Until we can discover (or invent?) the perfect materials, our best approach to de-icing is to get really comfortable with pavement temperatures. Each de-icing material has a different range of temperatures where it is most effective, so by understanding those ranges and where our road temperatures currently stand, we can lay down chemical de-icers (read: the ones with the highest price tag) sparingly and strategically.
How De-Icers Work
De-icing materials are natural or man-made chemicals that lower the point where water freezes, making ice and snow on a surface melt.
Historically, the approach has been the more salt, the better for de-icing roads and parking lots. However, snow professionals are getting more innovative with what products and how much they use to be effective. Knowing the right application rates can have a lasting positive impact on your budget, infrastructure, and the environment.
What to Consider When Choosing a De-Icer
The following list of materials definitely won’t be a fit for everyone. There are dozens of variables that can factor into which de-icing material is best for your specific situation. Primary considerations should be your budget, surface type, and surface temperature.
As you read through the list below, you’ll see that the surface temperature at which the materials are most effective ranges greatly. As a general (although not absolute) rule, the lower the temperature the material is effective, the more expensive the material is. This is why knowing your surface temperature is so critical; you don’t want to be spending 20x the cost of rock salt on a chemical de-icer when salt will do just fine.
Your surface types should also be a consideration. Surfaces like asphalt are much more tolerant of rock salt than concrete, which can erode with consistent salt exposure.
Rock Salt and Salt Brine
When it comes to de-icing, it’s no surprise that rock salt and salt brine are the most popular materials out there. Costs are manageable for any size snow removal operation, and it’s easy to get access to salt in large quantities. But of course there is a catch: rock salt will only be effective in melting ice above 15°F, and salt brine is most useful from 20-35°F. The colder it is, the more salt will be needed (up to 3x more), until salt doesn’t work at all.
Salt is fairly damaging to water quality if overused and has a significant impact on soil and vegetation. It is also corrosive to metals and concrete reinforcing, so oversalting may be friendlier on your short-term budget, but is going to hurt infrastructure in the long run. Similarly, salt brine can be damaging if overused, but is typically less impactful when applied correctly because of the dilution. A typical salt brine is 23% salt and 77% water.
Calcium Chloride
Calcium chloride has been a recent darling of snow and ice removal professionals due to its ability to remove ice down to -15°F. It’s the second most common choice after salt products, and is often combined with salt to create a combination product. White salt can be treated with calcium chloride to create an only incrementally more expensive product that will melt ice at lower temperatures, but higher concentrations of calcium chloride will cost about 3x more than standard salt.
In addition, calcium chloride is even more corrosive to metal than salt and still is hard on vegetation and water quality. While it may be a requirement to use in super cold conditions, calcium chloride should be used with care. If too much is used, roads can become slippery, environment and infrastructure can become damaged, and your budget may be blown.
Potassium Chloride
Potassium chloride, also sometimes referred to as KCI or potassium salt, has a number of uses from fertilizer to medicine. While it may be versatile, it doesn’t do well in frigid temperatures (the lowest possible temperature to use it at full effectiveness is around 25°F, but some may use potassium chloride down to about 12°F). Potassium chloride was introduced in de-icing as a more pet friendly option, but it still contains chlorides which can inhibit plant growth and burn foliage. You can also expect KCl to cost more than twice the amount of standard rock salt and comparable in price to calcium chloride.
So why are snow and ice management folks using potassium chloride?
It is still considered one of the more environmentally friendly options out there, and won’t chemically harm concrete. Like any of these materials, though, overuse is going to cause problems on both infrastructure and vegetation. Cost-wise, blending potassium chloride into other materials may be a good compromise to reduce your impact on the environment.
Magnesium Chloride
Magnesium chloride, like potassium chloride, is more pet and vegetation friendly than some other options. It also is not corrosive to metal, but will damage concrete. Magnesium chloride will melt ice down to -5°F, making it one of the more flexible materials in terms of temperature. However, the reason it hasn’t taken off like some of the other chemical de-icers is because of cost. As of October 2022, you should expect to pay 2-3x more than rock salt and you’ll need at least double the amount of product on the same area.
Urea
Urea, also referred to as carbamide, is a widely used chemical in fertilizer, but snow and ice professionals have found applications for winter weather, too. Since it is an organic compound, it can be fairly environmentally friendly (especially to grass) when used correctly, but overuse is still going to cause issues with vegetation.
Despite its benefits to foliage, it still releases a lot of nitrogen into the environment and will cost you up to 10x more than salt. Many use urea down to 12°F, but it really loses effectiveness under 25°F and should be used with caution at any temperatures below that. Lastly, urea breaks down pretty quickly, meaning you’ll need to re-treat more often. However, rapid breakdown is a positive for runoff into the environment.
Acetates
When snow and ice management companies discuss acetates, they are usually referring to one of two materials: Potassium acetate or calcium magnesium acetate. While they may both boast “acetate” in the name, they are very different.
Potassium acetate works to -26°F and, thus, is critical to the airline industry to get planes off the ground in frigid temperatures. Potassium Acetate is biodegradable, but can lower oxygen levels in water. Because it is primarily used in the airline industry, it goes without saying that it is non-corrosive to metal and concrete.
On the other hand, calcium magnesium acetate works differently. It essentially turns snow and ice to a slushy, oatmeal-like texture to prevent it from bonding to pavement. This makes it effective as a pre-treat material (ideally when pavement temperature is still above 21°F). It is not extremely damaging to soil, vegetation, metal, or concrete, but it will cost a significant amount and require a lot of product to get similar results as NaCl.
One other acetate you may have heard of is sodium acetate, which will work down to 0°F and melts ice quickly. It is also a common material at airports, but will cost $1,000+ per ton, putting it in the category of “effective, but often out of reach” for most commercial snow removal companies.
Agricultural Byproducts
Agricultural and other organic byproducts have introduced a new set of benefits to the ice melt landscape. These products can be derived from corn, beets, beer, cheesemaking, or other crops and products. While typically they are mixed with another material or two, agricultural byproducts can lower the freeze point of liquid de-icers and are environmentally and infrastructure-friendly.
The most common agricultural byproduct in snow and ice removal tends to be beets. The state of Missouri, for example, has 30,000 gallons of a beet juice brine on hand. They use the beet brine below 25°F and above 5°F, so there is a “sweet spot” for beets.
Another emerging material in the agricultural byproduct space is Beet Heat, a beet-based blend. Beet Heat incorporates chlorides with beet juice and claims to melt ice down to -40°F!
More Materials in the Mix
- Formates: Most common in the form of Sodium or Potassium formate, formates are often used at airports because they work down to -20°. The pricetag is high, comparable to acetates, but you won’t see much corrosion in formate use. Formates will, however, affect oxygen levels in water, meaning overuse can become dangerous quickly.
- Glycols: Glycols are liquid de-icers also most commonly used at airports. The most common are propylene glycol and ethylene glycol, which work to extremely low temperatures.
- Succinates: Succinates are a type of salt derived from fermenting organic matter (usually sugarcane, corn, etc.). Corrosion is minimal, but usage and research has been limited. We’ll keep our eye on Potassium succinate in the coming years to see if it becomes more readily available and more widely used.
- Blends: While mentioned last, we know blending multiple ingredients on this list is likely the most common and most reasonable option for many professionals managing ice. Most frequently used de-icers are a combination of NaCl/rock salt, potassium chloride, and/or calcium chloride, but plenty of other blends are out there on the market and worth trying for your unique situation.
Have you heard of or experimented with other materials for de-icing?
Sources used in this article: Minnesota DOT Research on Alternative De-Icers, Clear Roads Ag-Based Deicers Research, Wisconsin Salt Wise, Meltsnow.com
To learn about how Frost’s mini-RWIS can help you understand pavement temperatures and conditions, reach out to us via the form below or at info@frostsolutions.io.