Smelting's a form of extractive metallurgy; its main use's to produce a metal from its ore. This includes iron extraction (for the production of steel) from iron ore, and copper extraction and other base metals from their ores. Smelting uses heat and a chemical reducing agent, commonly a fuel that's a source of carbon such as coke, or in earlier times charcoal, to change the oxidation state of the metal ore. The carbon or carbon monoxide derived from it removes oxygen from the ore to leave the… (More on Smelting)