Magnesia-chrome bricks are refractory products with magnesium oxide (MgO) and chromium oxide (Cr2O3) as the main components, and periclase and spinel as the main mineral components. Generally, those with chrome ore added less than 50% are called magnesia-chrome bricks, and those with more than or equal to 50% are called chrome-magnesia bricks.
| Item/Grade | MGe-16A | MGe-16B | MGe-12A | MGe-12B | MGe-8A | MGe-8B | |
|---|---|---|---|---|---|---|---|
| ω (MgO)/% | μ0 ≥ | 50 | 45 | 60 | 55 | 65 | 60 |
| ở | 2.5 | ||||||
| ω (Cr2O3)/% | μ0 ≥ | 16 | 16 | 12 | 12 | 8 | 8 |
| ở | 1.5 | ||||||
| Apparent Porosity/% | μ0 ≤ | 19 | 22 | 19 | 21 | 19 | 21 |
| ở | 1.5 | ||||||
| Cold Crushing Strength/MPa | μ0 ≥ | 35 | 25 | 35 | 30 | 35 | 30 |
| Xmin | 30 | 20 | 30 | 25 | 30 | 25 | |
| ở | 15 | ||||||
| 0.2MPa Refractoriness Underload T0.6/℃ | μ0 ≥ | 1650 | 1550 | 1650 | 1550 | 1650 | 1530 |
| ở | 20 | ||||||
| Model | SRMGe16 | SRMGe18 | SRMGe20 | SRMGe22 | SRMGe26 | RMG0e12 | RMGe14 |
|---|---|---|---|---|---|---|---|
| MgO % | 68 | 64 | 65 | 56 | 56 | 75 | 75 |
| Cr2O3 % | 16 | 18 | 20 | 22 | 26 | 12 | 14 |
| SiO2 % | 1.5 | 1.5 | 1 | 2.5 | 2.5 | 1.5 | 1.5 |
| Apparent Porosity % | 16 | 16 | 14 | 16 | 16 | 15 | 15 |
| Bulk Density g/cm3 | 3.1 | 3.1 | 3.1 | 3.1 | 3.1 | 3.2 | 3.2 |
| Cold Crushing Strength Mpa | 40 | 40 | 40 | 40 | 40 | 50 | 50 |
| Refractoriness Under Load °C | 1700 | 1700 | 1700 | 1700 | 1700 | 1700 | 1700 |
Ordinary magnesia-chrome bricks (silicate-bonded magnesia-chrome bricks), which are made of chrome ore and magnesia with more impurities (SiO2 and CaO). The firing temperature is around 1550°C. The microstructure of bricks is characterized by silicate bonding between refractory grains.Directly bonded magnesia bricks are made of chrome concentrate with low impurity content and relatively pure magnesia. The structural feature of this kind of refractory brick is that the refractory grains are mostly in direct contact. Therefore, its high temperature performance, corrosion resistance and erosion resistance are better than ordinary magnesia chrome bricks.
Semi-rebonded magnesite-chrome brick refers to a refractory product fired with part of fused magnesite-chrome sand as raw material. Semi-rebonded magnesite-chrome brick have low density, low porosity, high-temperature strength, thermal shock resistance is better than recombined magnesia-chrome bricks, and strong slag erosion resistance.
Directly bonded magnesia-chrome bricks are developed on the basis of ordinary magnesia-chrome bricks. There are two main characteristics of their production. One is to use relatively pure raw materials, and the other is to use higher firing temperatures.
Fused cast magnesite chrome brick refers to a fused cast refractory product made of magnesite and chromite as the main raw materials. Also known as fused magnesia chromium refractory products.Fused-cast magnesia-chrome bricks have good high-temperature strength and slag resistance, but poor resistance to sudden temperature changes. It is suitable for parts with severe slag invasion, corrosion, wear and erosion, and it is better used in continuous operation furnaces.
Mainly used in the metallurgical industry, such as constructing open-hearth furnace tops, electric furnace tops, external refining furnaces and various alkali-resistant non-ferrous metal smelting furnaces.