It is used for dust control on some highways, as its hygroscopic nature keeps a liquid layer on the surface of the roadway, which holds dust down.However chloride ion leads to corrosion of steel rebars, so it should not be used in reinforced concrete. It is used in concrete mixes to help speed up the initial setting.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). It is also more effective at lower temperatures than sodium chloride. Unlike the more-common sodium chloride (rock salt or halite), it is relatively harmless to plants and soil. Aided by the intense heat evolved during its dissolution, calcium chloride is also used as an ice-melting compound.Small children are more susceptible to burns than adults, and calcium chloride pellets should be kept out of their reach. This can result in burns if humans or other animals eat dry calcium chloride pellets. It is converted to a brine as it absorbs the water or water vapor from the substance to be dried: CaCl 2 + 2 H 2O → CaCl 2♲H 2O 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 can also be added to liquids to remove suspended or dissolved water. 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. Because it is strongly hygroscopic, air or other gases may be channeled through a column of calcium chloride to remove moisture.Millions of tonnes of calcium chloride are made each year in the US alone, and in 1990 the bulk price there was $182 per tonne. It can also be produced by the action of hydrochloric acid on calcium carbonate CaCO 3( s) + 2 HCl → CaCl 2(aq) + H 2O( l) + CO 2( g) Molten CaCl 2 can be electrolysed to give calcium metal:Ĭalcium chloride is a by-product of the Solvay process used for the manufacture of sodium carbonate. Because of its hygroscopic nature, it must be kept in tightly-sealed containers.Ĭalcium chloride can serve as a source of calcium ions in solution, for instance for precipitation because many calcium compounds are insoluble:ģ CaCl 2( aq) + 2 K 3PO 4( aq) → Ca 3(PO 4) 2( s) + 6 KCl( aq) It can be produced directly from limestone, but large amounts are also produced as a by-product of the Solvay process. It has several common applications such as brine for refrigeration plants, ice and dust control on roads, and in cement. It is a salt that is solid at room temperature, and it behaves as a typical ionic halide.

It is highly soluble in water and it is deliquescent. Materials in their standard state (at 25☌, 100 kPa)Ĭalcium chloride is a chemical compound of calcium and chlorine.

Except where noted otherwise, data are given for

Calcium chloride precipitation