Alumina là gì ứng dụng của nhôm oxit

What is Alumina? The application of aluminum oxide surprises you

Aluminum oxide – alumina is one of the substances with many valuable applications from medicine, cosmetics, water filtration technology, and food.

What is Alumina?

Alumina has the chemical formula AL2O3, also known as aluminum oxide.

Aluminum oxide is a protective layer for metallic aluminum from the corrosion of the air. Because aluminum is a highly active metal, it reacts immediately when exposed to air. But it is aluminum oxide that protects, prevents further reactions of the metal rod.


Properties of alumina (aluminum oxide)

Chemical properties:

Alumina is an amphoteric oxide. Hence both reacts with acids and with bases.

Al2O3 + 6HCl → 2AlCl3 + 3H2O

Al2O3 + 2NaOH → 2NaAlO2 + H2O


The bonding of Al3 ions and O2 ions is very stable. The melting point is very high (2050 degrees C) and difficult to reduce to Al metal.

Alumina in nature

Account for more than 55% by volume of bauxite ore, together with the components such as iron oxide III, CaO, SiO2, TiO2, MgO.

Especially, Alumina is also the main ingredient of Corindon – the gemstone second only to diamonds. The color of this gem is due to impurities containing chromium, iron, vanadium and many other compounds. Corindon is divided into many types, which are named according to different names. Red corindon is rubi, blue corindon is sapphire.

Aluminum oxide is the main component of the Corindon gemstone

Aluminum oxide is the main component of the Corindon gemstone

Application of aluminum oxide:


When the water molecule (H2O) comes in contact with aluminum oxide, the aluminum and oxygen atoms on the surface will separate (the distance between the atoms can increase by 50%). As a result, the outer oxide layer is hydrated. This process is reversed (regenerates the desiccant) when they are heated at 200 degrees Celsius.

Aluminum oxide is used in the manufacture of desiccants

Application in the manufacture of desiccants

At the same time its structure is just enough to become chemically more inert. It is therefore not possible to react rapidly with water and oxygen molecules in the atmosphere. This is why aluminum oxide is considered as the protective film of aluminum bars.

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Also thanks to this feature, alumina is used as a trap to prevent oil from the propeller pumps of the engine system.

In ceramic materials

Thanks to its high melting point, aluminum oxide is used to make alumin ceramics. This material is kept almost completely at a temperature of 1100 degrees Celsius. Used to make heat-resistant details: grinding details, tools, cutting knives, bearings at high temperatures, …

They are added to increase the strength of the enamel. The aluminum oxide content makes the enamel harder, more durable, more stable, and has greater heat resistance.

In medicine

Based on mechanical properties, the same ability in the biological environment. So aluminum oxide is used to cover the internal frictional surfaces of body prostheses such as hips, shoulders, … (biological materials)


With its bright, smooth polishing properties, aluminum oxide is used in some cosmetic products. Like sunscreen, cheek powder, lipstick, nail polish, and many sandpaper types. Especially concealer products.

Water purification applications

Alumina Activated (AA) is the only filter material specifically designed to remove fluoride and arsenic out of water. Activated alumina is a substance made from aluminum oxide with a very high surface-to-surface ratio – the ability to absorb fluoride good. Most water sources have an additional 2 ppm fluoride. AA filters can reduce fluoride concentrations below 0.1 ppmIn other words, 99% of normal fluoride water level.

Alumina is used in fluoride water filtration

Application in fluoride water filtration

Nanofilters are made of aluminum oxide

Follow greenoptimisticThe low-cost, aluminum-oxide nano-filter requires no (very little) energy from a liquid metal galium.

The researchers found that when aluminum is added to the core of the liquid gallium at room temperature. Aluminum oxide nanoplates are rapidly produced at the surface of the gallium, which is highly porous. Proven to be suitable for filtration of ions as well heavy metal and oil pollution at an unprecedented rate.

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