What to Know About Using Magnesium Chloride for Ice Removal

Ginny Bartolone
Written by Ginny Bartolone
Updated November 22, 2022
Woman shoveling snow in yard
Photo: Guido Mieth / DigitalVision / Getty Images

Highlights

  • Magnesium chloride is effective at melting ice at low temperatures.

  • It’s also more effective than rock salt. 

  • However, it can be more expensive than other options.

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No one likes to go slipping and sliding down a set of icy stairs in the winter. You can keep outdoor surfaces safe during the iciest of months with the careful application of deicers like magnesium chloride. However, if you’re unsure if this compound is right for you and your family, we’ve broken down what it is and rounded up some pros and cons to know before you buy a bucket. 

What Is Magnesium Chloride Ice Melt?

Magnesium chloride is a naturally occurring salt that lowers the freezing point of water. When applied to ice, the compound causes the ice to melt. It then mixes with the water resulting in a solution called brine. This brine spreads, causing the ice to melt more quickly and preventing more ice from forming, creating a safe walking or driving surface during icy winter months.

This salt is processed from saltwater and comes as a flakey, white compound. You can find magnesium chloride in small and large quantities at most home improvement stores.

Benefits of Magnesium Chloride Ice Melt

When it comes to making your walkway safe for snowball fights and heading out to the car, magnesium chloride has some major ice-melting benefits. 

Effective at Low Temperatures

Magnesium chloride is an effective solution for icy walkways, stairs, and driveways down to about -5 degrees Fahrenheit. 

Less Corrosive

Magnesium chloride causes less corrosive damage to concrete, stone, tiles, and outdoor vegetation than some other ice removers. Since it’s naturally occurring, magnesium chloride is considered environmentally friendly.

Leaves Less Residue

Ice melt and rock salt products can be messy. When the salts dissolve into a brine, they can adhere to shoes and leave unsightly messes on indoor surfaces. Magnesium chloride leaves less residue than other products and is less likely to make it from the outdoors to the indoors.

More Effective Than Rock Salt

Magnesium chloride can melt ice and snow twice as fast as rock salt, another common deicer. The quicker action means magnesium chloride is better for heavily trafficked areas.

Gentle on Landscaping and Vegetation

Salts from deicers build up over the winter. When snow and ice begin to melt and the water runs off, these salts can damage grass and other vegetation. Magnesium chloride is gentler on greenery than other options, resulting in less damage to your outdoor green spaces.

Gentler on Skin

Magnesium chloride is less likely to cause skin irritation than other deicing options, making it a safer choice if you have pets or children who may come into contact with the material. Also, it is less likely to damage your skin during application, though wearing gloves and eye protection is still advised.

Cons of Magnesium Chloride

Winter walk path with gate
Photo: Maryia Tsikhanava / iStock / Getty Images Plus / Getty Images

However, depending on your needs, magnesium chloride may not be the ice melt solution for you.

Cost

Magnesium chloride is more expensive than both calcium chloride and rock salt. Magnesium chloride generally costs $20 for 25 pounds compared to $20 for 50 pounds of calcium chloride or $10 for 50 pounds of rock salt.

Larger Quantities

You’ll need to apply magnesium chloride in higher quantities than other ice melt products like calcium chloride. With the higher cost, magnesium chloride might not be an economical solution if you live in a high-ice area.

How to Use Magnesium Chloride Ice Melt

Always begin by reading the specific instructions provided on your magnesium chloride ice melt packaging. Magnesium chloride products come in different forms—primarily pellet, flake, or liquid—and may be mixed with other chemicals or abrasive materials like sand to be more effective. It's important to note the safety precautions, the correct amount for usage, and spreading recommendations for the specific brand. 

Timing is also everything. It is often best to use magnesium chloride at the start of a storm after the ground is already slick or after shoveling snow off the top of a layer of ice. Applying magnesium chloride to dry ground or on top of a pile of fluffy snow can waste the product and ineffectively melt the ice. 

Have your spreader ready when those flakes start to fall or after you give the walk a good shoveling.

Spread Pellets

Pellets are a popular form of magnesium chloride since they allow you to spread larger pieces of concentrated chemicals directly on the ice. They work quickly and spread widely, which is helpful on large driveways or walkways.

Keep in mind, however, that pellets like to bounce and roll once they hit the ground. If you're trying to melt ice in a highly concentrated area, stick to the flake or liquid forms below.

Here's how to apply magnesium chloride pellets:

  1. Wear gloves and protective clothing before handling magnesium chloride for an extra layer of safety.

  2. Pour the magnesium chloride ice melt into a handheld or push salt spread, specifically one that has not carried pesticides in the past.

  3. You can also distribute magnesium chloride pellets with a shovel or cup, but keep in mind that the pellets will bounce and roll when applied from above.

  4. Spread a thin, even layer across the icy area.

  5. Wait at least 30 minutes before testing the area for more traction.

Keep It Close With Flakes

Flakes or granules of magnesium chloride land on the ground and stay put far better than pellets. While this means you won't have to worry about them flying into your yard, it does take a bit longer to cover a larger area. 

Many companies combine magnesium chloride with other popular de-icers such as rock salt, calcium chloride, or sand and gravel, so always make sure the mixture is safe for your surfaces before beginning.

  1. Don your protective equipment to avoid prolonged contact with the magnesium chloride flakes or additional chemicals.

  2. Depending on your mixture's instructions, you can either use a salt spreader or a shovel to distribute the flakes.

  3. Move slowly and carefully and add an even and thin layer to the ice.

  4. Wait 30 minutes before breaking up thicker ice and ensuring the walkway is safe for use.

Pre-Treat With Liquid

While all magnesium chloride both melts ice and prevents it from forming, a liquid application is one the easiest ways to cover a large area before a storm. It is even more important in this case to wear proper PPE, including a mask, gloves, and eye protection. Most liquid magnesium chloride products will come with a sprayer set to the proper flow levels on your roads and walkways.

  1. Wear all protective equipment recommended on the product's safety warnings.

  2. Pump or release the trigger valve on your sprayer on thin, newly formed ice, rain that may freeze in the near future, or on the ice below shoveled snow. 

  3. If you use a garden sprayer from your own tools, ensure it has never contained pesticides.

Safety Tips

Even though brands often advertise magnesium chloride products as safe and natural, it's still best to prevent contact with your skin, eyes, and mouth. On top of this, you're working with slippery surfaces in the cold, so it's in your best interest to wear gloves, work boots, and protective clothing anyway. If you choose liquid magnesium chloride, goggles and a mask are necessary as well.

Here are a few other safety and usage tips to keep in mind:

  1. Always check the label to ensure the product is safe for your pets. While magnesium chloride is commonly considered safer than other products, it can still cause irritation. It may also come mixed with other chemicals that can pose risks to your furry friends.

  2. Avoid walking on the icy area for at least half an hour after application, and always test a small area before walking.

  3. Keep in mind that magnesium chloride only works down to a certain temperature (around 5 degrees Fahrenheit). For very low temperatures, you may need a stronger product.

  4. Always apply the suggested amount of magnesium chloride per square foot on the label. Over-applying de-icer can damage the area below the ice.

  5. Store your magnesium chloride away from sun, moisture, and access by pets or children. A sealed, airtight container is best.

  6. Remove your shoes outside to avoid tracking magnesium chloride into your home.

Frequently Asked Questions

Both rock salt and ice melt are naturally occurring salts. Rock salt is sodium chloride, which is the same as table salt. Ice melt products can be made from a combination of salts like magnesium chloride and calcium chloride or can be those salts alone.

Rock salt comes in large crystals, so it helps provide traction on icy surfaces, whereas ice melt products need to be mixed with sand to provide traction. Ice melt products work at lower temperatures than rock salt, so they might be a better choice if you have a harsh winter climate.

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