What Is Calcium Chloride?
Calcium chloride is a calcium and chlorine compound, occurring naturally in limited ores and trace amounts in seawater. It appears as colorless or white crystals, highly soluble in water, and soluble in ethanol and acetone.
Uses of Calcium Chloride
1. Desiccant
Known for its excellent hygroscopicity, calcium chloride is used as a dehumidifying agent, outperforming silica gel in moisture absorption by five times. Its moisture absorption, unlike that of activated carbon or silica gel, is chemical (covalent bonding). It is also applied on road surfaces for dust control by maintaining moisture.
2. Snow Melting/Anti-freezing Agent
Calcium chloride releases heat upon reacting with moisture, making a 30% solution an effective anti-freeze and snow-melting agent that operates down to nearly -50℃. It is preferred over other agents like sodium or magnesium chloride.
3. Pharmaceuticals
It finds applications in medical treatments, including injections, infusions, and sometimes in osteoporosis therapy.
4. Food Products
As a food additive, calcium chloride adjusts the hardness and pH of beverages and serves as a coagulant in cheese and tofu production.
5. Petrochemicals
In the petrochemical industry, it enhances oil extraction efficiency by water absorption and is used for the dehydration of ethylene gas.
6. Other Uses
Calcium chloride aids in gypsum production through reactions with sulfates and fluorine removal from wastewater by forming precipitates of calcium fluoride.
Properties of Calcium Chloride
With a molecular weight of 111, specific gravity of 2.15, melting point of 772°C, and CAS number 10043-52-4, calcium chloride is notably soluble in water. Its flame reaction yields a dark orange color.
Types of Calcium Chloride
Available in hydrated forms and as a liquid, calcium chloride’s applications vary by its form, including dihydrate and hexahydrate versions, each with specific properties and uses.
1. Calcium Chloride Dihydrate (CaCl2-2H2O)
With a molecular weight of 147.01 and a melting point of 175.5°C, this form is water-soluble and serves as the main component of sinjalite.
2. Calcium Chloride Hexahydrate (CaCl2-6H2O)
Characterized by its needle-like crystals and a low melting point of 29.8°C, it is ideal for educational purposes in crystal growth demonstrations.
Other Information on Calcium Chloride
How Calcium Chloride Is Produced
Production methods include the ammonia-soda process for sodium carbonate, yielding calcium chloride as a byproduct, and direct reaction of hydrochloric acid with limestone or calcium hydroxide.