In general, the solvent extraction behavior of Pt(IV) and Pd(II) by many amine extractants and solvating extractants is similar, so the separation of Pt(IV) and Pd(II) is not good. Therefore, the separation of Pt(IV) and Pd(II) by extractants other than amine extractants and solvating extractants has been investigated.
In the present study, the extraction and separation of Pt(IV) and Pd(II) from hydrochloric acid solutions by mixed extractants of APT 6500 as an acidic extractant, and TBP as a solvating extractant were investigated. It was found that extraction of Pd(II) can be suppressed and Pt(IV) can be preferentially extracted and separated by mixing APT 6500 and TBP in an appropriate ratio. In addition, good separation of Pt(IV) and Pd(II) was obtained regardless of the concentration of hydrochloric acid by using mixed extractants with APT 6500 and TBP concentrations adjusted to about 10 vol% each.
