If you live in a city that receives a lot of snow and ice, then you are familiar with road salt. Most likely your city and your local government have several melting trucks that distribute salt on roads, roads and sidewalks to melt ice. But how exactly does it work?
First, road salt is only coral salt, rock salt, which is salt in its original form. The difference is that salt is experiencing a long process of purification, while rock salt is not. And because rock salt still has dirt, it's brown or gray.
Why is salt?
Ice forms when the water temperature reaches 32 degrees Fahrenheit (0 degrees Celsius), and that includes ice on the road. Road salt works by reducing the freezing point of water through a process called freezing depression. The freezing point of water decreases after salt is added, making it harder for salt to freeze. The 10 percent salt solution freezes at 20 degrees Fahrenheit (-6 degrees Celsius), and a 20 percent solution freezes at 2 degrees Fahrenheit (-16 Celsius).
The key is that at least there must be water on the road so that the freezing depression works. That is why trucks often handle roads with a solution of salt water (a mixture of salt and water) when ice and snow are estimated. If the road is dry and the DOT only removes salt from the road, it might not make much difference. But pretreatment with a salt water solution can help keep ice from forming, and will help reduce the amount of salt that will be needed for salt trucks to dissolve later.
pros and cons
Stone salt is one of the most used deicers, but not without criticism. On the one hand, rock salt has its limits. If the road temperature is below about 15 degrees F (-9 C), salt will not affect ice. Solid salt cannot enter the frozen water structure to begin the dissolution process. In this case, DOT usually spreads sand on ice to give it an attraction.
Stone salt also has significant environmental problems, such as sodium and chlorine that seep into the soil and water. And as we mentioned before, because rock salt is not purified and contains contaminants, such as tin, iron, aluminum and phosphorus, when the salt spreads, they also spread. However, rock salt remains the most widely used and affordable de-icer in the market. And while there are also other chemical removers, nothing is 100% risk free.
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