How Does Calcium Chloride Work to Fight Snow and Ice?

Calcium chloride (CaCl2) is one of nature’s uncommon wonders. It’s a specialty salt with unique properties that improve driving and pedestrian safety, remove unhealthy dust from the air we breathe, and enhance the performance of products and processes that contribute to the supply of energy, food, and other essentials of life.

Calcium chloride from OxyChem (Occidental Chemical) in Ludington, Michigan and Distributed by Great Lakes Chloride, is refined from natural brines found in sandstone formations beneath the earth. By processing naturally occurring brine, reactions with chemicals such as hydrochloric acid or ammonia used in other CaCl2 manufacturing processes can be avoided. The national Organic Standards Board noted this distinction when it classified the brine process OxyChem uses to produce CaCl2 as “non-synthetic.”

The Magic of Moisture & Heat

While similar chemically to sodium chloride (NaCl), better known as rock salt, calcium chloride contributes three unique and highly valuable performance properties unavailable from rock salt:

1. It is hygroscopic, strongly attracting moisture from its surroundings.
2. Solid calcium chloride is deliquescent, meaning it can absorb enough moisture to convert to liquid brine.
3. When dissolved in water, solid calcium chloride releases heat in an exothermic reaction.
The hygroscopic, deliquescent and exothermic properties of calcium chloride are highly beneficial in quickly melting ice on sidewalks and steps. Ice melter speed of action is determined by how easily it dissolves when exposed to snow or ice to form a brine solution. This brine lowers the freezing point of water to melt additional snow and ice on contact. By attracting moisture from its surroundings, CaCl2 speeds up the creation of brine compared to rock salt and other ice melt materials.

The performance of calcium chloride is further increased because the reaction that creates CaCl2 brine actually releases heat, making calcium chloride a more effective ice melter than rock salt and most other ice melt materials that must draw heat from a cold environment to begin the melting process.

Purely Different

How clear are the advantages of calcium chloride’s hygroscopic, deliquescent and exothermic properties? No need to take our word for it. Suppliers of rock salt blends claim that even the small amount of CaCl2 they add to their products makes a significant performance difference on icy sidewalks and steps. As flattering as those claims are, a fraction of calcium chloride won’t significantly change the performance of a bag of rock salt. It takes pure calcium chloride to melt ice faster and more thoroughly in a full winter’s range of weather conditions.


About Dave Budd

Vice President of Product Development and Marketing, Great Lakes Chloride, Inc. Serving Michigan, Indiana, Illinois, Ohio and Kentucky. Retired Michigan DOT, October 2010 after 32 years experience in Maintenance/Operations. Specializing in winter operations and liquid de-icers and anti-icers.
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