Magnesium Hydroxide (Mg(OH)₂) in Manufacturing: A Comprehensive Overview
Magnesium hydroxide [Mg(OH)₂] is a multifunctional inorganic compound valued for its non-toxicity, flame-retardant capabilities, and alkaline properties. Its applications span diverse industries, from environmental protection to pharmaceuticals, due to its safety, cost-effectiveness, and chemical stability. Below is an expanded breakdown of its key manufacturing uses.
1. Flame Retardant Applications
Magnesium hydroxide serves as a halogen-free, environmentally friendly flame retardant, making it a preferred choice in industries where fire safety is critical.
Key Uses:
Plastics & Polymers:
Added to electrical cables, wiring insulation, and circuit boards to inhibit combustion. When exposed to heat, it decomposes endothermically (absorbing heat) and releases water vapor, which dilutes flammable gases and cools the material.
Used in automotive components, appliance casings, and electronic enclosures to meet fire safety standards (e.g., UL94, RoHS).
Rubber & Textiles:
Incorporated into fire-resistant conveyor belts, gaskets, and protective clothing to enhance thermal stability.
Construction Materials:
Mixed into fireproof coatings, insulation foams, and composite panels for buildings and transportation (e.g., aircraft, trains).
Advantages Over Traditional Flame Retardants:
√ No toxic fumes (unlike brominated or chlorinated retardants).
√ Smoke suppression properties, improving safety in fires.
√ Compatible with recycling processes, unlike some synthetic retardants.
2. Environmental & Wastewater Treatment
Magnesium hydroxide is widely used in pollution control and water purification due to its mild alkalinity and metal-binding properties.
Key Applications:
Acid Neutralization in Industrial Wastewater:
Used in mining, metal plating, and chemical manufacturing to neutralize acidic effluents (pH adjustment).
More controllable and safer than caustic soda (NaOH) or lime (Ca(OH)₂), reducing the risk of over-alkalization.
Heavy Metal Removal:
Precipitates lead, cadmium, arsenic, and mercury from contaminated water, forming insoluble hydroxides that can be filtered out.
Flue Gas Desulfurization (FGD):
An alternative to limestone in scrubbing sulfur dioxide (SO₂) from coal-fired power plants, reducing air pollution.
Benefits in Water Treatment:
√ Slow-release alkalinity prevents pH spikes.
√ Produces less sludge compared to lime treatment.
√ Non-corrosive, extending equipment lifespan.
3. Pharmaceuticals & Cosmetics
Due to its non-toxic and gentle alkaline nature, magnesium hydroxide is used in healthcare and personal care products.
Key Uses:
Medical Applications:
Antacid: Found in Milk of Magnesia to relieve heartburn and indigestion by neutralizing stomach acid.
Laxative: Promotes bowel movements by drawing water into the intestines.
Cosmetics & Skincare:
Acts as a pH adjuster in creams, lotions, and deodorants.
Used in toothpaste as a mild abrasive and whitening agent.
Advantages in Healthcare:
√ Gentler on the stomach compared to aluminum-based antacids.
√ Naturally occurring, making it suitable for sensitive skin formulations.