| abstract |
A process for mutual separation of platinum group metals (PGM) from a material containing impurities comprising a first step 1 where the material is leached in the presence of an oxidant while being suspended in hydrochloric acid to prepare a leach liquor containing the PGM, a second step 2 where impurities are solvent extracted with an ether, a third step 3 where palladium is solvent extracted with an alkyl sulphide, a fourth step 4 where impurities are solvent extracted, a fifth step 5 where the solution is oxidised to precipitate iridium, ruthenium and rhodium leaving an aqueous solution of platinum, a sixth step 6 where the precipitate is leached in the presence of an oxidant in an alkaline solution to leave a residue containing iridium and rhodium and a leach liquor containing ruthenium, a seventh step 7 where the residue is dissolved in hydrochloric acid and solvent extracted with tributyl phosphate to extract iridium. |