What Is Aluminum Phosphate?
Aluminum phosphate is an inorganic compound consisting of aluminum and phosphate ions.
It is denoted by the chemical formula AlPO4 and appears as a white powdery solid under standard temperature and pressure. Berlinite, a naturally occurring form of aluminum phosphate, is considered an ore.
Aluminum phosphate is produced by combining aqueous solutions of aluminum ions and phosphate ions, which leads to crystallization. Upon heating, the compound decomposes into aluminum oxide and diphosphorus pentoxide.
Uses of Aluminum Phosphate
1. Alumina Ceramics
Aluminum phosphate serves as a raw material for alumina ceramics, known for their exceptional hardness, heat resistance, corrosion resistance, and thermal conductivity, while maintaining low electrical conductivity.
Its low electrical conductivity makes it ideal for use in various mechanical parts, especially electrical insulating components.
2. Cement
In dentistry, aluminum phosphate contributes to the formulation of dental cements, enhancing their resistance to acids, bases, pressure, and tension.
3. Binder
Acid aluminum phosphate, derived from phosphoric acid and aluminum hydroxide, is used in refractory binders and foundry sand binders.
This water-soluble acidic phosphate, with the formula Al2O3-3P2O5-6H2O, hardens and binds through condensation by dehydration and crystal transition when heated to high temperatures. It functions as a binder, metal surface treatment agent, and fire retardant.
4. Other Uses
Aluminum phosphate is utilized as an adsorbent, in firebricks, refractory concrete, non-alkali glass, the ceramic industry, and as a special coating agent. It also finds applications in the chemical industry, particularly in the production of acetic anhydride at high temperatures.
Properties of Aluminum Phosphate
Aluminum phosphate is odorless and has a molecular weight of 121.95 g/mol and a CAS number of 7784-30-7.
Its melting point is not defined above 450°C, and it has no specific boiling or flash point data, aligning with its non-flammable classification under GHS. The density is 2.56 g/mL at 25°C, and it has a solubility in water of 6.92 g/L at 20°C. It is chemically stable under normal atmospheric conditions, though contact with strong bases should be avoided.
Other Information on Aluminum Phosphate
1. Handling Instructions
Despite not being classified as hazardous under GHS criteria, handling should involve protective eyewear and safety gloves, especially to mitigate dust exposure. While not inherently flammable, precautions against dust explosions require adequate ventilation. Always wash hands after handling and maintain cleanliness to prevent product dissemination outside the work area.
2. First Aid Measures
In case of exposure, despite its non-hazardous classification, ensure fresh air for inhalation incidents, water rinsing for skin contact, abundant water flushing for eye exposure, and water intake if ingested, consulting a physician if discomfort persists.
3. Fire Precautions
Extinguish fires using water, foam, or carbon dioxide powder, selecting the extinguishing agent based on the environment and conditions, while wearing self-contained breathing apparatus to avoid inhaling potentially toxic combustion products.
4. Storage
Ensure storage in a dry, tightly sealed environment away from strong bases, adhering to proper disposal protocols for industrial waste in compliance with laws, regulations, and local ordinances.