Kinetics of Solvent Extraction of Iron(III) from Sulfate Medium by Purified Cyanex 272 using a Lewis Cell

Abstract

The kinetics of the forward and backward extraction of the title process have been investigated using a Lewis cell operated at 3 Hz and flux or (F) -method of data treatment. The dependences of (F) in the forward extraction on [Fe 3þ ], [H 2 A 2 ] (o) , pH, and [HSO 4 2 ] are 1, 0.5, 1, and 21, respectively. The value of the forward extraction rate constant (k f ) has been estimated to be 10 27.37 kmol 3/2 m 27/2 s 21 . The analysis of the experimentally found flux equation gives the following simple equation: F f ¼ 10 0.13 [FeHSO 4 2þ ] [A 2 ], on considering the monomeric model of BTMPPA and the stability constants of Fe(III)-HSO 4 2 complexes. This indicates the following elementary reaction occurring in the aqueous film of the interface as rate determining: [FeHSO 4 ] 2þ þ A 2 ! [FeHSO 4 .A] þ . The very high activation energy of 91 kJ mol 21 supports this chemical reaction step as rate-determining. The negative value of the entropy change of activation (294 J mol 21 K 21 ) indicates that the slow chemical reaction step occurs via the S N 2 mechanism.The backward extraction rate can be expressed by the equation:20.5 . An analysis of this equation leads to the following chemical reaction step as rate-determining:2 . However, the activation energy of 24 kJ mol 21 suggests that the backward extraction process is intermediate controlled with greater contribution of the diffusion of one or the other species as a slow process. The equilibrium constant obtained from the rate study matches well with that obtained from the equilibrium study.

Iron and Copper Recovery/Removal from Industrial Wastes: A Review

“…The extractant solution also provides a fair selectivity to the extraction of Fe 3+ in the presence of some commonly associated metals, namely Cr 3+ , Co 2+ , Ni 2+ , Cu 2+ , and Zn 2+ . Biswas et al 83 investigated the kinetics of the forward and backward extraction of Fe(III) from sulfate medium using a Lewis cell operated at 3 Hz and flux method of data treatment. Biswas et al 84 studied the interfacial adsorption property of purified Cyanex 272 and its characteristics toward Fe(III) from sulfate medium.…”

Solvent Extraction of Fe(III) from Aqueous Chloride Solution by Cyanex 301 Dissolved in Kerosene

“…Mono-2-ethylhexylphosphoric acid (M2EHPA) has been used for the same by several workers [16,17]. The phosphinic acid derivative, bis-2,4,4-trimethylpentylphosphinic acid (abbreviated as BTMPPA, commercially known as Cyanex 272) has also been used for the extraction of Fe(III) [18][19][20][21]. Using Cyanex 301 as an extractant, the extractions of Ti(IV) [1], Zn(II) [22], In(III) [23], Sb(III), Bi(III), Pb(II) and Sn(IV) [24], Cu(II) [25], Co(II) and Ni(II) [26], Ag (I) [27], Zr(IV) [28], etc.…”

AliCy as Extractant to Remove Iron from Copper-Free Extreme AMD for Further Extraction of Zinc

“…(Pappu et al 2006;Pradel et al 1993) that frequently have economical disadvantageous. It is known that Fe 3+ can be extracted from different solutions by SX using different extractants (Biswas et al 2007;Stefánsson 2007;Principe and Demopoulos 2004). Not only iron separation from extremely concentrated AMD will prevent its coextraction in the recovery of zinc, but also its extraction in a pure state will allow to produce iron in a markable form and contribute to the economic viability of metals recovery from AMD (Agrawal and Sahu 2010;Mishra et al 2010).…”