Understanding Synergistic Solvent Extractants for Rhodium

Solvent extraction is a technology used to recycle platinum group metals (PGMs), which are classed as critical materials because of their importance in UK manufacturing. It is one of the more sustainable and efficient processes in PGM recycling, and can be used commercially to separate all PGMs except rhodium. To purify rhodium, most PGM recyclers depend on unsustainable and energy intensive precipitation/calcination processes which do not allow for ligand recycling. Recent work in the Love and Morrison labs discovered that a combination of two simple extractants, neither of which will extract rhodium on its own, can result in the synergistic recovery of rhodium by solvent extraction.