Calcium chloride can act as an irritant by desiccating moist skin. Solid calcium chloride dissolves exothermically, and burns can result in the mouth and esophagus if it is ingested. Ingestion of concentrated solutions or solid products may cause gastrointestinal irritation or ulceration.Consumption of calcium chloride can lead to hypercalcemia. Properties
Calcium chloride dissolves in water, producing chloride and the aquo complex [Ca(H2O)6]2+. In this way, these solutions are sources of "free" calcium and free chloride ions. This description is illustrated by the fact that these solutions react with phosphate sources to give a solid precipitate of calcium phosphate:

3 CaCl2 + 2 PO3−4 → Ca3(PO4)2 + 6 Cl−Calcium chloride has a very high enthalpy change of solution, indicated by considerable temperature rise accompanying dissolution of the anhydrous salt in water. This property is the basis for its largest-scale application. Molten calcium chloride can be electrolysed to give calcium metal and chlorine gas:

CaCl2 → Ca + Cl2

Preparation
In much of the world, calcium chloride is derived from limestone as a by-product of the Solvay process, which follows the net reaction below:
2 NaCl + CaCO3 → Na2CO3 + CaCl2North American consumption in 2002 was 1,529,000 tonnes (3.37 billion pounds).In the US, most of calcium chloride is obtained by purification from brine.As with most bulk commodity salt products, trace amounts of other cations from the alkali metals and alkaline earth metals (groups 1 and 2) and other anions from the halogens (group 17) typically occur, but the concentrations are trifling.
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 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. 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.