Understanding the Composition of Fused Magnesia

June 29, 2023

Magnesia, a widely used material in various industries, plays a crucial role in many applications. One of its most notable forms is fused magnesia, renowned for its exceptional properties and extensive utility. In this comprehensive article, we delve into the composition of fused magnesia, its manufacturing process, and its diverse range of applications.


What is Fused Magnesia?


Fused magnesia, also known as electrofused magnesia, is a high-purity refractory material primarily composed of magnesia (MgO). It is produced through the fusion of magnesite (MgCO3), a naturally occurring mineral, at high temperatures. The resulting fused magnesia boasts excellent thermal and chemical stability, making it an ideal choice for numerous industrial purposes.

Fused Magnesia


The Composition of Fused Magnesia


Fused magnesia is characterized by its remarkable purity, typically exceeding 98% MgO content. This high level of purity ensures its superior performance in various applications. The composition of fused magnesia may also contain trace amounts of impurities such as calcium oxide (CaO), silicon dioxide (SiO2), and iron oxide (Fe2O3). However, the concentration of these impurities is minimal, ensuring the overall quality and integrity of the material.


Manufacturing Process


The production of fused magnesia involves several essential steps. Let's take a closer look at the manufacturing process:


Raw Material Selection: The process begins with the careful selection of high-quality magnesite, which serves as the primary raw material. Magnesite with low impurity levels is preferred to ensure the final product's purity and consistency.


Calcination: The selected magnesite is subjected to calcination, a process that involves heating the mineral in a controlled environment. This step removes any moisture and carbon dioxide present in the magnesite, leaving behind a more concentrated form of magnesia.


Fusion: The calcined magnesite is then fused at extremely high temperatures, typically exceeding 2,800 degrees Celsius, in electric arc furnaces. This intense heat causes the magnesite to melt, forming a molten mass.


Cooling and Solidification: The molten magnesia is carefully cooled to allow solidification. The cooling process influences the crystal structure of the fused magnesia, affecting its final properties.


Crushing and Sizing: The solidified fused magnesia is crushed into various particle sizes to meet the specific requirements of different applications. This step ensures the availability of a range of fused magnesia grades tailored for diverse industries.


Quality Control: Throughout the manufacturing process, rigorous quality control measures are implemented to maintain the desired composition and physical properties of the fused magnesia. Advanced analytical techniques and testing procedures are employed to ensure consistent quality and purity.


Applications of Fused Magnesia


Fused magnesia finds widespread application across various industries due to its exceptional characteristics. Some of the key applications include:



Fused magnesia serves as a fundamental component in refractory materials, which are widely used in high-temperature environments. Its excellent resistance to heat, corrosion, and thermal shock make it a preferred choice for lining furnaces, kilns, and other equipment used in industries such as steel, cement, and glass manufacturing.



The steel and metallurgical industries heavily rely on fused magnesia for various applications. It is utilized in the production of refractory bricks, ladle linings, and crucibles, providing crucial protection against the extreme conditions encountered during metal melting, casting, and refining processes.


Electrical Industry

In the electrical industry, fused magnesia is utilized in the manufacturing of electrical insulation materials. Its high electrical resistivity and thermal stability make it an excellent choice for insulation components in electrical heating elements, such as those used in electric furnaces and industrial heating systems.


Chemical Industry

Due to its resistance to chemical corrosion, fused magnesia plays a vital role in the chemical industry. It is used for lining reaction vessels, storage tanks, and chimneys, where it protects against the corrosive effects of acids, alkalis, and other reactive chemicals.


Other Applications


Apart from the industries mentioned above, fused magnesia finds utility in various other sectors. It is utilized in the production of ceramics, abrasives, grinding wheels, and specialized coatings. Its versatility and superior properties make it a valuable material in a wide range of applications.




In conclusion, fused magnesia is a high-purity refractory material composed primarily of magnesia. Its exceptional composition, manufacturing process, and versatile applications make it a sought-after material across multiple industries. Understanding the composition and properties of fused magnesia provides valuable insights into its potential uses and benefits. We are a fused magnesia supplier. If you are interested in our products, please contact us now!

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