Direct bonded magnesia chrome brick in fire resistance

Direct bonded magnesia chrome bricks:

The main difference between direct bonded magnesia chrome brick and ordinary magnesia chrome brick production process is that the former uses raw materials with less impurities and is fired at a relatively high temperature.

For magnesia used to produce directly bonded magnesia chrome bricks, the mass fraction of MgO is generally more than 95%, preferably more than 97%, and the particle volume density is about 3.25g/cm3. The mass fraction of SiO2 in chrome ore is generally limited to less than 3%. When using chrome concentrate, the mass fraction of SiO2 can be less than 1.0%.

According to different needs and uses, sometimes 1~2 kinds of magnesia and 1~2 kinds of chrome ore can be selected for batching.

The cement kiln uses directly bonded magnesia chrome bricks. Generally, magnesia is used as the fine powder and part of the granular materials, while chrome ore is used as the granular materials. The mass fraction of Cr2O3 is 3%~14%;

The direct bonded magnesia chrome bricks used as metallurgical furnace linings sometimes require a higher Cr2O3 mass fraction (such as 20%). When pure magnesia and chrome ore are used as the matrix, the products tend to expand during firing.

The direct bonded magnesia chrome brick generally refers to the products fired from chrome ore with low impurity content and pure magnesia at a temperature above 1700 ℃, and the refractory grains are mostly in direct contact.

In the chemical composition of directly bonded magnesia chrome bricks, there are few impurities, and the direct bonding rate between refractory grains is high, so the slag resistance and high temperature performance are good.