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How does froth flotation separate copper minerals from gangue?
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copper processing
Molten copper being made into plates.
Froth flotation separates copper minerals from gangue by exploiting differences in the surface properties of minerals, specifically their wettability.12
The process involves the following steps:
- Preparation: The ore is finely ground to liberate copper minerals from waste material and mixed with water to form a slurry.1
- Chemical Conditioning: Specific reagents are added to the mixture to make the surfaces of the copper minerals hydrophobic (water-repelling), while the gangue minerals remain hydrophilic (water-attracting).32
- Aeration and Agitation: The slurry is agitated in a flotation cell, where mechanical or pneumatic devices introduce air bubbles.1
- Separation: Because the copper minerals are hydrophobic, they adhere to the rising air bubbles and are carried to the surface to form a mineral-rich froth. The hydrophilic gangue minerals do not attach to the bubbles and remain in the cell as tailings to be discarded.132
- Collection: The froth is skimmed from the surface to yield a copper concentrate, which is then dewatered and filtered for further processing.1