With winter on its way, there is always a rush for ice-melting products. But wait, which do you choose? I cover all there is to know about ice melt vs rock salt.
You may even want to make your own homemade ice melts, although these won’t be as effective and are no use for extreme conditions.
Read on for a detailed look into all the different ice melts and what they are best for, along with calcium chloride vs magnesium chloride.
What Is Rock Salt?
I start with the ice melt I think you will all know, and one of the most popular ice melting products available. The brown traditional rock salt, also known as Halite is actually a rock, unlike your table salt which is a mineral form of salt.
Found all around the world Halite is mined, whereas the white rock salt is harvested from evaporating salty waters usually in countries with warm climates.
An interesting fact for you, brown regular rock salt is the one that will leave marks and white salt stains on your shoes and carpets. Whereas white rock salt is purer and for this reason, you will often find large offices and schools, etc. using it.
Having said that, there is a downside, white rock salt is more expensive, although it can save on cleaning bills.
By using sodium chloride (rock salt) you have a lower freezing point for water. This, in turn, helps prevent ice from forming. However, depending on how low the ambient temperature is, varies the answer to how long does it take for salt to melt ice.
While water has a freezing point of 32°F (0°C), the freezing point of rock salt is 14 °F (-10°C). Although rock salt works well, should the temperature drop below 14 °F (-10°C) it will no longer have its de-icing capabilities. Although of course, it does still provide instant traction underfoot.
Benefits & Downsides Of Using Rock Salt To Melt Snow
As with all of the best performing ice melt products, using rock salt has its pro and cons. Below I will list a few of the main points that will help you decide on whether you want to use it.
- Melts ice quickly
- Gives instant traction when spread in a thin even layer
- Readily available
- Remains active down to 14°F (-10 °C)
- Has a long shelf life
- Salt damage may affect some asphalt and concrete as it melts, especially if used regularly
- Harmful to animals paws and dangerous if ingested (animals and humans)
- Rock salt and ice melt runoff can damage plants
- Runoff can contaminate the ground and even the water supply
- The least environmentally friendly
- Can kill grass and plant life if runoff reaches them
What Is Ice Melt & What Is It Made Of?
Although all ice melts will vary to a degree, an ice melt will usually consist of the chemical composition of various ice melts. These are sodium chloride, calcium chloride, and magnesium chloride pellets. I have already covered the sodium chloride (rock salt) above, so now will cover the others in more detail.
Here’s a breakdown of what each active ingredient is, why they are used, along with their pros and cons.
Calcium Chloride Vs. Magnesium Chloride
As mentioned, calcium chloride (CaCl2) along with magnesium chloride (MgCl2) are both common ingredients and found in most ice melt products. And, there are specific reasons that each is included in ice melting products found on the shelves.
So, let’s dig deeper and found out exactly what these active ingredients in your ice melts do.
What Is Calcium Chloride? Benefits & Downsides
The main benefit of using CaCl2 (calcium chloride) is that it will still melt existing ice in extremely low temperatures. Standard rock salt has a freezing point of 14 °F. Whereas calcium chloride remains active and achieves the low freezing point of -25°F (-32°C), this figure is often referred to as the ‘effective temperature’ on labeling.
Contrary to rock salt, calcium chloride is not produced by nature itself. Instead, a chemistry process is used and combines a solution of sodium chloride (brine water) with limestone. When calcium chloride pellets touch water they actually generate heat, making melting ice fast and efficient.
Although you will see CaCl2 used as a stand-alone ice melt, the chemical composition of at least two components can be more beneficial. The benefits of combining these chemicals are wide and varied. One good example is by using sodium chloride mixed with calcium chloride you lower the environmental impact that the rock salt would otherwise have.
This is because calcium chloride increases the melt rate of ice quite considerably, meaning you will be using less of the more harmful rock salt. That, along with the fact that it also stays active for longer than rock salt, makes the two a great winter deicing combination.
When you purchase calcium chloride you may get the choice of either flakes or pellets, although pellet form is the most popular. Here’s a good example of CaCl2 in pellet form along with your basic sodium chloride (rock salt). You will be able to spot what I mean when I say calcium chloride is the more expensive.
- Has a freezing point of -25°F (-32°C) great for the Mid Atlantic area
- Less corrosive than sodium chloride (rock salt)
- Less harmful to plants
- Longer active life
- Although less than rock salt, it can still damage wood and concrete, etc
What Is Magnesium Chloride? Benefits & Downsides
Now for the last ice melt on my hit list, magnesium chloride (MgCl2). Although this is said to be one of the more environmentally friendly ice melts, it does actually depend on weather conditions. Unlike calcium chloride MgCl2 is a naturally occurring mineral that is then processed for use as an ice melt.
Again this can be purchased in either flake or pellet form and is classed as being ‘safer’ for pets and nicer for the surrounding environment. However, all forms of rock salt and ice melts carry with them some toxicity no matter how small, so be sure to read the label carefully.
Here is an example of a great product with great reviews called Pet safe. The label on this product clearly states ‘safer for pets paws’ and ‘not pet safe’.
Let’s get to it, what are the benefits and downsides of using magnesium chloride as a deicer when compared to other products.
- Less irritating for skin
- Safer for use around pets
- Leaves no residue
- Can corrode metal over time
- Can still damage concrete if used regularly or incorrectly
- The freezing point of 0°F (-17°C), less than calcium chloride
- Most expensive when compared to others
Can Ice Melt Harm The Environment?
Sadly, although essential to keep us moving safely about in the freezing temperature of winter, ice melts can harm the surrounding environment. The chloride element contained within the three most popular ice melts, sodium chloride, calcium chloride, and magnesium chloride.
Unfortunately, due to runoff from roads, driveways, and sidewalks, etc., these elements make their way not only into the drains and sewers but also the soil.
Ice Melt vs Rock Salt: Which Should I Use?
So, what is the difference between rock salt and ice melt? Because rock salt is cheap and readily available it has become extremely popular, and, it works so why not?
Below I’ll make various comparisons between ice melt vs salt and let you make the decision that is right for you.
Which Works The Fastest?
Although rock salt will give you instant traction underfoot, it actually melts the ice slower than other options. You can have the best of both worlds, to a certain degree, by mixing rock salt with calcium chloride. This will give you good traction, and the melting process will still be fast.
Which Works Best In Extreme Cold
For extreme snow zones, low temperatures, and certain types of heavy and wet snow, calcium chloride is definitely the best. Although it is quite expensive it can be mixed with sodium chloride. This reduces the amount of harmful rock salt used and still works effectively.
WhichIs Most Cost-Effective
Rock salt wins hands down when it comes to cost. But, it is also the most environmentally harmful.
Which Is Most Environmentally Friendly
When compared against rock salt and calcium chloride, magnesium chloride is the most eco-friendly ice melt.
You may have noticed in the above ice melt vs salt summary that each ice melt compound is best for different things. It is because of this that you will very often find at least two if not all three, in the combined ice melt mixes available.
If there is anything I have gained from studying this subject. It’s the knowledge of how much harm ice melts can actually do. When using any of the ice melts it is recommended that you remove the majority of snow first. So, why not consider buying a machine or check out my blog on how to remove snow quickly and easily.
Especially if you live in an area where temperatures frequently drop, and you have a large snow accumulation. Both will help reduce the amount of ice melt needed making it more environmentally friendly.
People Also Ask (FAQ)
Well, that’s about it from me now, but here are some answers to the questions I’ve found are most asked about this subject.
What is the safest ice melt for concrete?
Between the three most popular ice melt products of rock salt (halite), calcium chloride, and, magnesium chloride). It is calcium chloride that is the least likely to damage concrete. However, always read the labels carefully as some concrete may still be affected.
Is magnesium chloride corrosive to cars?
You will find many ice melt products that contain magnesium chloride, this is because it is great for both preventing and melting ice. However, the one downside is that magnesium chloride can be corrosive to metal and unfortunately that includes cars.
Is magnesium chloride harmful?
Although the safest of main deicers, as with all chemicals, used incorrectly magnesium chloride can still be harmful. Having said that studies have shown that it is highly unlikely to cause irritation to your skin or pet’s paws.
What is the safest ice melt for pets?
Unfortunately, in the snowy winter months, we are forced to use salt or ice melt, but are they pet-friendly? Out of the three, most popular products, studies have shown that magnesium chloride is the safest ice melt for pets.
Can you use vinegar to melt ice?
Although vinegar will not melt ice, spread as a solution over the surface it can reduce the possibility of ice forming. This is due to the fact that vinegar will lower the freezing point of water – slightly, realistically vinegar is not an ice melt.