Ferrous Sulfate Granules

Granular Ferrous Sulfate is a 1-4mm granular product made from ferrous sulfate heptahydrate/monohydrate via granulation, featuring good fluidity, low dust and excellent oxidation stability. It is suitable for mechanical fertilization, BB fertilizer blending, large-scale agriculture and precise metering scenarios.

Product Name: Granular Ferrous SulfateForm Basis: A granular product made from ferrous sulfate heptahydrate or monohydrate via granulation process, which is an upgraded form that combines the advantages of dry powder and optimizes storage, transportation and user experience.

Product Characteristics

• Physical Form: The particle diameter is usually 1-4 mm, in spherical or irregular granular form, with good fluidity (sand-like) and no dust pollution.
• Chemical Stability: The granular structure reduces contact area with air, resulting in slower oxidation rate and better stability than wet ferrous sulfate.
• Solubility: Slow dissolution rate (stirring required), with certain slow-release properties, which can extend the duration of effects such as fertilizer efficiency.

Application Fields

• Suitable for modern, large-scale agricultural fertilization scenarios; can be directly mixed with granular fertilizers (e.g., urea, compound fertilizer) to make bulk blending (BB) fertilizer;
• Applicable to fertilizer scenarios requiring slow-release effects, and application occasions with high requirements for metering accuracy.

Cost and Usage Characteristics

• Production cost is higher than wet and dry ferrous sulfate, making it the most costly among the three forms;
• Excellent storage and transportation performance: not easy to agglomerate, low dust, convenient for mechanical fertilization and packaging, and more friendly to the environment and operators;
• Not suitable for scenarios requiring immediate rapid response (e.g., emergency phosphorus removal in sewage treatment).

The working principle of granular ferrous sulfate relies on the synergy between its chemical properties and granular form, with core processes as follows:

1. Dissolution and Ion Release: The granules dissolve slowly in water, gradually releasing ferrous ions (Fe²⁺) and sulfate ions (SO₄²⁻). The granular form extends dissolution time, achieving a slow-release effect.
2. Soil Improvement: Fe²⁺ supplements iron in the soil and promotes chlorophyll synthesis in plants; SO₄²⁻ reacts with carbonates in the soil via displacement, neutralizing alkaline substances, reducing soil pH, and improving compaction and nutrient absorption efficiency.
3. Water Treatment: Fe²⁺ is converted to ferric ions (Fe³⁺) under oxidative conditions, which hydrolyze to form ferric hydroxide colloid that adsorbs suspended particles and organic impurities. It also reacts with phosphate to form ferric phosphate precipitate, enabling phosphorus removal, flocculation, and decolorization.
4. Fertilizer Synergy: The granular form is suitable for mechanical fertilization and can be mixed with other granular fertilizers (e.g., BB fertilizer), releasing nutrients evenly and extending the duration of fertilizer efficiency.

• Main Component Content: Calculated as ferrous sulfate heptahydrate/monohydrate, content is usually ≥90%; iron (Fe) content is about 19%-21% (slightly different by crystal water form).
• Granule Form: Particle diameter 1-4 mm, spherical or irregular granules, fluidity meets mechanical fertilization standards (angle of repose ≤35°).
• Physical Properties: Moisture content ≤5%, dust-free (dust emission rate ≤0.5%), not easy to agglomerate (agglomeration rate ≤2%).
• Chemical Stability: Oxidation degree (proportion of ferric iron to total iron) ≤10% (fresh product), ≤15% after 3 months of storage.
• Impurity Index: In industrial/agricultural grade products, heavy metals (Pb ≤0.002%, Cd ≤0.001%), insoluble matter content ≤1.0%, free acid (as H₂SO₄) ≤0.3%.
• Solubility: At 20℃ in water, dissolution rate ≥60% in 30 minutes (stirring required).

Physical Properties

• Form and Fluidity: 1-4 mm spherical/irregular granules with sand-like fluidity, suitable for mechanical fertilization and mixing (e.g., BB fertilizer), and not easy to agglomerate during packaging and transportation.
• Low Dust: The granulation process greatly reduces dust emission during production and use, making it more friendly to the operating environment and personnel.
• Low Moisture Content: Moisture content ≤5%, much lower than wet ferrous sulfate, making storage and transportation lighter.

Chemical Properties

• Improved Stability: The granular structure reduces contact area with air, resulting in slow oxidation (ferric iron proportion ≤10% in fresh products), and slower performance attenuation during storage.
• Slow-release Solubility: Slow dissolution rate (stirring required) can extend the duration of fertilizer efficiency or water treatment effects, avoiding excessive local concentration.

Application Properties

• Scenario Adaptability: Suitable for large-scale agricultural fertilization, slow-release fertilizers and precise metering scenarios, and can be directly mixed with other granular fertilizers; however, it is not suitable for scenarios requiring rapid response (e.g., emergency phosphorus removal).
• Storage and Transportation Advantages: Not easy to get damp or agglomerate, transportation cost is lower than wet products, and storage conditions are relatively loose (still need moisture protection).

 

Core Component Parameters

• Main Component Content: ≥90% (calculated as ferrous sulfate heptahydrate/monohydrate); iron (Fe) content 19%-21% (slightly fluctuates with crystal water type).
• Crystal Water Form: Optional heptahydrate or monohydrate, corresponding to moisture content differences (heptahydrate type has slightly higher moisture content).

Physical Parameters

• Particle Size: 1-4 mm in diameter, particle size uniformity ≥85% (meets target particle size range).
• Fluidity: Angle of repose ≤35°, suitable for mechanical fertilization equipment.
• Moisture Content: ≤5% (industrial/agricultural grade standard).
• Dust Emission Rate: ≤0.5%, no obvious dust during operation.
• Agglomeration Rate: ≤2% (within 3 months of storage).

Chemical Stability Parameters

• Initial Oxidation Degree: Proportion of ferric iron (Fe³⁺) to total iron ≤10% (fresh product).
• Storage Oxidation Degree: After 3 months of storage, ferric iron proportion ≤15%.

Impurity Parameters (Industrial/Agricultural Grade)

• Heavy Metal Content: Lead (Pb) ≤0.002%, Cadmium (Cd) ≤0.001%.
• Insoluble Matter Content: ≤1.0%.
• Free Acid (as H₂SO₄): ≤0.3%.

Solubility Parameters

• Dissolution Rate in 20℃ Water: ≥60% in 30 minutes (under stirring); full dissolution time is about 2-3 hours.