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How are gold and silver separated after the Parkes process?

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Metallurgy — lead processing A zinc-lead blast furnace and lead-splash condenser. This technology is utilized mainly for producing zinc while managing both lead and zinc from raw materials, a technique that was highly influential in 20th-century smelting.

After the Parkes process removes gold and silver from lead bullion as a zinc-rich crust, the precious metals must be separated from the zinc and then from each other.12

First, the zinc is recovered from the skimmed crust through vacuum retorting. The remaining lead-gold-silver residue undergoes cupellation, where it is heated to approximately 800 °C (1,450 °F) under strongly oxidizing conditions. During this stage, the lead oxidizes and is removed, leaving behind a gold and silver alloy.2

To separate the gold and silver from this alloy, the mixture is refined using the Moebius or Thum Balbach process. Finally, any remaining residue from this silver refining stage is treated by affination or parting to concentrate the gold, which is then purified using the Wohlwill process.2