What are the components and uses of alumina ceramics?

What are the components and uses of alumina ceramics?

Alumina ceramics are produced by chemically treating bauxite raw materials to remove oxides such as silicon, iron, and titanium. They are highly pure alumina raw materials, with an Al2O3 content generally above 99%. The mineral phase is composed of 40% to 76% γ- Al2O3 and 24% to 60% α- Al2O3 composition. γ- Al2O3 can be transformed into α- Al2O3 (corundum) undergoes significant volume shrinkage at the same time.

Main uses of alumina:

The main component of Ruby and sapphire is aluminum oxide, which presents different colors due to other impurities. Ruby is red with chromium oxide, and sapphire is blue with iron oxide and titanium oxide.

Among the main components of aluminum ore, ferrite, alumina has the highest content. In industry, ferrite is purified into alumina by Bayer process and then transformed into aluminum metal by Hall Heroultprocess.

Aluminum oxide is the reason why metal aluminum is not easily corroded in the air. Pure metal aluminum easily reacts with oxygen in the air, forming a thin layer of aluminum oxide film covering the surface of aluminum exposed to the air. This layer of alumina film can prevent aluminum from further oxidation. The thickness and properties of this oxide film can be enhanced through a process called Anodizing (anodic corrosion prevention).

Aluminum is a good conductor of electricity and heat. The crystalline form of aluminum, carborundum, is suitable for use as grinding materials and cutting tools due to its high hardness.

Aluminum oxide powder is commonly used as a medium for color layer analysis.

High temperature sintered alumina, also known as artificial corundum or gemstone, can be used to make diamonds in mechanical bearings or watches. Alumina is also used as high-temperature refractory to make Fire brick, crucibles, porcelain, artificial gemstones, etc. Alumina is also the raw material for aluminum smelting. Calcination of Aluminium hydroxide can produce γ- Al2O3. γ- Al2O3 has strong adsorption capacity and catalytic activity, and can be used as an adsorbent and catalyst.

Main components of corundum α- Al2O3. A cubic crystal in the shape of a barrel or cone. Has a glass or diamond luster. The density is 3.9-4.1g/cm3, the hardness is 9, and the melting point is 2000 ± 15 ℃. Not soluble in water, nor in acids and alkalis. High temperature resistance. The colorless and transparent ones are called white jade, and the red ones containing trace trivalent chromium are called Ruby; Blue colored sapphire containing divalent iron, trivalent iron, or tetravalent titanium; A dark gray or dark color containing a small amount of ferric oxide is called corundum powder. It can be used as bearings for precision instruments, diamonds for clocks, grinding wheels, polishing agents, refractory materials, and electrical insulators. Colorful gemstones that can be used for decoration. Artificial Ruby single crystal can be used as laser material. In addition to natural minerals, Aluminium hydroxide can be produced by melting with hydrogen oxygen flame.

What are the uses of alumina ceramics?

Aluminum oxide has a high hardness and density, with a British hardness of 9, slightly lower than diamond, and a volume density generally greater than 3.5g/cm ³， Some can reach up to 4.0g/cm ³。 Alumina ceramics are divided into 99 porcelain, 95 porcelain, 90 porcelain, 85 porcelain and other varieties according to the different Al2O3 content. Among them, 99 alumina ceramic materials are used to make high-temperature crucibles, refractory furnace tubes, and special wear-resistant materials, such as ceramic bearings, ceramic seals, etc; 95 alumina ceramics are mainly used as corrosion-resistant and wear-resistant components.

Widely used in coal-fired power plants, steel, smelting, machinery, coal, mining, chemical, cement, port terminals and other enterprises' coal conveying, material conveying systems, pulverizing systems, ash discharge, dust removal systems and other heavily worn mechanical equipment, we can provide different types of products according to different needs.

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