Toshio Izaki

Reductive stripping of Fe(III)-loaded D2EHPA with the aqueous solutions containing sulfur dioxide

The stripping of Fe(III)-loaded D2EHPA, which is known to be difficult, was studied in the presence of SO2. The stripping reaction of Fe(III) was greatly accelerated by the presence of SO2, generating Fe(II) as a stripped species. In the presence of SO2, the stripping of Fe(III) was favorable with all acids studied, including HC1, HC1O4, and H2SO4, and even with water. Among various factors, the partial pressure of SO2 was found to be the most important factor in controlling the rate of stripping as well as the rate of reduction of stripped Fe(III) in the aqueous phase. The removal of SO2 dissolved in an organic phase was easily done by washing with aqueous H2O2 solution.