Overview
Calcium chloride (CaCl₂) is an inorganic compound derived from limestone and brine. It exists in anhydrous and hydrated forms, with the anhydrous variant being highly hygroscopic. Industrially, it is produced as a byproduct of the Solvay process or through direct reaction of calcium carbonate with hydrochloric acid. Its versatility stems from unique properties like high solubility, exothermic dissolution, and ability to lower the freezing point of water. These traits make it indispensable in sectors ranging from construction to food processing.
Physical and Chemical Properties
Anhydrous calcium chloride appears as white, odorless crystals or flakes with a density of 2.15 g/cm³. It readily absorbs moisture from the air, often forming hydrates (e.g., CaCl₂·2H₂O). Its aqueous solutions exhibit low freezing points (-52°C at 30% concentration), making them effective antifreeze agents. The compound undergoes exothermic dissolution in water, releasing significant heat. Chemically, it reacts with carbonates to precipitate calcium carbonate and with sulfates to form gypsum. These reactions are leveraged in wastewater treatment and oil drilling applications.
Main Applications
In winter maintenance, calcium chloride melts ice faster than sodium chloride at lower temperatures (-20°C vs -9°C). It is also used for dust suppression on unpaved roads due to its moisture-retention ability. Construction industries employ it as a concrete accelerator, reducing setting time in cold weather. Food-grade CaCl₂ (E509) acts as a firming agent in canned vegetables and a electrolyte in sports drinks. Other uses include desiccant in drying tubes, brine for refrigeration plants, and additive in swimming pools to balance calcium hardness.
Safety and Storage
Though non-flammable, calcium chloride requires careful handling. Its hygroscopic nature can cause clumping if stored improperly; use sealed moisture-proof containers in ventilated areas. Contact with skin may cause irritation or burns due to exothermic reactions with moisture. For large-scale storage, bulk bags should be placed on pallets in dry warehouses. Spills should be neutralized with sodium carbonate or bicarbonate before disposal. Always use PPE (gloves, goggles) when handling, especially the anhydrous form.
B2B Procurement Guide
Bulk buyers should prioritize suppliers with ISO certification for consistent quality. Key specifications include purity (94-97% for industrial use, 74-77% for de-icing), particle size (flakes/pellets), and impurity levels (alkali metals, magnesium). Packaging options range from 25kg bags to 1-ton super sacks. Logistics considerations: Coastal regions often source from brine-based producers, while inland buyers may prefer limestone-derived product. Spot prices fluctuate with seasonal demand (higher in winter). Long-term contracts (6-12 months) typically offer 5-10% cost savings over spot purchases.