Kk. Sahu et Rp. Das, SYNERGISTIC EXTRACTION OF IRON(III) AT HIGHER CONCENTRATIONS IN D2EHPA-TBP MIXED-SOLVENT SYSTEMS, Metallurgical and materials transactions. B, Process metallurgy and materials processing science, 28(2), 1997, pp. 181-189
Citations number
32
Categorie Soggetti
Material Science","Metallurgy & Metallurigical Engineering
The extraction of iron(III) from chloride solutions at macrolevel conc
entration by different solvents such as tri-n-butyl phosphate (TBP), d
i(2-ethylhexyl) phosphoric acid (D2EHPA), and their mixture in various
proportions has been investigated at different acid concentrations. T
he synergistic extraction of iron(III) with a mixture of TBP and D2EHP
A was studied and the results were compared with that of the extractio
n by individual solvent alone. An increase in the concentration of the
synergist, TBP, in the D2EHPA-TBP solvent system resulted in an incre
ase in the synergistic coefficient value. The experimental data are tr
eated graphically to explain the formation of organic phase extracted
species, and the equilibrium extraction constants for the species are
determined. It is found that a maximum of two molecules of TBP are add
ucted to the extracted species of the corresponding nonsynergistic sys
tem. Stripping of iron(III) with hydrochloric acid from loaded D2EHPA
was found to increase with an increase in acid concentration. In the c
ase of D2EHPA-TBP mixtures, stripping efficiency was increased with an
increase in acid concentration up to a certain level and then it was
decreased. The experimental results indicate that an iron exchange rea
ction between loaded D2EHPA and TBP proceeds during stripping at a hig
her concentration of hydrochloric acid (from mixed loaded solvent syst
em). A plausible mechanism for iron(III) extraction and stripping has
been discussed.