What is the principle of salt thawing?

Solubility: Soluble in water. It is difficult to form ice when salt is dissolved in snow water.

Moisture absorption: The surface of snowmelt salt is usually surrounded by a film-like saturated salt solution. When the vapor pressure of this membrane solution is lower than the partial pressure of water vapor in the air, the snowmelt salt absorbs the moisture in the air and deliquesces; On the contrary, when it is higher than the partial pressure of water vapor in the air, it will dry. Of course, this phenomenon will only occur when the snowmelt salt is exposed to the air, and the snowmelt salt sealed in the packaging bag and isolated from the surrounding air will not deliquesce.

Low freezing point: If the snowmelt salt solution contains 20% salt, its freezing point will be reduced to-16℃.

Extended data:

Hazards of using snowmelt salt:

1. The main difference between chlorinated salt and edible salt is the different purity. The purity of edible salt is high, and there are many impurities in industrial salt. Impurities are mainly water and calcium, and may also contain a lot of toxic substances such as lead, mercury and arsenic. Long-term consumption may lead to chronic poisoning.

2. Pay attention to the impact on greening. Chlorinated salt, used for melting snow. After chloride permeates the soil, it will increase the soil salinity, resulting in the salt concentration of plant cells being lower than that of the soil, and the water in the cell fluid will flow back. Among them, the death rate of plants near the road is high, and some low plants, such as Chinese rose and boxwood, are most likely to die. In addition to the impact on garden plants, chlorinated salts will also corrode roads and bridges.

Baidu encyclopedia-snowmelt salt

People's Network-Can salt melt snow? Salt used for snow melting is different from edible salt.