Three extraction routes
The method used for extraction varies with the reactivity of the metal — there are three routes.
1 — electrolysis (top)
Extracting reactive metals such as sodium (Na) and potassium (K) requires electrolysis, a powerful method of extraction. The molten chlorides of these metals are electrolysed and the metal is obtained.
(Discussed in grade 11.)
2 — reduction (middle)
For metals of moderate reactivity such as iron (Fe), tin (Sn), zinc (Zn) and lead (Pb), the method used is reduction by other compounds.
3 — physical methods (bottom)
Metals of low reactivity such as silver (Ag), gold (Au) and platinum (Pt) occur as the free metal mixed with other things, so they are extracted by physical methods of separating mixtures.
The rule in one sentence
Metals high in the activity series are extracted by powerful methods such as electrolysis. Metals low in the series are extracted by easier, physical methods.
Over the following pages we look at the middle route (iron) and the bottom route (gold) in detail.