The chemical formula for fused calcium chloride is CaCl₂.
Fused calcium chloride refers to the anhydrous (water-free) form of calcium chloride, typically obtained by heating to melt and then solidify the compound, or by thorough drying. This form is often granular, commonly found as particles approximately 0.5-2.0 mm in size, making it suitable for various industrial and laboratory applications, including elementary analysis.
Understanding Fused Calcium Chloride
Calcium chloride is an ionic compound composed of one calcium ion (Ca²⁺) and two chloride ions (Cl⁻). The term "fused" specifically indicates that it is in its anhydrous state, meaning it contains no water molecules within its crystalline structure. This characteristic differentiates it from its various hydrated forms, such as calcium chloride dihydrate (CaCl₂·2H₂O) or hexahydrate (CaCl₂·6H₂O).
Anhydrous calcium chloride is a highly versatile chemical known for its strong hygroscopic and deliquescent properties – it readily absorbs moisture from the air, and if enough moisture is absorbed, it can dissolve into a liquid solution.
Key Properties and Characteristics of Fused Calcium Chloride
| Property | Description |
|---|---|
| Chemical Formula | CaCl₂ |
| CAS Number | 10043-52-4 (Calcium Chloride on PubChem) |
| Appearance | White or off-white granular solid, typically in sizes ranging from 0.5 to 2.0 mm. |
| Nature | Highly hygroscopic: Strongly attracts and holds water molecules from the surrounding environment. Deliquescent: Absorbs enough moisture from the air to dissolve and form a solution. |
| Solubility | Highly soluble in water, a process that is exothermic (releases heat). It is also soluble in alcohol. |
| Melting Point | Approximately 772 °C (1422 °F). |
| Applications | De-icing roads, desiccant (drying agent), dust control, food additive (firming agent), concrete accelerator, brine for refrigeration systems, wastewater treatment, oil and gas drilling fluids, and laboratory use for elementary analysis. |
For more general information on calcium chloride, you can refer to Wikipedia's article on Calcium Chloride.
Common Applications
The anhydrous form of calcium chloride, particularly the fused granular type, is highly valued for its potent desiccant properties and wide range of uses across various industries:
- Drying Agent: Its strong affinity for water makes it an excellent choice for drying gases, organic liquids, and maintaining dry conditions in desiccators or storage areas.
- De-icing: Widely used to melt ice and snow on roads, sidewalks, and other surfaces, especially in cold climates, due to its ability to lower the freezing point of water more effectively than many other salts.
- Dust Control: When applied to unpaved roads, it absorbs moisture from the air, which helps bind dust particles to the road surface, significantly reducing airborne dust.
- Food Industry: Serves as a firming agent in canned vegetables and fruits, helps maintain the texture of processed foods, and is used as an electrolyte in some beverages.
- Construction: Acts as an accelerator for concrete, speeding up the setting time and increasing early strength, which is particularly beneficial in cold weather.
- Oil and Gas: Utilized in drilling fluids to increase their density, prevent hydration of clay minerals, and stabilize shale formations.
- Laboratory Analysis: The pure, granular form is critical for applications like elementary analysis, where precise and anhydrous conditions are required.
Fused vs. Hydrated Forms
It's important to distinguish between fused (anhydrous) calcium chloride and its hydrated counterparts. While they all contain calcium and chloride ions, the presence of water molecules drastically alters their properties and specific uses.
- Fused Calcium Chloride (CaCl₂): This is the anhydrous form, offering the highest concentration of calcium chloride and maximum desiccant power.
- Calcium Chloride Dihydrate (CaCl₂·2H₂O): Contains two molecules of water per formula unit and is a common commercial form.
- Calcium Chloride Hexahydrate (CaCl₂·6H₂O): Contains six molecules of water per formula unit, often appearing as flakes or larger crystals.
The "fused" designation specifically points to the anhydrous state, typically produced through a high-temperature process to ensure minimal moisture content, which is crucial for applications where water absorption or precise concentration is paramount.
