De-icing and freezing-point depression By
depressing the freezing point of water, calcium chloride is used to prevent ice formation and is used to
de-ice. This application consumes the greatest amount of calcium chloride. Calcium chloride is relatively harmless to plants and soil. As a de-icing agent, it is much more effective at lower temperatures than
sodium chloride. When distributed for this use, it usually takes the form of small, white spheres a few millimeters in diameter, called
prills. Solutions of calcium chloride can prevent freezing at temperatures as low as , making it ideal for filling agricultural implement tires as a liquid ballast, aiding traction in cold climates. It is also used in domestic and industrial chemical air
dehumidifiers.
Road surfacing , giving it a wet appearance even in dry weather. The second largest application of calcium chloride exploits its
hygroscopic nature and the tackiness of its hydrates; calcium chloride is highly hygroscopic and its hydration is an
exothermic process. A concentrated solution keeps a liquid layer on the surface of
dirt roads, which suppresses the formation of dust. It keeps the finer dust particles on the road, providing a cushioning layer. If these are allowed to blow away, the large aggregate begins to shift around and the road breaks down. Using calcium chloride reduces the need for
grading by as much as 50% and the need for fill-in materials as much as 80%.
Food In the food industry, calcium chloride is frequently employed as a firming agent in canned vegetables, particularly for canned tomatoes and cucumber pickles. It is also used in firming
soybean curds into
tofu and in producing a
caviar substitute from vegetable or fruit juices. It is also used to enhance the texture of various other products, such as whole apples, whole hot peppers, whole and sliced strawberries, diced tomatoes, and whole peaches. The firming effect of calcium chloride can be attributed to several mechanisms: In
brewing beer, calcium chloride is sometimes used to correct mineral deficiencies in the brewing water. It affects flavor and chemical reactions during the brewing process, and can also affect yeast function during fermentation. In
cheesemaking, calcium chloride is sometimes added to processed (pasteurized/homogenized) milk to restore the natural balance between calcium and protein in
casein. It is added before the coagulant. Calcium chloride is also commonly used as an
electrolyte in
sports drinks and other beverages; as a
food additive used in conjunction with other inorganic salts it adds taste to
bottled water. The average intake of calcium chloride as food additives has been estimated to be . Calcium chloride is permitted as a food additive in the
European Union for use as a
sequestrant and
firming agent with the
E number E509. It is considered as
generally recognized as safe (GRAS) by the U.S. Food and Drug Administration. Its use in
organic crop production is generally prohibited under the US
National Organic Program. Calcium chloride has a very salty taste and can cause mouth and throat irritation at high concentrations, so it is typically not the first choice for long-term oral supplementation (as a
calcium supplement). Calcium chloride is highly soluble in water and efficiently absorbed from the intestine. The dissolution of calcium chloride in water is exothermic; releasing energy as heat. If undissolved calcium chloride is ingested, this can lead to burns in the mouth, throat,
esophagus, and stomach. Ingestion of large amounts of undissolved calcium chloride has been reported to result in burns, and rarely, necrosis of the stomach. The extremely
salty taste of calcium chloride is used to flavor
pickles without increasing the food's
sodium content. Calcium chloride is used to prevent
cork spot and
bitter pit on apples by spraying on the tree during the late growing season.
Laboratory and related drying operations Drying tubes are frequently packed with calcium chloride.
Kelp is dried with calcium chloride for use in producing
sodium carbonate. Anhydrous calcium chloride has been approved by the FDA as a packaging aid to ensure dryness (CPG 7117.02). The hydrated salt can be dried for re-use but will dissolve in its own water of hydration if heated quickly and form a hard amalgamated solid when cooled.
Metal reduction flux Similarly, is used as a flux and
electrolyte in the
FFC Cambridge electrolysis process for
titanium production, where it ensures the proper exchange of calcium and oxygen ions between the electrodes.
Medical use Calcium chloride
infusions may be used as an
intravenous therapy to prevent
hypocalcemia. Calcium chloride is a highly soluble calcium salt. Calcium chloride when taken orally completely dissociates into calcium ions () in the gastrointestinal tract, resulting in readily bioavailable calcium. The high concentration of calcium ions facilitates efficient absorption in the small intestine. When tasted, calcium chloride exhibits a distinctive bitter flavor alongside its salty taste. The bitterness is attributable to the calcium ions and their interaction with human taste receptors: certain members of the
TAS2R family of bitter taste receptors respond to calcium ions; the bitter perception of calcium is thought to be a protective mechanism to avoid ingestion of toxic substances, as many poisonous compounds taste bitter. While chloride ions () primarily contribute to saltiness, at higher concentrations, they can enhance the bitter sensation. The combination of calcium and chloride ions intensifies the overall bitterness. At lower concentrations, calcium chloride may taste predominantly salty. The salty taste arises from the electrolyte nature of the compound, similar to sodium chloride (table salt). As the concentration increases, the bitter taste becomes more pronounced: the increased presence of calcium ions enhances the activation of bitterness receptors.
Other applications Calcium chloride is used in concrete mixes to
accelerate the initial setting, but chloride ions lead to corrosion of steel
rebar, so it should not be used in
reinforced concrete. The anhydrous form of calcium chloride may also be used for this purpose and can provide a measure of the moisture in concrete. Calcium chloride is included as an additive in plastics and in
fire extinguishers, in
blast furnaces as an additive to control scaffolding (clumping and adhesion of materials that prevent the furnace charge from descending), and in
fabric softener as a thinner. The exothermic dissolution of calcium chloride is used in
self-heating cans and
heating pads. Calcium chloride is used as a water hardener in the maintenance of
hot tub water, as insufficiently hard water can lead to corrosion and foaming. In the
oil industry, calcium chloride is used to increase the density of solids-free
brines. It is also used to provide inhibition of swelling clays in the water phase of invert
emulsion drilling fluids. Calcium chloride () acts as
flux material, decreasing the melting point, in the Davy process for the industrial production of sodium metal through the
electrolysis of molten . Calcium chloride is also used in the production of
activated charcoal. Calcium chloride can be used to precipitate
fluoride ions from water as insoluble . Calcium chloride is also an ingredient used in ceramic
slipware. It suspends clay particles so that they float within the solution, making it easier to use in a variety of slipcasting techniques. For watering plants to use as a fertilizer, a moderate concentration of calcium chloride is used to avoid potential toxicity: solutions are generally effective and safe for most plants. That is of anhydrous calcium chloride () per liter of water or of calcium chloride hexahydrate () per liter of water. Calcium chloride dihydrate (20 percent by weight) dissolved in
ethanol (95 percent ABV) has been used as a
sterilant for male animals. The solution is injected into the testes of the animal. Within one month,
necrosis of testicular tissue results in sterilization.
Cocaine producers in
Colombia import tons of calcium chloride to recover solvents that are on the
INCB Red List and are more tightly controlled. ==Hazards==