What Is Ammonium Sulfate and Why Is It Widely Used in Agriculture and Industry?

Technical Introduction

Ammonium sulfate [(NH₄)₂SO₄] is an inorganic salt composed of two ammonium cations (NH₄⁺) and one sulfate anion (SO₄²⁻). It appears as a white crystalline solid with excellent solubility in water but low solubility in alcohol or acetone.

This compound has long been used as one of the earliest synthetic fertilizers, supplying both nitrogen and sulfur—two essential macronutrients for plant growth. Beyond agriculture, it is employed in food processing, pharmaceuticals, water treatment, and laboratory applications, particularly in protein purification by “salting out.”

Applications

• Agriculture (Fertilizer): A key nitrogen and sulfur fertilizer used for alkaline soils; improves soil pH balance and provides readily available nutrients.

• Food Industry: Serves as a dough conditioner, acidity regulator, and food additive (E517).

• Pharmaceutical & Biotech: Used in protein purification and precipitation in laboratory processes.

• Water Treatment: Helps remove contaminants and assists in coagulation processes.

• Industrial Uses: Employed in flame retardants, leather tanning, and textile finishing.

• Agricultural Blends: Often combined with ammonium nitrate or urea for custom fertilizer formulations.

Advantages

• Dual Nutrient Supply: Provides nitrogen for plant growth and sulfur for protein synthesis.

• Soil pH Management: Ideal for alkaline soils as it reduces pH while fertilizing.

• High Purity: Stable and non-volatile, making it safer and easier to handle than other nitrogen fertilizers.

• Versatility: Applicable across multiple industries beyond agriculture.

• Cost-Effective: One of the most affordable nitrogen-sulfur fertilizers.

Specifications (Typical Parameters)

FAQ

Q1: Why is ammonium sulfate popular as a fertilizer?
A: It provides two key nutrients—nitrogen and sulfur—in one compound and helps manage alkaline soils by lowering pH.

Q2: Is ammonium sulfate safe in food?
A: Yes, in regulated amounts, it is classified as food additive E517 and is used as an acidity regulator and dough enhancer.

Q3: How does ammonium sulfate compare to urea as a fertilizer?
A: Ammonium sulfate has lower nitrogen content (~21%) than urea (~46%), but it adds sulfur and is less prone to volatilization losses.

Q4: What role does it play in protein purification?
A: It is used in the “salting out” technique to precipitate proteins by reducing solubility in aqueous solutions.

Q5: How should ammonium sulfate be stored?
A: Store in a dry, cool place to avoid clumping, as it is slightly hygroscopic. Keep away from strong oxidizers.