Fused alumina is a versatile abrasive made by melting or fusing aluminum oxide in an electric arc furnace and is used in a wide range of applications in many different industries. It is composed of 94% to 99% aluminum oxide and comes in different particle sizes and shapes depending on the intended use. fused alumina is known for its high hardness, excellent wear resistance and good chemical stability.
How is fused alumina made?
The raw materials used to produce fused alumina are bauxite, anthracite and iron filings. The materials are mixed together in the right proportions and then smelted in an electric arc furnace at temperatures around 2,000 degrees Celsius. The resulting molten alumina is then cooled and solidified, pulverized and graded into different sizes and shapes.
Characteristics of fused alumina
Fused alumina has a variety of properties that allow it to be used in different applications. It has a high melting point of around 2,050 degrees Celsius, making it ideal for high temperature applications. It is also chemically inert, meaning it does not react with most chemicals. Fused aluminum oxide is extremely hard and wear-resistant, making it ideal for abrasive applications.
Classification of fused alumina
Brown Fused Alumina
This is the most widely used class of fused alumina, accounting for over 70% of global production. Brown corundum is made from bauxite and has the characteristics of high toughness and low brittleness. It is commonly used in grinding and cutting applications, as well as refractory products and sandblasting.
This type of fused alumina is made of high-purity alumina and is characterized by high hardness and good toughness. It is typically used in applications that require high-performance abrasives, such as grinding wheels, sandpaper, and cutting tools.
Tabular Fused Alumina
Made from high-purity aluminum oxide, this type of fused alumina is resistant to high temperatures and thermal shock. It is commonly used in refractory materials such as high temperature furnace linings.
Black Fused Alumina
Made from low-iron bauxite, this type of fused alumina is characterized by high hardness and low porosity. It is commonly used in abrasive applications such as grinding and polishing stainless steel and other metals.
Microcrystalline Fused Alumina
The crystal size of this type of fused alumina is smaller than that of conventional fused alumina, so the material has improved fracture toughness and wear resistance. It is commonly used in cutting tools and other applications that require high strength and durability.
Application of fused alumina
Abrasive
fused alumina is widely used as abrasives due to its high hardness, toughness and thermal stability. It is commonly used in grinding and polishing applications, as well as sandblasting in industries such as construction, automotive and aerospace.
Refractory materials
fused alumina is also used to produce refractory products, which are materials that can withstand high temperatures and harsh environments without degrading. The high melting point and thermal stability of fused alumina make it an ideal material for refractory materials such as kiln linings, furnace linings and crucibles.
Ceramics
Fused alumina is used to produce advanced ceramics due to its high purity, high strength, and excellent thermal and electrical properties. It is commonly used in ceramic components of electronic devices such as substrates, insulators and circuit boards.
Surface treatment
Fused alumina is used for surface treatment in industries such as metalworking, construction and shipbuilding. It is commonly used in sandblasting and shot blasting, processes that remove surface contaminants and create a rough surface to improve coating or paint adhesion.
Water filtration
Fused alumina is used as a filtration media in water treatment applications due to its high porosity and ability to remove contaminants such as heavy metals and organic compounds.
Other apps
Molten alumina is also used in a variety of other applications, such as the production of catalysts, cutting tools and welding electrodes.
Advantages and limitations of fused alumina
There are many advantages to using fused alumina in different applications. It has high hardness and excellent wear resistance, making it ideal for abrasive applications. It is also highly resistant to thermal shock, making it ideal for use in high-temperature applications.
However, there are some limitations to using fused alumina. For example, compared with other abrasives, its price is relatively high and it is difficult to produce in large quantities.
Choose the right fused alumina for your application
There are several different types of fused alumina available, each with different properties and particle sizes. When selecting the right fused alumina for your application, it is important to consider factors such as the material's hardness, toughness, and wear resistance, as well as the shape and size of the abrasive particles.
For example, if you need a material with high cutting capabilities and high cutting forces, coarse-grained fused alumina may be the best choice. On the other hand, if you require a material with a good surface finish, a finer-grained fused alumina may be more suitable.
