Activated Alumina

Activated alumina, also known as active aluminum oxide or activated alumina (Al2O3), is commonly referred to as "active aluminum oxide" when applied in catalytic reactions. It is a solid raw material with a porous structure and high granularity, possessing a large surface area. The surface of its microporous plates exhibits characteristics required for catalytic reactions, such as adsorption properties, surface activity, and excellent heat resistance. Therefore, it is widely used as a catalyst and catalyst carrier in chemical transformations.

The spherical activated alumina DC transformer oil adsorbent is a milky white, spherical porous structure granule. The particle size distribution of activated alumina is uniform, with a smooth surface, high impact toughness, and strong water absorption. After absorbing moisture, it retains its original state without swelling or cracking. It is non-toxic, odorless, and insoluble in water and ethyl acetate.

Main Parameters of Aluminum Oxide:

Chemical Formula: Al2O3

Appearance: White powder

Relative Density: 3.9–4.0 g/cm³

Melting Point: 2050℃; Boiling Point: 2980℃

Solubility: Insoluble in water; slowly soluble in sulfuric acid.

Aluminum oxide can be used to refine metallic aluminum and is a raw material for producing pots, ceramics, refractory insulation materials, and synthetic gemstones.

As an absorbent, metal catalyst, and catalyst carrier, aluminum oxide is referred to as "activated alumina," characterized by a porous structure, high granularity, and large specific surface area. It is widely used in wastewater treatment, petrochemical equipment, bioengineering, microbiology, and the pharmaceutical industry.

Properties of Aluminum Oxide

Large Specific Surface Area: Activated alumina has a high specific surface area, effectively controlling the calcination system of aluminum oxide to produce activated alumina with a specific surface area reaching up to 360 m²/g. When using NaAlO2 solution-derived aluminum hydroxide gel as a raw material, the activated alumina produced can have a specific surface area exceeding 600 m²/g.

Adjustable Diameter Structure: Generally, activated alumina of medium diameter is produced by calcining pure aluminum hydroxide. Using aluminum gel and other compounds can yield products with smaller diameters, while adding certain organic compounds during the production of activated alumina, such as ethylene glycol or fibers, can lead to larger-diameter products after ignition.

Slightly Acidic Surface and Excellent Heat Resistance.

Types and Main Uses of Aluminum Oxide

γ-Series Ultra-Low Temperature Aluminum Oxide: Its chemical formula can be represented as Al2O3·nH2O. This form is formed at temperatures not exceeding 600℃ in dehydrated environments, including ρ, χ, η, γ-alumina with relatively poor crystallinity.

δ-Series Continuous High-Temperature Aluminum Oxide: This series, formed between 800℃ and 1000℃, is known as structural agents, including k, θ, δ-alumina, with relatively good crystallinity.

ρ-Alumina: ρ-Alumina is an unstable body formed by rapidly heating trihydrate bauxite; its key feature is hydratability. Based on its hydrating properties, various types of activated alumina products (e.g., rod-shaped, spherical) can be produced.

Functions of Activated Alumina

Activated alumina, classified under chemical products of aluminum oxide, is primarily used as an absorbent, coagulant, metal catalyst, and catalyst carrier. It selectively adsorbs moisture from gases, water vapor, and certain solutions. Once saturated, it can be regenerated by heating at approximately 175–315℃, allowing for multiple cycles of adsorption and regeneration.

In addition to being used as a moisture-proof agent, it can also absorb lubricating grease vapors from polluted air, hydrogen, carbon dioxide, natural gas, etc. Furthermore, it serves as a metal catalyst and catalyst carrier, as well as a chromatographic analysis medium.

It can be utilized as a defluorinating agent for high-fluoride drinking water (with a large defluorination capacity), a defluorinating agent in the cyclic production of ethane in alkylbenzene manufacturing, a reconstituting agent for degreasing insulating oils, and for drying gases in oxygen production, textile, electronics industries. Additionally, it functions as a drying agent for automation instruments, fertilizers, and petrochemical equipment (with a dew point reaching -40℃), while in certain types of vacuum swing adsorption systems, the dew point can reach -55℃.

It is also a highly effective moisture-proof agent suitable for low-water-depth drying applications in non-thermal regeneration equipment.