solution as a receiving phase (internal phase) was used. Emulsion liquid membrane method has high mass transfer flux due to high surface to volume ratio, which causes high extraction efficiency and fast transfer of thorium ions from its low concentrations. Important operational parameters affecting thorium transfer rate such as extractant concentration, feed phase acidity, contact time, stripping agent concentration, stirring speed, volume ratio of emulsion to feed, volume ratio of internal phase to organic phase in the membrane were evaluated. In addition, the stability of the emulsion was checked by measuring its breaking and swelling rate. Proper extraction and stripping of thorium were optained in operational conditions including cyanex 272 concentration of 0.11 M, pH of the feed phase equal to 1, contact time of 25 min, sulfuric acid concentration of 0.65 M in the internal phase, stirring speed of 300 rpm, the volume ratio of emulsion to the feed phase of 0.4 and the volume ratio of the internal phase to the organic phase of 1. Under these conditions, thorium extraction and stripping were 99% and 88%, respectively. The experiments were conducted on the actual leaching solution using the values of the derived parameters, and the results showed that the extraction efficiency for thorium was 95% and the stripping efficiency was 70%. Additionally, research revealed that thorium is selectively separated from the leaching solution. The measurement of emulsion stability also revealed that the swelling rate of the emulsion can be managed to be less than 10% and that the rate of emulsion breakage is very minimal
  9. Keywords:
  10. Emulsion Liquid Membrane ; Thorium ; Cyanex 272 ; Emulsion Breakage ; Emulsion Swelling ; Thorium Extraction

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