Cation-exchange in thiourea-hydrochloric acid solutions

Ion-exchange distribution coefficients are reported for several transition and post-transition elements in solutions of hydrochloric acid (0.1-3.0M) and thiourea on AG50W resins. Some typical elution curves illustrate use of the systems with special reference to the separation of small amounts of gold, palladium, platinum, rhodium and iridium from large amounts of numerous base metals by using 1.5M hydrochloric acid-0.1M thiourea as eluent. Also illustrated is the use of a bromine-containing solution to strip thiourea complexes from a cation-exchange column.