How is copper commercially extracted from ore?

The commercial extraction of copper from ore is a multi-stage process typically involving three major phases: mineral processing, extraction (via smelting or leaching), and refining.1

1. Mineral Processing

The process begins by crushing and grinding the ore to liberate copper minerals from waste rock, known as gangue. For sulfide ores, this is followed by selective flotation, where the ground ore is mixed with water and reagents and agitated with air bubbles. The copper minerals attach to the bubbles and rise to the surface as a froth, which is collected as a copper concentrate.2

2. Extraction

• Smelting (Pyrometallurgy): The concentrate is heated to high temperatures to separate the copper from impurities like iron and sulfur. Modern flash or bath smelting uses oxygen-enriched air to produce a molten matte (a copper-iron sulfide) and slag. The matte is then processed in a converter, where air is blown through the molten bath to remove remaining iron and sulfur, resulting in "blister" copper.134
• Leaching (Hydrometallurgy): This method involves dissolving copper from the ore using an aqueous solvent, such as sulfuric acid. The resulting solution is purified and concentrated, often through solvent extraction, before the copper is recovered.35

3. Refining

The final step removes remaining impurities to achieve 99.99 percent purity. This is typically accomplished through electrolytic refining, where copper is dissolved from an anode and deposited in a purer form onto a cathode. This process also allows for the recovery of valuable by-products like gold and silver.13