CaCl₂: action against the cold and effective dust control

In 1998, production of CaCl₂ in the US was 0.7 Mt, significantly lower than CaO (22.5 Mt) but nonetheless indicating its great commercial importance. Approximately 30% of the CaCl₂ manufactured is used for de-icing of roads and public walkways, and is sometimes applied in combination with NaCl. This application of CaCl₂ arises because the anhydrous salt takes up water in an exothermic reaction; the heat evolved melts surrounding ice and is sufficient to maintain effective de-icing action at temperatures as low as 222 K. The second major use of CaCl₂ is in dust control.

     Again this application relies on the ability of anhydrous CaCl₂ to absorb water, this time from the atmosphere. Addition of anhydrous CaCl₂ to dry road surfaces and hard shoulders provides a means of trapping water, helping to aggregate the dust particles.