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CAS NUMBER: 21645-51-2

EC NUMBER: 244-492-7




Alumina Trihydrate is the most widely used flame retardant in the world due to its versatility and low cost.  
Available in different particle sizes, Alumina Trihydrate can be used in a wide range of polymers at processing temperatures below 220°C. 

Alumina Trihydrate is non-toxic, halogen-free, chemically inert, and has low abrasiveness. 
Additional benefits are arc and track resistance in plastics exposed to electrical arcing, acid resistance, and smoke suppression. 

At about 220°C, Alumina Trihydrate begins to decompose endothermically releasing approximately 35% of its weight as water vapor.
Alumina Trihydrate acts as heat sink thereby retarding pyrolysis and reducing the burning rate. 

The water vapor released has an added effect of diluting combustion gases and toxic fumes.
The vast majority of aluminium trihydrate is derived from bauxite ore. 

Aluminium trihydrate is used as a feedstock for the manufacture of other aluminium compounds such as calcined aluminas, aluminium sulfate, polyaluminium chloride, aluminium chloride, zeolites, sodium aluminate, activated alumina, aluminium nitrate.
A white, translucent powder that is also called aluminum hydroxide. 

Alumina trihydrate is obtained from Bauxite. 
When Alumina Trihydrate is strongly heated, alumina trihydrate will convert to Aluminum oxide with the release of water. 

Alumina Trihydrate is also used as an inert filler in paints and tends to increase the transparency of colors when dispersed in oils. 
Alumina trihydrate is used commercially as a paper coating, flame retardant, water repellant, and as a filler in glass, ceramics, inks, detergents, cosmetics, and plastics.

Alumina Trihydrate is the hydrated oxide of aluminium. 
Alumina hydrate is separated from bauxite ore using the Bayer process, with average particle size ranging from 80-100 micron. 

The block crystals of alumina hydrate impart good chemical reactivity. 
Alumina hydrate can react with a base as well as an acid, and finds use in many applications as raw material.

Alumina trihydrate contain 3 molecules of water. 
On exposure to heat above 220°C, alumina hydrate decomposes into aluminium oxide (alumina) and water. 

This irreversible, endothermic reaction process makes alumina hydrate an effective flame retardant. 
Also, the smoke generated by decomposition is non-corrosive and non-poisonous. 

Ground alumina hydrate is used as fire retardant filler in applications like polymer composites, cable compounds, solid surface counter tops, etc.
Alumina Trihydrate has a number of common names used throughout the chemical industry which include: Hydrate Alumina, Alumina Hydrate, Aluminium Tri Hydroxide, ATH, Aluminium Hydrate and Aluminium Hydroxide. 

Alumina Trihydrate is a white, odorless, powdery, solid substance. 
Alumina Trihydrate demonstrates a very low solubility in water but is considered to be amphoteric, meaning Alumina Trihydrate will dissolve in both acids or a strong alkali. 

The most common use of Alumina Trihydrate is for the production of aluminum metal. 
Alumina Trihydrate is also used as a flame retardant and smoke suppressant filler in polymers such as rubber products and carpet backing.

AluminIum trihydrates are obtained by digestion of bauxite throughout the Bayer process.
Alumina trihydrate starts to remove constitution water above 180 ° C. 

Water removal cools the surface and eliminates entry of oxygen, which confers flame retardant properties and smoke suppressant. 
Accordingly Alumina trihydrate is a necessary raw material for products like rubber, polyurethane, polyester, silicone, thermoplastic, cables, etc. with fire retardant properties.

Due to their good chemical resistance and physical properties, aluminium trihydrate is a basic raw material for the manufacture of solid surface. 
The solid surface is a material widely used in sanitary, kitchen, hotels, hospitals, façade cladding and construction in general.

Aluminium trihydrates also is used in the ceramic industry, in the manufacture of enamel and pigments and catalyst for chemical reactions.
Alumina trihydrate is a white filling material that provides flame retardant and self-extinguishing properties for polyester resins and gelcoats. 

Alumina trihydrate exposes water molecules within the body at high temperatures to reduce flame spread and smoke formation. 
Alumina trihydrate is used in GRP pipe applications, in acrylic applications and in other multicomponent applications.

Alumina trihydrates thermodynamic properties, endothermic dehydration cools the plastic 6 rubber parts and dilutes the combustible gases with water vapours that is generated in case of fire.
Alumina Trihydrate widely use in Paper Industries as a whitening agent in place of titanium dioxide.

Alumina trihydrate is also use in  Paints Industries.  
Alumina trihydrate can replace upto 25% of the Titanium dioxide pigment & therefore is an economical extender reducing production cost.

Ideal for the manufacture of mortars used for floors with epoxy resins, polymer concrete parts, decorative resin parts, etc.
Alumina trihydrate is an inorganic white fine crystalline, non-hygroscopic powder. 

Alumina trihydrates solubility in water and organic solvents is very low. 
By volume, Alumina trihydrate is the largest flame retardant (FR) used in diverse end applications. 

The working principle is based on the thermal decomposition of aluminium hydroxide into aluminium oxide and water(vapour). 
This endothermic reaction starts at about 200 °C and consumes energy from the ignition source. 

The generated water vapour cools the polymer surface and dilutes the concentration of burnable gases in the surroundings. 
The remaining metal oxide residue has a high internal surface where sooty particles, respectively polycyclic aromatic hydrocarbons, are absorbed, making ATH also a smoke suppressant. 

The oxide layer acts as a barrier protecting the polymer against further decomposition.
Alumina trihydrate is commercially available in grain sizes ranging from 0.5 – 80 µm in median particle size (D50). 

In Halogen Free Flame Retardant (HFFR) wire and cables (W&C), one of the largest markets for ATH, fine precipitated ATH is used in sheathing and insulation. 
HFFR-compounds are based on blends of EVA ((poly(ethylene-co-vinyl acetate)) and LLDPE (Linear Low Density Polyethylene). 

In plasticised PVC fine precipitated Alumina trihydrate is used as FR and smoke suppressant. 
Major use is in so called Low Smoke Flame Retardant (LSFR) cables. 

Another very important end application is thermal insulation foams made of PVC/NBR blends. 
These elastomers have also to fulfil severe fire resistant requirements, especially when used for e.g. insulating heating and plumbing pipework in multi store buildings. 

Other applications are floorings based on PVC, EPDM or other polymers, used in public area buildings, and conveyor belts used in mines, power plants and in public buildings like airports (NR/NBR based).
Coarser Alumina trihydrate types produced by grinding are used in large volume in thermoset applications. 

Cast resins and glass fibre reinforced products like BMC (Bulk Moulding Compounds) and SMC (Sheet Moulding Compounds) are processed in electrical and electronic appliances as well as in construction applications.
Alumina trihydrate has been shown to have a favourable environmental and health profile. 

Alumina trihydrate is listed as GRAS (Generally Recognized as Safe) under Code of Federal Regulations and therefore is considered as safe in food and food packaging applications.
The absolute environment friendliness and their favourable price-performance ratio make Alumina trihydrate a sustainable flame retardant.

Alumina trihydrate is a dry free-flowing coarse powder. 
This same process imparts properties that lead to rapid dissolution in strong acid or strong bases.





Aluminium trihydrate also finds use as a fire retardant filler for polymer applications in a similar way to magnesium hydroxide and mixtures of huntite and hydromagnesite. 
Alumina trihydrate can also be applied as an ultra-low iron source for aluminium oxide (Al2O3) in glass melting furnaces.

Alumina Trihydrate is used as a filler for epoxy, urethane, or polyester resins, where fire retardant properties or increased thermal conductivity are required. 
Alumina trihydrate is white in color.


-A raw material in the production of Aluminium chemicals

-A raw material in the manufacture of glass and glazes

-A raw material in catalyst production

-A flame retardant and smoke suppressant filler in plastics (for example: Cables, rubber products and carpet backing)

-A raw material for fertilizers, and fiber cement board products

-An extender and bodying agent in paper, solvent- and water-borne paints, UV curable coatings, inks, and adhesives

-A polishing and cleansing agent

-Mould wash and separating agent

-A filler of cast polymer products such as onyx and solid surfaces




Alumina trihydrate or alumina trihydrate is the hydrated oxide of aluminium. 
Alumina trihydrate is separated from ore bauxite using Bayer process with average particle size ranging from 80-100 micron. 
The blocky crystals of Alumina trihydrate impart good reactivity. 

Alumina trihydrate can react with a base as well as an acid and finds many applications as raw material. 
Alumina trihydrate or alumina hydrate is used in the manufacture of many inorganic chemicals like:


-Non- ferric alum

-Poly aluminium chloride

-Aluminium fluoride

-Sodium aluminate



-Aluminium hydroxide gel


Over 90% of all Alumina Trihydrate produced is converted to Aluminium Oxide (alumina) that is used to manufacture aluminum. 
As a flame retardant, Alumina Trihydrate is chemically added to a polymer molecule or blended in with a polymer to suppress and reduce the spreading of a flame through a plastic. 
Alumina Trihydrate is also used as an antacid that can be ingested in order to buffer the pH within the stomach.


-Coatings and polymers

-Construction (counters and other solid surfaces)


-Pharmaceuticals and hygiene products

-Solid surfacing

-Fire retardancy in coatings

-Flame retardancy in polymers




-Physical Form: Powder

-Particle Morphology: Hexagonal Platelet

-Color: White

-Specific Gravity: g/cm3 2.42

-pH Value: 9 - 10

-Hardness, Mohs: 2.5 – 3.5

-Refractive Index: 1.57

-Temperature of Decomposition: 220°C / 428°F

-Heat of Decomposition, cal/g: 280

-Theoretical loss on ignition: % 34.6




The following properties are important to most applications:

-Exceptional whiteness

-Good translucency

-Resistance to chemicals and weathering

-Impact resistance

The softness of the mineral contributes to making materials machinable with loading levels between 40% and 70% becoming possible and providing the best properties.


-Soluble in mineral acids and caustic soda. 

-Insoluble in water.

-Fine grains. 

-No birefringence.

-Under plane-polarized light, particles are colorless with low relief




-Powdery substance



-Contains thermal characteristic that provides translucency and whiteness to

-Solid surface material




-Flame retardant



-Longer shelf life

-Flame retardant



Room Temperature



Dried aluminum hydroxide gel
Aluminium hydroxide gel, dried
aluminium trihydroxide
aluminum hyroxide
Hydroxyde d' aluminium
Dried aluminium hydroxide
Aluminium hydroxide, dried
Aluminum hydroxide gel, dried
Aluminum, di-mu-hydroxytetrahydroxydi-






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