Sodium in Our Time

The abundance of sodium chloride in the oceans is well known but common salt is also found in  

Chile saltpeter is composed of sodium nitrate, NaNOj. It is found in South America, particularly in Chile. It occurs in beds that vary in thickness from 15 cm to 3.6 m. These beds, called caHche, are interspersed with deposits of gypsum, sodium chloride and other salts, and sand. The caliche is quarried and purified in Chile before the product is ejcported. It is used extensively as a fertiHzer but not in the manufacture of gunpowder because of its deliquescence. 

Very much of the soda used today, especially in the USA, is obtained from natural sources, such as the mineral trona Na COj NaHCOj 2H2O, found in vast deposits in western Wyoming and in dry lakes in California. 

Sodium and most sodium compounds are manufactured, directly or indirectly, from the earth s giant supply of sodium chloride. 

Sodium compounds are among the most used within the chemical industry. Aimu-ally about 30 million tonnes of sodium hydroxide (caustic soda) NaOH are manufactured in the world. The bulk is produced by electrolysis of a common salt solution, with chlorine and hydrogen as important by-products. This process is described in Chapter 50 Halogens. 

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