Critical review on PGM treatments in E-scrap

Recovery of precious metals like Au and PGMs is essential in E-scrap recycling. Many processes have been proposed and used commercially. Of course, pretreatments using physical separation techniques when considering total recovery process but we focus only on hydrometallurgical processes in this review. PGM recovery processes are roughly categorized three types. One of main target resource is waste catalysis of ELV. Other target is printed circuit boards from E-scrap. Both resources are treated in pyro-metallurgical at first stage and high content PGM alloys are produced. Other attractive resource is high grade scrap from dental hospitals. Those high content PGM alloys are treated by various hydrometallurgical processes. A dissolution of high content PGM alloys is the first step in hydrometallurgical process. Point of this stage is how to oxidize the alloys. Aqua regia is very popular agent and other strong acids containing Cl gas and H2O2 also used. After dissolution processes depend on impurities. Various processes are introduced in separation of PGMs from other metals and between PGMs in this review.