Rock salt has many uses. The most important uses in the United States are described below. Highway Deicing The leading use of rock salt in the United States is highway deicing. In calendar year 2020, an estimated 43% of rock salt consumption was used for this purpose. The amount of highway salt consumed varies significantly…

The United States Geological Survey Mineral Commodity Summaries for 2021 reports that “almost every country in the world has salt deposits or solar evaporation operations of various sizes”. Eight countries (China, the United States, India, Germany, Australia, Canada, Chile, and Mexico) each produced at least 9 million tons of salt in calendar year 2020. The accompanying pie chart illustrates their relative importance. Much of…

People have been producing solar salt from ocean water for thousands of years. Solar salt can be produced in parts of the world where evaporation rates significantly exceed precipitation rates. The name “solar” means that the sun acts as a heat source to evaporate ocean water (or brine brought up from the subsurface), leaving behind…

Vacuum pan salt is produced in large enclosed tanks known as vacuum pans or vacuum salt crystallizers. The tanks are filled with brine, which is heated by injecting steam into the tank. The steam heats the brine and causes it to boil. As the brine boils it produces additional steam, which is fed into a…

Solution mining of salt is done by injecting hot water under pressure down a well into a subsurface layer of rock salt. That same water is then withdrawn up to the surface through a nearby recovery well. While the water travels through the layer of rock salt – from the injection well to the recovery…

Companies interested in developing a salt resource located hundreds to thousands of feet below the surface usually drill numerous wells down to and through the salt layer. They drill to learn the thickness of the salt and what types of rocks enclose it. They also obtain core samples of the salt (see accompanying photo) that…

In 2020 about 39 million tons of salt were produced in the United States. There are four important categories of rock salt production: The United States consumes more salt than it produces. To satisfy demand in 2020, about 16 million tons of salt were imported. The amount of imported salt has been increasing in the…

If you visit a store where cooking supplies and spices are sold, you might see salt in a wide variety of colors and textures being sold. Many of these “specialty salts” are natural materials. Others have been crystallized by people or processed to make a distinctive product. Salt is sometimes crystallized to produce flake-shaped grains…

Pure rock salt under bright illumination will range in color between colorless and white. Colorless salt is usually the most pure because the most common cause of color is impurities. White salt often contains minute gas-filled or fluid-filled cavities. Specimens or zones of other colors can be caused by mineral grains included in the salt,…

Deposits of rock salt thick enough for underground mining or solution mining form under a rare set of geological conditions. The deposits shown on the accompanying map formed during times of high sea level, when shallow seas spread over extensive areas of continental crust. To deposit a thick layer of salt, long periods of sea…