Magnesium Sulfate Monohydrate, Magnesium Sulfate Anhydrate, Epsom Salt, English Salt, Bitter Salt, Bath Salt, Kieserite, E518, 7487-88-9, 14168-73-1

MAGNESIUM SULFATE (MgSO₄·nH₂O, E518)

1. Chemical Identity and Material Classification

• Chemical Name: Magnesium Sulfate, Sulfuric Acid Magnesium Salt

• Synonyms: Epsom Salt (heptahydrate), English Salt, Bitter Salt, Bath Salt, Kieserite (monohydrate – natural mineral)

• CAS Numbers:

  • Anhydrous: 7487-88-9

  • Monohydrate: 14168-73-1

  • Heptahydrate: 10034-99-8

• EC Numbers (EINECS):

  • Anhydrous: 231-298-2

  • Monohydrate: 231-298-2 (same as anhydrous)

  • Heptahydrate: 231-298-2 (same)

• Molecular Formulas:

  • Anhydrous: MgSO₄

  • Monohydrate: MgSO₄·H₂O

  • Heptahydrate: MgSO₄·7H₂O

• Molecular Weights:

  • Anhydrous: 120.37 g/mol

  • Monohydrate: 138.39 g/mol

  • Heptahydrate: 246.47 g/mol

• E Number: E518 (food additive)

• Chemical Class: Inorganic salt (sulfate)

• HS Code: 2833.21

• UN Number: Not regulated (non-hazardous for transport)

2. Physical Properties – Comparison of Forms

2.1 Solubility in Water (g/100 mL)

2.2 Solubility in Other Solvents

3. Hydrate Forms – Comparison

4. Chemical Properties

4.1 Dehydration Behavior (Heptahydrate → Monohydrate → Anhydrous)

4.2 Aqueous Solution Properties

4.3 Chemical Reactivity

4.4 Stability

4.5 Incompatibilities

5. Quality Specifications

5.1 Anhydrous Grade (Technical)

5.2 Monohydrate Grade (Kieserite – Technical)

5.3 Heptahydrate (Epsom Salt) – Food / Pharmaceutical Grade (E518)

6. Production Methods

6.1 From Natural Brines (Most Common – Heptahydrate)

Source: Natural brines and seawater (Dead Sea, Great Salt Lake)

Process:

1. Brine concentrated by solar evaporation

2. Sodium chloride (NaCl) crystallizes first

3. Magnesium sulfate crystallizes as heptahydrate (Epsomite)

4. Purification, drying

6.2 From Magnesite or Dolomite (Monohydrate – Kieserite)

Reaction (via acid digestion): MgCO₃ + H₂SO₄ → MgSO₄ + H₂O + CO₂↑

Process:

1. Magnesite (MgCO₃) or dolomite reacted with sulfuric acid

2. Solution purified (removal of Ca, Fe)

3. Crystallization → monohydrate or heptahydrate

6.3 From Kieserite (Monohydrate)

Source: Natural mineral Kieserite (MgSO₄·H₂O) mined in Germany, Austria, Russia

Process: Mining → crushing → screening → drying

6.4 Anhydrous Production

Process: Dehydration of heptahydrate or monohydrate at >200°C

Reaction: MgSO₄·7H₂O → MgSO₄·H₂O → MgSO₄

7. Mechanism of Action

7.1 Laxative Effect (Oral – Epsom Salt)

• Magnesium ions are poorly absorbed from the gastrointestinal tract

• Osmotically draws water into the intestinal lumen

• Increases intraluminal volume

• Stimulates peristalsis

• Results in bowel movement within 30 minutes to 6 hours

7.2 Anticonvulsant Effect (IV – for Preeclampsia)

• Magnesium blocks NMDA receptors (glutamate)

• Reduces neuronal excitability

• Prevents seizures in preeclampsia/eclampsia

• Also reduces cerebral vasospasm

7.3 Topical Analgesic (Muscle Pain, Soaking)

• Reduces inflammation and edema (hyperosmotic effect)

• Relaxes muscle spasms

• Improves blood flow (vasodilation)

• Provides relief for sore muscles, arthritis, fibromyalgia

7.4 Agricultural (Fertilizer)

• Provides magnesium (essential for chlorophyll synthesis)

• Provides sulfur (essential for amino acid synthesis)

• Corrects Mg deficiency in plants (interveinal chlorosis, leaf curling)

8. Industrial Applications

8.1 Agriculture (Fertilizer) – Largest Application

Crops that benefit: Potatoes, tomatoes, peppers, roses, citrus, apples, corn, soybeans

Mg deficiency symptoms: Interveinal chlorosis (yellowing between veins), leaf curling, stunted growth

8.2 Food and Beverage Industry (E518)

8.3 Pharmaceutical and Medical Applications

8.4 Cosmetics and Personal Care

8.5 Chemical Industry

8.6 Water Treatment

8.7 Animal Feed

8.8 Industrial Drying (Anhydrous)

Note: Anhydrous MgSO₄ is a common laboratory drying agent for organic solutions.

8.9 Textile Industry

9. Magnesium Sulfate Forms – Comparison Table

10. Magnesium vs. Other Magnesium Salts – Comparison

11. Toxicology and Safety

11.1 Acute Toxicity

11.2 Clinical Effects (Overdose)

11.3 GHS Classification (Typical)

11.4 NFPA Rating

12. Safety Precautions and Personal Protective Equipment (PPE)

• Hazards:

  • Low acute toxicity

  • Dust may cause mild eye and respiratory tract irritation

  • Non-flammable

  • Hygroscopic (absorbs moisture – heptahydrate less so)

• PPE (recommended – industrial handling):

  • Safety glasses (EN 166)

  • Dust mask (FFP1/FFP2) – for dusty operations

  • Protective gloves (nitrile – optional)

  • Protective clothing (dust protection)

• Engineering controls:

  • Local exhaust ventilation (LEV) for dust control

  • Eyewash stations

• Storage conditions:

  • Keep tightly closed in original container (HDPE, PP, paper bags with liner)

  • Store in cool, dry, well-ventilated area

  • Protect from moisture (hygroscopic – especially anhydrous)

• First aid:

  • Inhalation: Move to fresh air

  • Eye contact: Rinse with water for 15 minutes; remove contact lenses; seek medical attention if irritation persists

  • Skin contact: Wash with soap and water

  • Ingestion: Rinse mouth; drink water; seek medical attention if large amount swallowed

13. Environmental Fate

14. Storage and Shelf Life

14.1 Storage Conditions

14.2 Shelf Life

15. Transport Information

16. Synonyms and Common Names

• English: Magnesium Sulfate, Epsom Salt, English Salt, Bitter Salt, Bath Salt, Kieserite (monohydrate), Sulfuric Acid Magnesium Salt

• French: Sulfate de magnésium

• German: Magnesiumsulfat

• Spanish: Sulfato de magnesio

• Turkish: Magnezyum Sülfat, İngiliz Tuzu, Epsom Tuzu

Trade names: Epsomite, Kieserite, Nigari (for tofu coagulant – impure magnesium chloride/sulfate mix)

17. Regulatory Status

18. Why Choose Magnesium Sulfate?

Limitations:

• Laxative effect – Unwanted diarrhea if taken orally in high doses

• Low Mg content (heptahydrate – 9.8%) – Less concentrated than other Mg salts

• Not suitable for IV use without medical supervision – Hypermagnesemia risk

• Efflorescence (heptahydrate) – Loses water of crystallization in dry air

• Hygroscopic (anhydrous) – Absorbs moisture; requires airtight storage

19. Frequently Asked Questions (FAQs)

Q1: What is the difference between Epsom salt and magnesium sulfate?
A1: Epsom salt is the common name for magnesium sulfate heptahydrate (MgSO₄·7H₂O). They are the same compound. The term "magnesium sulfate" refers to the chemical compound (anhydrous, monohydrate, or heptahydrate).

Q2: Is Epsom salt safe to eat?
A2: Epsom salt (magnesium sulfate heptahydrate) is FDA-approved as a laxative (oral) and food additive (E518) at regulated doses. However, excessive consumption can cause diarrhea, nausea, and hypermagnesemia. Always follow dosing instructions.

Q3: How does Epsom salt work as a laxative?
A3: Magnesium ions are poorly absorbed in the intestine. They osmotically draw water into the intestinal lumen, increasing intraluminal volume and stimulating peristalsis, resulting in a bowel movement within 30 minutes to 6 hours.

Q4: Is Epsom salt safe for plants?
A4: Yes, Epsom salt (magnesium sulfate) is used as a fertilizer to correct magnesium deficiency. It is especially beneficial for tomatoes, peppers, potatoes, roses, and citrus. Use 1–2 tablespoons per gallon of water as a foliar spray or soil drench.

Q5: Why is magnesium sulfate used in beer brewing?
A5: Magnesium sulfate (Epsom salt) is added to brewing water to adjust water hardness and provide sulfate ions, which enhance hop bitterness and improve yeast health during fermentation. It is commonly used in brewing ales and lagers.

Q6: What is the difference between anhydrous, monohydrate, and heptahydrate forms?
A6:

• Anhydrous (0 H₂O) – high Mg content (~20%), used as a laboratory drying agent

• Monohydrate (1 H₂O) – intermediate, used as fertilizer (Kieserite)

• Heptahydrate (7 H₂O) – most common, used for baths, laxatives, food (Epsom salt)

20. Summary Table – Key Specifications at a Glance

This TDS is prepared in compliance with ISO 11014-1 format and is intended for agricultural specialists, food technologists, pharmaceutical scientists, cosmetic formulators, chemical engineers, and procurement professionals. Certificates of Analysis (CoA), Safety Data Sheets (SDS), and sample validation reports are available upon request.