Abstract

Calcium chloride, CaCl₂, is a white, crystalline salt that is very soluble in water. Solutions containing 30–45 wt % CaCl₂ are used commercially. Of the alkaline-earth chlorides it is the most soluble in water. It is extremely hygroscopic and liberates large amounts of heat during water absorption and on dissolution. It forms a series of hydrates containing one, two, four, and six moles of water per mole of calcium chloride. Commercial applications of calcium chloride and its hydrates exploit one or more of its properties with regard to aqueous solubility, hygroscopic nature, and the heat gained or lost when one hydrated phase changes to another. Because of its high solubility in water, calcium chloride is used to obtain solutions having relatively high densities. Viscosity is an important property of calcium chloride solutions in terms of engineering design and in application of such solutions to flow-through porous media. In the United States the principal route for making calcium chloride is by the evaporation of underground brines. Significant markets in the United States are for deicing during the winter, and roadbed stabilization, and as a dust palliative during the summer. Use as an accelerator in the ready-mix concrete industry is sizable, but there is concern about the possible corrosion of steel in, highways and buildings. Calcium chloride is also used in oil and gas well drilling. Food-grade calcium chloride is used in cheese making to aid in rennet coagulation and to replace calcium lost in pasteurization. In the canning industry it is used to firm the skin of fruit such as tomatoes, cucumbers, and jalapenos. Food-grade calcium chloride is used in the brewing industry as a basic component of certain beers. Calcium Chloride is not considered to be harmful to the environment. Above certain levels chloride is toxic to plants and animals.