How are platinum palladium and rhodium recovered from used catalytic converters?

The recovery of platinum, palladium, and rhodium from used catalytic converters is a specialized process designed to isolate these valuable materials from their substrate.1

The recovery process involves the following steps:

• Smelting: The catalyst is melted at very high temperatures alongside iron or copper. This process fuses the catalyst substrate and allows the platinum-group metals to dissolve into the molten metal.1
• Leaching: The resulting alloy of copper or iron and precious metals undergoes a leaching process. This dissolves the base metal (iron or copper), leaving behind a concentrated mixture of platinum, palladium, and rhodium.1
• Refining: The remaining concentrate is then processed using complex chemical separation techniques to isolate and refine the materials into pure metals.12

Once separated, these metals are typically recovered as a finely divided metallic powder, which can then be converted into a massive metal form through techniques such as electron-beam melting or induction melting.3