Liquid–liquid extraction (LLE) of iron and titanium by bis-(2-ethyl-hexyl) phosphoric acid (D2EHPA)

Towards the Utilization of Fly Ash as a Feedstock for Smelter Grade Alumina Production: A Review of the Developments

“…Organo phosphates such as bis-(2-ethyl-hexl) phosphoric acid (D2EHPA) and tributyl phosphoric acid (TBP) are popular because of their commercial availability and lower price. Da Silva et al [43] showed that D2EPHA in n-dodecane was able to extract iron and titanium in sulfuric acid solution with the possibility of recycling the reagents used. However, the selective removal of iron and titanium from aluminumcontaining leach solutions was not possible with D2EHPA due to co-extraction of aluminum [14,41].…”

“…However, the selective removal of iron and titanium from aluminumcontaining leach solutions was not possible with D2EHPA due to co-extraction of aluminum [14,41]. Organo-phosphate extractants are also difficult to strip, requiring expensive stripping agents such as fluorine and hydrogen peroxide to improve the stripping kinetics [43,44] hence, their use in the purification of CFA leach solutions is limited.…”

Extraction of Cu(II) from aqueous solutions by vegetable oil-based organic solvents

“…Among the various types of extractants, di-2-ethylhexylphosphoric acid (D2EHPA) has been reported as an effective extractant for the separation of Cu(II) from aqueous solutions [11][12][13]. The application of D2EHPA in the removal of other metal ions such as Cd(II) [14], Zn(II) [15], Fe(III) and Ti(IV) [16], as well as other dye stuff [17] from aqueous solutions has also been reported. Tributylphosphate (TBP) is normally used as a phase modifier in Cu(II) extraction [18].…”

Heavy Metal Ion Extraction Using Organic Solvents: An Application of the Equilibrium Slope Method

“…Some examples of solvents applied in heavy metals extraction are: a. Di-2-ethylhexylphosphoric acid (D2EHPA), extensively used as an extractant for the separation of Cu(II) from aqueous solutions (Gherrou et al, 2002;Ren et al, 2007;Cox, 2008). Other applications of this popular extractant include the removal of Cd(II) (Kumar et al, 2009), Zn(II) (Vahidi et al, 2009), Fe(III) and Ti(IV) (Silva et al, 2008); b. Tributylphosphate (TBP), used to act as a phase modifier in Cu(II) extraction (Cheng, 2000). The extractant and phase modifier are diluted at certain ratios in the petroleumbased organic diluents such as kerosene and chloroform (Ak et al, 2008;Ren et al, 2008), cumene (Svendsen et al, 1990), dichloromethane (Memon et al, 2003), isododecane (Mortes and Bart, 2000), n-dodecane (Simonin et al, 2003), n-decanol (Lin et al, 2005), nheptane (Morais and Mansur, 2004), and n-hexane (Valenzuela et al, 2002); c. LIX 84 and Cyanex 272, applied to extract Cu(II), Ni(II), and Al(III) (Mohapatra et al, 2007;Agrawal et al, 2008); d. Cyanex 921, used to extract Cu(II) from HCl (Mishra and Devi, 2011); e. Miscellaneous organic solvents such as I) 1-phenyl-3-heptyl-1,3-propanedione, II) 1-phenyl-4-ethyl-1,3-octanedione, III) 1-(4'-dodecyl) phenyl-3-tert-butyl-1,3-propanedione in kerosene, used to extract Cu(II) (Fu et al, 2011).…”