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The main function of alumina

wallpapers Industry 2021-04-06
1. The main components of ruby and sapphire are alumina, which exhibits different colors due to other impurities, while sapphire contains iron oxide and titanium oxide and is blue.
2. In the main component of bauxite, alumina has the highest content. Industrially, bauxite is purified into alumina by the Bayer process and then converted into aluminum metal by the Hall-Heroult process.
3. Aluminum reacts with oxygen in the air to form a dense aluminum oxide film covering the aluminum surface exposed to the air.
4. Aluminum is a good conductor of electricity and heat. The crystal form of alumina is suitable for abrasive materials and cutting tools due to its high hardness.
5. Alumina powder is often used as a medium for chromatography.
6. In August 2004, a scientist working for 3M in the United States developed an alloy synthesized with aluminum and rare earth elements to produce a strengthened glass called transparent alumina.
Manufacturing strengthened glass
Alumina 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 aluminum oxide film covering the surface of aluminum exposed to the air. This aluminum oxide film can prevent aluminum from being oxidized further. The thickness and properties of the oxide film can be enhanced by a process called anodic treatment (anodic corrosion protection).
(Al2O3·H₂O and Al2O3·3H₂O) are the main minerals of aluminum that exist in nature. After crushing it, it is impregnated with high-temperature sodium hydroxide solution to obtain sodium meta aluminate solution; the residue is filtered out, the filtrate is cooled and aluminum hydroxide crystals are added After a long time of stirring, the sodium aluminate solution will separate out the aluminum hydroxide precipitate; the precipitate is separated and washed, and then calcined at a temperature of 950-1200 ℃ to obtain α-type alumina powder. The mother liquor can be recycled. This method was invented by the Austrian scientist KJ Bayer in 1888, and it is still the main method of industrial production of alumina, known as the "Bayer method."
Abrasive alumina
Alumina is suitable for a variety of wet and dry treatment processes. It can grind the rough surface of any workpiece finely. It is one of the most economical abrasives. This kind of sharp and water chestnut synthetic abrasive has a hardness second only to diamond and is especially suitable for use when there are strict requirements for iron pollution. Used for the roughest cutting, it can also be made into a pebble shape to process precision-sized workpieces to achieve extremely low roughness. Due to its high density, sharpness, and rhombohedral structure, it is one of the fastest cutting abrasives.
Alumina is used to produce brown corundum by fusing high-quality bauxite ore, while high-quality aluminate is used to produce powder corundum and white corundum. Their natural crystal structure gives them high hardness and fast cutting performance. At the same time, they are often used as raw materials for bonded abrasive tools and coated abrasive tools.
Alumina can be recycled many times, and the number of cycles is related to the grade of the material and the specific process. Most standard abrasive blasting equipment can be used.
Applicable industries: Aerospace industry, automotive industry, consumer goods processing, casting/die casting, OEM distributors, semiconductor industry, and other fields.
Applicable process range: surface electroplating, painting, glazing, and pretreatment before PTFE coating; deburring and pot scaling of aluminum and alloy products; mold cleaning; pretreatment before metal sandblasting; dry grinding and wet grinding; Precision optical refraction; grinding of minerals, metals, glass, and crystals; glass carving and paint additives.
Ceramic effect
Alumina is divided into calcined alumina and ordinary industrial alumina. Calcined alumina is an essential raw material for the production of antique bricks, while industrial alumina can be used to produce microcrystalline stones. In traditional glazes, alumina is often used for whitening. As antique tiles and microcrystalline stones are favored by the market, the amount of alumina is also increasing year by year.
Therefore, alumina ceramics emerged in the ceramic industry-alumina ceramics is a ceramic material with Al₂O₃ as the main raw material and corundum as the main crystal phase. Because of its high mechanical strength, high hardness, and high-frequency dielectric, It has the advantages of low loss, high insulation resistance at high temperature, good chemical resistance, and thermal conductivity, and other excellent comprehensive technical performance.

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