🌟 Ammonium Sulphate – Comprehensive Chemical Insig...

🌟 Ammonium Sulphate – Comprehensive Chemical Insight Ammonium sulphate, chemically denoted as (NH₄)₂SO₄, is a white, crystalline, inorganic compound known primarily for its use as a highly efficient nitrogenous fertilizer. In addition to agriculture, it finds utility in industries ranging from pharmaceuticals to water treatment and laboratory applications. Let’s delve deeper into its properties, structure, uses, and handling. 🔹 Chemical Profile Molecular Formula: (NH₄)₂SO₄ Molecular Weight: 132.14 g/mol IUPAC Name: Ammonium tetraoxosulphate(VI) Structure: It comprises two ammonium ions (NH₄⁺) and one sulfate ion (SO₄²⁻) held together via ionic bonding. 🔸 Physical Properties Property Description Appearance White crystalline solid or granules Odor Odorless Taste Saline, slightly acidic Solubility Highly soluble in water (approx. 70 g/100 mL at 20°C); insoluble in alcohol and acetone Density 1.77 g/cm³ Melting Point Decomposes at ~235–280°C; does not melt cleanly Thermal Stability Stable at room temperature; decomposes at high heat releasing ammonia and sulfur oxides 🔸 Chemical Properties Dissociation in Water: ( 𝑁 𝐻 4 ) 2 𝑆 𝑂 4 → 2 𝑁 𝐻 4 + + 𝑆 𝑂 4 2 − (NH 4 ​ ) 2 ​ SO 4 ​ →2NH 4 + ​ +SO 4 2− ​ pH of Solution: ~5.5 to 6.5 (slightly acidic) Reacts With: Strong bases → liberates ammonia gas (NH₃) Calcium salts → forms calcium sulphate precipitate (CaSO₄) Combustibility: Non-flammable Corrosiveness: Non-corrosive to metals but can accelerate rusting in moist conditions 🔸 Forms & Grades Available Crystalline Powder – For laboratory or small-scale agricultural use Granular Fertilizer Grade – For direct field application, easier handling Food & Pharma Grade – Higher purity, low heavy metal content Caprolactam Grade – Derived from caprolactam byproducts, used in industrial processing 🌾 Agricultural Significance Ammonium sulphate is a dual-purpose fertilizer, providing both nitrogen (21%) and sulfur (24%) — two essential macronutrients for plant health. It plays a vital role in: Enhancing leaf development and chlorophyll production Stimulating protein synthesis and enzyme activity Improving flavor and quality of crops like onion, garlic, oilseeds, and leafy greens Acidifying alkaline soils and improving nutrient uptake Aiding in early crop development when applied as a starter fertilizer Application Methods: Broadcasting (pre-sowing) Fertigation (with irrigation water) Foliar spray (diluted solution) Side dressing (around plant base) 🧪 Industrial and Technical Applications While agriculture is the dominant sector, ammonium sulphate also finds wide industrial usage: 1. Laboratory Use Precipitating agent in protein purification (salting out) Source of nitrogen in microbial culture media 2. Pharmaceutical Industry Component in some intravenous fluids and topical formulations Used in buffer solutions and crystallization processes 3. Food Processing (E517) Approved food additive for yeast fermentation and dough strengthening Common in bakery industries under strict dosage limits 4. Textiles & Leather Used in dye-fixation processes and tanning baths 5. Water Treatment Applied as a coagulant aid to remove contaminants and soften hard water 6. Explosives & Mining Combined with fuels or nitrate-based materials in ANFO-type explosive mixes (in specific technical-grade uses) 🌿 Environmental Impact & Soil Chemistry Ammonium sulphate contributes to both plant nutrition and soil modification: Benefit Explanation Acidifies alkaline soils Releases H⁺ ions during nitrification Reduces soil pH Improves uptake of phosphorus, iron, and zinc Low Volatilization Losses Unlike urea, less ammonia loss in open fields Compatible with Micronutrients Can be blended with boron, zinc, etc. However, over-application may lead to: Soil acidification beyond optimal range Nitrogen leaching in sandy soils Risk of eutrophication in nearby water bodies 🧯 Safety & Storage Aspect Description Health Hazards Non-toxic in agricultural use; mild eye/respiratory irritation from dust Ingestion Low toxicity, but not suitable for consumption in raw form Storage Store in dry, cool, ventilated areas away from strong alkalis Packaging Typically packed in 25kg/50kg HDPE bags or bulk in woven sacks ⚖️ Comparison with Other Nitrogen Fertilizers Parameter Ammonium Sulphate Urea Ammonium Nitrate Nitrogen Content 21% 46% 33–34% Sulfur Content 24% None None pH Effect Acidifying Slightly alkaline Acidifying Volatility Loss Low High (urease loss) Medium Hygroscopicity Low High Moderate 🏭 Manufacturing Routes Reaction of ammonia with sulfuric acid: 2 𝑁 𝐻 3 + 𝐻 2 𝑆 𝑂 4 → ( 𝑁 𝐻 4 ) 2 𝑆 𝑂 4 2NH 3 ​ +H 2 ​ SO 4 ​ →(NH 4 ​ ) 2 ​ SO 4 ​ As a by-product from: Caprolactam (nylon-6 production) Steel plants Coke oven gas recovery ✅ Final Thoughts Ammonium sulphate stands out due to: Its dual nutrient profile (N + S) Low cost, high stability, and predictable behavior in soil Compatibility with blended fertilizers and micronutrient formulations Low risk of volatilization, making it suitable for humid or rainy environments