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Interaction between TBP and D2EHPA during Zn, Cd, Mn, Cu, Co and Ni solvent extraction: A thermodynamic and empirical approach
, Article Hydrometallurgy ; Volume 98, Issue 1-2 , 2009 , Pages 143-147 ; 0304386X (ISSN) ; Darvishi, D ; Etemadi, S ; Eivazi Hollagh, A. R ; Keshavarz Alamdari, E ; Salardini, A. A ; Sharif University of Technology
2009
Abstract
The objective of this study was to investigate the synergistic effect of TBP on the system D2EHPA/kerosense/M2+ with respect to the extraction of some transitional metals. Although the presence of M2EHPA as an impurity in D2EHPA shifts the extraction curves to lower pH, empirical results show that the extraction curves shift to the right due to the addition of TBP and the counterbalance effect of M2EHPA. The results indicate that the equivalent concentration of D2EHPA decreases as a function of concentration of TBP because of the formation of hydrogen bonds between TBP and D2EHPA. Based on this finding, the D2EHPA equivalent concentration was determined by using a modifying factor for TBP...
Thermodynamics of vanadium (V) solvent extraction by mixture of D2EHPA and TBP
, Article International Journal of Mineral Processing ; Volume 138 , May , 2015 , Pages 49-54 ; 03017516 (ISSN) ; Ardakani, M. S ; Keshavarz Alamdari, E ; Haghshenas Fatmesari, D ; Darvishi, D ; Sadrnezhaad, S. K ; Sharif University of Technology
Elsevier
2015
Abstract
In the present study, the thermodynamics and mechanisms of vanadium extraction by a mixture of bis-2-ethylhexyl phosphoric acid (D2EHPA) and tri-n butyl phosphate (TBP) from sulfate medium were investigated. It was found that the maximum extraction percent of vanadium occurs at pH 1.8 under ambient conditions; this phenomenon was ascribed to the predominant presence of cationic species of vanadium (VO2 +) at this pH. Based on the Fourier Transform Infrared (FT-IR) spectrums, the POH bond of D2EHPA was found responsible for the extraction of VO2 + species through a cationic exchange mechanism. Employing the slope analysis method showed that the stoichiometric reaction...
Synergistic effect of Cyanex 272 and Cyanex 302 on separation of cobalt and nickel by D2EHPA
, Article Hydrometallurgy ; Volume 77, Issue 3-4 , 2005 , Pages 227-238 ; 0304386X (ISSN) ; Haghshenas, D. F ; Keshavarz Alamdari, E ; Sadrnezhaad, S. K ; Halali, M ; Sharif University of Technology
2005
Abstract
Synergistic effects of Cyanex 272 mixed with D2EHPA and Cyanex 302 mixed with D2EHPA were investigated for the separation of cobalt and nickel from a dilute sulfate media with the aim of reducing the reagent cost. Selective extraction of cobalt over nickel improved with respect to D2EHPA, but worsened with respect to Cyanex 272. By the application of the slope analysis method, the stoichiometric coefficient of the extractant was found to be four for cobalt and five for nickel, in a mixture of D2EHPA with Cyanex 302. However, it was four for both cobalt and nickel in a mixture of D2EHPA with Cyanex 272. Fourier Transform Infrared Spectroscopy (FT-IR) was utilized to examine the...
Extraction of ZN, MN and CO from ZN-MN-CO-CD-NI containing solution using D2EHPA, Cyanex® 272 and Cyanex® 302
, Article International Journal of Engineering, Transactions B: Applications ; Volume 24, Issue 2 , 2011 , Pages 183-192 ; 1728-144X (ISSN) ; Haghshenas, D. F ; Alamdari, E. K ; Sadrnezhaad, S. K ; Sharif University of Technology
2011
Abstract
Effects of pH, D2EHPA, Cyanex® 272 and Cyanex® 302 on extraction of zinc, manganese and cobalt from a Zn-Mn-Co-Cd-Ni containing solution at the room temperature was comprehensively investigated. Addition of Cyanex® 302 indicated a left-shifting-effect on the extraction curve of zinc, a right-shifting-effect on the extraction curve of manganese and no effect on the extraction of cobalt. Addition of Cyanex® 272 shifted all three curves to the right. Therefore, the most suitable extractant for separation of zinc from manganese was therefore 0.3-0.3 mixture of D2EHPA and Cyanex® 302, and that for separation of manganese from cobalt was pure D2EHPA. The stoichiometric coefficient for the...