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Direct Bonded Magnesia Chrome Brick (DMK)

Direct Bonded Magnesia Chrome Brick (DMK)

Direct Bonded Magnesia Chrome Bricks (DMK) refer to refractory products that are directly combined with periclase and magnesia-chrome spinel as the main crystal.  The direct bonding degree of the product increases with the decrease of SiO2 content and the increase of sintering temperature.

 

In the presence of silicate, the binding between periclase and periclase will be strengthened by Cr2O3, but reduced by Al2O3 and Fe2O3. Adding Al2O3 or Fe2O3 in Magnesia Chrome Brick can reduce the melting point of silicate, and adding Cr2O3 can increase the melting point.

Therefore, chromite with high Cr2O3 content has higher high-temperature strength than chromite with low Cr2O3 content.

Secondary spinel is the characteristic of directly bonded brick. The higher the content of Cr2O3, the more intragranular and intergranular spinels, the higher the strength of the product and the stronger the slag resistance.

 

Direct Bonded Magnesia Chrome Bricks (DMK) with properties of excellent thermal shock stability, slag attack resistance, thermal fatigue resistance, vacuum damage resistance. In addition, they are resistance to oxidation-reduction, comparatively better wear resistance and erosion resistance. Under vacuum refining conditions, or strong oxidation atmosphere, or ultrahigh temperature liquid erosion, or high alkaline slag liquid and alkalinity changes slag liquid attacks, the service life is second after RMK, and even more economical furnace lining refractories. They are widely used at Steel Smelting Furnaces working linings (e.g. RH Degasser, VOD Ladles, AOD Converters, EAF Furnace, Converters etc.) or critical parts safety linings, Non-ferrous Smelting Furnaces working linings (IC3 Converters, Pierce Smith Furnaces, Noranda Furnaces, Outokumpu Flash Smelting Furnaces, Reverberatory Furnaces etc.).  Sometimes they are used at Chemical Industries and Paper Industries furnaces working lining bricks.

 

Introduction:

Direct Bonded Magnesia Chrome Bricks (DMK) are a class of high-performance refractory products, characterized by their unique combination of periclase and magnesia-chrome spinel as the main crystals. These bricks are renowned for their exceptional thermal and chemical stability in demanding industrial environments.

 

Manufacturing Insights:

The Direct Bonded Magnesia Chrome Bricks (DMK) is intricately linked to their composition and manufacturing process. A lower SiO2 content and higher sintering temperatures contribute to an increased degree of direct bonding, enhancing the brick’s overall performance and durability.

 

Composition and Strength:

In Direct Bonded Magnesia Chrome Bricks (DMK), the interaction between periclase crystals is significantly influenced by the presence of silicate. The addition of Cr2O3 strengthens this bond, whereas Al2O3 and Fe2O3 can reduce it. Interestingly, adding Al2O3 or Fe2O3 decreases the melting point of silicate, while Cr2O3 increases it. This unique composition ensures that bricks with higher Cr2O3 content exhibit superior high-temperature strength and enhanced resistance to slag attacks.

 

Characteristic Features:

A hallmark of Direct Bonded Magnesia Chrome Bricks (DMK) is the secondary spinel formation, which is directly correlated with the Cr2O3 content. Higher Cr2O3 levels lead to an increase in both intragranular and intergranular spinels, resulting in a stronger and more slag-resistant brick.

 

Performance Advantages:

Direct Bonded Magnesia Chrome Bricks (DMK) are noted for their excellent thermal shock stability, resistance to slag attack, thermal fatigue, and vacuum damage. Additionally, these bricks offer superior oxidation-reduction resistance, wear resistance, and erosion resistance. Under extreme conditions like vacuum refining, strong oxidation atmospheres, ultrahigh temperature liquid erosion, and variable high alkaline slag attacks, DMK bricks demonstrate remarkable durability, second only to Rebounded Fused Magnesia Chrome Bricks (RMK) in terms of longevity and economic efficiency.

 

Applications:

These Direct Bonded Magnesia Chrome Bricks (DMK) find extensive applications in various industrial settings. They are crucial in the working linings of steel smelting furnaces, such as RH Degassers, VOD Ladles, AOD Converters, EAF Furnaces, and Converters. Their reliability also extends to critical safety linings in non-ferrous smelting furnaces, including IC3 Converters, Pierce Smith Furnaces, Noranda Furnaces, Outokumpu Flash Smelting Furnaces, and Reverberatory Furnaces. Beyond metallurgical applications, DMK bricks are sometimes employed in the chemical and paper industries.

 

Conclusion:

Direct Bonded Magnesia Chrome Bricks (DMK) stand out as a highly economical and resilient choice for furnace lining refractories. Their tailored composition and advanced properties make them indispensable in high-stress furnace environments, offering unmatched durability and cost-effectiveness.

Direct Bonded Magnesia Chrome Brick 06 www.osymen.com 1  Direct Bonded Magnesia Chrome Brick 04 www.osymen.com 1

Direct Bonded Magnesia Chrome Brick 07 www.osymen.com  Direct Bonded Magnesia Chrome Brick 01 www.osymen.com 1

Direct Bonded Magnesia Chrome Brick 03 www.osymen.com 1  Direct Bonded Magnesia Chrome Brick 07 www.osymen.com 1

Direct Bonded Magnesia Chrome Brick 05 www.osymen.com 1

 

After Impregnation process treatment, the physical and chemical properties of Direct Bonded Magnesia Chrome Brick (DMK) are greatly improved. The porosity will be reduced by 7%, the bulk density will increase by 0.05g/cm3, and the Cold Crushing Strength will increase by about 30MPa. This is an additional procedure.

Direct Bonded Magnesia Chrome Brick 08 www.osymen.com 1Semi Rebonded Mag-chromite Brick impregnation process treatment

 

 

rhimagnesita We can produce RHI Magnesita standard Direct Bonded Magnesia Chrome Brick

Refrateknik1 We can produce Refratechnik standard Direct Bonded Magnesia Chrome Brick

We can produce Harbinson Walker International standard Direct Bonded Magnesia Chrome Brick, such as:

N 50 DBRG:  NARMAG 50 DBRG
N 60 DB: NARMAG 60 DB
N 80 DB: NARMAG 80 DB
N HNF27: NARMAG HNF27
SN 142: SUPER NARMAG 142

OSYMEN

MgO

SiO2

Cr2O3

A.P

B.D

C.C.S

R.U.L

T.S.R

1100 oC Water

%

%

%

%

g/cm3

MPa

(Ta)oC

Cycles

DMK-8A-DA

78.0

1.5

8-11

15.0

3.20

70

>1700

6

DMK-8AS

78.0

1.2

8-11

17.0

3.17

50

>1700

6

DMK-8A

78.0

1.5

8-11

17.0

3.15

50

>1700

6

DMK-8B

78.0

2.0

8-11

18.0

3.10

45

>1680

7

DMK-8C

76.0

2.5

8-11

18.5

3.05

40

>1650

7

DMK-12A-DA

72.0

1.5

12-15

15.0

3.20

70

>1700

6

DMK-12AS

72.0

1.2

12-15

17.0

3.17

50

>1700

6

DMK-12A

72.0

1.5

12-15

17.0

3.15

50

>1700

6

DMK-12B

72.0

2.0

12-15

18.0

3.10

45

>1680

7

DMK-12C

70.0

2.5

12-15

18.5

3.05

40

>1650

7

DMK-16A-DA

64.0

1.5

16-19

15.0

3.20

70

>1700

6

DMK-16AS

65.0

1.2

16-19

17.0

3.18

50

>1700

6

DMK-16A

64.0

1.5

16-19

17.0

3.15

45

>1700

6

DMK-16B

62.0

2.0

16-19

18.0

3.10

40

>1680

7

DMK-16C

61.0

2.5

16-19

18.5

3.05

35

>1650

7

DMK-20A-DA

58.0

1.5

20-23

16.0

3.20

70

>1700

6

DMK-20AS

59.0

1.2

20-23

18.0

3.20

45

>1700

6

DMK-20A

58.0

1.5

20-23

18.0

3.15

40

>1700

6

DMK-20B

56.0

2.0

20-23

19.0

3.10

35

>1700

7

DMK-20C

55.0

2.5

20-23

20.0

3.05

35

>1700

7

DMK-24A-DA

48.0

1.5

24-27

18.0

3.20

70

>1700

6

DMK-24AS

48.0

1.2

24-27

20.0

3.18

45

>1700

6

DMK-24A

48.0

1.5

24-27

20.0

3.15

40

>1700

6

DMK-24B

48.0

2.0

24-27

21.0

3.10

35

>1700

7

DMK-24C

46.0

2.5

24-27

21.5

3.05

35

>1700

7

DMK-28A-DA

42.0

1.5

28-31

18.0

3.20

70

>1700

6

DMK-28AS

42.0

1.2

28-31

20.0

3.18

45

>1700

6

DMK-28A

42.0

1.5

28-31

20.0

3.15

40

>1700

6

DMK-28B

42.0

2.0

28-31

21.0

3.10

35

>1700

7

DMK-28C

40.0

2.5

28-31

21.5

3.05

35

>1700

7

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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