Complete Guide to Magnesium Sulfate Heptahydrate | Grades, Applications & Procurement Tips for Global Buyers

1. Basic Physical & Chemical Properties & Shipping Notes

Chemical formula: MgSO₄·7H₂O, CAS No.: 10034-99-8, commonly known as Epsom salt. It appears as colourless transparent columnar crystals with excellent water solubility and dissolves quickly even in cold water, matching automatic batching systems for irrigation and industrial production.
Key storage & shipping features: Stable under cool and dry conditions; long-term exposure to sunlight and humid air will cause efflorescence and reduce effective magnesium content. It is non-hazardous chemical goods, deliverable by regular container sea freight. Standard packages include 25kg woven bags with inner PE lining and bulk jumbo bags. HS code: 28332100 with complete customs clearance documents for smooth customs declaration. Three regular particle sizes are available: fine powder, fine granules and large granules for different feeding requirements.

2. Four Main Grades & Overseas Application Scenarios

Agricultural Grade (Largest Export Volume)

Complies with GB/T 26568 standard, minimum main content ≥99%, with strict control of chloride and iron impurities. Magnesium is the core element for chlorophyll synthesis, effectively solving yellow leaves and premature ageing of fruit trees, tomatoes, potatoes, rice and cash crops; sulfur activates solidified nutrients in soil to improve saline-alkali land.
Applicable usage modes: base fertilizer broadcasting, drip irrigation flushing, foliar spraying, and additive for compound fertilizer and water-soluble fertilizer. Low-chloride type fits chlorine-sensitive crops such as citrus, grapes and strawberries. Major importers are Vietnam, the Philippines and Indonesia.

Feed Grade (Strict Compliance Requirements)

Executes mandatory standard GB 32449 with rigid limits on heavy metals including lead and arsenic. It acts as essential mineral additive for livestock and aquaculture industries. Added in feed for pigs, chickens, cattle and sheep to prevent convulsion and postpartum paralysis while promoting bone development. In aquaculture, it stabilizes water osmotic pressure, facilitates molting of shrimps and crabs and maintains healthy algae phase. Large overseas feed enterprises require full COA test reports before formal orders.

Industrial Grade (Widest Application Range)

Follows HG/T 2680 standard, divided into premium grade and first grade. Low-iron specification works as weighting and color fixing agent for silk and cotton printing & dyeing to avoid uneven dye spots. It is also widely used as filling material for papermaking, tanning auxiliary for leather making, flotation regulator for mineral processing and basic electrolyte material for electroplating. In recent years, demand keeps rising in overseas wastewater treatment projects for adjusting water hardness and precipitating heavy metal suspended solids. It also serves as flame retardant filler for fireproof boards and ceramic ingredients.

Food & Pharmaceutical Grade (High-end Segment with Stable Premium Price)

Produced with intensive purification procedures under strict impurity control. Food grade works as magnesium fortifier in drinking water, bakery food and dairy products. Pharmaceutical grade is famous for external wet compress to relieve swelling and internal use as laxative; it is also core raw material for Epsom bath salt in daily chemical industry. Output is relatively limited, with priority delivery for long-term fixed orders.

3. Practical Tips for Overseas Procurement

1. Prioritize core indicators over unit price: agricultural clients focus on chloride content; printing & dyeing factories require low iron index; feed grade orders must attach complete heavy metal test certificates and inspection documents.
2. Reduce shipping loss: jumbo sealed bags are recommended for long sea transportation to avoid caking caused by sea humidity; finished goods should be placed on pallets instead of open-air storage after arrival.
3. Mixing restriction: aqueous solution is weakly acidic; direct mixing with strong alkaline fertilizers and chemicals will form magnesium hydroxide precipitation and lose efficacy.

4. Current Export Industry Status & Future Procurement Trend

Main domestic production bases locate in Shandong and salt lake areas with two mature production processes: ore-sulfuric acid synthesis and brine extraction, capable of supporting large-volume stable export orders. Homogeneous competition exists among ordinary industrial grade products, while high-purity low-chloride agricultural grade and certified feed grade maintain obvious premium advantages.
Global demand remains steady: Southeast Asia keeps stable agricultural purchasing volume; India and Bangladesh have growing demands on wastewater treatment raw materials; the Middle East places increasing orders for saline-alkali soil improvement fertilizer. Factories with ISO certification and full MSDS & COA documents enjoy better cooperation stability with long-term buyers.

Contact & Cooperation Invitation

Our factory supplies full series of magnesium sulfate heptahydrate (agricultural / feed / industrial / food grades) with complete particle specifications and customizable indicators. We support sample testing and full-container sea shipment, providing complete inspection, MSDS and COA documents to meet import standards of different countries.
Welcome overseas customers to leave messages for samples, quotations and long-term bulk cooperation negotiation.