Separation of bismuth from lead, copper and other elements by means of anion exchange

The anion-exchange behaviour of bismuth and various other elements has been investigated in media consisting of methyl glycol and nitric acid. Through the determination of the distribution coefficients in such mixtures, a method for the anion-exchange separation of bismuth from many metal ions has been developed. A mixture of 90% methyl glycol and 10% 5M nitric acid is a suitable medium for this separation on the strongly-basic anion exchanger Dowex 1, X8. Only bismuth, thorium and lanthanum are strongly retained on the resin in these conditions. All other elements investigated, such as lead, copper, iron, etc., are either only weakly adsorbed or are not absorbed. By means of this ion-exchange procedure, a series of analyses of copper-base alloys for bismuth has been carried out. The results show that this method can be used successfully for the quantitative isolation of bismuth from such materials. The final determination of bismuth in the eluates is performed by complexometric titration.