Salt and potassium are combined to produce iodised salt, used when iodine is lacking in diet. It's absence cause goitre, the swelling of the thyroid gland.
Livestock as well as humans need salt, and this provided in the form of solid blocks, known as 'salt-licks'.
Salt is also crucial to the food industry. It is used in meat packing sausage-making and fish-curing both for seasoning and as a preservative. It is also used in the curing and preserving of hides and in the form of brine of brine for refrigeration purposes.
Salt is extensively used in the chemical industry; in the manufacture of baking soda, sodium bicarbonate; of caustic soda, sodium hydroxide; of hydrochloric acid, of chlorine etc. It is also used in soap-making, and in the manufacture of glaze and porcelain enamel. It also enters metallurgic processes as flu, a compound used to assist the fusing of metals.
Salt lowers the melting point of water, so in combination with grit, it is used for clearing roads of snow and ice. It is also used for water-softening by means of removing calcium and magnesium compounds from tap water.