The Spent loaded-Pd cordierite honeycomb ceramic automotive catalytic converters,which were roasted to remove the deposit charcoal and other organic compounds,and were milled less then 100 mesh were reduced by HCOOH,which PdO was reduced to Pd and then the Pd was selectively leached with HCl-NaClO3.Palladium was determined by DDO spectrophotometry.In this paper,the determined results of several leaching methods were compared.The key factors which affected the Pd leaching by the system of HCl-NaClO3 were discussed and the optimal leaching conditions were proposed.The results indicated the Pd in automotive catalysts can be quantitatively analyzed by DDO spectrophotometry with HCl-NaClO3 for Pd leaching and at the same time the palladium of Pd-catalysts can be quantitatively determined.
