Ion exchange recovery of gold from iodine–iodide solutions

The recovery of gold from iodine–iodide solutions using strong base anion exchange resin has been investigated. The gold iodide complex can be effectively loaded on the resin provided the resin is not heavily loaded with triiodide. The loading of triiodide is found to be extremely strong due to the dissociation of the loaded triiodide to iodide and iodine, the latter being deposited on the resin by physiosorption thereby fouling the surface. This may be potentially detrimental to the gold recovery process but can be overcome by pre-reduction to remove most of the triiodide before loading. To strip the iodine from the resin it requires a reductive elution process. A sodium chloride based eluant solution containing sulfite is found to be highly effective for the elution of both gold and iodine.

► Gold can be effectively recovered from iodide solutions using ion exchange resin.
► Triiodide loading is extremely strong and may be detrimental for gold loading.
► Triiodide is loaded as iodine by physiosorption releasing iodide back to solution.
► An eluant containing NaCl and Na2SO3 is very effective for gold and iodine elution.