I. Basic Attribute Labels
Chemical Name: Sodium Carbonate
Common Names: Soda Ash, Washing Soda, Soda
Chemical Formula: Na₂CO₃
Molecular Weight: 105.99
CAS Number: 497-19-8
Appearance: White powder or granular crystals
Extended Information:
- Historical Context: Historically produced via the Leblanc process (using sulfuric acid, coal, and salt), now predominantly manufactured by the Solvay process (ammonia-based) for higher purity.
II. Chemical Property Labels
Acid-Base Character: Strong base-weak acid salt; aqueous solutions are alkaline (pH ~11 for 1% solution). Solubility: Highly soluble in water (21.5 g/100 mL at 20°C); slightly soluble in ethanol. Thermal Stability: Decomposes at high temperatures (>850°C) into sodium oxide (Na₂O) and carbon dioxide (CO₂):\(\text{Na}_2\text{CO}_3 \xrightarrow{\Delta} \text{Na}_2\text{O} + \text{CO}_2\uparrow\) Reaction Characteristics:
- Acid Reaction: Releases CO₂ with strong acids (e.g., HCl, H₂SO₄):\(\text{Na}_2\text{CO}_3 + 2\text{HCl} \rightarrow 2\text{NaCl} + \text{H}_2\text{O} + \text{CO}_2\uparrow\)
- Metal Salt Reaction: Forms insoluble carbonates with calcium/barium salts (e.g., CaCl₂ → CaCO₃ precipitate).
- Hydrolysis: Undergoes partial hydrolysis in water:\(\text{CO}_3^{2-} + \text{H}_2\text{O} \rightleftharpoons \text{HCO}_3^- + \text{OH}^-\)
Extended Information:
- Buffer Capacity: Forms a buffer system with sodium bicarbonate, widely used in industrial pH control.
III. Physical Property Labels
Density: 2.53 g/cm³ (solid) Melting Point: 856°C (decomposes rather than melts) Boiling Point: Non-existent (decomposes before boiling) Hygroscopicity: Highly hygroscopic; absorbs moisture from air to form sodium bicarbonate and sodium hydroxide (requires airtight storage).
Extended Information:
- Anhydrous vs. Hydrated Forms: Anhydrous Na₂CO₃ (soda ash) vs. hydrated forms like Na₂CO₃·10H₂O (washing soda), which lose water at 32°C.
IV. Classification Labels
Material Category: Inorganic compound, carbonate salt, sodium salt Industrial Grades:
- Industrial Grade: For glass, textiles, and chemicals.
- Food Grade: Compliant with FDA/GB standards for food additives.
- Reagent Grade: ≥99.5% purity for laboratory use. Hazard Rating: Non-hazardous (UN3077 for bulk transport), but dust may irritate eyes/respiratory tract.
Extended Information:
- UN Number: Classified as “Environmentally Hazardous Substance” (UN3077) in large quantities due to alkalinity.
V. Application Field Labels
Industrial Applications
- Glass Manufacturing: Core ingredient in soda-lime glass (with silica and limestone), reducing melting point of silica (70% of global soda ash use).
- Chemical Production: Precursor for sodium bicarbonate, silicates, and detergents.
- Metallurgy: Acts as a flux to remove silicate impurities in metal smelting.
- Textiles & Dyeing: Softens hard water and adjusts dye bath pH for cotton processing.
- Paper Industry: Used in kraft pulping to dissolve lignin from wood chips.
Food Applications
- Food Additive:
- Leavening agent in baked goods (reacts with acids in batters to produce CO₂).
- Acidity regulator in soy sauce and instant noodles (improves texture).
- Beverage Production: Neutralizes acidity in carbonated drinks and wine stabilization.
Other Applications
- Pharmaceuticals: Antacid for heartburn (e.g., in sodium bicarbonate formulations); laboratory reagent for pH calibration.
- Environmental Use: Treats industrial wastewater by precipitating heavy metals (e.g., Pb²+, Cu²+) as carbonates.
- Fire Extinguishers: Used in dry chemical extinguishers for Class B/C fires (releases CO₂ upon heating).
Extended Information:
- Glass Industry Insight: Soda ash accounts for ~18% of glass production costs; global demand correlates with construction and automotive sectors.
VI. Safety and Storage Labels
Safety Instructions:
- PPE Required: Wear dust masks and gloves to prevent inhalation/skin contact.
- Storage Guidelines: Store in dry, ventilated areas away from acids (reacts to produce CO₂). Hazard Summary: Non-toxic (LD₅₀ > 4000 mg/kg in rats), but dust may cause coughing or eye redness. Storage Methods: Airtight containers; protect from moisture and direct sunlight.
Extended Information:
- Spill Handling: Neutralize spills with acetic acid before sweeping; avoid wet cleanup (forms slippery solution).
VII. Upstream and Downstream Industry Chain Labels
Upstream Raw Materials:
- Salt (NaCl), limestone (CaCO₃), ammonia (NH₃) (Solvay process).
- Natural soda ash deposits (e.g., trona in Wyoming, USA). Downstream Products:
- Glass, soap, sodium bicarbonate, water glass (Na₂SiO₃), detergents.
- Derivatives: Sodium phosphates (for detergents), sodium silicates (adhesives).
Extended Information:
- Solvay Process: Emits ~1.5 tons of CO₂ per ton of soda ash; green initiatives focus on carbon capture technologies.
VIII. Industry Standard Labels
Chinese Standards:
- GB/T 210.1-2004: Industrial Sodium Carbonate – Test Methods (specifies purity, chloride, and sulfate limits).
- GB 1886.1-2015: Food Safety Standard – Sodium Carbonate as a Food Additive (defines heavy metal limits: Pb ≤ 2 mg/kg). International Standards:
- ISO 3755:1976: Industrial Sodium Carbonate – General Methods of Test (adopted by EU and ASEAN countries).
- ASTM D513-18: Standard for Carbon Dioxide in Water (relevant for soda ash solution analysis).
Extended Information:
- Regional Compliance: Food-grade soda ash exported to the EU must meet EC No 1333/2008 (E 500i for sodium carbonates).
Additional Insights
- Market Trends: Global soda ash market size exceeded $30 billion in 2023, driven by EV glass demand (e.g., electric vehicle displays).
- Sustainability: “Green soda ash” production using renewable energy is gaining traction to reduce carbon footprints.