Two techniques that are used in metallurgy: Electrometallurgy and hydrometallurgy involve the extraction of metals from ores, the refinement of them, the purification of them, and the preparation of them for practical applications.

While some metals, such as gold and silver, can be found uncombined with other elements in nature, most metals occur as minerals; that is, in chemical combination with nonmetallic elements.

When the combination is such that the extraction of a metal from a mineral is economically attractive, the combination is called an ore. The technique of producing metals from ore is called "process metallurgy" or "extraction metallurgy".