Solvent extraction of iron(III) from hydrochloric acid solution by sulphoxides and their mixtures

The extraction of iron(III) from hydrochloric acid solution by the series of sulphoxides (R2SO) from dipentyl to didecyl sulphoxide in 1,1,2-trichloroethane has been studied. At a given strength of the extractant, extraction increases initially with increase in the acid concentration to a maximum at 8 M and decreases thereafter. Increase in H+ at constant Cl- strength or increase in Cl- at a given H+ increases the extraction. Under otherwise identical conditions, extraction increases with increase in the extractant concentration. The extracted species would appear to be HFeCl4,2R2SO. A mixture of two sulphoxides or of a sulphoxide and tributyl phosphate extracts the metal ion more than the sum of extractions due to the individual components.