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Breaking the Ice: How Hygroscopic and Endothermic Ice Melt Products Work

November 27, 2023 | Categories: ,
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Winter is nearly here, which means it’s time to stock up on ice melt to keep sidewalks and pavement safe for pedestrians and motorists. But have you ever wondered what makes some ice melt products more effective than others? The answer lies in the science.

How Hygroscopic Materials Work

Hygroscopic materials have a unique ability to draw in moisture, which, in the context of ice melt, results in a liquid solution known as brine. The moisture the ice melt gathers from snow and air introduces liquid brine water to the ice surface, which lowers the freezing point of the ice, making it easier for the melting process to begin. While standard rock salt is hygroscopic, other compounds like calcium chloride and magnesium chloride are more hygroscopic than standard sodium chloride and act as accelerants, eliminating ice quicker than standard salt at lower temperatures, which is especially important for de-icing high-traffic areas that can prove dangerous.

Essentially, the calcium and/or magnesium in ice melt attract(s) moisture to the area to keep the area wet and keep the ice from refreezing. Rock salt itself is great, but its efficacy decreases when it reaches a certain temperature because there’s less moisture in the air, and is extremely slow compared to more advanced products. If the temperature is at or around 31°F, there will be more wet snow, and that water will assist the salt as it should. But, when it gets any further below freezing, calcium- and magnesium-based ice melts suck moisture out of the air and snow to get the brining process going.

These compounds are like moisture magnets, ensuring that ice melt isn’t just battling the ice directly but also leveraging the environment to its advantage, especially when conditions render regular rock salt less effective. So, when a puddle begins forming after applying ice melt, know that it’s working as intended and that the area will be clear of ice soon.

How Endothermic Processes Absorb Heat

Endothermic processes absorb heat from their surroundings. Much like coats keep people warm by trapping heat, endothermic processes actively absorb heat.

When ice melt is spread, it draws in heat, causing ice to lose energy and begin to melt. It may sound like the ice melt should produce heat as opposed to absorbing it, but heat absorption is essential for breaking the bonds in the ice crystals and turning them into liquid water. Some ice melt products are specifically formulated to have endothermic properties, enhancing their effectiveness in colder temperatures.

Many ice melt products will list a maximum effective temperature on the packaging, which indicates the product’s eutectic point, the lowest point where the product will be effective. For instance, an ice melt advertising that it melts up to -15°F implies that the product will melt ice up to that temperature. At -16°F, the product will not be effective until the temperature increases back to -15°F.

Temperatures aren’t the only thing to account for when choosing an ice melt, though; moisture is important too. Keep in mind that the amount of ice melt used and the weather conditions will affect how quickly the product works, which is why it’s always a good idea to treat surfaces before the first freeze.

Ice Melt with Exothermic Properties

Ice melts that contain calcium chloride are hygroscopic, as mentioned, but are also exothermic, meaning that the calcium chloride itself heats up when it comes into contact with water or ice. This is different than purely hygroscopic compounds that pull moisture from the air. A calcium chloride-based ice melt combines the power of moisture and heat into a powerful ice-melting duo.

How Hygroscopic Materials Work with Endothermic Processes

In summary, hygroscopic ice melts attract moisture and lower the freezing temperature of ice, promoting the formation of a liquid solution (brine) on the ice surface that aids the melting process. Meanwhile, endothermic processes allow ice melt to absorb heat from its surroundings, facilitating the melting of ice by breaking down its structure.

When hygroscopic materials and endothermic properties join forces, they create an ice-melt product that not only attracts moisture and forms a brine but also one that actively harnesses heat from its surroundings. This powerful combination ensures that icy surfaces are not just wet but actively melting, even in the chilliest winter conditions.

Choosing the Right Ice Melt

As the winter season rolls in, armed with the knowledge of hygroscopic materials and endothermic processes, you can make an informed choice when selecting your ice melt.

While a sodium chloride ice melt like Morton Safe-T-Salt is the most commonly used type of product and comes at the lowest cost, it’s not as fast-acting as other products and leaves residual. 

A magnesium chloride-based product like MAG Ice Melting Pellets is hygroscopic, while a calcium chloride-based product like Peladow Calcium Chloride Pellets is both hygroscopic and exothermic—a combination that lowers the freezing temperature and clears out ice faster than other de-icers.

Remember, it’s not just about clearing the ice; it’s about doing it smarter, and ice melts that contain chlorides will provide immense value at a reasonable cost. If you want to talk to someone, whether you’re looking for winter products or just want some advice, one of our representatives would be happy to help.

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