Recovery of Cerium from Automotive Catalytic Converters

Platinum group metals (PGM) and cerium as one of the rare-earth elementsare considered as critical raw materials, thus their recycling and re-use is ofutmost importance. Among the PGMs, platinum (Pt), palladium (Pd), andrhodium (Rh) are the basic and most valuable metals used in catalytic con-verters. Due to the high price of PGMs, there are already recycling routes inEurope and especially in Germany. For PGM and rare-earth elements, re-search is focusing on greener, plain recovery techniques, which utilize milderreagents, offer better energy efficiency, and replace the existing recyclingroutes. In this work, a hydrometallurgical process is proposed to add ahydrometallurgy method to the mostly pyrometallurgical industrial recyclingroutes, resulting in recovery rates for cerium and PGMs of 63.21% and only1.03% with sulfuric acid, respectively. With hydrochloric acid, the leachingefficiency for cerium is even lower, and for PGM it is comparable. In themethod proposed in the present paper, the main PGMs remain in monolithsand can be recycled in existing recycling routes like pyrometallurgical recycling.