Natural magnesium hydroxide (brucite powder) is the first choice for the preparation of environmentally friendly inorganic flame retardant. It has three major functions – flame retardant, smoke suppression, and filling, and can be used as flame retardant filler for plastics, rubber, cables, etc.
Magnesium hydroxide decomposes at about 332°C (630°F), generating magnesium oxide and water. Water can dilute and isolate the air on the surface of the burning material. Decomposition of the active magnesium oxide solid, a high-temperature resistant material, can attach to the surface of the burning material to prevent burning.
Chemical reaction that occurs during burning: Mg(OH)2 → MgO + H2O
Natural magnesium hydroxide powder is widely used in engineering plastics, epoxy resin, rubber, wire and cable, mining cable filler, etc. Compared with aluminum hydroxide, magnesium hydroxide has high heat absorption by decomposition, good thermal stability, and low relative hardness.
Physical & Chemical Properties
Insoluble in water and alcohol, soluble in dilute acid and ammonium solution
The test of making flame retardant with polypropylene as the substrate shows that magnesium hydroxide has a good fire retardant effect, and is an ideal non-toxic, smoke-free, non-polluting, high-temperature flame retardant. It can also play the role of filler to enhance the mechanical properties of materials.
When burning, it decomposes and releases crystalline water to absorb a large amount of heat, while isolating the air on the surface of the burning material. The generated high-temperature resistant activated magnesium oxide can attach to the surface of the burning material to prevent burning.
The decomposition doesn’t generate corrosive or toxic gases. It is alkaline and can absorb and neutralize the acidic gases released when burning, such as carbon dioxide, sulfur dioxide, and nitrogen oxides. Activated magnesium oxide can absorb harmful gases, smoke, and molten residues that are incompletely burning.
Other industrial uses: extraction of magnesium or magnesium oxide, production of electrofused magnesite, enhancing material for insulation materials, filler for alkali paper-making, etc.
Product Technical Index
Mg(OH)2 Content (%)
Fe Content (%) ≤
Decomposition Temperature (°C)
D50 Particle Size (μm) ≤
D97 Particle Size (μm) ≤
2μm Particle Size (%) ≥
Moisture (%) ≤
Oil Absorption (ml/100g)
Loss on Ignition 750°C (%)
Hoyonn Chemical has been in the polymer industry since 2001. We specialize in mineral development, powder processing, R&D innovation, and global sales of barium sulphate and various functional fillers and additives. We have our plants and know-how to supply worldwide customers from powder coatings, paints, plastics, rubber, ink, and more industries.
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