Sodium

Sodium chloride is the most widely used sodium compounds. Due to its availability and minimal amount of preparation, there is no need for it to be manufactured commercially. A large fraction of the sodium chloride used commercially goes to the production of other sodium compounds, such as sodium hydroxide, sodium carbonate, sodium sulfate, and sodium metal itself.

For many centuries, sodium chloride has also been used in the food industry, primarily as a preservative and to enhance the flavors of foods. In fact, many seemingly distinct methods of food preservation, such as curing, pickling, corning, and salting differ only in the way in which salt is used to preserve the food. Scientists are uncertain as to the mechanism by which salting preserves foods, but they believe that some combination of dehydration and high salinity create conditions unfavorable to the survival of pathogens.

Sodium hydroxide and sodium carbonate traditionally rank among the top 25 chemicals in terms of volume produced in the United States. In 1988, for example, the first of these was the seventh most widely produced chemical, with a production of 24.0 billion lb (10.9 billion kg), and the latter ranked number eleven, with a production of 19.1 billion lb (8.65 billion kg).

The number one use of sodium hydroxide is in the manufacture of a large number of other chemical products, the most important of which are cellulose products (including cellulose film) and rayon. Soap manufacture, petroleum refining, and pulp and paper production account for about one tenth of all sodium hydroxide use.

Two industries account for about one third each of all the sodium carbonate use in the United States. One of these is glass-making and the other is the production of soap, detergents, and other cleansing agents. Paper and pulp production, the manufacture of textiles, and petroleum production are other important users of sodium carbonate.

Ranking number 45 on the list of the top 50 chemicals produced in the United States in 1988 was sodium sulfate. For many years, the largest fraction of sodium sulfate (also known as salt cake) was used in the production of kraft paper and paperboard. In recent years, an increasing amount of the chemical has gone to the manufacture of glass and detergents.

Just behind sodium sulfate on the list of top 50 chemicals in 1988 was sodium silicate, also known as water glass. Water glass is used as a catalyst, in the production of soaps and detergents, in the manufacture of adhesives, in the treatment of water, and in the bleaching and sizing of textiles.