White Salt or Red Salt
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Do I Use White Salt or Red Salt for Road Gritting?
When it comes to de-icing, both Red Rock Salt and White Rock Salt are effective. Both salts prevent the development of ice and gathering of snow, work to dissolve fallen snow and ice, and thus create a safer path on pavements and roads.
Red Rock Salt
When the term ‘Rock Salt’ is used, it generally refers to red rock salt. It is mined from ancient rock seams.
These are ribbons of salt that go through the rock from which it is mined. These were formed from dried sea beds, locking the salt mineral in the rocks underground.
Salt is red or brown when it’s mined due to other small mineral deposits collected by the surrounding rocks. These minerals do not affect the salt and its de-icing properties.
Red rock salt is valued lower, and thus more cost-effective, in the UK, as it is mostly sourced in the UK.
White Rock Salt
White rock salt comes from evaporated seawater and is commonly called Solar Marine Salt.
This salt comes from hotter countries such as Spain, Italy, and Egypt.
White salt is obtained from salt pans or salt beds, which are flooded and then left in the hot sun.
The water evaporates, leaving the salt behind.
With enough time, these salt deposits become big enough to be collected. The salt is then exported to the UK.
Which Salt Should I Use?
Between red rock salt and white rock salt, white rock salt is preferred. It is often seen as a ‘cleaner’ product because it lacks the mineral deposits seen in the red rock salt.
Because of this, white rock salt is used in high foot-traffic areas, or outside entryways where people will be moving indoors.
This means there is no salt residue won’t be tracked inside, unlike with the red rock salt, which does leave a residue. It is popular for places such as hospitals, schools, shopfronts, etc.).
To use white rock salt, we recommend using a hand-held or push spreader, which allows for a more free-flowing spread. Likewise, white rock salt won’t clog in either of these devices.
Red rock salt, on the other hand, is typically used to cover larger areas due to its lower cost, as mentioned earlier.
Regardless of which salt you choose, both red and white rock salts are effective de-icers, and both are safe to use.
How does De-Icing Work?
An alternative to salt is grit, which does works more for friction and traction rather than as a de-icer. There is nothing in grit that causes the ice or snow to melt.
However, often when referring to ‘gritting the roads’, sodium chloride (NaCl), or more commonly named, rock salt, is the agent used.
Rock salt is an equal component of sodium and chloride, which creates a lower freezing point, and prevents ice from developing or snow from sticking. It is effective in temperatures as low as -18°C.
As the rock salt dissolves, it dilutes the water on the surface, making ice formation more difficult. However, in some cases, additional salt may be required for optimal effectiveness, depending on how low the temperature gets.
Salt on the roads is most commonly red or brown rock salt. As mentioned before, the name comes from its colour, and the colour comes from mineral deposits from the surrounding rocks during the mining process.
This can leave a gritty residue, which is why it is sometimes referred to simply as ‘grit.’
Some gritting companies may add small amounts of sand or gravel to their salt to create more traction on surfaces. However, neither sand nor gravel is effective de-icing agents.
We offer rock salt spreading throughout Aberdeen, Peterhead, Dundee and Aberdeenshire. Follow the link below to find out more about the areas that we offer road gritting in north Scotland.