Ammonium Sulfate ((NH₄)₂SO₄)
Versatile inorganic salt used as agricultural fertilizer, food additive and in industrial applications
Overview
Ammonium Sulfate ((NH₄)₂SO₄, CAS No: 7783-20-2) is an inorganic salt in white crystalline form. It finds widespread use as a nitrogen and sulfur source fertilizer in agriculture, acidity regulator in food industry (E517) and chemical reagent in industrial processes.
Ammonium sulfate has high water solubility (70.6 g/100 mL at 0°C) and is hygroscopic. It dissociates into ammonium (NH₄⁺) and sulfate (SO₄²⁻) ions in soil, providing plant-available nutrients. In food applications, it is used as a pH regulator and dough processing agent.
Applications
Ammonium Sulfate has a wide range of industrial, agricultural and commercial applications:
Agricultural Fertilizer
Provides both nitrogen (21% N) and sulfur (24% S) for plants. Preferred especially in sulfur-deficient soils. Has soil pH lowering effect in alkaline soils.
Food Additive (E517)
Used as dough conditioner, acidity regulator and flour treatment agent. Regulates yeast activity in bread making and improves dough workability.
Water Treatment
Used as nitrogen source for microbial growth in wastewater treatment plants. Preferred in disinfection processes to prevent chloramine formation.
Chemical Production
Used as starting material in production of ammonium persulfate and other ammonium salts. Also used in textile dye production and leather processing.
Fire Extinguishers
Used as flame retardant in dry chemical fire extinguishers. Particularly effective in agricultural and forest fires.
Laboratory Applications
Used in protein precipitation (salting out), salt baths and some analytical chemical tests.
Technical Specifications
| Property | Value | Unit | Test Method |
|---|---|---|---|
| Chemical Name | Ammonium Sulfate | - | - |
| CAS Number | 7783-20-2 | - | - |
| EC No | 231-984-1 | - | - |
| Formula | (NH₄)₂SO₄ | - | - |
| Molecular Weight | 132.14 | g/mol | - |
| Appearance | White crystalline powder or granules | - | Visual |
| Odor | Odorless | - | - |
| Purity | ≥99.0 | % | ISO 3422 |
| Nitrogen (N) Content | ≥21.0 | % | ISO 3332 |
| Sulfur (S) Content | ≥24.0 | % | ISO 3423 |
| Moisture Content | ≤0.2 | % | Karl Fischer |
| pH Value (1% sol.) | 5.0-6.0 | - | ISO 1842 |
| Solubility (Water, 20°C) | 70.6 | g/100 mL | ISO 918 |
| Density | 1.77 | g/cm³ | ISO 787 |
| Melting Point | 235-280 (decomposes) | °C | ISO 6321 |
| Lead (Pb) Content | ≤2 | mg/kg | ISO 172 |
| Arsenic (As) Content | ≤1 | mg/kg | ISO 2590 |
Safety Information
Hazard Symbols and Statements
Irritant Environmental Hazard
Personal Protective Equipment (PPE)
- Dust mask (in high dust concentrations)
- Chemical-resistant gloves (for prolonged contact)
- Goggles (against dust or solution splash)
- Lab coat or protective clothing
Storage Conditions
- Store in a cool, dry and well-ventilated place
- Keep in original packaging, tightly closed
- Storage temperature: 15-30°C
- Keep away from alkaline substances and strong oxidants
- Protect from moisture, prevent water contact
Fire Fighting
- Non-combustible substance
- At high temperatures decomposes releasing toxic gases (ammonia, sulfur oxides)
- Suitable methods: Water spray, dry chemical powder, CO₂
- Firefighting personnel must use full respiratory protection
Handling and Storage
Transportation
- Ensure containers are tightly closed
- Prevent moisture contact
- Transport separately from strong acids and bases
- Have absorbent material available for spills
- Provide ventilation during transport
Storage
- Store in dry, cool and well-ventilated areas
- Display appropriate signage in storage area
- Protect from direct sunlight
- Store on elevated shelves
- Storage temperature should not exceed 40°C
Spill Response Measures
- Evacuate exposed personnel from area
- Use appropriate personal protective equipment
- Collect spill by dry method (sweeping)
- Do not use water - forms solution
- Wash spilled area with plenty of water
Regulatory Information
GHS Classification
- Eye Irritation Category 2
- Respiratory Irritation Category 2
- Acute Aquatic Hazard Category 1
Important Regulations
- REACH: Registered
- EPA: Listed in TSCA inventory
- European Food Additives Regulation: Approved as E517
- FDA: GRAS (Generally Recognized As Safe) status
- Food Codex: Maximum permitted 0.1% in certain foods
Compliance Certificates
- ISO 9001:2015 Quality Management System
- ISO 22000:2018 Food Safety Management System (for food grade)
- Fertilizer Regulation Compliant (for fertilizer grade)
- Food grade certificate (for specific batches)
Environmental Information
Environmental Impact
Ammonium sulfate can cause eutrophication in aquatic environments at high concentrations. It can acidify soil. However, when used correctly, it is fully absorbed by plants and has minimal environmental impact. Direct mixing into water sources should be prevented.
Biodegradation
- Oxidized to nitrate by microbial activity in soil
- Water: Decomposed by nitrification and denitrification processes
- Air: No direct decomposition, but ammonia gas release possible
Waste Management
- Classified as non-hazardous waste
- Can be used as soil conditioner (without uncontrolled distribution)
- Do not discharge to sewers or surface waters
- Dispose in accordance with local regulations
- For large amounts, consider recycling or reuse
Frequently Asked Questions
What are the advantages of ammonium sulfate fertilizer?
Ammonium sulfate is a fertilizer containing both nitrogen and sulfur. It has soil pH lowering effect in alkaline soils. Preferred especially in sulfur-deficient areas. Shows less leaching compared to other nitrogen fertilizers and is in easily absorbable form for plants.
Why is ammonium sulfate used in foods?
Ammonium sulfate (E517) is used in foods as acidity regulator and dough processing agent. Regulates yeast activity in bread making and improves dough workability. Also acts as stabilizer in some foods and used in fermentation processes.
How should ammonium sulfate be stored?
Ammonium sulfate should be stored in a dry, cool and well-ventilated place. Protect from moisture and water. Keep in original packaging, tightly closed. Storage temperature should be 15-30°C. Keep away from alkaline substances and strong oxidants.
What should I do if ammonium sulfate contacts skin?
Remove contaminated clothing immediately and wash skin with plenty of water and soap. Seek medical attention if irritation persists. In case of eye contact, rinse eyes with plenty of water for at least 15 minutes and seek medical attention urgently. If swallowed, rinse mouth with water and seek medical help.
What is the difference between ammonium sulfate and urea fertilizer?
Ammonium sulfate (21% N + 24% S) contains both nitrogen and sulfur, while urea (46% N) contains only nitrogen. Ammonium sulfate has acidifying effect on soil, while urea has neutral pH. Plant uptake of ammonium sulfate is faster; urea is taken up after conversion to ammonium in soil. Ammonium sulfate shows less leaching compared to urea.