How did early metalworkers extract copper from ore?

Early metalworkers initially utilized native copper found in its free metallic state, which they shaped through cold hammering. As surface deposits were depleted, they developed techniques to extract copper from copper-bearing ores.123

The extraction process evolved through several key stages:

• Smelting: Early metallurgists discovered that heating copper-bearing minerals—particularly oxide minerals like malachite—in a charcoal bed at temperatures exceeding 700 °C (1,300 °F) reduced the ore to metal. Carbon monoxide, produced within the charcoal bed, acted as the necessary reducing agent.12
• Fluxing: To effectively separate the molten copper from associated minerals, workers introduced iron oxide as a flux.1
• Roasting: As surface deposits were exhausted, miners began extracting deeper copper sulfide ores (such as chalcopyrite). These ores required an initial roasting process to remove sulfur as sulfur dioxide and convert the material into copper oxide before it could be smelted.34

These advancements in smelting and pyrotechnology marked the transition into the Copper Age and the birth of metallurgy.12