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Magnesia Alumina Spinel Brick

Magnesia Alumina Spinel Brick

Magnesia Alumina Spinel Bricks: The Refractory Choice for High Durability and Performance

 

Introduction:


Magnesia Alumina Spinel bricks are renowned for their high-temperature performance and durability. Used in various industries, these refractory products are critical for processes requiring robust materials that can withstand extreme conditions. With periclase and magnesia-alumina spinel as their main mineral phases, these bricks offer exceptional properties that make them a preferred choice for many applications​​.

 

Composition and Benefits

Magnesia Alumina Spinel bricks are composed of magnesia (MgO) and spinel, which is a combination of alumina (Al2O3) and magnesium oxide. This composition offers excellent thermal stability, corrosion resistance, and mechanical strength. The main component, periclase, provides high refractoriness, making these bricks suitable for use in environments with temperatures exceeding 1500°C​​.

Mechanical Properties and Manufacturing

The mechanical properties of Magnesia Alumina Spinel bricks, such as bend strength, modulus, and fracture toughness, are optimized through precise manufacturing processes. These processes often involve hot-pressing magnesia powder with varying percentages of spinel powder, which affects the brick’s overall performance. This meticulous preparation ensures that the bricks can meet the demanding requirements of industrial applications​​.

 

Environmental Impact and Applications

Magnesia Alumina Spinel bricks emerged as a superior alternative to magnesia chromite refractories due to the latter’s environmental concerns related to chromium compounds. Not only are they environmentally friendly, but they also boast a higher eutectic point, making them ideal for lining the cooling and transitional zones in cement kilns, where temperatures can reach up to 2135°C​​.

 

Innovative Synthesis Techniques

Advancements in the synthesis of Magnesia Alumina Spinel bricks involve using alumina–magnesia–silica ternary equilibrium phase diagrams. By exploring various sources of alumina and magnesia, manufacturers can produce aggregates that meet specific industrial requirements, further enhancing the bricks’ suitability for high-performance applications​​.

 

The Evolution and Production

China has been at the forefront of producing the first-generation magnesia-spinel bricks. These bricks are typically made from a combination of high-purity magnesia and synthetic magnesia-alumina spinel or from magnesia with bauxite clinker fine powder. The controlled addition of alumina content, ranging from 5–10%, allows for the production of bricks that can perform under the most demanding conditions​​.

Conclusion:

Magnesia Alumina Spinel bricks represent a significant advancement in refractory materials, offering a combination of high-temperature capability, mechanical strength, and environmental safety. As industries continue to push the boundaries of temperature and performance, these bricks stand out as a key component in achieving operational excellence and sustainability.

 

Magnesia Alumina Spinel Brick (MS) /Magnesia Spinel Brick have been more broadly used in recent years. The term “spinel” as used in describing this type of brick refers to the mineral MgO•AI2O3. In discussing magnesite chrome brick and chrome ores, the term “spinel” is often used to refer to the family of minerals that crystallize in the cubic system and have the general formula RO•R2O3, where RO may be MgO, and FeO and R2O3 may be Fe2O3, Al2O3 and Cr2O3. While usage of the term “spinel” in this broader sense is accepted practice, the mineral spinel has the chemical formula MgO•Al2O3. It has become accepted usage to use the term Magnesite-Spinel Brick (MSB) to refer to the products containing MgO•Al2O3.

A family of magnesite-spinel brick has been developed by combining the constituent raw materials in various ways. Some magnesite-spinel bricks are made by adding fine alumina to compositions composed mainly of magnesia. On firing, the fine alumina reacts with the fine magnesia in the matrix of the brick to form an in-situ spinel bond. An alternative is to add spinel grain to a composition containing magnesia. One of the principal benefits of combining spinel and magnesia is that the resulting compositions have better spalling resistance than brick made solely with dead burned magnesite. This feature results in the avoidance or inhibition of peel spalling caused by temperature cycling and infiltration of constituents from the service environment. Spinel additions also lower the thermal expansion coefficients of magnesite compositions. This can reduce thermal stresses that could contribute to cracking in certain environments.

A desire to use chrome-free basic brick for environmental reasons has increased the importance of Magnesite Spinel Brick (MAS). Trivalent chromium (Cr+3) present in magnesite-chrome brick can be converted to the hexavalent state (Cr+6) by reaction with alkalies, alkaline earth constituents and other compounds that are present in some service environments. These factors have led to broad use of magnesite-spinel brick in rotary cement kilns. They have excellent spalling resistance, good thermal expansion characteristics and have been shown to provide excellent service results in many rotary kilns.

 

Magnesia Alumina Spinel BrickMagnesia Alumina Spinel Brick

Magnesia Alumina Spinel BrickMagnesite Spinel Brick for Cement Kiln 06 www.osymen.com 1

 

Magnesia Alumina Spinel Brick (MAS) is made primarily of magnesia (corundum grain) and a few synthetic spinels, is pressed under high temperature and produced by high temperature firing. It is the upgrade product of pure magnesia brick and magnesia alumina brick. Compared with Magnesia Alumina Brick (corundum brick) of same substrate, it has excellent RUL and TSR. Therefore, it was used at area where it stands for fierce thermal shock damage and longtime high temperature in the high temperature industrial furnaces such as VOD ladle molten metal line and free zone.

%E4%B8%8B%E8%BD%BD We can produce Harbinson Walker International standard Magnesia Alumina Spinel Brick, such as:

VESTA

rhimagnesita We can produce RHI Magnesita standard Magnesia Alumina Spinel Brick

Refrateknik1 We can produce Refratechnik standard Magnesia Alumina Spinel Brick, such as:

TOPMAG A1
TOPMAG AF
TOPMAG TR
RG S

OSYMEN

MgO

Al2O3

A.P

B.D

C.C.S

R.U.L

T.S.R

1100°C Air

%

%

%

g/cm3

MPa

(Ta)°C

Cycles

MAS-5A

88.0

5-7

17.0

2.95

55

>1700

>100

MAS-5B

88.0

5-7

18.0

2.93

50

>1700

>100

MAS-5C

87.0

5-7

19.0

2.92

45

>1700

>80

MAS-10A

84.0

9-11

17.0

2.95

55

>1700

>100

MAS-10B

84.0

9-11

18.0

2.93

50

>1700

>100

MAS-10C

82.0

9-11

19.0

2.92

45

>1700

>80

MAS-90A

5.0

92.0

15.0

3.10

80

>1700

>4 water

MAS-90B

5.0

92.0

15.0

3.05

70

>1650

>4 water

AP: Apparent Porosity   |  BD: Bulk Density  |  CCS: Cold Crushing Strength  |  RUL: Refractories Under Load  |  TSR: Thermal Shock Resistance

Last updated: 2024-01-03
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