Salt is all around us. Underground and on the earths surface in the dried up residues of ancient seas. Some salt has even arrived from outer space in meteors. But our biggest source of salt is in our seas and oceans. With an average of 26 million tonnes per cubic kilometre, sea water offers a seemingly inexhaustible supply which if extracted, would cover the worlds total land mass to a depth of 35 metres.
There are many different types and grades of salt and a number of different methods of production. White salt is produced by evaporating solution-mined brine in pressure vessels. The rock salt we use for gritting roads comes from mining ancient deposits. In some countries the natural energy of the sun is used to evaporate brine produced from sea water.
