Ore to metal
Methods of extracting metals
The Earth’s crust contains metals and metal compounds such as gold, iron oxide and aluminium oxide, but when found in the Earth these are often mixed with other substances. To be useful, the metals have to be extracted from whatever they are mixed with. A metal ore is a rock containing a metal, or a metal compound, in a high enough concentration to make it economic to extract the metal.
The method used to extract metals from the ore in which they are found depends on their reactivity. For example, reactive metals such as aluminium are extracted by electrolysis, while a less-reactive metal such as iron may be extracted by reduction with carbon or carbon monoxide.
Thus the method of extraction of a metal from its ore depends on the metal’s position in the reactivity series:
Note that gold, because it is so unreactive, is found as the native metal and not as a compound, so it does not need to be chemically separated. However, chemical reactions may be needed to remove other elements that might contaminate the metal.