What Makes Iron(II) Sulfate Anhydrous the Most Concentrated Form of Ferrous Sulfate?

Technical Introduction

Iron(II) sulfate anhydrous (FeSO₄) is the water-free form of ferrous sulfate.
It contains around 36–37% elemental iron, making it the highest iron content among the ferrous sulfate types (heptahydrate, monohydrate, anhydrous).
Its pale gray to yellowish powder form is highly reactive due to the absence of bound water molecules.
It is used in agriculture, feed, industrial chemistry, and water treatment where maximum iron concentration is desired.

Applications

1. Agriculture

• High-Purity Iron Supplement: Corrects severe iron deficiencies in crops quickly.

• Soil Amendment: Strong acidifying effect, improving nutrient solubility in alkaline soils.

• Turf Care: Suppresses moss and enhances grass greenness.

2. Animal Feed

• Concentrated Feed Additive: Supplies iron in premixes and feed formulations with minimal bulk.

3. Industrial Uses

• Pigment Production: Source material for iron oxide pigments.

• Cement Additive: Converts toxic Cr(VI) to non-toxic Cr(III) efficiently.

• Chemical Synthesis: Precursor in various iron-based compounds.

4. Water Treatment

• Phosphate Removal: Acts as a coagulant to control eutrophication.

• Sulfide Control: Suppresses odor in sewage systems.

Advantages

• Highest Iron Content: ~37% Fe, maximizing nutrient delivery.

• Lower Dosage Needs: Less product required for same iron input compared to hydrated forms.

• Reduced Transportation Cost: More iron per kilogram shipped.

• Longer Storage Stability: Less prone to clumping under dry conditions.

Typical Parameters

FAQs

Q1: How does anhydrous differ from monohydrate and heptahydrate?
A1: Anhydrous has no water of crystallization, so it offers the highest iron concentration and lowest weight per unit of iron supplied.

Q2: Is it more reactive than other forms?
A2: Yes, the lack of water molecules makes it more reactive and faster to oxidize; store properly to maintain quality.

Q3: Can it be used in foliar sprays?
A3: Yes, but must be well-diluted to avoid leaf burn.

Q4: Is it suitable for animal feed?
A4: Yes, but strict dosing is necessary due to its high concentration.

Q5: Does it change soil pH?
A5: Strongly acidifies soil, beneficial for alkaline conditions but requires careful dosage.