Production Method And Technology For Different Magnesia Chrome Bricks

Raw materials for producing magnesia chrome bricks contain natural raw materials, synthetic raw materials, industrial oxidation of chromium and industrial alumina. Natural raw material contains various grades of sintered magnesia chrome ore, ordinary chrome ore and low impurity content of chromium concentrate. Synthetic raw materials contain sintered magnesia chrome materials produced by magnesia ore and chrome concentrate, fused magnesia chrome material produced by baudisserite and chrome ore and fused magnesia ore.

The different combinations of the above raw materials and formulations can be made of a wide range of magnesia chrome brick as below,

1. Normal magnesia chrome bricks
The bricks are made by chrome ore (containing impurity SiO2 and CaO) and magnesia sand. The sintered temperature is about 1550℃, and the microstructure characteristics of the bricks is that The grain of fire bricks is made of silicate.
 

2. Direct bonded magnesia chrome bricks
Direct bonded magnesia chrome bricks are made by chromium concentrate with low impurity content and pure magnesia sand which are sintered at temperature of 1700℃. The microstructure characteristics of the bricks are that the grains of refractory contact directly, so the property of high temperature, erosion resistance and crush resistance is better than normal magnesia chrome bricks.

3. Bonded again magnesia chrome bricks
Bonded again magnesia chrome bricks should be sintered above 1750℃ or at super high temperature. The microstructure characteristics of the bricks are that the spinel distributes even and the grain of the refractory are directly contacted. The erosion resistance and crush resistance are stronger than the first two.

4. Fused cast magnesia chrome bricks
Fused cast magnesia chrome bricks are made of magnesia sand and chrome ore by adding a certain amount of additives, after mixing, compacting and burning, broking into pieces, and putting into the electric melting furnace, then injecting into the mold and through annealing to produce a mother brick. The mother brick is through cutting, grinding and form different models of the refractory brick.
The microstructure characteristics of the bricks are that the spinel distributes even and the grain of the refractory are directly contacted. This refractory brick is especially good for resisting melt erosion, infiltration and erosion.