Several experiments were performed eluting neodymium bands behind copper bands with dilute ammonia-EDTA solutions. · A few other experiments were performed eluting only copper bands. If there were a certain amount of ammonium and hydrogen mixed homogeneously with the copper in the resin, very flat elution curves were obtained. Thus, the concentrations of the ions in J •. solution were constant throughout the band, and the composition oi the resin changed very little during the elution
