Aluminum oxide
[CAS# 1344-28-1]

Identification

• Classification: Inorganic chemical industry >> Inorganic salt >> Oxides and peroxides >> Metal oxide
• Name: Aluminum oxide
• Synonyms: alpha-Alumina; alpha-Alumina trihydrate; Activated alumina
• Molecular Formula: Al₂O₃
• Molecular Weight: 101.96
• CAS Registry Number: 1344-28-1
• EC Number: 215-691-6
• SMILES: [O-2].[O-2].[O-2].[Al+3].[Al+3]

Properties

• Solubility: Soluble (hexane, toluene)
• Density: 3.985 g/mL
• Melting point: 2045 °C
• Boiling point: 2980 °C
• Refractive index: 1.7265

Safety Data

• Hazard Symbols: GHS07 Warning
• Risk Statements: H302-H315-H319-H335
• Safety Statements: P261-P271-P304+P340-P312

Hazard Classification

Hazard	Class	Category Code	Hazard Statement
Specific target organ toxicity - single exposure	STOT SE	3	H335
Specific target organ toxicity - single exposure	STOT SE	3	H370
Specific target organ toxicity - repeated exposure	STOT RE	1	H372
Eye irritation	Eye Irrit.	2	H319
Specific target organ toxicity - repeated exposure	STOT RE	2	H373
Skin irritation	Skin Irrit.	2	H315
Acute toxicity	Acute Tox.	4	H332
Germ cell mutagenicity	Muta.	2	H341
Chronic hazardous to the aquatic environment	Aquatic Chronic	3	H412
Reproductive toxicity	Repr.	2	H361
Skin sensitization	Skin Sens.	1	H317
Carcinogenicity	Carc.	1B	H350
Acute toxicity	Acute Tox.	4	H302
Flammable liquids	Flam. Liq.	2	H225
Serious eye damage	Eye Dam.	1	H318
Carcinogenicity	Carc.	2	H351

Discovery and Applications

Aluminum oxide, with the chemical formula Al₂O₃, is a compound with significant industrial and scientific applications due to its remarkable properties. This oxide of aluminum is notable for its hardness, thermal stability, and chemical resistance, making it a critical material in various sectors.

The discovery of aluminum oxide can be traced back to the early 19th century when the compound was first identified as a distinct substance separate from alum, which was commonly used in ancient times. Its name "alumina" is derived from the Latin "alumen," referring to a type of potassium alum known since antiquity. The modern understanding of aluminum oxide emerged with the development of advanced analytical techniques and the isolation of pure aluminum oxide from bauxite ore. The Bayer process, developed by Karl Bayer in 1887, revolutionized the extraction of aluminum oxide from bauxite and facilitated the commercial production of aluminum metal.

One of the primary applications of aluminum oxide is as an abrasive. Due to its exceptional hardness, which ranks just below that of diamond on the Mohs scale, it is extensively used in grinding, cutting, and polishing materials. Aluminum oxide is a critical component in sandpapers, grinding wheels, and other abrasive tools used in metalworking, woodworking, and manufacturing. Its durability and effectiveness in material removal make it indispensable in these applications.

Aluminum oxide also plays a crucial role as a refractory material. Its high melting point and chemical stability under extreme temperatures make it ideal for use in furnaces, kilns, and reactors. Refractory bricks and linings made from aluminum oxide are employed in industries where high-temperature processes are essential, such as steelmaking, glass production, and cement manufacturing. The ability of aluminum oxide to withstand intense heat and corrosive environments ensures the longevity and efficiency of industrial equipment.

In addition to its industrial applications, aluminum oxide is used in the production of high-performance ceramics. These ceramics benefit from the hardness, strength, and wear resistance of aluminum oxide, making them suitable for applications in electronic devices, medical implants, and aerospace components. The use of aluminum oxide ceramics in electronic substrates and insulators enhances the performance and reliability of electronic devices by providing excellent electrical insulation and thermal conductivity.

Aluminum oxide is also employed as a catalyst and catalyst support in various chemical reactions. Its use as a catalyst support material in processes such as petroleum refining and petrochemical production enhances the efficiency and selectivity of chemical reactions. The high surface area and stability of aluminum oxide support catalysts and improve the performance of catalytic processes.

In addition to its practical applications, aluminum oxide is used in scientific research. It serves as a model system for studying the properties of metal oxides and their interactions with other substances. Research into aluminum oxide's properties and behavior contributes to the development of new materials and technologies.

Handling aluminum oxide requires standard safety precautions, particularly when dealing with fine powders or dust. Proper ventilation and personal protective equipment are essential to minimize exposure and ensure safe working conditions.

Ongoing research continues to explore new applications and improvements in the use of aluminum oxide. Advances in materials science and engineering are leading to the development of novel aluminum oxide-based materials with enhanced properties for various industrial and technological applications.

In summary, aluminum oxide is a versatile compound with significant applications in abrasives, refractories, ceramics, catalysts, and scientific research. Its discovery and development have had a substantial impact on various industries, and continued research holds promise for expanding its applications further.

References

1984. Adsorption of Phosphate by Aluminum Hydroxycarbonate. Journal of Pharmaceutical Sciences, 73(10).
DOI: 10.1002/jps.2600731007

1994. Sandblasting and silica coating of a glass-infiltrated alumina ceramic: Volume loss, morphology, and changes in the surface composition. The Journal of Prosthetic Dentistry, 71(5).
DOI: 10.1016/0022-3913(94)90182-1

2024. Alumina-enriched sunflower bio-oil in machining of Hastelloy C-276: a fuzzy Mamdani model-aided sustainable manufacturing paradigm. Scientific Reports, 14(1).
DOI: 10.1038/s41598-024-80254-z