Chemicals
- Ammonium Sulphate
Ammonium Sulphate (Crystal)
Introduction:
CAS：7783-20-2
Molecular weight：132.139
Density：1.77g/cm³
Melting point：235℃-280℃
Ammonium Sulfate ((NH₄)₂SO₄) is a high-quality, inorganic salt widely used as a nitrogen fertilizer in agriculture and as a raw material in various industrial processes.
Product Details
1. Production Process and Technical Features
Caprolactam-grade ammonium sulfate is a by-product of caprolactam (a precursor to nylon-6) production. Large crystals are formed through the following processes:
- Raw Materials and Reaction: High-purity liquid ammonia reacts with industrial sulfur to produce a sulfuric acid neutralization solution. Approximately 1.4 tons of ammonium sulfate is generated per ton of caprolactam.
- Crystallization Technology:
- Deceleration Crystallization: Gradual reduction of stirring speed (e.g., from 750 rpm to 450 rpm) controls crystal growth rate, ensuring ordered formation and avoiding rapid nucleation of fine crystals.
- Additive Optimization: Manganese sulfate (1.0–1.1%) and ammonium sulfamate (0.70–0.75%) are added as compound additives to refine crystal structure and suppress impurity adsorption.
- Temperature and Pressure Control: Crystallization temperature is maintained at 60–62°C under a system pressure of 15–18 kPa, ensuring stable growth in a low supersaturation environment.
2. Technical Breakthroughs in Large Crystals
- Particle Size Advantage: Traditional processes yield crystals below 0.5 mm, while large-crystal technology achieves 1.4–4 mm, increasing product value (price premium of $30–45/ton).
- Energy Efficiency: Utilizes neutralization reaction heat for water evaporation, reducing reliance on external heat sources. Low-pressure steam is recycled for other processes.
- Reduced Losses: Two-stage separation (settling tanks and mother liquor tanks) minimizes caprolactam residue entrapment to <0.1%, enhancing purity.
3. Product Characteristics and Advantages
- Chemical Specifications: Nitrogen (N) ≥21%, sulfur (S) ≥24%, free acid ≤0.03%, moisture ≤0.2%, purity >99.5%.
Physical Properties: Large crystals exhibit excellent flowability and anti-caking properties, ideal for bulk transportation and mechanized fertilization.
4. Applications
- Industrial Uses:
- Pharmaceuticals and Biotechnology: Antibiotic fermentation, protein purification (salting-out agent).
- Rare Earth Smelting: Ion-exchange agent for rare earth ore processing (5 tons required per ton of ore).
- Agricultural Uses:
- High-End Water-Soluble Fertilizers: Suitable for high-value crops (fruits, vegetables) and sulfur-deficient soil remediation (India, Brazil).
- Direct Fertilization: Slow nutrient release reduces field losses.
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