How Does Ice Melt Work : An Overview

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December 20, 2017 at 12:00 pm Category:

With winter in full swing, driveways, walkways and roadways are quickly turning into a slippery nightmare.

If your sidewalk or driveway isn’t already covered in ice, in most places, it soon will be. Now is the time to be thinking about the best way to melt ice quickly, cost-effectively and in a low-impact way.

Before we get into how you can do this, let’s cover some of the basics about ice melt first.

How does ice melt work?

The simple answer to how ice melts work is ice melt products lower the overall freezing point of water.

This means that water will only freeze when it reaches the required lowered temperature based on the type of ice melt product used.

Depending on the type of ice melt product you’re using, the effectiveness of melting ice on sidewalks, driveways, roads, and highways will change based on the overall temperature.

As an example, rock salt ice melt products will lose their effectiveness once the temperature outside goes lower than 20°F.

Calcium chloride ice melt products, on the other hand, will continue to be effective down to temperatures of negative 25°F (negative 25 degrees Fahrenheit).

When we talk about how ice melt works, we often get the question about whether or not the ice melting is a chemical change or a physical one.

Is ice melting a chemical change?

A lot of people interested in knowing more about how ice melt products actually work often ask the question: is ice melting a chemical or physical change?

The specific change of ice melting into water form is a physical change; however, if you are using a compound such as calcium chloride (common salt) to melt the ice, you will also have a chemical change happening separately, yet at the same time.

So, what’s the difference between a physical and chemical change?

Physical change: A physical change is a change which affects the physical form of a substance, but not its chemical form.

Chemical change: A chemical change is a change which affects the chemical form of a substance, and often produces energy in the process (e.g. produces heat).

What temperature does ice melt at?

The normal freezing point for water is 32°F (32 degrees Fahrenheit). Conversely, the normal melting point for ice is also 32°F (32 degrees Fahrenheit).

The freezing point of water and the melting point of ice can be altered with the use of external compounds, such as ice melt.

What makes ice melt faster?

Temperature is the main factor in what will make ice melt faster or not (this should be obvious to most people). The higher the temperature, the faster the ice melts; the lower the temperature—you guessed it—the slower the ice will melt. 

But how do ice melt products affect how fast ice melts outside?

That’s a great question which first requires us to talk a little bit about the different type of ice melt products available.

Types of Ice Melt

There are many types of ice melt, as well as places where you can shop ice melt products online, but some common types of ice melt include potassium chloride, urea, rock salt (sodium chloride), magnesium chloride and calcium chloride.

These types of products are unique in their own right, with varying chemical makeup and effectiveness when applied for the purposes of de-icing, or melting or ice.

Types of Ice Melt

Type of Ice Melt Chemical Makeup Lowest Effective Temperature Melt Type Things to Note Warnings
Potassium Chloride KCl 25°F (-4°C) Endothermic (requires heat) Better as a fertilizer than a de-icer Moderate potential for corrosion and environmental impact
Urea (NH2)2CO 25°F (-4°C) Endothermic (requires heat) Better as a fertilizer than a de-icer Low impact to plant life, but poses threat to aquatic life
Rock Salt (Sodium Chloride) NaCl 20°F (-7°C) Endothermic (requires heat) Slow acting and ineffective a low/coldest temps Moderate potential for corrosion and environmental impact
Magnesium Chloride MgCl2 0°F (-18°C) Exothermic (produces heat w/ moisture) Slow acting and more expensive than other ice melt products Moderate potential for corrosion and environmental impact
Calcium Chloride CaCl2 -25°F (-32°C) Exothermic (produces heat w/ moisture) Fast acting and very effective at low/coldest temps Moderate potential for corrosion and environmental impact

Depending on the surface you need to de-ice, along with the quantity you will purchase and the cost you wish to purchase it at, the type of ice melt you choose to use for your business, or home will vary.

Out of these options, one of the most effective de-icing solutions (which is also a winter contractor favorite) is Calcium Chloride Ice Melt.