Sodium Carbonate, Disodium Carbonate, Calcined Soda, Light Soda, Washing Soda, Soda Ash, E500, 497-19-8

SODIUM CARBONATE (SODA ASH LIGHT, E500)

1. Chemical Identity and Material Classification

• Chemical Name: Sodium Carbonate, Disodium Carbonate, Carbonic Acid Disodium Salt

• Synonyms: Soda Ash Light, Light Soda Ash, Washing Soda, Calcined Soda, Soda Crystal, Na-X, Bisodium Carbonate

• CAS Number: 497-19-8

• EC Number (EINECS): 207-838-8

• Molecular Formula: Na₂CO₃

• Molecular Weight: 105.99 g/mol

• E Number: E500 (food additive)

• Chemical Class: Inorganic salt (alkaline carbonate)

• HS Code: 2836.20

• UN Number: Not regulated (non-hazardous for transport)

2. Physical Properties

2.1 General Physical Properties

2.2 Thermal Properties

2.3 Solubility in Water

2.4 Solubility in Other Solvents

2.5 Hygroscopicity

3. Chemical Properties

3.1 Molecular Structure

Structure: Na₂CO₃

• Strongly alkaline salt (conjugate base of weak carbonic acid)

• Dissociates in water: Na₂CO₃ → 2Na⁺ + CO₃²⁻

• Hydrolysis: CO₃²⁻ + H₂O ⇌ HCO₃⁻ + OH⁻ (produces alkaline solution)

3.2 Aqueous Solution Properties

3.3 Chemical Reactivity

3.4 Hydrate Forms

3.5 Thermal Decomposition

3.6 Incompatibilities

4. Quality Specifications

4.1 Light Soda Ash – Industrial Grade (Typical)

4.2 Food Grade (FCC / E500)

4.3 Food Grade – Pharmacopeia Specifications (BP, Ph. Eur., NF)

5. Particle Size Distribution (Light Grade) 

6. Production Methods

6.1 Solvay Process (Most Common – 90% of global production)

Reaction sequence:

1. NaCl + NH₃ + CO₂ + H₂O → NaHCO₃ + NH₄Cl

2. 2NaHCO₃ → Na₂CO₃ + H₂O + CO₂↑ (calcination)

Process:

• Brine (NaCl solution) saturated with ammonia

• Carbon dioxide passed through ammoniated brine

• Sodium bicarbonate precipitates

• Bicarbonate calcined to produce soda ash

• Ammonia recovered and recycled

Quality: Light soda ash (low density, fine particles)

6.2 Trona Mining (Natural Soda Ash – USA, Kenya, Botswana)

Source: Natural trona ore (Na₂CO₃·NaHCO₃·2H₂O)

Process:

• Ore mining → crushing → calcination → dissolution → crystallization → drying

Quality: Equivalent to synthetic soda ash

6.3 Dense Soda Ash (Denser Grade)

Production: Hydration of light soda ash followed by recalcination

Properties: Higher bulk density (800–1,100 kg/m³), larger particles
Application: Glass manufacturing (preferred due to lower dusting)

7. Mechanism of Action

7.1 Water Softening

Reaction: Ca²⁺ (aq) + CO₃²⁻ (aq) → CaCO₃ (s) ↓

• Precipitates calcium and magnesium ions as insoluble carbonates

• Removes hardness from water

• Prevents soap scum formation

7.2 pH Buffering (Water Treatment)

Equilibrium: HCO₃⁻ ⇌ CO₃²⁻ + H⁺

• Maintains alkaline pH (9–11) in water systems

• Neutralizes acidic conditions (e.g., swimming pools)

7.3 Detergency Enhancement

8. Industrial Applications

8.1 Glass Manufacturing (Largest Application – ~50% of consumption)

Benefits:

• Lowers melting point of silica from 1,700°C to 1,200°C

• Reduces energy consumption

• Improves workability of molten glass

8.2 Detergents and Cleaning Products

Benefits:

• Effective water softening (precipitates Ca²⁺/Mg²⁺)

• Maintains optimal alkaline pH (10–11)

• Cost-effective builder

8.3 Water Treatment

8.4 Chemical Production

8.5 Pulp and Paper Industry

8.6 Food and Beverage Industry (E500)

Food additive status: E500 – permitted as GRAS (FDA) and EFSA

8.7 Textile Industry

8.8 Metallurgy and Mining

8.9 Environmental Applications

9. Toxicology and Safety

9.1 Acute Toxicity

9.2 GHS Classification (EC 1272/2008) 

9.3 NFPA Rating

9.4 Occupational Exposure Limits

10. Safety Precautions and Personal Protective Equipment (PPE)

• Hazards:

  • Causes serious eye irritation (H319)

  • Dust may cause respiratory tract and skin irritation

  • Hygroscopic – absorbs moisture from air

  • Non-flammable

  • May form dust explosion in air at high concentrations

• PPE (recommended – industrial handling):

  • Safety glasses (EN 166) or chemical goggles – mandatory 

  • Dust mask (FFP2/N95) – for dusty operations

  • Chemical-resistant gloves (nitrile – for prolonged contact)

  • Protective clothing (dust protection)

• Engineering controls:

  • Local exhaust ventilation (LEV) for dust control

  • Eyewash stations

  • Avoid dust generation

• First aid:

  • Eye contact: Rinse immediately with plenty of water under eyelids for at least 15 minutes; remove contact lenses; seek medical attention if irritation persists 

  • Skin contact: Wash with warm water and soap; remove contaminated clothing 

  • Inhalation: Remove victim from dusty environment to fresh air; if unconscious, place in recovery position; if symptoms persist, seek medical attention 

  • Ingestion: Rinse mouth; do NOT induce vomiting; give water; seek medical attention 

11. Environmental Fate

12. Storage and Shelf Life

12.1 Storage Conditions

12.2 Shelf Life

13. Transport Information

14. Synonyms and Common Names

• English: Sodium Carbonate, Soda Ash Light, Light Soda Ash, Washing Soda, Calcined Soda, Disodium Carbonate, Carbonic Acid Disodium Salt, Na-X, Soda Crystal

• Trade names: Soda Ash Light (Tata Chemicals) , Soda Ash (Tokuyama) 

• French: Carbonate de sodium

• German: Natriumcarbonat, Soda

• Spanish: Carbonato de sodio

• Turkish: Sodyum Karbonat, Hafif Soda, Çamaşır Sodası, Soda Külü

15. Regulatory Status

16. Why Choose Sodium Carbonate (Soda Ash Light)?

Limitations:

• Hygroscopic – Absorbs moisture; requires airtight storage

• Causes serious eye irritation (H319) – Requires PPE (goggles)

• Dust may cause respiratory irritation – Requires dust control measures

• Alkaline (pH 11.4) – Corrosive to aluminum and zinc in presence of moisture

• Not compatible with strong acids – Violent reaction, CO₂ evolution

17. Comparison: Light Soda Ash vs. Dense Soda Ash

18. Comparison with Other Alkaline Agents

19. Frequently Asked Questions (FAQs)

Q1: What is the difference between light soda ash and dense soda ash?
A1: Light soda ash has lower bulk density (480–650 kg/m³) and finer particles, making it dissolve faster – preferred for detergents and chemical production. Dense soda ash has higher bulk density (800–1,100 kg/m³) and larger particles, producing less dust – preferred for glass manufacturing .

Q2: Is sodium carbonate safe to eat?
A2: Yes, food-grade sodium carbonate (E500) is GRAS (Generally Recognized as Safe) by FDA and EFSA for use as an acidity regulator, anticaking agent, and raising agent in food products .

Q3: Is sodium carbonate the same as baking soda?
A3: No. Sodium carbonate (Na₂CO₃, soda ash) is more alkaline (pH 11.4) and caustic. Baking soda is sodium bicarbonate (NaHCO₃, pH 8.3), which is milder. Sodium carbonate can be produced by heating baking soda (2NaHCO₃ → Na₂CO₃ + H₂O + CO₂).

Q4: How does sodium carbonate soften water?
A4: Sodium carbonate precipitates calcium and magnesium ions as insoluble carbonates: Ca²⁺ + CO₃²⁻ → CaCO₃↓. This removes hardness from water, allowing detergents to work more effectively.

Q5: Why is sodium carbonate used in swimming pools?
A5: Sodium carbonate (soda ash) is used to raise the pH of swimming pool water. Chlorine products tend to lower pH over time; soda ash neutralizes acidity and maintains optimal pH (7.2–7.8) for chlorine effectiveness and swimmer comfort.

20. Summary Table – Key Specifications at a Glance

This TDS is prepared in compliance with ISO 11014-1 format and is intended for glass manufacturers, detergent formulators, water treatment specialists, chemical engineers, food technologists, and procurement professionals. Certificates of Analysis (CoA), Safety Data Sheets (SDS), and sample validation reports are available upon request.