Calcium Sulfate Anhydrous, Calcium Sulfate, Calcium Sulfate Anhydrite, E516, 7778-18-9

Calcium Sulfate Anhydrous, Calcium Sulfate, Calcium Sulfate Anhydrite, E516, 7778-18-9

Calcium Sulfate Anhydrous (CAS 7778-18-9)

General Properties

• Chemical formula: CaSO₄

• Molecular weight: 136.14 g/mol

• Appearance: White, odorless crystalline powder

• Solubility: Poorly soluble in water (~0.2 g/100 mL at 25 °C)

• Stability: Thermally stable; decomposes at very high temperatures to calcium oxide and sulfur oxides

Applications

• Construction: Used in cement and plaster formulations as a binder.

• Food industry: Approved as additive E516 (acidity regulator, flour treatment agent, brewing aid).

• Agriculture: Soil conditioner and source of calcium and sulfur.

• Laboratory: Drying agent (commercially known as “Drierite”).

• Pharmaceuticals: Filler in tablets and capsules.

Safety & Handling

• Hazards: Low toxicity; dust may irritate eyes, skin, and respiratory tract.

• Precautions:

  • Use protective eyewear and masks in dusty environments.

  • Ensure proper ventilation.

  • Store in a dry, cool, well-ventilated place.

• First aid:

  • Eye contact → rinse with plenty of water.

  • Inhalation → move to fresh air.

  • Skin contact → wash with soap and water.

Comparison with Calcium Sulfate Dihydrate (Gypsum)

📊 Sectoral Usage and Suitability

🔎 Notes

• 🔵 Low → Small-scale or trace usage (food, lab).

• 🔵🔵 Medium → Moderate proportions in formulations (construction, pharma, plastics).

• 🔵🔵🔵 High → Large-scale application (agriculture).

• ⚠️

Calcium Sulfate and their CAS numbers, with comparisons:

Types of Calcium Sulfate

Key Comparisons

• Water content:

  • Anhydrous → no water

  • Hemihydrate → 0.5 mol water

  • Dihydrate → 2 mol water

• Solubility in water:

  • Anhydrous → lowest solubility

  • Hemihydrate → moderate solubility

  • Dihydrate → relatively higher solubility

• Thermal stability:

  • Anhydrous → highest stability

  • Hemihydrate → less stable, reverts to dihydrate in humid conditions

  • Dihydrate → decomposes when heated, forming hemihydrate or anhydrous

• Usage differences:

  • Anhydrous → drying agent, food/pharma additive

  • Hemihydrate → quick-setting plaster for construction and art molds

  • Dihydrate → gypsum for plasterboards, soil treatment, cement industry

Risk–Benefit Notes

• Anhydrous: Stable, versatile, but dust can irritate eyes/respiratory tract.

• Hemihydrate: Useful for fast-setting applications, but sensitive to moisture.

• Dihydrate: Cheap and widely available, but mechanically weaker compared to cementitious materials.

📌 General Description

• Chemical Name: Calcium Sulfate Anhydrite

• CAS No: 7778-18-9

• Formula: CaSO₄

• Appearance: White crystalline powder, odorless

• Key Property: Water-free form of calcium sulfate; strong desiccant and filler

🧪 1. Laboratory & Analytical Chemistry

• Application: Powerful drying agent, desiccant, reagent carrier.

• How to Use: Place directly in desiccators or mix into analytical formulations.

• Typical Amounts:

  • Desiccators: 200–500 g per unit.

  • Reagent carrier: 5–10% of mixture.

• Note: More effective than hemihydrate for moisture removal due to complete absence of water.

🏗️ 2. Construction & Building Materials

• Application: Cement additive, self-leveling floor compounds, plasterboard core.

• How to Use: Incorporated into cement or plaster formulations to control setting time and improve strength.

• Typical Amounts:

  • Cement: 3–8% additive.

  • Self-leveling compounds: 10–20% filler.

  • Plasterboard: 20–30% of core composition.

• Note: Provides dimensional stability and fire resistance.

🏺 3. Ceramics & Glass

• Application: Mold-making, filler, stabilizer.

• How to Use: Mixed with clay or glass batch to improve hardness and reduce shrinkage.

• Typical Amounts:

  • Ceramic molds: 5–15% additive.

  • Glass batch: 2–5% stabilizer.

• Note: Ensures uniformity and reduces cracking during firing.

🌱 4. Agriculture

• Application: Soil conditioner, calcium source, desiccant for fertilizers.

• How to Use: Applied directly to soil or blended into fertilizer formulations.

• Typical Amounts:

  • Soil conditioning: 200–400 kg per hectare.

  • Fertilizer drying: 5–10% additive.

• Note: Less soluble than dihydrate, so effect is slower but longer-lasting.

💊 5. Pharmaceuticals & Cosmetics

• Application: Tablet excipient, filler, desiccant in packaging.

• How to Use: Incorporated into formulations or sachets for moisture control.

• Typical Amounts:

  • Tablets: 2–5% filler.

  • Packaging desiccant: 1–5 g per unit.

• Note: Used in non-ingestible applications more commonly than hemihydrate.

🎨 6. Pigments, Paints & Polymers

• Application: Filler, pigment carrier, viscosity regulator.

• How to Use: Added to paints, plastics, and rubber formulations.

• Typical Amounts:

  • Paints: 5–15% filler.

  • Plastics/Rubber: 10–20% additive.

• Note: Improves mechanical strength and reduces production cost.

📦 7. Industrial & Specialty Uses

• Application: Paper, adhesives, sealants, fireproofing materials.

• How to Use: Incorporated as filler or stabilizer.

• Typical Amounts:

  • Paper/Cardboard: 5–10% filler.

  • Adhesives/Sealants: 10–20% additive.

• Note: Enhances fire resistance and dimensional stability.

🎯 Summary

• Essential Sectors: Laboratory (drying agent), construction (cement/plasterboard), industrial fillers.

• Limited Use: Agriculture (slow-release calcium), pharmaceuticals (excipient/desiccant).

• Not Suitable: Direct food additive (dihydrate form E516 is used instead).

• Typical Usage Range: 2–30% additive depending on sector, or 200–500 kg/ha in agriculture.