Magnesium Chloride (MgCl₂) for Aluminum Smelting & Industrial Use

氯化鎂 (Magnesium Chloride)
Magnesium Chloride (MgCl₂) Product Overview | Maeda Enterprises

Magnesium Chloride

氯化鎂 · MgCl₂

An inorganic compound with the chemical formula MgCl₂. Colorless flake crystals that are highly hygroscopic. Soluble in water, ethanol, methanol, and pyridine; slightly soluble in acetone. Available in anhydrous and hexahydrate forms, widely used in aluminum smelting, road de-icing, and construction materials.

Basic Chemical Information

Chemical Formula
MgCl₂
CAS (Anhydrous)
7786-30-3
CAS (Hexahydrate)
7791-18-6
Appearance
Colorless to white flake crystals
Solubility
Readily soluble in water and alcohols
Hygroscopicity
High — deliquesces in moist air

Applications in Aluminum Smelting & Alloy Production

In secondary aluminum alloy facilities, magnesium chloride serves as a flux and refining agent, typically used in combination with sodium chloride (NaCl) and potassium chloride (KCl) across three key process stages:

  • 1

    Melting

    Added to the furnace as a flux in combination with NaCl and KCl. Effectively lowers the melting point of the aluminum melt, reduces surface oxidation, stabilizes the molten state, and improves melting efficiency.

  • 2

    Refining & Degassing

    Post-melting aluminum melt typically contains dissolved hydrogen and oxide inclusions. MgCl₂-based refining agents assist in degassing and slag removal, promoting oxide flotation, reducing porosity defects in castings, and ensuring a clean melt.

  • 3

    Pre-Alloying Treatment

    Before adding alloying elements such as Mg, Mn, Zn, and Cu, the refining action of MgCl₂ ensures a clean base metal, promotes uniform distribution of alloying elements, and prevents impurities from degrading final alloy performance.

Typical Flux Combination

Magnesium Chloride MgCl₂ Sodium Chloride NaCl Potassium Chloride KCl

Recommended Dosage Range

Share in flux / refining agent
5% – 20%

Actual ratios are adjusted based on melt purity, alloy specifications, and plant process requirements.


Other Important Industrial Applications

Road De-icing & Snow Melting
More effective than rock salt at lower temperatures; lower corrosivity, suitable for bridges and precision infrastructure
Construction & Cement
Used in the production of Sorel cement (magnesite cement) for industrial flooring and kiln refractory linings
Detergent Softener & Fixative
Used as a textile processing auxiliary to improve color fastness and fabric softness
Agricultural Magnesium Fertilizer
Replenishes soil magnesium to support chlorophyll synthesis and improve crop quality
Drilling Mud Weighting Agent
Used as a stabilizer in oil and natural gas drilling operations
Wastewater Treatment
Used to adjust wastewater pH and precipitate specific metal ions

Everyday Applications

Food Processing (Tofu Coagulation)

  • The key component of traditional Japanese nigari (bittern) used to set tofu
  • Produces a smooth, tender texture; classified as GRAS (Generally Recognized as Safe)

Health & Topical Use

  • A source ingredient in magnesium supplement capsules
  • Used in topical bath salts for muscle relaxation and skin care

Aquariums & Swimming Pools

  • Replenishes magnesium ions in reef aquariums to support coral health
  • Balances mineral content in pool water for stable water quality

Residential De-icing

  • Used on driveways and parking lots during winter
  • Lower corrosivity than rock salt; considered more pet-friendly

Packaging & Logistics

25 kg / 50 kg
Woven polypropylene bag with inner plastic liner; easy to handle and store
1,000 kg Bulk Bag
Flexible intermediate bulk container (FIBC); ideal for factory bulk purchasing
Liquid Drum
Hexahydrate liquid form; suitable for specific process requirements

Storage: Keep in a dry location, away from moisture and heat. Avoid direct sunlight.

Logistics & Delivery: Factory-direct delivery available across Asia. Contact us for shipping arrangements and freight quotations.


Hazard Classification & Safety Information

Low Toxicity Not classified as a controlled hazardous chemical — however, observe the following precautions
Inhalation

Dust or mist inhalation may irritate the respiratory tract; prolonged occupational exposure requires monitoring

Skin & Eye Contact

May cause mild irritation on direct contact; if eye contact occurs, flush immediately with clean water

Heat or Strong Acid Exposure

Decomposes to release HCl (hydrogen chloride) gas when heated or in contact with strong acids; ensure adequate ventilation

Packaging Damage

If bags are torn and dust is released, avoid dry sweeping; collect using wet methods to prevent airborne dust

Handling & Personal Protective Equipment
  • Wear a dust mask rated N95 or equivalent during handling
  • Use chemical-resistant gloves (nitrile rubber recommended)
  • Wear safety goggles to prevent dust or liquid splashing into eyes
  • Ensure good ventilation in the work area; avoid high-concentration exposure in enclosed spaces
  • Do not store together with strong acids or strong oxidizers
  • Wash hands thoroughly with water after handling; avoid ingestion

Frequently Asked Questions (FAQ)

Q1: What is the CAS number for magnesium chloride?
The anhydrous form is CAS 7786-30-3; the hexahydrate form is CAS 7791-18-6.
Q2: What role does magnesium chloride play in aluminum smelting?
It functions as a flux and refining agent, removing dissolved hydrogen and oxide inclusions from the aluminum melt, reducing casting defect rates, and improving overall product quality. Typically used with NaCl and KCl, accounting for 5–20% of the flux formulation.
Q3: At which process stages is magnesium chloride applied?
Primarily across three stages: Melting, Refining & Degassing, and Pre-Alloying Treatment.
Q4: Is magnesium chloride a hazardous chemical?
It is a low-toxicity substance and not classified as a controlled hazardous chemical. However, dust inhalation and HCl gas released during high-temperature decomposition require precautions — use a mask, gloves, and goggles, and maintain ventilation.
Q5: What packaging options are available?
Available in 25 kg and 50 kg bags, 1,000 kg bulk bags (FIBC), and hexahydrate liquid drums. Options can be adjusted to match your facility's requirements.
Q6: How does magnesium chloride compare to rock salt (NaCl) for de-icing?
Magnesium chloride remains effective at lower temperatures (approximately −15°C and below) and is less corrosive to metals, making it preferable for bridges and sensitive infrastructure.

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