Selective Recovery of Platinum Group Metals from Spent Automobile Catalyst by Integrated Ion Exchange Methods

Abstract

Selective recovery of platinum group metals (PGMs), such as Pd, Pt, and Rh, from spent automobile catalyst has been investigated by integrated ion exchange method using dihexyl sulfide (DHS) impregnated resin and commercial weak anion exchange resin (Diaion WA-21) as adsorbents. Batchwise adsorption revealed that the DHS impregnated resin possesses the selective adsorption ability for Pd and WA-21 possesses selectivity for all PGMs, especially Rh. Chromatographic separation of Pd with column packed with DHS impregnated resin can be selectively achieved. The chromatographic separation of Pd and Pt with a column packed with WA-21 is effectively progressed, while that of Rh is insufficient yield due to a slow adsorption rate. Separation of Rh from other two PGMs can therefore be achieved by switching the eluent. Both adsorbents show almost no adsorption abilities for other heavy metals containing in the spent automobile catalyst. Sequential chromatographic operation of the column packed with DHS impregnated resin followed by the column packed with WA-21 can be finally achieved to recover mutual PGM from leaching solution of spent automobile catalyst.

Keywords:

• Automobile catalyst
• ion exchange
• platinum group metal
• selective recovery

ACKNOWLEDGEMENTS

This work was supported by Environment Research & Technology Development Fund (K2127, K22091, and K2340) from Ministry of Environment, Japan.