Solvent Extraction of Rhenium in Ionic Liquid with N235

Abstract

Extraction of rhenium into the ionic liquids phase from aqueous solutions was investigated using N235 as extractant. At temperatures from 293.15 to 318.15 K, the equilibrium molalities of ReO4 – were measured at an ionic strength from 0.2 to 2.0 mol·kg–1 in the aqueous phase containing NH4Cl as supporting electrolyte. The standard extraction constants K 0 at various temperatures were obtained by methods of the Pitzer polynomial approximation. Thermodynamic properties for the extraction process were calculated.

Rhenium(VII) extraction from sulfuric aqueous solutions using ionic liquids as diluent and extractant: insights on the extraction stoichiometry and process parameters

“…However, in that study, a phase modifier was also required. More recent studies using ILs as diluents used around 1% (w/w) of amine extractant (triisooctylamine) to obtain over 99% extraction of this metal ion from acid solutions 4,20 . In this work, only 3% (v/v) of [TOMA][BA] allows the extraction of around 95% of Re(VII) using an organic‐solvent‐free extracting solution without any phase modifier.…”

“…More recent studies using ILs as diluents used around 1% (w/w) of amine extractant (triisooctylamine) to obtain over 99% extraction of this metal ion from acid solutions. 4,20 In this work, only 3% (v/v) of [TOMA][BA] allows the extraction of around 95% of Re(VII) using an organic-solvent-free extracting solution without any phase modifier. On the other hand, it has been also demonstrated that the use of ILs as diluents enhances the extraction percentages.…”

“…In industry, Re(VII) is normally recovered from molybdenite leach liquors by solvent extraction (SX) using amine extractants such as trioctylamine (TOA) or Alamine 336 diluted in kerosene 3,4 . These extractants exhibit high extraction percentages (90–100%); for instance, Sato and Sato 3 showed high distribution ratios of Re(VII) by the use of TOA in kerosene, and Nguyen et al 5 .…”

“…2 In industry, Re(VII) is normally recovered from molybdenite leach liquors by solvent extraction (SX) using amine extractants such as trioctylamine (TOA) or Alamine 336 diluted in kerosene. 3,4 These extractants exhibit high extraction percentages (90-100%); for instance, Sato and Sato 3 showed high distribution ratios of Re(VII) by the use of TOA in kerosene, and Nguyen et al 5 achieved high extraction percentages when using Alamine 336 and tributyl phosphate (TBP). However, Alamine 336 is not selective to Re(VII), and both metal ions, molybdenum (Mo) and Re, are extracted in acid conditions.…”

“…16 Overall, this work proposes an extraction phase free of conventional organic substances. So far, only a few works have used ILs for Re(VII) extraction, 4,6,20,21 where they have been used only as diluents in combination with conventional extractants. However, to our knowledge, there are no previous works where the combination of two ILs are used for extracting Re(VII) from aqueous solution.…”