Separating Platinum, Palladium, Iridium, Osmium, Rhodium and Ruthenium

Separating Platinum, Palladium, Iridium, Osmium, Rhodium and Ruthenium 

Methods for separating the different platinum metals are comphcated and are partly kept secret. The traditional method with dissolution in aqua regia is still used, in which platinum, palladium and gold are dissolved while the other platinum metals stay undissolved. Gold is obtained from the solution by reduction, platinum is precipitated as ammonium hexachloroplatinate and palladium as a dichlorodiammine compound. The residue after the first aqua regia treatment contains iridium, rhodium, osmium and ruthenium. They are separated in several complicated steps. 

The Hquid-liquid extraction technique is increasingly used for separation. A solution containing the PGMs passes an organic solution in a counter-flow process. For each metal a specific extractant complexes the ions and transfers them into the organic phase. This phase is then stripped and the metal in question is obtained. Additional distillations are used for osmium and ruthenium as well as a final ion-exchange procedure for rhodium. 

Quantities of Piatinum, Palladium and other PCMs Produced 

World production in 2000 of PGMs, by country, is shown in Table 32.5. Table 32.5 Quantities of metals produced in the year 2000 

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