🔷 Chemical Identity and Basic Profile Ammonium sul...

🔷 Chemical Identity and Basic Profile Ammonium sulphate is a crystalline inorganic salt comprising ammonium ions (NH₄⁺) and the sulphate ion (SO₄²⁻). It's widely known for its role in agriculture and nitrogen-based fertilization. The compound appears as a colorless or white solid, highly stable under ordinary conditions. Molecular formula: (NH₄)₂SO₄ Molecular weight: 132.14 g/mol Chemical structure: Two NH₄⁺ ions ionically bonded to one SO₄²⁻ ion 🔷 Physical and Thermal Behavior Ammonium sulphate exists as a free-flowing, odorless, granular or crystalline substance. Melting point: Decomposes at ~235–280 °C (no distinct melting phase; releases ammonia) Boiling point: Not applicable – decomposes before boiling Appearance: Fine white granules or powder Density: 1.77 g/cm³ (solid) Solubility in water: ~70.6 g/100 mL at 20°C (very high); solubility increases with temperature Solubility in ethanol, acetone: Practically insoluble Hygroscopicity: Low; does not absorb moisture from the air under typical storage conditions 🔷 Chemical and Ionic Properties In aqueous solution, ammonium sulphate dissociates completely: (NH₄)₂SO₄ → 2 NH₄⁺ + SO₄²⁻ pH of 1% solution: ~5.5–6.5 (mildly acidic) Reactivity: Compatible with most neutral and acidic substances; incompatible with strong bases (produces ammonia gas) and oxidizers Thermal decomposition: Produces ammonia (NH₃) and sulfur dioxide (SO₂) when strongly heated 🔷 Agronomic Function and Role Ammonium sulphate is a dual-nutrient fertilizer, delivering both nitrogen (21%) and sulfur (24%) in plant-available forms. It supports: Leafy growth and protein synthesis due to nitrogen content Enzyme activation, chlorophyll production, and disease resistance with sulfur Ideal for alkaline soils, where the acidic reaction of ammonium sulphate helps to lower pH It is widely used in crops like: Rice Wheat Sugarcane Potatoes Oilseeds Also used in fertigation, broadcast application, and direct soil mixing. 🔷 Industrial & Non-agricultural Usage Beyond fertilizers, ammonium sulphate is used in: Protein purification: Used in salting-out technique during biochemical separation Textile dyeing: Fixing agent for dyes Flame retardants: Component in fireproofing mixtures Wastewater treatment: Flocculant for industrial effluents Food processing (additive E517): Used as a dough conditioner, yeast nutrient (within regulated limits) Chemical synthesis: Intermediate in making persulfates and other ammonium salts 🔷 Environmental & Safety Considerations Biodegradability: Inorganic – not degradable but fully soluble and absorbed by plants Ecotoxicity: Overuse in farming can cause eutrophication in water bodies via nitrogen leaching Human toxicity: Low; non-toxic in moderate exposure; dust may cause minor respiratory or eye irritation Storage: Should be kept dry and away from bases or oxidizers 🔷 Formulation & Manufacturing Typically produced by reacting ammonia with sulfuric acid: 2 NH₃ + H₂SO₄ → (NH₄)₂SO₄ The process may be integrated in industries using: By-product ammonia from coke ovens Sulfuric acid waste recovery systems Continuous granulation or crystallization methods Commercial grades are available as: Standard grade: fine crystals Granular grade: coarse particles for bulk fertilizer applications Caprolactam grade: high-purity form for food and pharma industries 🔷 Key Differentiators vs Other Nitrogen Fertilizers Parameter Ammonium Sulphate Urea Ammonium Nitrate Nitrogen Content 21% 46% 33–34% Sulfur Content 24% None None Soil Reaction Acidic Neutral–alkaline Acidic Leaching Risk Moderate High High Hygroscopic Nature Low High Moderate 🔷 Conclusion Ammonium sulphate stands out for its stability, ease of storage, and dual-nutrient contribution. Its lower nitrogen concentration is compensated by excellent sulfur availability, which is critical in sulfur-deficient or alkaline soils. The compound is also appreciated for non-volatility, making it more predictable than urea in certain conditions.