Solvent Extraction Separation of Titanium(IV) and Iron(III) from Acid Chloride Solutions by Trioctylphosphine Oxide

The solvent extraction of calcium(II), magnesium(II), aluminum(III), titanium(IV) and iron(III) from acidic chloride solutions by trioctyl phosphine oxide (TOPO) in kerosene has been investigated. The solvent extraction results demonstrate that the dissolved titanium and iron is present as TiCl4 center dot 2TOPO and HFeCl4 center dot TOPO. Extraction of titanium(IV) and iron(III) increase with increased hydrochloric acid concentration in the aqueous phase. On the other hand, aluminum(III), calcium(II) and magnesium(II) are not extracted under these experimental conditions. IR spectral studies of the extracted complexes were further used to clarify the nature of the extracted complexes. Titanium(IV and iron(III) can be selectively recovered from the loaded organic phase by controlling the acidity of the stripping agent. The loading capacity of the TOPO system has been evaluated and the potential for the separation and recovery of titanium(IV) and iron(III) from acid chloride liquors has been assessed through extraction and stripping isotherms.