Road salt, also known as halite is a natural mined mineral form of sodium chloride or table salt. While the table salt comes in a more purified version, road salt contains several mineral impurities which eventually changes its appearance from a plain white to typical brown or gray. Road salt is mined by the machines and then it is crushed and packaged for the delivery.
The major purpose of road salt is its use as a sprinkler on the sidewalks and roads to melt the ice. Thus, road salt is an acute deicing agent. Additives are usually mixed with the road salt so as to prevent them from any kind of caking. Typically, road salt is composed of sodium chloride (NaCl), but the additives into it may include sugar as well as sodium hexacyanoferrate (II).
Working of Road Salt:
Road Saltworks by the way of lowering down the freezing point of water which is done by the process of freezing point depression. In this particular process, salt breaks down into its component ions in a tiny amount of liquid water. Additional particles of such water make it difficult to freeze itself into ice, hence lowering down the freezing point of water. Thus, a tiny amount of water is always required for the road salt to function well. This causes difficulties in terms of the use of road salt in the extreme cold conditions when the water freezes down too easily.
Upon the forecast of the cold water, it becomes a common practice to pre-treat all the roads with brine that includes a solution of water and salt. This eventually helps to ward off the ice from forming which further helps as to the reduction of the amount of road salt which is required to de-ice the surface.
Once the ice starts to form, the salt is applied on to the pea-sized chunks or the gravels. Road salt is also mixed with the dry and damp sand to accelerate the process.
Safer alternatives to Road Salt:
Road salt possesses several environmental dangers and therefore a number of communities are trying to search for safer alternatives for road salt.
Cheese brine is a safer alternative to deice the roads blocked with snow and ice. This brine is considered to be a by-product which is generally thrown away by the people, hence it is free of cost and can be effectively used to serve the purpose. Some towns also make the use of molasses in order to reduce the corrosiveness of salt. Molasses is combined with a solution of saline and hence the freezing point always remains active. Another eco-friendly remedy to clear the snowy roads is the use of solar power that helps to melt snow and ice.