Snow melting agent

Snow melting agent refers to a chemical substance that can lower the melting temperature of ice and snow. The raw materials for ordinary snow melting agents are easy to obtain and inexpensive. Their main ingredients are potassium acetate and chloride salts, which are classified according to these two types. Snow melting agents melt snow on roads by reducing the melting temperature of ice and snow, making it easier to clear the road and have a significant spraying effect. However, they are harmful. Studies have found that residual snow melting agents can corrode road surfaces and car rubber tires. In the northern region, sand and snow shoveling vehicles are still the main methods used during the winter season, with snow melting agents as a supplement, to remove ice and snow from the road surface and ensure smooth traffic.

As the name suggests, snow melting agents are used to melt snow and ice. They are mainly used as de icing agents for urban roads, highways, airports, ports, bridges, and other facilities instead of salt. Some snow melting agents can also be used as rapid melting agents and antifreeze additives for winter construction of building projects.

Types and performance

There are many types of snow melting agents developed in China, which are divided into solid and liquid states according to their physical states; Classified by composition, it can be divided into inorganic substances and mixtures of inorganic and organic substances, with mixtures of inorganic and organic substances being the most common. Among them, environmentally friendly snow melting agents are mostly mixtures of chemicals such as MgCl2- that do not contain or contain little chlorine; It can also be classified according to different purposes. Generally, it has lower quality for urban roads and higher quality requirements for bridges, airports, and other places, but its quality must meet the standards. Environmentally friendly snow melting agents not only rely on the proportion of ingredients as a technical key, but also keep the additives (such as solubilizers) confidential.

The production and sales data of domestic snow melting agents are roughly calculated based on the production of calcium chloride. The annual production of domestic snow melting agents is around 1 million tons, with exports accounting for one-third of the total. There are mainly two types of snow melting agents, organic snow melting agents and chloride salt snow melting agents. Organic snow melting agents have no corrosive effect on infrastructure, and due to their high price, they are only applied in small quantities in places such as airports and golf courses; Chlorine salt snow melting agents are widely used in cities and highways for snow melting.

Types of snow melting agents

One type is organic snow melting agents mainly composed of potassium acetate. This type of snow melting agent has good snow melting effect and basically no corrosion damage, but its price is too high and it is generally used in important places such as airports.

Another type is inorganic snow melting agents mainly composed of "chloride salts", such as sodium chloride, calcium chloride, magnesium chloride, potassium chloride, etc., commonly known as "deicing salts". Its advantage is that it is cheap, only equivalent to 1/10 of organic snow melting agents, but it is very corrosive to large public infrastructure. The common snow melting agents we use belong to this category, and the most commonly used ones are chloride salts containing impurities (i.e. industrial salts).

Snow melting principle

The snow melting principle of "chloride salt" snow melting agent is that after dissolving in water (snow), its freezing point is below zero degrees. For example, sodium chloride (the main component of table salt) has a freezing point of -10 ℃, calcium chloride is around -20 ℃, and acetic acid can reach around -30 ℃ when dissolved in water. The freezing point of saltwater is lower than that of water, so it is difficult to form ice cubes after dissolving salt in snow water. In addition, after the snow melting agent dissolves in water, the ion concentration in the water increases, causing the liquid vapor pressure of water to decrease, but the solid vapor pressure of ice remains unchanged. To achieve a state of solid-liquid vapor pressure in the mixture of ice and water, the ice melts. This principle can also explain the reason why saltwater is not easily frozen. Simply put, snow melting agents lower the melting point of snow, making it easier to melt.

We know that water is a special substance, and its density decreases after freezing (generally, the density of a substance in its solid state is greater than that in its liquid state). Therefore, the higher the pressure, the lower the melting point of ice. It is often seen that snow tends to melt easily where the wheels run over it. After sprinkling snow melting agent on the snowy road surface, it is easier for the snow to melt under the rolling of vehicles.

From the above, it can be seen that sprinkling snow melting agent is beneficial for snow removal.

Usage Introduction

Since chloride salt snow melting agents have such great harm, can we not use snow melting agents? Snow disasters cause transportation difficulties, especially endangering personal safety. Improper or untimely handling may affect the economic development of cities and countries, and even cause local traffic paralysis and large-scale accidents. From the comparison of snow melting efficiency, speed, convenience and cost-effectiveness, it can be seen that chloride salt snow melting agents are still difficult to replace. However, the practice abroad is to minimize the use of manual and mechanical snow removal methods, supplemented by snow melting agents. At the same time, protective measures are added to road and bridge facilities to minimize losses.

For the problem of urban winter snow melting, the environmental protection practices in European and American countries are: after mechanical snow shoveling, materials such as charcoal slag, coarse sand, and tree branch debris are sprinkled on the road to prevent slipping, and the dark color of these slag materials is also used to absorb the heat of the sun and increase the ground temperature to melt the snow. The used charcoal residue and tree branch residue can be placed in the green space by the roadside without pollution. For roads that really require snow melting agents, first use a snow shovel to sweep away most of the snow on the ground, and then sprinkle a small amount of snow melting agent to prevent the road from freezing. And make full use of surface heat, solar radiation heat, and the heat released by the car itself during driving to help melt snow on the road. In order to prevent saltwater from seeping into the ground or polluting surface water after snowmelt, the UK has adopted the method of "collecting saltwater". Special pipelines are laid next to urban roads and bridges to collect saltwater after snowmelt, which is finally drained to sewage treatment plants for treatment and reuse. This is worth learning from.

To reduce the corrosion damage caused by chloride salts, for municipal infrastructure construction, one approach is to use high-performance concrete to increase its impermeability. The second is to use corrosion-resistant steel bars as much as possible, or use rust inhibitors on the steel bars. The third is to apply an impermeable outer coating on the exterior of the building. The solution to plant protection is to use salt tolerant plants near the roadside near the snow melting agent, and to use snow season shading for trees and greenery to prevent the snow melting agent from coming into contact with plants.

Note: The product can be customized according to customer needs.