Separation of Platinum Group Metals (PGM) from Liquid Media
Technetium (particularly Tc7+), ruthenium (particularly Ru4+), rhodium (particularly Rh4+ and Rh3+), rhenium (particularly Re7+), and iridium (particularly Ir4+ and Ir3+) can be ionically grouped with the Platinum Group Metals (PGM) because they form stable oxyanion complexes
Many mining projects are underway in which ores are leached under oxidizing and acidic conditions. Under these conditions, AmberLite™ Anion Exchange Resins have proven to be tough, steady performers.
In chloride solutions PGMs form chloroanion complexes which are readily adsorbed on strong base anion exchangers such as AmberSep™ 21K XLT Resin. Interestingly, the PGMs are also strongly adsorbed on weakly basic anion exchange resins such as AmberLyst™ A21 Resin. Weakly basic anion exchangers are often effective in their conjugate acid forms (in acidic media) or in their free-base forms (neutral ligand-metal complexes). Elution of metal from the resin may require the use of a complexing agent such as alkaline citrate or acidic thiourea. In some cases, the best way to recover metal values from the resin is to thermally decompose the resin (fuming).
Additional information about the recovery of precious metals from acidic halogen leach solutions can be provided by contacting a DuPont expert.
DuPont offers a thiouronium-functionalized resin designated AmberSep™ 43600. The resin is a macroporous, uniform particle size resin which has good exchange kinetics and is highly selective for PGMs. It is a tough and rugged product for resin in pulp applications. Note that the thiouronium group is subject to base hydrolysis so the product should be used under acidic to neutral pH conditions. For alkaline applications, other products are more suitable.
If you have a commercial PGM recovery application, please contact us and include information about your particular PGM removal application.
NOTICE: If products, such as DOW™ XUS products, are described as “experimental” or “developmental”:
(1) product specifications may not be fully determined;
(2) analysis of hazards and caution in handling and use are required;
(3) there is greater potential for Dow to change specifications and/or discontinue production; and
(4) although Dow may from time to time provide samples of such products, Dow is not obligated to supply or otherwise commercialize such products for any use or application whatsoever.