Magnesium Nitrate Hexahydrate - The Cross-Border Legend from Chemical Crystal to Agricultural "Dual-Efficiency Expert"

I. Basic Information

1. Chemical Formula: Mg(NO₃)₂·6H₂O

2. Molecular Weight: 256.41

3. CAS Number: 13446-18-9

4. Appearance: Typically appears as colorless monoclinic crystals or white crystalline material. Some products may exhibit a slight yellowish tint due to impurities or manufacturing variations. Forms include crystalline, granular, or flake types:

   • Crystals: Regular geometric structure

   • Granules: Usually spherical or near-spherical, smooth surface, semi-transparent

   • Flakes: Regular shape, certain thickness and surface area

5. Odor: Odorless

   
   

II. Physical Properties

1. Melting Point: ~95°C — transitions from solid to liquid

2. Boiling Point: 330°C (decomposes), producing MgO and nitrogen oxides

3. Density: 1.464 g/cm³

4. Solubility: Easily soluble in water, forming a clear, colorless solution at 20°C. Also soluble in methanol and ethanol, but not in ethers.

5. Hygroscopicity: Highly hygroscopic, readily absorbs moisture from air and may deliquesce; moisture-proof storage is critical.

III. Chemical Properties

1. Oxidizing Nature: A strong oxidizer, reacts with reducing agents, organics, or metal powders—potentially explosive under friction or shock. Keep away from such substances and heat sources.

2. Thermal Stability:

   • Begins losing crystal water at 150°C (forming dihydrate)

   • Decomposes at 260°C into MgO and nitrogen oxides

3. pH: Neutral aqueous solution, can be used in pH-sensitive processes as a neutral source of Mg²⁺ and NO₃⁻.

IV. Quality Standards (Industrial and Agricultural Grades)

Item	Industrial Premium	Industrial Grade 1	Industrial Qualified	Agricultural Grade 1	Agricultural Qualified
Magnesium Nitrate Hexahydrate (%)	≥99.0	≥98.5	≥98.0	≥98.0	≥96.0
Water Insolubles (%)	≤0.01	≤0.01	≤0.02	≤0.03	≤0.1
Chlorides (as Cl⁻, %)	≤0.02	≤0.02	≤0.02	-	-
Iron (Fe, %)	≤0.0002	≤0.0002	-	-	-
pH	4–7	4–7	4–7	-	-
Clarity	≤0.5	≤0.5	-	-	-
Heavy Metals (as Pb, %)	≤0.0002	≤0.0002	≤0.001	≤0.0002	≤0.001
Ca²⁺ (%)	≤0.1	-	-	-	-
Nitrites (as NO₂⁻, %)	≤0.0002	-	-	-	-

V. Production Methods

1. Magnesium Oxide Method: Reacts light MgO with 30–50% nitric acid at <60°C, followed by filtration, evaporation, crystallization, and drying.

   • Reaction: MgO + 2HNO₃ → Mg(NO₃)₂ + H₂O

2. Magnesium Carbonate Method: Reacts magnesite (MgCO₃) with 35–40% nitric acid at 40–50°C, then filtered and crystallized.

   • Reaction: MgCO₃ + 2HNO₃ → Mg(NO₃)₂ + CO₂ + H₂O

3. Hydroxide Cake from Lithium Brine: Purified Mg(OH)₂ from lithium extraction is reacted with nitric acid (1:1.05–1.10 mol ratio) at 80–90°C, crystallized at 30°C, and dried.

   • Reaction: Mg(OH)₂ + 2HNO₃ → Mg(NO₃)₂ + 2H₂O

4. High Tower Granulation: Heated Mg(NO₃)₂ solution sprayed from the top of a granulation tower, forming solid spheres through air cooling.

5. Flake Production: Steel belt granulation or controlled solidification on a cooling conveyor to form flake shapes.

VI. Application Fields

1. Agriculture

• Enhances chlorophyll formation, photosynthesis, and crop quality.

• Benefits include:

  • Water-soluble nitrate nitrogen + magnesium

  • Improved disease resistance

  • Soil improvement for acidic conditions

  • Stable and long-lasting effect

  • Promotes chlorophyll, sugar metabolism, vitamin A & C formation

  • Free from chlorine and sulfur; ideal for seedlings and hydroponics

2. Industry

• Explosives & Fireworks: Oxidizer and dehydrating agent

• Chemical Manufacturing: Catalyst for organic reactions, concrete additive, flocculant for wastewater treatment

3. Laboratory & Pharmaceutical

• Analytical reagent for magnesium

• Intermediate for pharmaceutical synthesis

Forms & Uses

• Flakes: High surface area, useful in catalysis

• Crystals: High purity, lab use

• Granules: Free-flowing, ideal for fertilizer and industrial dosing

Selection Guide

Form	Features	Application
Crystals	High purity, may cake	Laboratory, pharma
Granules	Good flow, high hardness	Fertilizers, industrial automation
Flakes	Controlled dissolution	Slow-release, catalysis

VII. Packaging, Storage & Transportation

• Packaging: Woven bags with inner PE liner (25kg/50kg), also available in bulk bags or custom formats

• Storage: Cool, ventilated, <30°C, RH<80%, sealed, moisture-proof, segregated from organics/reducers/metals

• Transport: Handled per hazardous chemical standards; not listed as dangerous goods per TDG SP332, but must comply with all maritime HAZMAT protocols. CIQ inspection required as per China Customs Announcement No. 129 (2020)

VIII. Safety Considerations

• Health Hazards: Irritant to skin, eyes, respiratory tract

• Protection: Wear PPE (gloves, goggles, mask); rinse with water upon contact

• Environmental: May accumulate in groundwater—prevent leakage

IX. Global Market Overview & Forecast

• 2023 Global Market Size: ~$1 billion

• 2028 Forecast: ~$1.5 billion (CAGR ~7%)

• China: 2025 estimate at ¥1.28B, targeting ¥3B by 2030

• Drivers: Demand in agriculture (foliar & soil conditioning), concrete, explosives, wastewater treatment

• Regional Highlights:

  • Asia-Pacific leads; Shanxi and Guangdong form key clusters

  • International competition: Spectrum Chemical, William Blythe vs. Chinese firms like Jinlan Chemical

  • Growth driven by: advanced granulation, electronic-grade development, environmental compliance

X. Conclusion

Magnesium Nitrate Hexahydrate is a vital multi-industry chemical product with agricultural, industrial, and scientific significance. Innovations in processing (e.g., tower granulation, steel belt flaking) and expansion into emerging applications like eco-agriculture and advanced materials highlight its future potential. Sustained growth will depend on technological innovation, environmental compliance, and supply chain resilience.