Extracting metals

Your phone, bike, wires and buildings all depend on metals, but you usually can’t pull those metals straight out of the ground ready to use. In nature, most of them are locked inside compounds or mixed with unwanted rocky material, so you need a way to separate the useful part from everything else.

Extraction: When you take a wanted substance out of a mixture or compound and end up with something much purer, that process is called extraction.

You’ll meet a few key words here. An ore is a rock worth processing because it contains enough of a metal compound to make getting the metal financially sensible. A mineral is a naturally formed substance in Earth’s crust, often a compound rather than a pure element. The useless material mixed in with the valuable part is called gangue.

Ore: An ore is rock that contains a metal substance in high enough amounts for extraction to be worthwhile.

Mineral: A mineral is a naturally occurring substance in the ground, usually made of elements chemically joined together.

Gangue: The unwanted rocky material that comes with an ore during mining is known as gangue.

You need extraction because modern life runs on purified materials. Manufacturing, transport, construction, electronics and medicine all rely on substances that have been separated and cleaned up before use.

A good example is iron, which is commonly found as iron(III) oxide, Fe₂O₃, in ores such as hematite. You extract and purify it so it can be turned into iron and steel for things like cars, bridges and building frames. Aluminium is another one: it comes from aluminium oxide, Al₂O₃, in bauxite, and you do not find aluminium metal sitting around naturally because it reacts so readily that it forms stable compounds instead.