PROCESS FOR RECOVERING PALLADIUM FROM SPENT CATALYSTS

摘要

The invention relates to a process for recovering palladium from spent catalysts by subaerial roasting at a temperature of 1,000 degree C, followed by decomposition in aqua regia and conversion to chlorides by repeated addition of concentrated HCl and acidity elimination. The solution containing H2(PdCl4) is then treated with 25% NH4OH for coarse separation of base-metal hydroxides and afterwards filtered. The palladium is precipitated with hydrazine hydrate, filtered and subjected to purification by usual processes.