CAS Number:
497-19-8 (anhydrous)
Chemical Name:
Sodium Carbonate. Commonly known as Soda Ash, Washing Soda
Molecular Formula:
Na2CO3
Molecular Weight:
105.99 g/mol (anhydrous)
Common Form:
White, odorless, hygroscopic powder or granules. Available in "light" (low density) and "dense" (high density) grades
Uses:
Soda ash is a primary source of alkalinity and sodium ions for a vast range of industries. Its largest use is in glass manufacturing.
Primary Applications:
· Glass Manufacturing: The single largest application (~50% of global use). It acts as a flux, lowering the melting point of silica (sand) in the production of container, flat, and fiberglass.
· Chemical Manufacturing: A key raw material for producing sodium bicarbonate (baking soda), sodium silicates, sodium phosphates, and chromium compounds.
· Detergents & Cleaners: Used as a builder and pH adjuster in powdered and liquid detergents, helping to soften water and enhance cleaning power.
· Water Treatment: Raises the pH of acidic water, neutralizes acidity, and aids in the precipitation of dissolved minerals.
· Metallurgy & Mining: Used in processing ores (e.g., bauxite to alumina) and as a flux in smelting.
· Pulp & Paper Industry: Used in the Kraft process for pulping wood and in bleaching.
What does Soda Ash do in a formulation?
- Alkali & pH Buffer: Provides a strong alkaline pH (approx. 11-12 in 1% solution) to neutralize acids and maintain alkalinity.
- Water Softening Agent (Builder): Precipitates calcium and magnesium ions as carbonates, preventing them from interfering with surfactants.
- Flux: In glass and metallurgy, it lowers the melting point of mixtures, reducing energy consumption.
- Source of Sodium Ions: Provides Na? for chemical reactions to form other sodium compounds.
- Electrolyte: Used in some electroplating and electrolysis processes.
Safety Profile:
· Hazard Classification: Danger. Causes serious eye damage, skin irritation, and may cause respiratory irritation. Not classified as flammable or combustible.
· Skin/Eye Contact: Dust is irritating. Can cause serious eye damage and skin burns, especially in the presence of moisture (where it can form a caustic solution). Flush eyes and skin with plenty of water.
· Inhalation: Dust can irritate the respiratory tract, causing coughing and sore throat. Use local exhaust ventilation.
· Ingestion: Harmful. Can cause corrosion of the digestive tract, with symptoms of nausea, vomiting, and diarrhea.
· Required PPE: Safety goggles, dust mask (NIOSH N95), chemical-resistant gloves, and protective clothing.
· Handling Note: Always add soda ash slowly to water, not water to the solid, to control heat and splashing from the exothermic reaction.
Technical profile:
| Property | Values |
| Appearance | White, free-flowing powder or granules |
| Bulk Density | Light Ash: ~0.5 - 0.6 g/cm³. Dense Ash: ~0.9 - 1.1 g/cm³ (key difference for handling and transport) |
| pH (1% solution) | 11.2 - 11.6 |
| Melting Point | 851 °C |
| Solubility in Water | Highly soluble (~22 g/100 mL at 20°C). Solubility increases with temperature |
| Hygroscopicity | Absorbs moisture and carbon dioxide from air to form sodium bicarbonate (monohydrate) |
| Typical Purity (Technical Grade) | ≥ 99.0% Na?CO? |
| Common Grades | Dense Soda Ash (for glass), Light Soda Ash (for chemicals/detergents), and refined grades (e.g., USP/Ph. Eur.). |