Magnesium Oxide (CAS 1309-48-4), With the chemical formula MgO and molecular weight 40.30 g/mol, it occurs naturally as the mineral periclase and is produced through calcination of magnesium hydroxide or carbonate sources. This highly stable oxide features exceptional thermal resistance, electrical insulation, and chemical inertness.

Key Physical and Chemical Properties

  • Appearance: Fine white powder (light or heavy grades available)
  • Purity: Typically ≥97–99.99% (depending on grade: technical, pharmaceutical, food, high-purity)
  • Melting Point: 2852 °C
  • Boiling Point: 3600 °C
  • Density: 3.58 g/cm³
  • Refractive Index: ~1.736
  • pH (saturated aqueous solution): ~10.3 (slightly basic)
  • Solubility: Poorly soluble in water (~0.0086 g/100 mL at 20 °C); reacts slowly to form Mg(OH)₂; soluble in dilute acids and ammonium salt solutions
  • Thermal Conductivity: 30–60 W/m·K (excellent heat transfer in refractory uses)
  • Crystal Structure: Cubic (rock-salt type, halite structure)

Primary Applications and Uses

  • Refractories and High-Temperature Materials: Used in furnace linings, crucibles, bricks, and castables for steel, cement, and glass industries due to its superior refractoriness and resistance to basic slags.
  • Pharmaceutical and Nutraceutical: Acts as an active pharmaceutical ingredient (API) in antacids for acid neutralization, laxatives for constipation relief, and magnesium supplements for deficiency correction; meets USP, Ph. Eur., BP, and FCC standards in pharma/food grades.
  • Food and Beverage Industry: Food-grade magnesium oxide serves as an anti-caking agent, pH regulator, color stabilizer, magnesium fortifier in supplements, infant formula, and processed foods (per 21 CFR 184.1431).
  • Rubber and Plastics: Vulcanization accelerator, acid acceptor, and flame retardant in elastomers, cables, and polymer compounds.
  • Environmental and Wastewater Treatment: Neutralizes acidic effluents, removes heavy metals, and acts as a precipitant in water purification.
  • Agriculture: Soil amendment to correct magnesium deficiency and adjust pH in fertilizers.
  • Other Specialized Uses: Electrical insulators, optical materials, cosmetics (as absorbent), and as a starting material for other magnesium compounds.

Why Choose Our High-Quality Magnesium Oxide?

Ours is available in multiple grades—light (high surface area for pharma/food), heavy (dense for refractories), fused (high crystallinity), nano, and ultra-high purity (≥99.99% trace metals basis)—to match exact application needs. We control key parameters like particle size, bulk density, impurity levels (low heavy metals, iron, calcium), and reactivity for consistent performance in sensitive formulations or extreme conditions. Packaged to prevent moisture absorption and maintain stability during storage and transport.

Safety and Handling Information

Magnesium oxide is generally considered low hazard (non-flammable, non-toxic in normal use), but inhalation of fine dust may cause respiratory irritation (fume fever possible with heated material). Use appropriate PPE (dust mask, gloves, eye protection) in dusty environments. Store in dry, sealed containers away from strong acids. It is not classified as hazardous under GHS for most applications, but refer to the latest SDS for detailed guidance.

Frequently Asked Questions (FAQs)

What is the CAS number for magnesium oxide?

The CAS number is 1309-48-4.

What is the difference between light and heavy magnesium oxide?

Light magnesium oxide has higher surface area and reactivity (ideal for pharmaceuticals, food, and antacids), while heavy magnesium oxide is denser with lower surface area (preferred for refractories and industrial uses).

Is magnesium oxide safe for food and pharmaceutical use?

Yes, food-grade and pharmaceutical-grade magnesium oxide comply with FCC, USP, Ph. Eur., and BP standards and are approved as a direct food additive, supplement, and API.

Why is magnesium oxide used in antacids and laxatives?

It neutralizes stomach acid quickly (antacid effect) and draws water into the intestines to promote bowel movement (osmotic laxative effect).

How does magnesium oxide compare to other magnesium supplements?

It has the highest elemental magnesium content per gram but lower bioavailability compared to citrate or glycinate; it excels for short-term laxative or antacid needs.

Is magnesium oxide soluble in water?

It has very low solubility in pure water but reacts slowly to form magnesium hydroxide; solubility increases in acids.

For quotations, certificates of analysis, samples, custom specifications, or bulk supply of magnesium oxide CAS 1309-48-4, please contact our team.

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