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Extraction of Fe (III) and In (III) from aqueous HCl by tri-n-octylamine in nitrobenzene

1965; Pergamon Press; Volume: 27; Issue: 2 Linguagem: Inglês

10.1016/0022-1902(65)80363-3

1878-1225

Austin Nelson, J. L. Fasching, R. L. McDonald,

Radioactive element chemistry and processing

A study has been made of the distribution of Fe (III) and In (III) between aqueous HCl and solutions of tri-n-octylamine (TOA) in nitrobenzene at trace metal concentrations and under metal loading conditions. The equilibrium between tri-n-octylamine and HCl was also investigated. The equilibrium constant for the reaction TOA + (HCl)a = TOACHl was found to be 5·6 × 106 over the amine salt concentration range 1·7 × 10−3−9·5 × 10−2 M; TOAHCl appears to be an essentially undissociated ion pair in nitrobenzene. The metal extraction data have been interpreted in terms of the extraction of the tetrachloro metal anions. The possibility of the addition of one or more amine hydrochlorides to the extracted metal species must also be considered; these “extra hydrochlorides” are not bound directly to the metal but, rather, are the result of electrostatic interactions. The results give not only an interesting example of the effect of organic phase ionization on the distribution ratio, but also emphasize the hazards of drawing conclusions concerning the metal species extracted from equilibrium extraction data.