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Cimbar Performance Minerals

Product MSDS
Magnesium Hydroxide
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(Our MgOH products save lives)


Filler and Flame Retardant/Smoke Suppressant in one product
Environmentally Acceptable
Halogen Free
Reduces Smoke Density
Largely Inert
Thermally Stable up to 340º C

How Does Magnesium Hydroxide Work?

By heating above 340º C magnesium hydroxide decomposes Endothermically emitting water according to the reaction:

Mg (OH) 2 ------ MgO + H2O

  • Endothermic effect leads to temperature reduction
  • Water vapor as decomposition product forms a protective steam layer in the gas phase
  • Surface-active Magnesium Oxide intermediates with absorption capability to reduce smoke density
  • Formation of an inert Magnesium Oxide protective layer inhibits further spread of flame

Compared to Alumina Trihydrate

Magnesium Hydroxide is much more reactive than Alumina Trihydrate (ATH). Whereas ATH releases the available water over a broad range (230º C to 430º C), Magnesium Hydroxide releases the available water over a much narrower range (330º C or 630º F to 430º C). In simple terms this compares to spraying a fine mist of water over a fire (ATH) as opposed to dousing the fire with a full bucket of water (Magnesium Hydroxide). The quick release of water enhances the flame retardant properties of Magnesium Hydroxide.

Water Release
Magnesium Hydroxide releases water at a higher temperature than ATH. The higher temperature release is at a more critical point that reduces the spread of the flame.

Particle Shape
Magnesium Hydroxide particles, if viewed under a microscope, are plate-like versus the spherical particles of ATH. These plate-like particles overlap one another similar to fish scales or roofing shingles. Pound for pound these plate-like particles offer much more exposed surface area than spherical ATH particles. Therefore more particles are directly exposed to the flame. Also, the plate-like particles provide more strength, flexibility and reinforcement in the finished product as opposed to spherical particles.

Particle Integration
Magnesium Hydroxide is a natural mix of particles. There is particle penetration and integration within Magnesium Hydroxide rather than having ATH and calcium carbonate particles mixed side by side. This allows a better distribution of the fire retardant and smoke suppressant properties.

Magnesium Hydroxide has stabilizing characteristics that tend to neutralize acid and toxic smoke. ATH does not provide these benefits.

Char Ash
Magnesium Hydroxide during the burning reaction forms a “Char-Ash” in front of the flame, which suppresses the flame.

Compared to Alumina Trihydrate
Physical properties such as viscosity cure rate, stress strain and durometer, suggest that magnesium hydroxide is virtually indistinguishable from ATH from a filler performance standpoint

It has been established that combinations of ATH and Magnesium Hydroxide produce less smoke than compounds filled with the same total loading of either mineral alone.

Magnesium Hydroxide, because of its acid scavenging properties, can play a useful role in halogenated compounds by reducing acid gas emissions.

By absorbing some of the heat, magnesium hydroxide prevents or delays ignition and retards combustion of polymeric materials.

Properties of ATH and Magnesium Hydroxide
  ATH Magnesium Hydroxide
Molecular Formula Al (OH) 3 Mg (OH) 2
Water Content Loss on Ignition (LOI) 34% 31%
Decomposition Temperature Greater than 230º C Greater than 330º C
Mohs hardness 2.5–3.5 2.0-3.0
Specific Gravity 2.42 2.36
pH 9-10 10.5
Electrical Conductivity   us/cm less than 350DIN 53208
Color White White
Physical Properties Powder Powder
Refractive Index 1.57 1.58
Particle Morphology Hexagonal Platelet Hexagonal Platelet

We offer standard dry ground products and a surface-treated product to aid with dispersion and workability.

Other products offer by Cimbar performance Minerals:
Calcium Carbonate (Crescent Series)
Barium Sulfate (Cimbar EX, UF, XF, 325 & PC to name a few)
Iron Oxide (4400 Series) Drilling Fluid Barite (Bara 200 Series)
Pharmaceutical Barite (Bariscan Series)
Bleached Industrial Barite (MitiWite Series
Sodium Bentonite Clay
Calcium Bentonite Clay

All U.S. Plant Locations:
Houston, Texas
Chatsworth, Georgia
Cartersville, Georgia
Potosi, Missouri

Contact Information:
14047 Industrial Road, Houston Texas 77015
Phone: 713-881-9466
Phone: 866-414-7504
Fax: 713-881-9471

The Statements Contained herein are based on data which is believed to be reliable, and is offered in good faith to be applied accordingly to the users own best judgment. We will not assume responsibility for the accuracy of this data, or liability, which may result from the use of these products. Likewise, no patent liability is assumed for the use of these products in any manner, which could or would infringe patent rights of others.


®Barifine and Bariace are registered trademarks of Sakai Chemical Industry Company Ltd