Extracting Metals

The metals need to be extracted from their ores in a process known as 'smelting'. Depending on how reactive the metal is, this will be done in a different way. The elements can be placed into order of reactivity:

Potassium		K		Most Reactive
Sodium		Na
Lithium		Li
Calcium		Ca
Magnesium		Mg
Aluminium		Al
Titanium		Ti
Carbon		C
Zinc		Zn
Iron		Fe
Tin		Sn
Lead		Pb
Hydrogen		H
Copper		Cu
Silver		Ag
Gold		Au
Platinum		Pt		Least Reactive

Unreactive metals such as Platinum and are found in the Earth as the metal itself (native) but most metals are found as compounds that require chemical reactions to extract the metal.

Metals that are reactive than carbon can be extracted using heating the ores, using carbon as a reducing agent eg:iron.

Metals that are reactive than carbon have to be extracted using electroysis eg: Aluminium.

Aluminium and Titanium useful metals because of their properties. They have a low density allowing objects to be made which have little weight - very useful in the avation and space industry. They are also resistance to corrosion dispite being reactive metals. This is due to an (unreactive) oxidation layer forming on any exposed metal. This layer remains attached to the metal, protecting it, unlike rust on iron.

It is realatively cheap to extract metals from their oxides by reduction with carbon. This cannot be done for these metals which is means the metals are expensive to produce. This is because current methods of extraction involve:

• many stages to the processes
• and much energy is needed.

Aluminium smelting plants have been set up near specially built Hydroelectric Power Station to supply the electricity for example The Manapouri Power Station, New Zealand.