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Which impurities are oxidized during the fire refining of copper?
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copper processing
Molten copper being made into plates.
During the fire refining of blister copper, the process relies on the fact that various impurities have a stronger affinity for oxygen than copper does. By blowing compressed air into the molten copper bath, the following impurities are oxidized:1
- Zinc
- Tin
- Iron
- Lead
- Arsenic
- Antimony
- Sulfur
Among these, sulfur is removed as sulfur dioxide gas, while the other listed impurities form an oxide slag that is skimmed off the surface of the molten metal.1