Calcium chloride (chemical formula: CaCl2) is a white or slightly yellow solid inorganic compound, belonging to the salt category. It is a typical ionic halide and widely used in multiple fields due to its high solubility, hygroscopicity, and dehydration. According to its hydrated form, it exists in different physical forms, with the most common being dihydrate (CaCl2 · 2H2O). Its high solubility allows it to quickly dissolve in water, releasing a large amount of heat, making it very useful in applications that require rapid heating or drying. In addition, calcium chloride is also commonly used in saltwater, road deicing agents, and desiccants used in refrigeration equipment.

Industrial use

1. Used as a versatile desiccant for drying gases such as nitrogen, oxygen, hydrogen, hydrogen chloride, sulfur dioxide, etc. Used as a dehydrating agent in the production of alcohols, esters, ethers, and acrylic resins. Calcium chloride aqueous solution is an important refrigerant for refrigerators and ice making, which can accelerate the hardening of concrete and increase the cold resistance of building mortar. It is an excellent building antifreeze. Used as a port defogger, road dust collector, and fabric fireproof agent. Used as a protective and refining agent for aluminum magnesium metallurgy. It is a precipitant for producing lake pigments. Used for deinking waste paper processing. It is the raw material for producing calcium salts.

2. Chelating agent; Curing agent; Calcium fortifier; Refrigerant for freezing; Desiccant; Anti caking agents; Microbial suppressants; Pickling agent; Organizational improvement agents.

3. Used as a desiccant, road dust collector, defogger, fabric fireproof agent, food preservative, and in the production of calcium salts.

4. Used as a lubricant additive.

5. Used as an analytical reagent.

6. Mainly used to treat tetany, urticaria, exudative edema, intestinal and ureteral colic, magnesium poisoning caused by decreased blood calcium.

7. Used as a calcium fortifier, solidifying agent, chelating agent, and drying agent in the food industry.

8. Can increase the permeability of bacterial cell walls.

desiccant

The strong moisture absorption ability of calcium chloride makes it an ideal desiccant in the manufacturing process, used to protect goods from moisture damage, especially when transporting and storing sensitive substances [22-23]. Granular anhydrous calcium chloride is often used as a desiccant to fill drying tubes, and dried giant algae (also known as seaweed ash) with calcium chloride can be used for the production of soda ash. Some household dehumidifiers use calcium chloride to absorb moisture from the air. Calcium chloride can also be used as a desiccant or dehydrating agent for gases and organic liquids. Due to its neutrality, calcium chloride can dry acidic or alkaline gases and organic liquids. It can also be used to dry small amounts of gases such as nitrogen, oxygen, hydrogen, hydrogen chloride, sulfur dioxide, carbon dioxide, nitrogen dioxide, etc. in the laboratory. But it cannot be used to dry ethanol and ammonia, as ethanol and ammonia will react with calcium chloride to produce alcohol compound CaCl2 · 4C2H5OH and ammonia compound CaCl2 · 8NH3, respectively. Anhydrous calcium chloride can also be made into household products and used as an air hygroscopic agent. Anhydrous calcium chloride has been approved by the FDA as an absorbent for first aid bandages, and its function is to ensure dryness at the wound site.

Spread anhydrous calcium chloride on a gravel road surface, and use the hygroscopicity of anhydrous calcium chloride to condense the moisture in the air when the humidity is below the dew point to keep the road surface moist, thereby controlling the rise of dust on the road.

Deicing agents and coolants

Calcium chloride can reduce the freezing point of water, and spreading calcium chloride hydrates on roads can prevent icing and de icing and snow melting. However, the salt water after the melting of ice and snow can damage the soil and vegetation along the road and deteriorate the concrete on the road surface.

Calcium chloride solution can also be mixed with dry ice to prepare a low-temperature cooling bath. Add rod-shaped dry ice in batches to the saline solution until ice cubes appear in the system. The stable temperature of the cooling bath maintained by different types and concentrations of salt solutions may vary. Calcium chloride is commonly used as a salt raw material, and the required stable temperature is obtained by adjusting the concentration. This is not only because calcium chloride is cheap and easy to obtain, but also because the eutectic temperature of the calcium chloride solution (i.e. the temperature at which the solution solidifies into granular ice salt particles) is quite low, reaching -51.0 ℃. This allows for an adjustable temperature range from 0 ℃ to -51 ℃. This method can be implemented in Dewar bottles that can provide insulation, or in general plastic containers to hold cooling baths when the volume of Dewar bottles is limited and a large amount of salt solution needs to be prepared. In this case, the temperature is also relatively stable to maintain.