Operational Tips for Sweeping Professionals
Special Report on Use of De-Icers
Ice season is always on the horizon, and since so many readers deal in snow and ice removal, an article on the latest in de-icing techniques seemed appropriate. Thanks to Nancy Lucas, Marketing Manager for Cargill Salt, for writing this for us.
How De-icers Work
De-icing chemicals (deicers) get ice off pavement by lowering the melting point of the ice. Dry granular deicers can actually bore down into the ice surface. The deicer and ice form a liquid brine and remain in a liquid form at temperatures where pure water would still be frozen solid. The liquid brine also seeps between the remaining ice and pavement, breaking the bond for easier plowing. Keeping pavement free of ice has become a science. Here's an overview of currently used products and techniques.
Sodium Chloride, also known as rock salt, is the cheapest and most commonly used deicing product. It is produced in various particle size gradiations. The larger of these are used for roadways, then progressively smaller for parking lots and sidewalks. It will work to -7 degrees F, although it is most effective around 10-15 degrees F. Salt has an excellent deicing capacity and sensible application rates can minimize the reported challenges associated with over-application, such as vegetation damage. Any deicing chemical, in excess, can be harmful to vegetation.
Calcium Chloride, sometimes called 'hot salt,' is often used during very cold weather conditions. It can continue to work to -60 degrees F, but is often considered most effective around -25 degrees F. It may run 3-5 times as expensive as rock salt, so limiting usage to cold temperatures may help those with tighter budgets.
Calcium magnesium acetate (CMA), is an alternative deicer with minimal corrosive properties. It was initially developed through government grants, to be created through corn fermentation process. Most commercial processes to date, however, are not utilizing this process. CMA can be quite expensive, often more expensive than calcium chloride.
Blended products are relatively new on the market, with different compositions offered by various manufacturers. Blended products reduce the use of sodium chloride, but their real advantage lies in utilizing the strengths of particular chemicals to maximize aspects of product performance, such as melting rate and melting capacity.
The newest development is a deicer which has anticorrosive characteristics and actual corrosion inhibitors. Cargill's product for this technological market niche is called CG-90.
Application before a storm is a newly developing, rapidly growing, technology call anti-icing, which prevents bond formation between the ice and pavement. Success is dependent on many variables, including good storm forecasting, timely application, appropriate application amount and plowing as soon as possible after the storm hits.
Another method being utilized more frequently is pre-wetting, which may speed up or maximize the deicing process. In pre-wetting, a liquid deicing product, usually magnesium chloride or calcium chloride, and sometimes liquid sodium chloride, is applied to dry granular sodium chloride to initiate melting as well as to wet the product for better adherence to the deicing surface. Once the brine begins to form, the sodium chloride can dissolve much more quickly.
To reach Nancy, or Carold Ueland, Alternate Deicing Manager, call Cargill at 1-800-544-2498.
This article is reprinted from American Sweeper magazine, v3n3.
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