How did charcoal help early people smelt copper?

Early people used charcoal as a critical component in the smelting process to recover copper from its oxide minerals.1

When heated in a charcoal bed at temperatures exceeding 700 °C (1,300 °F), the charcoal acts as a reducing agent. Specifically, the combustion of charcoal produces carbon monoxide, which becomes increasingly stable at these high temperatures. This carbon monoxide reacts with the copper-bearing minerals, effectively stripping away the oxygen and reducing the ore to metallic copper.12

By providing both the necessary high heat and the chemical environment required for reduction, charcoal enabled early metallurgists to successfully extract the metal from its ore.12