Technical aluminum oxide: properties and applications

Technical aluminum oxide (alumina, Al₂O₃) is one of the most important products of inorganic chemistry and metallurgy, appearing as a white crystalline powder. Its molecular mass is 101.96. In industry, technical aluminum oxide is produced in several modifications — α, β and γ — which determine its properties and applications. The main raw materials for alumina production are bauxite, nepheline and alunite.

Regulatory Framework and Grades

Requirements for metallurgical alumina in Russia and CIS countries are regulated by GOST 30558-98 "Metallurgical alumina. Specifications" (with 2017 amendments). The standard applies to alumina, a crystalline hygroscopic powder consisting of various modifications of aluminum oxide and intended primarily for the production of aluminum by electrolytic reduction. By chemical composition, alumina is divided into grades: G-00, G-0, G-1, G-2, G-3, G-4, GEB, GN, GNK, GK, GSK. Grade G-00 is used for primary aluminum production, G-1 and G-2 — for the production of electric corundum and ceramics.

For activated alumina of the γ-modification, GOST 8136-85 "Activated aluminum oxide. Specifications" applies, covering the product in the form of cylindrical granules used as a catalyst support, desiccant and raw material for producing mixed catalysts. Activated alumina is produced in three grades: AOA-1, AOA-2 and AOA-3.

Production Technology

The main industrial method for producing alumina is the alkaline Bayer process, which includes the following stages: crushing and wet grinding of bauxite in the presence of alkali; leaching (dissolution) of aluminum oxide in autoclaves at elevated temperature; separation of the insoluble residue (red mud); crystallisation of aluminum hydroxide from the aluminate solution; calcination of the hydroxide at about 1200 °C to form anhydrous aluminum oxide. In Russia, the combined Bayer-sintering process is used at the Ural plants, allowing the processing of complex diasporic-boehmite bauxites.

Properties

Alumina is a crystalline hygroscopic powder consisting of various modifications of aluminum oxide. Depending on its physical properties, technical alumina is divided into three groups: "floury" (specific surface area less than 5 m²/g), "sandy" (specific surface area more than 35 m²/g) and "under-calcined". Sandy alumina dissolves better in cryolite, which is important for electrolytic aluminum production. Activated alumina of the γ-modification has a specific surface area of 180 to 300 m²/g, a bulk density of 450–550 g/dm³ and an attrition strength of at least 65%. The mass fraction of loss on ignition does not exceed 5%, and the iron and sodium contents are no more than 0.05% and 0.03%, respectively.

Applications

Aluminium metallurgy. This is the largest consumption area for alumina — it accounts for about 90% of global production. Primary aluminum is obtained from alumina by electrolytic reduction in cryolite. Producing 1 tonne of aluminum requires about 1.9–2 tonnes of alumina.

Production of electric corundum. White electric corundum (fused alumina) is used to manufacture abrasive materials, grinding wheels, abrasive papers and pastes. Russia is one of the few producers of white electric corundum.

Corundum ceramics. Technical alumina serves as the main raw material for the production of dense corundum ceramics used in electrical insulators, integrated circuit substrates, instrument parts operating at high temperatures and in aggressive environments.

Refractories. High-alumina refractories are used for lining furnaces, ladles and other metallurgical equipment. Tabular alumina is used in the production of foundry moulds, refractory castables and ramming masses.

Catalysts and adsorbents. Activated alumina grades AOA-1, AOA-2 and AOA-3 are used as catalyst supports in the petrochemical and chemical industries, as well as desiccants for gases and liquids.

Other applications. Aluminum oxide is used in glass production, as a filler and pigment, in the electronics industry for substrates, in medicine for bioceramics (implants), as a sorbent and in water treatment systems.

Global Market

Estimates of the global aluminum oxide market volume vary depending on the methodology. According to 360iResearch, the market was valued at USD 67.02 billion in 2025, projected to reach USD 70.40 billion in 2026 and USD 96.94 billion by 2032 at a CAGR of 5.41%. According to Fortune Business Insights, the market was valued at USD 64.91 billion in 2025, USD 68.02 billion in 2026, and is projected to reach USD 103.43 billion by 2034 at a CAGR of 5.4%. According to IMARC Group, the market for special high-purity grades was valued at USD 6.6 billion in 2025 and is projected to reach USD 10.0 billion by 2034 at a CAGR of 4.49%.

Global alumina production reached approximately 154.1 million tonnes in 2025. The Asia-Pacific region dominates the global market with a 68.41% share in 2025, driven by large-scale aluminum production in China. China is the largest alumina producer, accounting for more than half of global output. The largest producers are Aluminum Corporation of China (Chalco), Alcoa, Rio Tinto, South32, Hindalco.

Key market growth drivers are increasing demand for aluminum, the development of electric vehicles and renewable energy, growth in corundum ceramics and refractories production, and expanding use of high-purity aluminum oxide in electronics and LED substrates. Main trends include the transition to low-carbon production, bauxite residue valorisation and improving the energy efficiency of Bayer processes.

Production in Russia

Russia is one of the world's largest alumina producers. The main capacities are concentrated at RUSAL facilities. In 2025, RUSAL increased alumina production by 6.7% to 6.86 million tonnes. The largest alumina facilities are: Achinsk Alumina Refinery (design capacity 1.069 million tonnes per year, operating on nepheline ore), Bogoslovsk Aluminium Smelter (produced 936,582 tonnes of high-quality alumina in 2025), Ural Aluminium Smelter, Boksitogorsk Alumina Refinery (the only enterprise in the company producing white electric corundum), Pikalevo Alumina Refinery. In 2025, the utilisation rate of the Ural alumina facilities was 96%.

According to data for the first 9 months of 2025, alumina imports from China to Russia increased by 32% in physical terms — China took the place of departed suppliers from Australia and Europe. Russia also increased alumina imports from Kazakhstan. Projects are underway to create new high-purity aluminum oxide production facilities: TVEL and AECC (Angarsk Electrolysis Chemical Combine) are developing the production of aluminum hydroxide and oxide for oil and gas catalysts; JSC Tagat Plant in the Tambov region is investing RUB 300 million in the production of high-purity grades of aluminum oxide and hydroxide.

Safety and Storage

Aluminum oxide is non-flammable and non-explosive. When working with the powdered product, personal protective equipment must be used: respirators, protective goggles and protective clothing, as prolonged exposure to dust causes irritation of the mucous membranes of the upper respiratory tract, mouth and eyes. Storage is carried out in dry, well-ventilated areas, in hermetically sealed containers, away from moisture and heat sources.

Conclusion

Technical aluminum oxide remains one of the key products of the global chemical and metallurgical industry, providing for the production of aluminum, abrasives, refractories, ceramics and catalysts. Growing demand for aluminum, the development of electric vehicles, the expansion of corundum ceramics production and high-purity grades for electronics create sustained demand for this essential material. China, Australia and Brazil remain the leading players in the global alumina market, and Russia, possessing significant production capacities and implementing projects for high-purity aluminum oxide production, maintains its position as one of the leading producers in the industry.