Separation of traces of silver from palladium by a surface replacement reaction

Abstract

An effective method has been developed for the enrichment of silver traces in palladium and of carrier-free¹¹¹Ag formed in it by thermal neutron capture and subsequent β-decay. A replacement reaction occurring between hydrogen atoms absorbed in metallic palladium and cations in aqueous solution has been observed. A new device is proposed for the measurement of hydrogen absorbed by finely divided palladium without the necessity of removing it from the metal. Both palladium and silver ions were quantitatively and selectively deposited in the presence of other cations from hydrochloric acid solutions, whereas the deposition proved to be selective and quantitative for silver from ammoniacal solutions. About 0.4 ppm silver in specpure palladium can be removed by this method. A practical example of a more than 500-fold enrichment of silver traces in palladium is described.