Reburned magnesite is mainly made of magnesite ore with a content of 46.5% and calcined at about 1500 ° C to 800 ° C through a high temperature shaft kiln. The color of the product is yellow-brown. The main components of reburned magnesia products are magnesia, calcium oxide, silicon dioxide, ferric oxide, alumina, and caustic soda. The main content of reburned magnesia Mgo magnesia is 80%. , 82%, 85%, 88%, 90%, 91%, 92%, 93%, the content of calcium oxide in reburned magnesia is about 2.5%, and the content of silica in reburned magnesia is 3.5%- 7%, the content of ferric oxide in reburned magnesia is 0.8% -1.5%, electrical grade magnesia powder, 97 fused magnesia, 98 fused magnesia The content of aluminum is about 1%, and the content of caustic soda in the reburned magnesia is below 1%. The reburned magnesite is mainly used as the main ideal raw material for brick making and the production of amorphous refractory materials. In addition, the reburned magnesia products can also be mainly used Used in industries such as steelmaking, electric furnace bottom and ramming furnace lining.

Magnesia is also called sintered magnesia. Magnesium hydroxide is produced from magnesite, brucite or by reacting seawater with lime milk. It is calcined at high temperature and has strong hydration ability. It is mainly used to make alkaline refractory materials, such as magnesium bricks, magnesia-aluminum bricks.

Magnesia can be divided into natural magnesia and seawater magnesia or synthetic magnesia. Natural magnesite mainly comes from natural magnesite. However, due to the restriction of the quality of the original ore, it is difficult to obtain high-purity and high-quality products. So far, seawater magnesite has become the main source of magnesia used in industrial developed countries.

According to the chemical composition of magnesia, the quality and phase composition of magnesia products can be predicted. When calculating its phase composition, only when the homogeneity of the raw material of magnesia and the calcination temperature of the material are sufficient to bring the phase composition into equilibrium, the calculated The phase composition will be consistent with the experimental results, and the higher the purity of the material, the more consistent.

Magnesite is calcined to 700 ° C to decompose and discharge CO2. It is calcined to light-burned magnesite (caustic magnesia) at about 1000 ° C, commonly known as bitter earth powder, which has a loose texture and high chemical activity. Continue to increase the temperature to above 1700 ~ 1800 ° C, the periclase grains gradually grow, the volume shrinks, the density increases, and the chemical activity is greatly reduced, that is, calcined into sintered magnesite.

There are two structural forms between the periclase grains in magnesite:

Silicate Bonding (Ceramic Bonding): The main crystalline phases are ed together by low melting point crystalline or amorphous silicates, which are sintered with the participation of the liquid phase.

Direct bonding; a bond formed by direct contact between high-melting-point grains, which belongs to solid sintering, and generally no liquid phase participates in sintering. The directly bonded magnesium products have high high temperature mechanical strength, slag resistance and volume stability.