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Separation of cobalt and nickel from sulfate media was investigated, using a extraction system of 30% 2-ethylhexyl phosphonic acid mono-2-ethylhexyl ester (P507)+15% trioctyl/decylamine (N235)+55% sulfonated kerosene. About 41 wt% Co2+was extracted with 1.6 wt% co-extraction of Ni2+at O/A ratio of 2:1. Scrubbing of Ni2+and stripping of Co2+could be achieved from the loaded organic phase, using water and 0.05 mol/L H2SO4, respectively. Cobalt extraction percentage decreased with increasing Mg2+concentration, but this influence was negligible as [Mg2+] < 0.1g/L. The favorable equilibrium pH was 4–4.8. A different E-pH curve was observed in the P507-N235 system compared to the saponified P507 system. [ABSTRACT FROM AUTHOR]

The solvent extraction of Ti(IV) from sulfate medium by the commercial extractant Cyanex 301 (HA) has been studied in order to examine this novel system. Heptan-1-ol (5% (v/v) in the organic phase) is used as a de-emulsifier. The equilibration time is 45 min. The experimental results suggest that the extracted species is always TiOA2 (o), though the composition of the reacting aqueous Ti(IV) species may vary depending on the concentration levels of Ti(IV), pH, HA and. The equilibrium constant (Kex) at 303 K is measured to be 101.117and 10−1.243for the reaction of monomeric, non-sulfated, mono, and non-hydrolyzed TiO2+, respectively. The effects of heptan-1-ol, temperature, loading, and diluent type have been reported. Stripping can be done effectively by a solution of 1 mol/dm3H2SO4containing 5%(v/v) of “100 volume” H2O2. The possibilities of separation of Ti(IV) from Cu(II), Zn(II), Fe(III), Co(II), and Ni(II) have been predicted. It is proved to be an effective extractant for Ti(IV)/Fe(III) separation from sulphate medium at pH ∼ 1. [ABSTRACT FROM PUBLISHER]

Extraction and separation of divalent Mn and Zn ions from acidic sulfate solutions containing 0.05 M of each metal ion have been carried out using 0.04 M Na-CYANEX 272 in kerosene. The influences of the following parameters were studied: shaking time, equilibrium pH, extractant concentration, diluents type, and temperature. The extraction percentage of both metal ions increased with increasing equilibrium pH in the range 2.0–4.0 and 2.75–6.0 for Zn(II) and Mn(II), respectively. The separation factor, S(Zn/Mn), increases with the increase in pH to reach a maximum value of about 24 × 103at pH 4.0. Extraction of both metal ions increased with increasing extractant concentration. Aliphatic diluents were preferred compared to aromatic diluents. The thermodynamic parameters (ΔH, ΔS, and ΔG) for Mn(II) and Zn(II) were calculated. The extraction mechanism of both metals by Na-CYANEX 272, stripping from loaded extractant and recycling of extractant used in the extraction process were also investigated. [ABSTRACT FROM PUBLISHER]

As one kind of the most important intermediate materials in rare earth (RE) industry, RE sulfates have been considered difficult to be extracted and separated directly by saponified extractants due to the dissolubility of RE double sulfate ofcation. By introducing a barrier agent such as Mg2+ion in the present work, we proposed and developed a process to extract RE cations in sulfate medium with saponified HEH(EHP). Further, a selection criterion of the barrier agent was discussed. The results have revealed that the natural distribution of the univalent ion, RE3+and Mg2+ions, as determined by their extraction sequence in the cascade, hinders the contact betweencation and RE ions, and thereby RE double sulfate precipitate does not form during the extraction. Consequently, the study can provide us a strong possibility for extracting and even separating RE using saponified extractants directly from sulfate solution in no need of any transformation of the RE salts employed. [ABSTRACT FROM PUBLISHER]