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REFINING >      

Proceeds from AuRIC's extraction circuits, and doré bars submitted by clients, are refined by use of the following circuits:


  • Gas injection furnace
  • Cupellation


  • Thum cells
  • Moebius cells
  • Wohlwill cells

Solvent extraction refining for platinum group metals
AuRIC uses separate solvent extraction circuits for platinum, palladium, rhodium and iridium. Proprietary technologies are employed to produce the optimal yield for a production process.




Cupellation is a process used to separate noble metals such as gold or silver from base metals such as lead. It is often used to assay gold in order to test its purity. Sometimes cupellation is called "fire assaying." In this process, an alloy consisting of both noble and base metals is placed in a crucible. This mixture is then melted and allowed to freeze. When solidified, a button consisting of precious metals and lead can be removed from the slag of metal oxides and other materials. When assaying ores this slag layer can be quite massive, but when assaying karat gold virtually non-existant. After cooling, the metals are placed in a special pot made of bone ash or clay called a cupel . Under high heat, lead turns to lead oxide, which is absorbed by the cupel or lost to the atmosphere. At the end of the cupellation process, a button of pure gold and silver remains in the bottom of the cupel. The button is then placed in nitric acid to dissolve the silver, and the remaining pure (24k) gold weighed to determine the gold content present in the original starting material.

Electrowinning and electrorefining involve the recovery and purification of metals using electrodeposition of metals at the cathode, and either metal dissolution or a competing oxidation reaction at the anode.

Information used from Wikipedia.com for cupellation and electrometallurgy.

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