The ore dressing (also known as mineral processing) of copper ore involves several stages to extract and concentrate copper minerals from the raw ore. Here’s a step-by-step breakdown of the process:
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1. Crushing
– Objective: Reduce large chunks of copper ore into smaller particles.
– Process:
– Primary crushing (jaw crusher or gyratory crusher).
– Secondary crushing (cone crusher or impact crusher).
– Tertiary crushing (if needed) to achieve finer particles (~5–10 mm).
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2. Grinding
– Objective: Further reduce particle size to liberate copper minerals from gangue (waste rock).
– Process:
– Ball mills or rod mills grind crushed ore into fine powder (~0.074–0.3 mm).
– Produces slurry mixed with water for flotation.
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3. Froth Flotation (Key Step for Sulfide Ores)
– Objective: Separate copper minerals (chalcopyrite, bornite, chalcocite) from waste.
– Process:
– Chemicals added:
– Collectors (e.g., xanthates) attach to copper minerals.
– Frothers (e.g., pine oil) create stable froth.
– Depressants (e.g., lime) suppress unwanted minerals (pyrite, silica).
– Air bubbles lift copper-rich froth to the surface.
– Froth is skimmed off as copper concentrate (~20–30% Cu).
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4. Dewatering & Thickening
– Objective: Remove excess water from flotation concentrate.
– Process:
– Thickeners settle solids.
– Filters (vacuum or pressure filters) produce damp concentrate (~8–15% moisture).
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5. Smelting & Refining
*(Not part of ore dressing but follows it)*
The concentrate undergoes:
– Smelting → Converted into blister copper (~98% Cu).
– Electrorefining → Produces pure cathode copper (>99.99% Cu).
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Alternative Processes for Oxide Ores
If the ore is oxidized (malachite, azurite, cuprite), leaching methods are used instead of flotation:
1. Heap Leaching: Ore stacked and sprayed with acid (H₂SO₄) to dissolve copper.
2. Solvent Extraction-Electrowinning
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