Magnesia Bricks

Magnesia brick is a basic refractory material that exhibits high resistance to basic slags, along with a high melting point and high load deformation temperature.

Item M98 M97A M97B M95A M95B M91 M89
MgO % ≥97.5 ≥97 ≥96.5 ≥95 ≥94.5 ≥91 ≥89
SiO2 % ≤1.0 ≤1.2 ≤1.5 ≤2.0 ≤2.5 / /
CaO % / / / ≤2.0 ≤2.0 ≤3.0 ≤3.0
Apparent Porosity, % ≤16 ≤16 ≤18 ≤16 ≤18 ≤18 ≤20
Bulk Density, g/cm3 ≥3.0 ≥3.0 ≥3.0 ≥2.95 ≥2.95 ≥2.9 ≥2.85
CCS, MPa ≥60 ≥60 ≥60 ≥60 ≥60 ≥60 ≥50
0.2MPa RUL°C ≥1700 ≥1650 ≥1560 ≥1500
TSR, Cycle 1100°C Water 1650°C×2h
-0.2~0		 1650°C×2h
-0.3~0		 1600°C×2h
-0.5~0		 1600°C×2h
-0.6~0

Ordinary magnesia-chrome brick

This is a traditional sintered refractory material of the magnesia-chromite system (MgO-Cr₂O₃). The main raw materials used are coarse-grained chromite with low CaO content and dense structure, as well as fused magnesite. The firing temperature ranges from 1550°C to 1600°C. The material has relatively low purity and a simple manufacturing process but is characterized by low cost. It serves as an economical choice for furnace sections where high thermal shock resistance is not required.

Item MG-16A MG-16B MG-12A MG-12B MG-8A MG-8B
MgO % ≥50 ≥45 ≥60 ≥55 ≥65 ≥60
Cr2O3 % ≥16 ≥16 ≥12 ≥12 ≥8 ≥8
Apparent Porosity % ≤19 ≤22 ≤19 ≤21 ≤19 ≤21
CCS, MPa ≥35 ≥25 ≥35 ≥30 ≥35 ≥30
0.2MPa RUL℃ ≥1650 ≥1550 ≥1650 ≥1550 ≥1650 ≥1530

Upgraded Magnesia-Chrome Brick

With the increasing scale of industrial furnaces, ordinary magnesia-chrome bricks can no longer meet the demands. Based on traditional magnesia-chrome bricks, upgrades have been implemented, including improvements in raw material purity and firing temperature, leading to the development of an enhanced version. High-quality chromite ore and sintered magnesite are used as raw materials, and the firing temperature ranges from 1750°C to 1850°C. In the finished product, periclase and spinel primarily form direct bonds, which is why this type of brick is also referred to as direct-bonded magnesia-chrome brick. Compared to traditional materials, it exhibits improved high-temperature performance, including significantly enhanced thermal shock resistance, compressive strength, operating temperature, and slag penetration resistance. During tests in a φ4×60m kiln, its service life reached 244 days, which is 185% of the average service life of ordinary magnesia-chrome bricks previously used in the same kiln, demonstrating a remarkable improvement.

Comparison Upgraded Ordinary
Max. Service Temperature 1800°C 1600°C
Cold Crushing Strength 1600°C 60Mpa 30 - 40Mpa
Slag Penetration Resistance 30% 10 - 15%
Item ZMG-16A ZMG-12A ZMG-8A ZMG-6
MgO % ≥60 ≥68 ≥75 ≥75
Cr2O3 % ≥16 ≥12 ≥8 ≥6
SiO2 % ≤1.5 ≤1.5 ≤1.5 ≤2.5
Apparent Porosity % ≤18 ≤18 ≤18 ≤18
CCS, MPa ≥40 ≥45 ≥45 ≥45
0.2MPa RUL℃ ≥1700

Re-bonded Magnesia-Chrome Brick

This type of refractory is produced through ultra-high temperature firing, using synthetic fused magnesia-chromite clinker as the primary raw material. It possesses excellent resistance to oxidation and reduction, exceptional ability to withstand overheating and spalling, high resistance to abrasive wear and erosive impact, as well as good thermal stability. Its outstanding resistance to slag corrosion and structural stability under vacuum conditions are particularly noteworthy.

Practice has confirmed that in vacuum melting furnaces, under strongly oxidizing atmospheres, when subjected to intense impact from superheated fluids, and while resisting erosion from highly basic slags or slags with fluctuating basicity, re-bonded magnesia-chrome brick is currently the lining material that ensures a long service life and high cost-effectiveness.

It is widely used in critical zones with severe operating conditions, such as: Vacuum melting furnaces (e.g., RH vacuum degassing units, VOD degassing ladles); Argon-oxygen decarburization furnaces (e.g., AOD converters); Ultra-high-power electric arc furnaces; Non-ferrous metallurgical furnaces. Applications within these vessels include the working lining, the hot spot zone, the slag line, the tuyere area, zones of intense erosive impact, and other vulnerable sections.

Item DMG-26 DMG-24 DMG-22 DMG-20 DMG-16 DMG-12
MgO % ≥50 ≥50 ≥55 ≥58 ≥62 ≥68
Cr2O3 % ≥26 ≥24 ≥22 ≥20 ≥16 ≥12
SiO2 % ≤1.5 ≤1.5 ≤1.5 ≤1.5 ≤1.5 ≤1.5
Apparent Porosity % ≤16 ≤16 ≤16 ≤16 ≤16 ≤16
CCS, MPa ≥40 ≥40 ≥40 ≥40 ≥40 ≥40
0.2MPa RUL℃ ≥1700 ≥1700 ≥1700 ≥1700 ≥1700 ≥1700

Semi-Re-bonded Magnesia-Chrome Brick

This type of periclase-chromite brick is manufactured using partially fused synthetic magnesia-chromite clinker, high-purity magnesite, and high-purity chromite concentrate. It is a product that combines the characteristics of both re-bonded and direct-bonded magnesia-chrome bricks: its thermal shock resistance surpasses that of re-bonded bricks, while its slag corrosion resistance is superior to that of direct-bonded bricks. It is widely used in the non-ferrous metallurgical industry.

Item BMG-26 BMG-24 BMG-22 BMG-20A
MgO % ≥50 ≥50 ≥55 ≥58
Cr2O3 % ≥26 ≥24 ≥22 ≥20
SiO2 % ≤2.0 ≤2.0 ≤2.0 ≤2.0
Apparent Porosity % ≤16 ≤16 ≤16 ≤16
CCS, MPa ≥40 ≥45 ≥45 ≥45
0.2MPa RUL℃ ≥1700
Item BMG-18 BMG-16A BMG-12A
MgO % ≥58 ≥60 ≥68
Cr2O3 % ≥18 ≥16 ≥12
SiO2 % ≤2.0 ≤2.0 ≤2.0
Apparent Porosity % ≤16 ≤16 ≤16
CCS, MPa ≥40 ≥45 ≥45
0.2MPa RUL℃ ≥1700

After treatment with brine impregnation, the physical, chemical, and operational properties of magnesia-chrome bricks can be significantly improved. Following impregnation, the product's porosity decreases by approximately 5.0%, the apparent density increases by about 0.05 g/cm³, and the compressive strength rises by roughly 30 MPa.

Magnesia-Spinel Brick, produced through high-pressure forming and high-temperature firing using magnesite and synthetic spinel as the primary raw materials, exhibits excellent load softening temperature and high thermal shock resistance. Due to these properties, it is used in industrial furnaces in areas subjected to intense thermal stress and prolonged high temperatures, such as the slag line of VOD steel ladles and the firing zone of cement kilns.

Item MLJ-90 MLJ-85 MLJ-80 MLJ-75
MgO % ≥90 ≥85 ≥80 ≥75
Al2O3 % 3~8 5~12 8~17 ≥8~12
Apparent Porosity % ≤17 ≤17 ≤16 ≤19
Bulk Density, g/cm3 ≥2.95 ≥2.95 ≥2.90 ≥2.85
CCS, MPa ≥45 ≥45 ≥55 ≥40
0.2MPa RUL℃ ≥1700 ≥1650
TSR, Cycle 1100°C Water ≥3 ≥8 ≥12 ≥8

Magnesia-Ferro-Aluminum Spinel Brick is manufactured using high-purity magnesite, high-iron magnesite, and magnesia-alumina spinel as the main raw materials through high-temperature firing. This brick exhibits good coating adherence and high thermal shock resistance. It is ideally suited for use in the firing zone of cement kilns, where its service life exceeds 12 months.

Item MF-85 MF-88
MgO % ≥85 ≥88
Fe2O3 % 5~7.5 5~6
Al2O3 % 3~5 4~7
Bulk Density g/cm3 ≥3 ≥2.9
Apparent Porosity % ≤17 ≤16
CCS MPa ≥45 ≥55
TSR, Cycle 1100°C Water ≥6 ≥8
0.2MPa RUL℃ ≥1600 ≥1650
Thermal Expansion Rate, % 1400 °C ≤1.6 ≤1.7
 Thermal Conductivity, W/(m·K)  350±25°C ≤2.6 ≤2.6

Magnesia-Graphite Brick is manufactured using magnesite and flake graphite as the primary raw materials. This brick exhibits excellent resistance to basic slags, erosion resistance against high-temperature molten steel, high thermal stability, spalling resistance, and good thermal conductivity. It is widely used in the working lining of steelmaking converters, electric furnaces, and ladles.

Item MT10A MT12A MT14A MT16A MT18A
MgO % ≥80 ≥78 ≥76 ≥74 ≥72
C % ≥10 ≥12 ≥14 ≥16 ≥18
Apparent Porosity % ≤4 ≤4 ≤3.5 ≤3.5 ≤3.0
Bulk Density g/cm3 ≥3.02 ≥2.97 ≥2.95 ≥2.92 ≥2.89
CCS MPa ≥40 ≥40 ≥38 ≥35 ≥35
 HMOR, MPa 1400°C×0.5h ≥6 ≥6 ≥10 ≥8 ≥10

Corundum-Magnesia-Graphite Brick is manufactured using corundum, magnesite, and flake graphite as the primary raw materials. This brick exhibits high slag resistance, excellent resistance to penetration and erosion by molten steel, outstanding thermal stability and spalling resistance, as well as superior mechanical flexibility at high temperatures. Due to these properties, it is widely used for the working lining of the walls and bottoms of steel ladles.

Item LMT75 LMT70 LMT65 LMT60 LMT55
Al2O3 % ≥75 ≥70 ≥65 ≥60 ≥55
Al2O3+MgO % ≥81 ≥77 ≥80 ≥75 ≥72
C % ≥5 ≥5 ≥7 ≥7 ≥8
Apparent Porosity % ≤7 ≤7 ≤7 ≤7 ≤7
Bulk Density g/cm3 ≥3.2 ≥3.15 ≥3.1 ≥3.0 ≥2.9
CCS MPa ≥60 ≥60 ≥60 ≥50 ≥50

Magnesia-Calcia Brick is produced through high-pressure pressing and medium-temperature firing, using sintered magnesia-dolomite clinker or dolomite sand and magnesite as the main raw materials. Compared to magnesia brick, it offers a higher load softening temperature, improved thermal shock resistance, and enhanced resistance to basic slags. It is widely used for the working lining of AOD converters and VOD steel ladles.

Item MCa-20A MCa-20B MCa-30A MCa-30B MCa-40A MCa-40B
MgO % ≥75 ≥75 ≥65 ≥65 ≥55 ≥55
CaO % ≥18~22 ≥18~22 ≥28~32 ≥28~32 ≥38~42 ≥38~42
Σ(SAF) % ≤3 ≤4 ≤3 ≤4 ≤3 ≤4
Apparent Porosity % ≤8,0 ≤8,0 ≤8,0 ≤8,0 ≤8,0 ≤8,0
Bulk Density g/cm3 ≥3,0 ≥2,95 ≥3,0 ≥2,95 ≥3,0 ≥2,95
CCS MPa ≥55 ≥50 ≥55 ≥50 ≥55 ≥50
0.2MPa RUL °C ≥1700 ≥1680 ≥1700 ≥1680 ≥1700 ≥1680

Magnesia-Zirconia Brick is characterized by a dense structure, fine and uniformly distributed pores, high hot strength, excellent thermal stability, good resistance to alkaline atmospheres and basic slags, as well as superior coating adherence. It is used in the firing zones of cement kilns and the regenerators of glass melting furnaces.

Item MZ8 MZ10 MZ13
MgO % ≥80 ≥75 ≥70
ZrO2 % ≥8 ≥10 ≥13
Apparent Porosity % ≤19 ≤18 ≤18
Bulk Density g/cm3 ≥2.95 ≥3.0 ≥3.05
CCS MPa ≥50 ≥45 ≥40
0.2MPa RUL°C ≥1600 ≥1550 ≥1600
Thermal Shock Resistance (950°C - Water) ≥10 ≥10 ≥10