Publisert 28. februar 2024
Two chlorides, different performance
Magnesium chloride and calcium chloride are the most widely used road salts, both against icy roads in winter and dusty roads in summer. Both draw in and hold moisture from their surroundings, but they perform differently.
Share of active substance
Calcium chloride draws in more moisture and has a higher share of active substance. The difference also shows in the big bag.
- 1 kilogram of calcium chloride absorbs 1.8 litres of water, against 1 litre for magnesium chloride
- Calcium chloride has 77 per cent active substance for dust binding, magnesium chloride 47 per cent
- A big bag of calcium chloride contains 278 kilograms of calcium, against 120 kilograms of magnesium in a big bag of magnesium chloride
- As a result, 1 kilogram of calcium chloride can replace 2.3 kilograms of magnesium chloride
Performance in the cold
Calcium chloride is often preferred over magnesium chloride because it contains a higher share of active substances.
"This makes calcium chloride more effective at binding dust and melting snow and ice, even in cold conditions from minus 6 to minus 40 degrees. In extreme cold, magnesium chloride is not as effective."
Anders Book, CEO of Saltimport
What does it mean in practice?
Because calcium chloride is more effective and lasts longer, you have to spread magnesium chloride twice to get the same effect as spreading calcium chloride once. When the gritting truck makes fewer rounds, it means lower CO2 emissions and lower costs.
Magnesium chloride has a lower concentration of chloride, which can be less harmful to the environment in some situations. At the same time, the higher efficiency of calcium chloride can mean that less salt is needed, which may reduce the total environmental load.
The conclusion
Magnesium chloride is often cheaper to buy, but calcium chloride is the more cost-effective solution in the long run because of its efficiency and longer duration of effect.
"If you want to compare prices for magnesium chloride and calcium chloride, you should convert the prices to an anhydrous basis. You do this by multiplying the price of MgCl2 by 2.12 and CaCl2 by 1.3."
Andreas Magnus Grimelund, Sales Manager for road salt
