The main raw material for the manufacture of magnesia bricks is magnesite (MgCO3) or Mg(OH) fused magnesia bricks extracted from seawater.

2 The magnesia-aluminum brick obtained by calcination at a high temperature (1600 to 1900 ° C) has a MgO content of more than 90%. In order to meet the needs of high-temperature new technologies, since the 1960s, high-purity magnesia with a MgO content of over 96% and ultra-high-purity magnesia with a content of 98-99% or more have been developed. High-purity magnesia must have a higher bulk density in addition to minimizing low-melting impurities. In addition, there is a metallurgical magnesia with a high content of impurities such as CaO and Fe2O3, which is used as a charging material for the metallurgical furnace. See the chemical composition of magnesia.

Magnesia bricks are mostly used in the metallurgical industry. Magnesia-aluminum bricks are mainly used for their high thermal stability and high temperature strength.

Important parts such as the top of the steelmaking furnace. High-purity magnesia bricks are used in the vulnerable areas of converters and furnaces outside the furnace. Magnesia carbon bricks are mainly used in important parts of converters, electric furnaces and refining furnaces outside the furnace. Magnesia-silica bricks or forsterite bricks with higher SiO2 can be used in the regenerators of open and glass furnaces and in the firing zone of cement rotary kiln. The molten granules are combined with magnesia bricks and are used in key parts of electric furnaces, furnace refining furnaces and non-ferrous metal smelting furnaces.

High-purity magnesia, added with carbon materials, such as electrode chips or natural graphite, made of asphalt and phenolic resin as a binder. After the raw materials are pulverized, sieved, and mixed according to a certain proportion and mixed, the bricks are sent to the tunnel baking room for heat treatment, and the treatment temperature is 150-350 ° C, and the time is not less than 24 hours. Magnesia carbon brick has good corrosion resistance and thermal shock resistance under the condition of large alkalinity of slag and severe temperature fluctuation. In addition, there are molten granules made of fused magnesia combined with magnesia bricks; magnesia-silica bricks and forsterite bricks made of high-silica magnesia and serpentine, and having a high SiO2 content.