In modern industrial production, refractories play an indispensable role, and white corundum, as one of the best, has become the favored object of many industries with its excellent performance and wide application. In this paper, the characteristics and application of white corundum and its important position in the field of refractories will be discussed in depth.

I.introduction of white corundum

White corundum, also known as white fused alumina and white corundum sand, is an inorganic nonmetallic material made of high-purity alumina powder as the main raw material through a series of processes such as high-temperature melting and cooling crystallization. Its appearance is white crystal, with extremely high hardness, good wear resistance and high temperature resistance. The chemical composition of white corundum mainly includes alumina (ALO) with a content of more than 99%, and also contains a small amount of impurities such as iron oxide (Fe₂O₃), potassium oxide (KO), sodium oxide (Na₂O) and silicon dioxide (SiO₂), which have certain influence on the properties of white corundum.

II. Physical and chemical characteristics of white corundum

The physical and chemical characteristics of white corundum are the basis of its wide application in the field of refractories. Its main features are as follows:

(1) high purity and high hardness

The alumina content of white corundum is as high as 99%, and this high purity ensures its excellent performance. Its Mohs hardness is 9, which is second only to diamond. This high hardness makes it perform well in grinding, polishing and other applications, and can effectively remove defects on the surface of materials and achieve ideal processing results.

(2) High temperature resistance

The melting point of white corundum is as high as 1850℃, which can maintain stable performance in high temperature environment and is not easy to melt or deform. This characteristic makes it an ideal refractory material, which can be used to make high-temperature furnace lining, ceramic firing kiln furniture, etc., and can withstand long-term high-temperature test and ensure the smooth production process.

(3) Acid and alkali corrosion resistance

White corundum has good acid and alkali corrosion resistance and can remain stable in acidic or alkaline environment. This characteristic makes it widely used in chemical industry, electronics and other industries, such as catalyst carrier, coating material, etc., which can resist the corrosion of chemical media and prolong the service life of materials.

(4) Wear resistance

The wear resistance of white corundum is excellent, and its wear resistance is several times or even dozens of times that of ordinary steel. In industrial production, white corundum is often used to make wear-resistant parts such as grinding balls, grinding discs and grinding rings, which can significantly improve the service life of equipment and reduce the maintenance cost of equipment.

III. Application fields of white corundum

The excellent performance of white corundum makes it widely used in many fields. The following are some main application fields:

(1) Abrasive abrasive industry

White corundum is one of the important raw materials for manufacturing abrasive tools. Its high hardness and good wear resistance enable it to be made into various types of abrasive tools, such as grinding wheels, abrasive belts, sandpaper, etc., which are used in cutting, grinding and polishing of metal materials. For example, in machining, white corundum grinding wheel can be used to grind difficult-to-machine materials such as high carbon steel and high speed steel, and can obtain good machined surface quality and dimensional accuracy.

(2) Refractory industry

White corundum is a key raw material for manufacturing advanced refractories. Its high temperature resistance, wear resistance and corrosion resistance make it an ideal refractory aggregate and powder. In the refractory products such as ceramic kiln furniture, high-temperature furnace lining and high-temperature furnace tube, white corundum can withstand the erosion of high-temperature flame and chemical medium, ensuring the structural stability and service life of refractory products. In addition, white corundum can also be used to make refractory castable, plastic refractory and other unshaped refractory materials, which are widely used in steel, building materials, chemical industry and other industries.

(3) Electronic industry

The fine powder of white corundum has excellent insulating properties and high hardness, and can be used for ultra-precision grinding and polishing in electronic industry. In semiconductor manufacturing, integrated circuit packaging and other processes, white corundum micro-powder can remove tiny defects on the surface of silicon wafer and improve the performance and quality of products. In addition, white corundum can also be used to make electronic ceramic materials, as insulating layers and supporting materials of electronic components, with good electrical insulation and mechanical strength.

(4) Chemical industry

The acid and alkali corrosion resistance of white corundum makes it have important application value in chemical industry. It can be used as a catalyst carrier to load various catalysts and improve the activity and stability of catalysts. For example, in chemical reactions such as petroleum cracking and synthetic ammonia, the white corundum carrier can withstand the corrosion of high temperature and chemical media, and ensure the efficient operation of the catalyst. In addition, white corundum can also be used to make chemical fillers, coating materials, etc., for anticorrosion, wear resistance and other purposes.

(5) Other fields

White corundum can also be used to make sand for precision casting, ceramic raw materials, glass raw materials, etc. In precision casting, white corundum sand can ensure the dimensional accuracy and surface quality of castings; In the production of ceramics and glass, white corundum can be used as raw material or additive to improve the quality and performance of products.

IV. Production process of white corundum

The production process of white corundum mainly includes raw material preparation, high temperature melting, cooling crystallization, crushing and screening. The following is a brief introduction of its production process:

(1) Preparation of raw materials

The main raw material of white corundum is high-purity alumina powder, and imported Bayer alumina is usually used to ensure the quality of products. In addition, a small amount of additives, such as iron oxide and potassium oxide, need to be added to adjust the properties of white corundum.

(2) high temperature melting

The prepared raw materials are put into an electric arc furnace and melted at high temperature. The melting temperature is generally above 2000℃, and the raw materials are melted by the high temperature arc of electric arc furnace to form a uniform melt.

(3) cooling and crystallizing

The melted white corundum melt needs to be rapidly cooled to promote the crystal growth. Usually, water cooling or air cooling is used to make the melt quickly cool and crystallize to form white corundum crystals.

(4) crushing and screening

The white corundum after cooling and crystallization needs to be crushed and screened to obtain products with different particle sizes. The crushed white corundum is classified by screening equipment to obtain white corundum particles with different particle sizes to meet the needs of different application fields.

V. Quality control and detection of white corundum

In order to ensure the quality of white corundum products, strict quality control and testing are needed. The following are some common quality control and testing methods:

(1) Chemical composition analysis

Through chemical analysis, the content of alumina and other impurities in white corundum is detected to ensure that it meets the requirements of product standards. Commonly used chemical analysis methods include X-ray fluorescence spectrometry (XRF) and chemical titration.

(2) Physical performance testing

The physical properties of white corundum are tested, such as hardness, density and wear resistance. Hardness testing usually adopts Mohs hardness tester or microhardness tester; Density detection can be measured by densitometer or Archimedes principle; Wear resistance can be tested by wear tester.

(3) particle size distribution detection

The particle size distribution of white corundum has an important influence on its application performance. The particle size distribution of white corundum is detected by laser particle size analyzer and other equipment to ensure that it meets the requirements of different application fields for particle size.

(4) High temperature resistance test

The high temperature resistance of white corundum was tested, such as melting point determination and high temperature flexural strength test. The melting point can be measured by high temperature furnace and optical pyrometer; The high-temperature flexural strength test can be carried out by a high-temperature flexural testing machine.

VI. Market Status and Development Trend of White Corundum

(1) the current market situation

With the continuous development of industrial production, the market demand of white corundum shows a steady growth trend. In the abrasive industry, with the continuous progress of machining technology, the quality and performance requirements of white corundum abrasives are getting higher and higher, which promotes the sustainable development of white corundum market. In the refractory industry, the demand for refractories in steel, building materials and other industries is increasing. As a high-quality refractory raw material, white corundum has a corresponding increase in market demand. In addition, in electronics, chemical industry and other industries, the application field of white corundum is expanding, and the market demand potential is huge.

(2) Development trend

High performance: with the continuous progress of industrial technology, the performance requirements of white corundum are getting higher and higher. In the future, white corundum will develop in the direction of higher purity, higher hardness, higher wear resistance and higher high temperature resistance to meet the needs of high-end applications.

Refinement: The granularity of white corundum has an important influence on its application performance. In the future, the production of white corundum will pay more attention to the fine control of particle size, and more products with uniform particle size and narrower particle size range will be developed to meet the strict requirements of particle size in different application fields.

Green: Under the background of increasingly strict environmental protection policy, the production of white corundum will pay more attention to green development. By optimizing the production process, reducing energy consumption and reducing pollutant emissions, the sustainable development of white corundum production can be realized.

Diversified application: the application field of white corundum will continue to expand and deepen. In addition to traditional abrasive tools, refractories and other fields, the application of white corundum in emerging fields such as electronics, chemical industry and new energy will continue to emerge, bringing new growth opportunities to the white corundum market.

VII. Conclusion

As a refractory with excellent properties, white corundum has a wide application prospect in industrial production. Its high purity, high hardness, high temperature resistance and acid and alkali corrosion resistance make it widely used in abrasive tools, refractories, electronics, chemical industry and other fields. With the continuous development of industrial technology and the changing market demand, white corundum will develop in the direction of high performance, refinement, green and diversified application, providing more high-quality, efficient and environmentally-friendly material support for industrial production. In the future development, white corundum will continue to play its important role and make greater contributions to promoting industrial progress.

As an important member in the field of refractories, white corundum has provided strong support for the development of modern industry with its excellent performance and wide application. In the future industrial development, white corundum will continue to escort the development of various industries with its unique performance and advantages, showing a broader application prospect and huge market potential.