Calcium Chloride Dihydrate Supplier South Africa

What Is Calcium Chloride Dihydrate?

Calcium chloride dihydrate (CaCl₂·2H₂O) is the dihydrated form of calcium chloride — white granules, prills, or flakes that are highly hygroscopic (absorb moisture from air) and highly soluble in water. Dissolution is strongly exothermic. Calcium chloride is the most readily available and cost-effective source of soluble calcium ions (Ca²⁺) for water treatment, concrete technology, industrial processing, and agricultural applications. The dihydrate form (74–77% CaCl₂ equivalent) is the most common commercial grade — the anhydrous (94–97% CaCl₂) and 77% flake forms are also available. Terracore Chemicals supplies the dihydrate grade in 25 kg and 1 MT bags across Southern Africa.

Water Treatment and Hardness Adjustment

In water treatment, calcium chloride is used to increase calcium hardness in process water, swimming pools, cooling towers, and potable water systems. Swimming pool calcium hardness (target: 200–400 mg/L as CaCO₃) must be maintained to prevent pool water from dissolving calcium out of plaster or concrete pool surfaces (low-calcium “aggressive” water). In potable water remineralisation — after reverse osmosis or lime softening removes calcium — calcium chloride is added alongside sodium bicarbonate to restore the Langelier Saturation Index (LSI) and prevent corrosion of distribution pipes. In cooling water systems, calcium hardness is maintained to control calcium carbonate scaling tendency and to balance corrosion inhibitor chemistry. Calcium chloride is also used as a flocculant aid in conjunction with polyelectrolytes.

Concrete Acceleration and Other Industrial Applications

In concrete technology, calcium chloride is used as an accelerating admixture — it accelerates Portland cement hydration, increasing early-strength gain (24-hour and 3-day compressive strength). Typical dosage: 1–2% CaCl₂ by mass of cement. It is used in cold-weather concreting and in precast concrete production. Note: CaCl₂ accelerator is not used in reinforced concrete or prestressed concrete, as chloride accelerates reinforcement corrosion. In dust suppression on gravel roads and mine haul roads, calcium chloride solution is sprayed to absorb atmospheric moisture and bind road fines, reducing dust. In food processing, calcium chloride is used in cheese production (to restore calcium lost during pasteurisation), in pickle and brine production, and as a firming agent. Terracore Chemicals supplies food-grade and technical-grade calcium chloride dihydrate.