With the rise in the price of metals and restrictions on the dumping of metallic wastes, has been considerable interest in the recovery of silver anionic complexes from both plating and photographic waste streams. For these applications we suggest the evaluation of the weakly basic anion exchange resins, Amberlite IRA-67. When operated in the partial sulfate form, the resin has a high affinity for both silver cyanide and silver thiosulfate anionic complexes, The resins have a high exchange capacity and are easily regenerated.

As is pointed out above, for best performance the resins should be operated in the partial sulfate form. To convert the resin to this form, pass 4 % sulfuric acid downflow through the resin until the pH of the effluent is the same as the pH of the influent.
Following this, the resin should be rinsed with several bed volumes of water draining the water level to approximately one inch above the surface of the beads. The silver-laden solution should be adjusted to pH 6∼7 with acid and then passed downflow through the resin at a flow rate of 0.5 gps/ft3 of about 4 bed volumes/hour. To regenerate for silver recovery, we suggest passing a sodium or potassium thiosulfate solution downflow through the resin at a flowrate of about 2 BV/hr. After regeneration the resin should be rinsed with several bed volumes of water before the next loading cycle is begun.