Copper production process from ore to cathode

1. Mining

• Copper ores are extracted from open-pit or underground mines.

• The most common copper-bearing minerals are chalcopyrite (CuFeS₂), bornite (Cu₅FeS₄), and malachite (Cu₂CO₃(OH)₂).

• Ore grades are typically low, often less than 1% copper

 

2. Crushing and Grinding

• The mined ore is transported to a concentrator.

• It is crushed and then ground into fine particles to liberate copper minerals from the surrounding rock.

 

3. Concentration (Flotation)

• The ground ore undergoes froth flotation.

• Reagents are added to make copper minerals hydrophobic.

• Air bubbles carry copper-rich particles to the surface, forming a froth that is skimmed off.

• The result is copper concentrate, typically containing 20–30% Cu.

 

4. Smelting

• Concentrate is dried and fed into a smelter (flash furnace or reverberatory furnace).

• At high temperatures, sulfides are oxidized, producing matte (a mixture of copper, iron sulfide, and other impurities).

• Slag (waste material) is removed.

• The matte usually contains 50–70% Cu.

 

5. Converting

• The matte is transferred to a converter furnace.

• Air or oxygen is blown through to oxidize iron and sulfur.

• The product is blister copper, about 98–99% pure, with a blistered surface due to escaping sulfur dioxide gas.

 

6. Fire Refining

• Blister copper is further refined in a refining furnace.

• Impurities are removed, producing anode copper (~99% purity).

• Large copper plates (anodes) are cast for electrorefining

 

7. Electrorefining

• Anodes are suspended in tanks containing an acidic copper sulfate solution.

• A thin sheet of pure copper serves as the cathode.

• When electric current passes through:

  • Copper dissolves from the anode into solution.

  • Pure copper plates onto the cathode.

  • Impurities either fall off as anode slime (containing precious metals) or remain in solution

 

8. Final Product – Copper Cathodes

• The cathodes are 99.99% pure copper.

• They are removed, washed, and packaged for sale.

• Cathodes are the standard form traded globally (LME Grade A copper).

• They serve as feedstock for wire, rods, tubes, sheets, and alloys.