Selective Recovery of PGMs and Cerium by a Hydrochloric Leaching Process for Automotive Catalysts

The nowadays common recycling of selected platinum group metals from catalysts, namely platinum, palladium, and rhodium, typically takes place in course of a pyrometallurgical processing. In course of that, the PGMs are dissolved in a collector metal, such as nickel or iron, while in parallel the whole
monolith and the wash coat on top of the ceramic carrier is liquified and transferred to the slag phase. As a result, the utilized rare-earth of the wash coat, mainly cerium, is not recovered and gets diluted by other slag
components. Therefore, the present paper introduces an innovative recycling process based on hydrochloric leaching utilizing H2O2 as an oxidation agent for redox potential adjustment. Compared to common pyrometallurgical catalyst recycling technologies the hydrometallurgical route offers additionally the recovery of cerium as a product while in the same moment the solution can be reused and a remaining cleaned ceramic material is left behind as an additional by-product.