What Are The Differences Between Dihydrate And Anhydrous Calcium Chloride?

Author:wftpchemical 2025-11-24 15:00:46 6 0 0

Calcium Chloride Dihydrate  vs  Calcium Chloride Anhydrous

 

Calcium chloride (CaCl₂) is a versatile inorganic salt widely used in de-icing, dust control, refrigeration brines, concrete acceleration, and more. It is sold in two primary forms:

PropertyDihydrate (CaCl₂·2H₂O)Anhydrous (CaCl₂)
Chemical FormulaCaCl₂·2H₂OCaCl₂
CAS No.10035-04-810043-52-4
Molecular Weight147.01 g/mol110.98 g/mol
Active CaCl₂ Content (theoretical)~75.5 %100 %
Typical Purity Range74 – 80 %90 – 98 %
Water of Crystallization20 % (two H₂O molecules)0 %
AppearanceWhite, deliquescent flakes/pelletsWhite, granular/powder
HygroscopicityModerately hygroscopicExtremely hygroscopic
Bulk Density~0.8 – 1.0 g/cm³~0.9 – 1.2 g/cm³

 

1. Chemical & Physical Differences

  • Water Content

    • Dihydrate contains two molecules of water for each CaCl₂ unit (≈20 % by weight).

    • Anhydrous contains no crystallization water, giving a higher active-ingredient concentration.

  • Purity & Strength

    • Dihydrate grades typically deliver 74 – 80 % CaCl₂ when measured by mass.

    • Anhydrous grades deliver 90 – 98 % CaCl₂, making them ideal where maximum chloride ion availability is required.

  • Handling & Storage

    • Both forms are hygroscopic, but anhydrous absorbs moisture more rapidly—pack and store in airtight, moisture-barrier bags or silos.

    • Dihydrate is slightly more stable in open air, but still benefits from dry, cool storage.


 

2. Technical & Economic Considerations

AspectDihydrateAnhydrous
Cost per kg of CaCl₂Lower (contains inert water weight)Higher (more active material per kg)
Transportation EfficiencyHeavier (water content ↑ shipping weight)Lighter (shipping more CaCl₂ per tonne)
Dissolution RateSlower (water of crystallization must release)Faster (pure salt dissolves readily)
Ideal ApplicationsDust suppression, medium-strength brinesHigh-strength brines, desiccants, cement accelerator
  • Economic Tip: Although dihydrate is cheaper per tonne, anhydrous delivers more active CaCl₂ per shipment—choose based on your application’s cost-vs. performance balance.

 

3. The difference between the application of calcium chloride dihydrate and anhydrous calcium chloride

ApplicationDihydrateAnhydrous
Road De-icing & Anti-icing✔ (widely used)✔ (more aggressive melting)
Dust Control & Soil Stabilization✔ (faster uptake, longer persistence)
Refrigeration Brines✔ (lower freezing point)✔ (stronger freezing point depression)
Concrete Acceleration✔ (often preferred for precast, rapid-set)
Desiccant & Drying Agent✔ (industrial-grade drying)
Industrial Water Treatment✔ (pH adjustment, hardness control)

 

4. Why Choose Weifang T&P Chemical Co., Ltd.

  • Factory Direct Supply
    We manufacture both Calcium Chloride Dihydrate and Anhydrous grades in our ISO-certified facility—guaranteed purity, competitive pricing.

  • Custom Packaging & Delivery
    Options from 25 kg moisture-barrier bags to bulk tankers or ISO-silos, tailored to your operation’s scale.

  • Technical Support
    Dedicated specialists to help you select the right grade, optimize dosage, and troubleshoot end-use performance.


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