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magnesia carbon brick manufacturer

Magnesia Carbon Brick Manufacturer

Magnesia Carbon Brick is a great choice for your steel production needs.

Magnesia Carbon Brick for EAF

Magnesia Carbon Brick for LF

What is magnesia-carbon brick ?

Magnesia-carbon bricks are made from high melting point Basic oxide magnesia (melting point 2800 ° C) and high melting point carbon materials which are difficult to be infiltrated by slag. Unburned carbon composite Refractory made from a combination of carbon binders.

Magnesia-Carbon brick is a great choice for converters, EAFs, ladles, and refining furnaces.

What are the types of magnesia-carbon brick ?

YB/T4074 -1991 ferrous metallurgical industry standard states that bricks are divided into three types according to their carbon content, each of which is further divided into three grades:
1. High-grade magnesia-carbon brick: large crystalline capacitor magnesia, 98% fused magnesia, 96% more than natural phosphorus flake graphite
2. Middle grade magnesia-carbon brick: 97% fused magnesia, more than 94% natural phosphorus flake graphite
3. Low-grade magnesia-carbon brick: Burnt Magnesia, high-purity magnesia. More than 90% natural phosphorous flake graphite

Application of magnesia-carbon brick

Mgo-carbon brick is mainly used for lining of converter, AC electric arc furnace, DC electric arc furnace, slag line of ladle and other parts.

In the early days, the slag line of ladle was Refractory with magnesia-chrome bricks, fused magnesia-chrome bricks and other high quality basic bricks. After the MgO-C brick was successfully used in the converter, the MgO-C brick was also used in the slag line of the refining ladle, and good results were obtained. In China and Japan, resin-bonded MgO-C bricks with carbon content of 12% ~ 20% are commonly used, while in Europe, bitumen-bonded MgO-C bricks with carbon content of about 10% are commonly used.
 
MGO-C bricks with MGO content of 83% and C content of 14-17% were used to replace directly bonded magnesia-chrome bricks at VAD slag line in Okura iron and steel works of Sumitomo Metal Company of Japan, the life of slag line is increased from 20 times to 30-32 times. Using MgO-C brick instead of magnesia-chrome brick, the life of slag line is increased from 20-25 times to 40 times. 

Advantages of Magnesia Carbon brick:

As a composite Refractory, magnesia-carbon brick makes good use of the slag resistance of magnesia and the high thermal conductivity and low expansion of carbon to compensate for the worst spalling resistance of Magnesia. Its main characteristics are: with good high temperature resistance, slag resistance, good thermal shock resistance, low creep at high temperature.

The results show that the MgO-C brick made of the mixture of fused magnesia and sintered magnesia, with 15% flake graphite and a small amount of mg-al alloy as the antioxidant, has good application effect, compared with MgO-C brick containing 18% C without anti-oxidant, the damage rate of 100 t LF ladle slag line is reduced by 20-30% , and the average corrosion rate is 1.2-1.3 mm/furnace.

magnesia-carbon-brick-refractory-lining-of-electric-arc-furnace

You can trust our products to help you achieve better results in your steel production !

Chemical composition of magnesia-carbon brick

Raw materials
The main raw materials of MgO-c brick include fused or sintered magnesia, flake graphite, organic binder and antioxidant.

 

Magnesia

Magnesite is the main raw material of MgO-c brick, which is divided into fused magnesite and sintered magnesite. Compared with sintered magnesite, fused magnesite has the advantages of coarse crystal grains and large particle volume density, and is the main raw material in the production of magnesia-carbon brick. In order to produce ordinary magnesia Refractory, the raw material of Magnesia is required to possess high temperature strength and corrosion resistance, so the purity of Magnesia and the C/s ratio and B2O3 content in its chemical composition are emphasized. With the development of metallurgical industry and the increasingly harsh smelting conditions, the magnesia used in MgO-c brick used in metallurgical equipment (converter, electric furnace, ladle, etc.) , in addition to its chemical composition, in the aspect of microstructure, high density and large crystallization are also required.

Carbon sources
Both the traditional MgO-C brick and the low-carbon MgO-C brick are widely used, and the flake graphite is mainly used as the carbon source.
As the main raw material of MgO-C brick, graphite mainly benefits from its excellent physical properties:
1 non-wettability to slag.
2 high thermal conductivity.
3 low thermal expansion.
In addition, graphite and Refractory do not melt at high temperature, high fire resistance. The purity of graphite has a great influence on the service performance of MgO-C brick. Generally, the carbon content of MgO-C brick should be more than 95% , preferably more than 98% .

In addition to graphite, carbon black is also widely used in the production of magnesia-carbon brick. Carbon Black is a kind of highly dispersed black powder carbonaceous material, which is produced by thermal decomposition or incomplete combustion of hydrocarbon hydrocarbons. The carbon black particles are small (less than 1 μm) , the specific surface area is large, and the mass fraction of carbon is 90-99% , high purity, high powder resistivity, high thermal stability, low thermal conductivity, is difficult to graphitized carbon. The addition of Carbon Black can effectively improve the spalling resistance of MgO-C brick, increase the amount of residual carbon and increase the density of brick.

 

Binders
Common binders for MgO-C bricks include coal tar, coal tar and petroleum asphalt, as well as special carbonaceous resins, polyols, modified Phenol formaldehyde resin, synthetic resins, etc. . The binders used are of the following types:

1) bituminous materials. Tar pitch is a thermoplastic material with high affinity to graphite and magnesium oxide, high residual carbon rate after carbonization, and low cost. It has been widely used in the past. However, tar pitch contains carcinogenic aromatic hydrocarbons, especially high content of benzol. Due to the strengthening of environmental awareness, the use of tar pitch is decreasing.
2) resins. The synthetic resin is made from phenol and formaldehyde. It can mix well with Refractory particles at room temperature and has a high residual carbon rate after carbonization. It is the main binder for MgO-C bricks, but the glassy network structure formed after carbonization is not ideal for the thermal shock resistance and oxidation resistance of Refractory.

If the binder is carbonized to form a mosaic structure and a carbon fiber material is formed in situ, then the binder will improve the high temperature performance of the Refractory.

 
Antioxidant
In order to improve the oxidation resistance of MgO-C brick, a small amount of additives are often added. The common additives are Si, Al, Mg, Al-Si, Al-Mg, Al-Mg-ca, si-mg-ca, SiC, B4C, BN and recently reported Al-B-C and AL-SIC-C additives [5-7] . The principle of action of additives can be roughly divided into two aspects: on the one hand, from the thermodynamic point of view, that is, at working temperature, additives or additives and carbon reaction to produce other substances, their affinity with oxygen is greater than that of carbon with oxygen, preferring to protect carbon from oxidation; on the other hand, that is, from a kinetic point of view, when considering additives with O2, cO or carbon reacts to produce compounds that alter the microstructure of the carbon Refractory, such as increasing density, clogging pores, and impeding the diffusion of oxygen and the products of the reaction.

Production process of magnesia-carbon brick

2.1 Ratio of mud (%)
Electric fusion sintered magnesia 70~85, flake graphite 15~20. Additive 5~10; phenolic resin (additional) 5~7, curing agent amount.

2.2 Mud mixing
The effect of mud mixing is directly related to the quality of the product. Therefore, the following technical measures should be taken for the forming process:
①Preheat the magnesia particles to about 40°C to ensure uniform mixing;
②The binder is preheated to 30~40°C to increase fluidity;
③ pre-mix the curing agent and resin and then add to the mud;
④ Strictly control the amount of resin added to ensure that it evenly wets the mud and prevents agglomeration, and it is necessary to ensure the time for the material to be trapped.
The feeding sequence is: magnesia particles→graphite→bonding agent→tube mill powder→asphalt, and the total mixing time must be ensured.

Magnesia Carbon Bricks specification standard

The sampling and acceptance of products shall be carried out in accordance with GB/T 10325, and the apparent porosity, bulk density, compressive strength at room temperature and the content of MgO and C shall be the acceptance inspection items.

For Electric Arc Furnace

 　MgO-C Brick
UnitLMM-S-NSA-108XMALMM-S-NSA-110XMALMM-S-NSA-112XMALMM-S-NSA-115XMALMM-S-NSA-120XMA
Apparent Porosity%33355
Bulk Densityg/cm33.123.053.022.952.88
Cold Crushing StrengthMPa4040403530
Refractoriness Under Load T2℃–––––
Chemical CompositionMgO%8784827873
F.C.810121520

For Ladle Furnace

UnitMgO-C Brick
LMM-LD-MG-18X-EY1LMM-LD-MG-18X-ELMM-LD-MG-18XK2ULMM-LD-MG-18XK2ULMM-LD-MG-15XTPULMM-LD-MG-15XU
Apparent Porosity%774655
Bulk Densityg/cm32.82.82.92.922.972.95
Cold Crushing StrengthMPa403535354035
Chemical CompositionMgO%757375767775
F.C.181818161515
         
UnitMgO-C Brick
LMM-LD-MG-14XFUKLMM-LD-MG-14XMC1LMM-LD-MG-13XULMM-LD-MG-12XEYLMM-LD-MG-9XLMM-LD-MG-19XKC2
Apparent Porosity%466656
Bulk Densityg/cm32.982.912.932.8833
Cold Crushing StrengthMPa403535334035
Chemical CompositionMgO%787578727881
F.C.1414131299
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LMM YOTAI Magnesia Carbon Brick

Raw materials
located at “Magnesium city”of China, we have material location advantage.
Technology
Japanese technology & management.
Equipment
• 1 set 2100 tons automatic hydraulic press.
• 2 sets 1850C Tunnel Kiln annual production capacity: 80000 tons.
Experience
we supplied to Greece, Bulgaria, Ukraine, Mexico etc.. we can also do OEM for you.

With our Magnesia Carbon Brick you can produce steel in a more environmentally friendly way. You won’t have to worry about your furnace overheating or corroding. Plus, our bricks resist spalling, so you’ll get longer life out of your furnace.

The company strictly according to modern enterprise management requirements set up a perfectquality assurance system, and passed the ISO9001:2008 quality management system certification, ISO14001:2004 environmental management system certification, OHSAS18001:1999 occupationalhealth and safety management system certification.

ABIDING BY THE HIGHEST CREDIBILITY FOR OUR CUSTOMERS

Pre-Sales Service

* Inquiry and consulting support.
* Planning layout and Design requires machinery
* Welcome visit our Factory.

After-Sales Service

* Engineers available to service machinery overseas.
* IN-TIME delivery goods.
* Free charges for installing, training and debugging.
* Long-term technical support.

Contact us today to learn more about our magnesia-carbon bricks !

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