Aluminium Hydroxide is the hydroxide of aluminium. Its chemical formula is Al(OH)₃. Due to its ability to react with both acids and strong bases, it is a typical amphoteric hydroxide. Industrial products are usually white powders. According to their uses, they are mainly divided into two categories: industrial grade (used as a flame retardant, filler) and pharmaceutical grade (used as an anti-acid medicine).

Basic parameters

CAS Number: 21645-51-2

Molecular formula: Al(OH)₃

Molecular weight: 78.0

EINECS Number: 244-492-7

Appearance: White amorphous powder or granules, odorless and tasteless

Melting point / Decomposition temperature: 300℃ (Water is lost and turns into alumina when heated to this point)

Density: Approximately 2.40 - 2.42 g/cm³

Solubility: Almost insoluble in water and ethanol. Soluble in hot hydrochloric acid, sulfuric acid and alkaline solutions.

pH value: The aqueous suspension of this substance is slightly alkaline, with a pH range of approximately 9-10.

Advantages and Characteristics

The wide application of aluminium hydroxide is based on its unique physical and chemical properties:

Flame retardant and smoke suppressant properties (core industrial characteristics)

• Thermal decomposition releases heat: It begins to lose moisture at around 200℃, and the decomposition becomes particularly intense at 300℃. This process absorbs a large amount of heat, reducing the surface temperature of the material.

• Dilution of oxygen and smoke suppression: The water vapor produced during decomposition not only dilutes the oxygen concentration in the air, but also effectively inhibits the generation of smoke and the release of toxic gases. Therefore, it is currently recognized as a recognized environmentally friendly inorganic flame retardant.

Sexual response characteristics

• It can be dissolved in acids to form aluminum salts, and also can be dissolved in strong bases to form metahalloysilicates. This property makes it highly valuable in chemical synthesis (such as the preparation of aluminum salts and polyaluminium chloride).

High purity and stability

• The purity of the commercially available reagent-grade products can reach over 99.0%. The high-purity nano-level (99.99%) can be used in advanced fields such as electronics.

• Chemically stable, non-flammable and non-toxic.

Biomedical characteristics

• It has the characteristics of slow and long-lasting anti-acid effect, with a strong potency. Moreover, it does not produce carbon dioxide (without causing abdominal distension), and it also has the functions of constricting and protecting the gastric mucosa.

Main purpose

Plastic and Rubber Industry (Flame Retardant Fillers)

• Application: As an environmentally friendly flame retardant, it is the largest consumer market for aluminum hydroxide. Widely used in wires and cables, electronic appliances (such as circuit boards), automotive parts, insulation materials, etc.

• Function: Its non-toxicity, low smoke production, and non-corrosive gas emission characteristics make it an ideal alternative to halogen-based flame retardants.

Medicine and Health Field

• Antacid: Used to treat excessive stomach acid, gastric ulcers, etc. It is usually processed into a gel form (such as aluminum hydroxide gel).

• Vaccine adjuvant: In vaccine production, it serves as an immune enhancer, helping to improve the immune efficacy of the vaccine.

Chemicals and Materials Field

• Basic chemical raw materials: Used for manufacturing polyaluminium chloride (PAC), aluminum sulfate, aluminum oxide (through calcination), and zeolite (molecular sieve), etc.

• Catalyst: As a carrier for the production of petrochemical products (such as Claus process sulfur recovery).

Environmental Protection and Water Treatment

• Water purifying agent: Utilizing its colloidal adsorption and coagulation properties, it is used as a flocculant in water treatment to remove suspended solids and pigments from the water.

Other Fine Applications

• Papermaking and Fillers: Used as a whitening filler for paper, a treatment agent for waterproof fabrics, a raw material for glassware, a thickening agent for printing inks, and a filler in cosmetics (such as lipstick and foundation).

Safety and Storage Precautions

• Safety: This product is non-flammable and non-explosive. The powder may cause mild irritation to the eyes and respiratory system. It is recommended to wear a mask and protective glasses when operating.

• Storage conditions: It should be stored in a cool, dry and well-ventilated warehouse. Pay attention to moisture prevention and keep it separate from strong acids and strong bases.