How is table salt generally produced?
Solution mining of salt or halite deposits is just like it sounds. Once the salt deposit is located, fresh and recycled water is injected through a well (or wells) drilled into an underground salt bed or salt dome, usually between 150 and 1,500 meters (500 to 5000 feet) deep. Dissolution of the salt forms a void or cavern in the salt deposit. Salt brine is withdrawn from the cavern and transported by pipeline to an onsite evaporating plant to make dry salt. Table salt is typical of the fine, granulated-evaporated salt produced in vacuum pan evaporators. Virtually all food grade salt sold or used in the United States is produced by vacuum evaporation of brine. Prior to mechanical evaporation, the brine may be treated to remove minerals that can cause scaling in the evaporators and adversely affect salt purity. Chemical treatment of the brine, followed by settling, reduces levels of dissolved calcium, magnesium and sulfate. Sulfuric acid treatment or chlorination may be used to remove hy
