The New Net Red in Refractory Industry -- The Origin of Magnesia

What is magnesia?

Magnesia is calcined from magnesite, brucite or magnesium hydroxide extracted from seawater at high temperature. Large-crystal fused magnesia is the product of magnesite and other magnesia raw materials that are processed at high temperature to reach the sintering process. The calcined magnesia made from natural magnesite by one or two step calcination process with high-temperature equipment such as shaft kiln and rotary kiln is called sintered magnesia; The magnesite and other raw materials are melted in the electric arc furnace and cooled to the molten state. The magnesite is called sea water magnesite, which is produced by extracting magnesium oxide from sea water.

Magnesia is one of the important raw materials of refractory material Z. It is used to manufacture various kinds of magnesia bricks, magnesia-alumina bricks, ramming materials, furnace repair materials, etc., and it contains many impurities, and is used to pave the bottom of steelmaking furnace, etc.

High-purity magnesia is produced by flotation purification of natural super-grade magnesite ore and calcination in ultra-high temperature oil shaft kiln with light burning fine grinding ball. It is a high-quality raw material for brick-making refractory.

The medium-grade magnesia is produced from light-burned magnesia with a MgO content of 97% by pressing ball and calcining in high temperature shaft kiln. The product has good sintering degree and dense crystallization, and is a high-quality raw material for producing medium-grade magnesia refractory products.

The fused magnesia is prepared by melting the selected special grade A natural magnesite or high-purity calcined magnesium particles in the electric arc furnace. This product has the characteristics of high purity, large crystal grain, compact structure, strong slag resistance, and good thermal shock stability. It is an excellent high-temperature electrical insulation material, and also an important raw material for making high-grade magnesia brick, magnesia-carbon brick and amorphous refractory.

Large crystalline fused magnesia

Raw materials for magnesia production

The main raw material for producing magnesia refractory is magnesia, which refers to sintered magnesite with certain particle composition. It is broken from sintered magnesite. Sintered magnesite can be obtained by calcining magnesite.

In addition, sintered magnesite can also be extracted from seawater, salt lake brine, dolomite, serpentine and brucite. But so far, sintered magnesite in China is still obtained by calcining natural magnesite, and the salt lake magnesium extraction project is still under construction.

The production of fused magnesia in China is mainly concentrated in Liaoning and Shandong, both of which are dominated by magnesite.