Extracting gold
Gold (Au) may be described as a metal with an even longer history with humankind than iron. There is evidence that gold has been used to make coins, images, inscriptions and much else.
There is no compound to break
Lying low in the activity series, this metal does not react with any of the active constituents of the atmosphere under ordinary conditions. For that very reason gold occurs naturally as the free element itself. It is, however, mixed with other impurities.
Two physical methods
1 — washing the ore
Washing the gold-bearing ore removes some quantity of the impurities.
2 — separating in a stream of water
When it is finely ground and mixed into a flowing stream of water, it is the gold that travels to the bottom first — because the density of gold is very high.
Various methods are then used to purify further the metal separated out by such physical means.
For extra knowledge
Solvents that dissolve gold have been found in modern times. When metal containing impurities is dissolved in these solvents, only the gold dissolves. The gold dissolved in the solvent is then recovered by displacing it with another metal.
Iron and gold compared
Iron — occurs as a compound, so it needs a furnace and a reducing agent.
Gold — occurs as the free metal, so it needs only separating.