Salt
"Salt" refers to sodium chloride, a chemical compound made up of equal parts sodium and chlorine atoms. It is a white crystalline substance with a characteristic salty taste and is commonly used as a seasoning for food to enhance flavor. Sodium chloride is also used for preserving food, as a de-icing agent, and in various industrial processes.
Salt, or sodium chloride (NaCl), is a naturally occurring mineral made up of two elements, sodium and chlorine, and is typically found in underground salt deposits or seawater. In food it serves two roles at once — as a seasoning and as a preservative — while as a nutrient the human body needs it in small amounts to maintain fluid balance and transmit nerve impulses. Beyond food, salt is used in a variety of industrial processes, including chemical manufacturing, water treatment, the production of paper and textiles, and the making of certain types of glass and ceramics.
The food industry is one of the primary drivers of the salt market. Salt is used in various food products, including processed meats, snacks and baked goods, and is also commonly used in restaurants and households worldwide. Several distinct product types serve these markets, including table salt, sea salt, Himalayan salt and kosher salt. The market is highly competitive, with significant global players including Cargill, K+S AG, China National Salt Industry Corporation, Tata Chemicals and Compass Minerals.
Commercial production follows four principal routes. Solar evaporation uses large shallow ponds or salt pans in which seawater evaporates under the sun's heat, leaving salt crystals that are harvested and washed to remove impurities. Mining extracts salt from underground deposits and is typically used for rock salt, found in large deposits in certain parts of the world. Solution mining injects water into underground salt deposits to create a brine solution, which is pumped to the surface and processed to extract the salt. Desalination, used where freshwater is scarce, yields salt as a byproduct of removing salt and other minerals from seawater to make it drinkable.
Whichever route is used, the salt is then processed and refined to remove impurities and to create the various grades required by different end uses — table salt, industrial salt and road salt. For a food plant, it is this refining and grading stage that determines whether the material is fit for direct food use, so it deserves the same design attention as any other product-contact process step.