How is silver recovered from copper concentrates?

Silver is recovered from copper concentrates through a multi-stage process involving smelting, electrolytic refining, and further purification.1

• Smelting and Converting: The process begins by smelting and converting copper sulfide concentrates to produce blister copper, which retains 97 to 99 percent of the original silver.1
• Electrolytic Refining: During the electrolytic refining of this copper, silver and other precious metals do not dissolve but instead settle at the bottom of the tank as insoluble impurities known as slimes. These slimes contain a significantly higher concentration of silver than the original ore.12
• Dore Production: The slimes are smelted in a furnace to oxidize base metals, leaving behind a mixture of silver, gold, and platinum-group metals called doré.1
• Final Electrolysis: The doré is cast into anodes and subjected to further electrorefining using either the Moebius (vertical electrodes) or Thum Balbach (horizontal electrodes) systems in a silver-copper nitrate solution. This final step typically yields silver with a purity of 99.9 percent or higher.1