Because it is strongly hygroscopic, air or other gases may be channeled through a column of calcium chloride to remove moisture. In particular, calcium chloride is usually used to pack drying tubes to exclude atmospheric moisture from a reaction set-up while allowing gases to escape. It can also be added to liquids to remove suspended or dissolved water. The dissolving process is highly exothermic and rapidly produces temperatures of around 60 °C (140 °F). In this capacity, it is known as a drying agent or desiccant. It is converted to a brine as it absorbs the water or water vapor from the substance to be dried:
Aided by the intense heat evolved during its dissolution, calcium chloride is also used as an ice-melting compound. Unlike the more-common sodium chloride (rock salt or halite), it is relatively harmless to plants and soil; however, recent observations in Washington state suggest it may be particularly harsh on roadside evergreen trees. It is also more effective at lower temperatures than sodium chloride. When distributed for this use, it usually takes the form of small white balls a few millimetres in diameter, called prills (see picture at top of page).
Used for its hygroscopic property, it can be applied to keep a liquid layer on the surface of the roadway, which holds dust down. It is used in concrete mixes to help speed up the initial setting, however chloride ion leads to corrosion of steel rebar, so it should not be used in reinforced concrete.
Aqueous calcium chloride (in solution with water) lowers the freezing point as low as -52°C (-62°F), making it ideal for filling agricultural implement tires as a liquid ballast, aiding traction in cold climates.
Other industrial applications include use as an additive in plastics, as a drainage aid for wastewater treatment, as an additive in fire extinguishers, as an additive in control scaffolding in blast furnaces, and as a thinner in fabric softener.
North American consumption in 2002 was 1,687,000 tons (3.7 billion pounds). A Dow Chemical Company manufacturing facility in Michigan, houses about 35% of the total U.S. production capacity for calcium chloride.
Calcium chloride is commonly used as an electrolyte and has an extremely salty taste, as found in sports drinks and other beverages such as Smartwater and Nestle bottled water. It can also be used as a preservative to maintain firmness in canned vegetables or in higher concentrations in pickles to give a salty taste while not increasing the food's sodium content. It is even found in snack foods, including Cadbury Caramilk chocolate bars (purpose unknown).
It can be used to make a caviar substitute from vegetable or fruit juices or added to processed milk to restore the natural balance between calcium and protein for the purposes of making cheese such as brie and stilton. Calcium chloride's exothermic properties are exploited in many 'self heating' food products where it is activated (mixed) with water to start the heating process, providing a non-explosive, dry fuel that is easily activated.
In brewing beers (esp. ales and bitters), calcium chloride is sometimes used to correct mineral deficiencies in the brewing water (calcium is important for enzyme function during the mash, for kettle protein coagulation (the "hot break") and yeast metabolism) and adds permanent hardness to the water. The chloride ions enhance flavour and give a perception of sweetness and fuller flavour, whereas the sulfate ions in Gypsum, which is also used to add calcium ions to brewing water, tend to impart a drier, crisper flavour with more bitterness.
It can help to protect the myocardium from dangerously-high levels of serum potassium in hyperkalemia. Calcium chloride can be used to quickly treat Calcium Channel Blocker toxicity, from the side effects of drugs such as Diltiazem (Cardizem)—helping avoid potential heart attacks.
The aqueous form of calcium chloride is used in genetic transformation of cells by increasing the cell membrane permeability, inducing competence for DNA uptake (allowing DNA fragments to enter the cell more readily).
It can also be used in the reef aquarium hobby for adding bio-available calcium in solution for calcium-using animals such as algae, snails, hard tube worms, and corals although the use of calcium hydroxide (kalkwasser mix) or a calcium reactor is the preferred method of adding calcium. However, calcium chloride is the quickest method to increase calcium levels as it dissolves readily in water.
Dry calcium chloride reacts exothermically when exposed to water. Burns can result in the mouth and esophagus if humans or other animals ingest dry calcium chloride pellets. Small children are more susceptible than adults (who generally have had experience trying to eat hot food, and can react accordingly) so calcium chloride pellets should be kept out of their reach.