#mgocbrick

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What is the erosion process of magnesia carbon bricks in the process of electric furnace smelting

The basic process of magnesia carbon brick erosion is:

(1) After the EAF magnesia-carbon brick is reacted, it is divided into three layers: the original brick layer (the brick body that has not reacted), the decarburized layer (the internal MgO and carbon undergo a self-consumption reaction), and the dense layer (the part in contact with the steel slag).

(2) The MgO and carbon inside the magnesia-carbon brick undergo a self-consumption reaction at high temperature:

(3) The oxides in the slag react directly:

Magnesium oxide is reduced to become magnesium gas, which migrates along the pores of the refractory material to the surface and is secondary oxidized to MgO, and forms a high-viscosity lithofacies structure with other impurity elements in the middle of the brick body, that is, the so-called dense layer.?

The erosion process is as follows:

(1) Physical wear. During the blowing process of these lithofacies, the movement of the physical steel slag furnace gas causes its physical and mechanical wear and peeling into the slag.

(2) Chemical attack. The chemical action is that various components in the middle of the slag will react with the dense layer of the brick body, and FeO can promote the dissolution and transfer of magnesia to the middle of the slag, increasing the erosion of EAF magnesia carbon bricks.

(3) The effect of temperature on erosion. The higher the temperature, the lower the viscosity of the steel slag, the intensified physical erosion, and the deepening of the decarburized layer, resulting in intensified erosion.

We Changxing Refractory Material Co.,LTD is professional manufacturer and supplier of refractory materials for more than 30 years. Our high quality EAF magnesia-carbon brick are good sold to many countries say South Africa, Bangladesh, Indonesia, Malaysia, etc. Shall any interests, welcome to contact us. Our team would make best to be your reliable partner!

Article Source:Why is the R.U.L of refractory materials a key indicator Company name: Henan Changxing Refractory Materials Co.,Ltd More refractory products:https://www.cxrefractories.com/en-product-solution Email:[email protected] Website:https://www.cxrefractories.com

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Factors influence MgO-C bricks quality

Magnesia carbon brick is a high melting point basic oxide magnesium oxide (melting point 2800 ° C) and a high melting point carbon material which is difficult to be infiltrated by slag as a raw material, and various non-oxide additives are added.

A non-burned carbon composite refractory material combined with a carbonaceous binder. Ladle Magnesia carbon brick is mainly used for the lining of converter, AC arc furnace, DC arc furnace, slag line of ladle and so on. The process factors affecting the performance of magnesia carbon bricks are mainly refractory raw materials, binders and additives. 1. Magnesite The high-purity sintered magnesia was used in the original production of magnesia carbon bricks abroad. With the in-depth study of the use of magnesia-carbon bricks, the following reactions were observed at high temperatures: MgO+C→Mg↑+CO↑ This reaction generally starts at 1650 ° C, and the reaction is intensified at l750 ° C. This is one of the important reasons for the loss during the use of magnesia carbon bricks, and it is also the reason why the loss of magnesia carbon bricks at 1700 ° C or above is significantly increased. The impurities such as SiO2 and Fe2O3 in the magnesia have a promoting effect on the above reaction, and therefore, it is desirable that the magnesia has a high purity. Compared with sintered magnesia, fused magnesia has a more complete crystal structure and a more stable carbon reduction. Especially the characteristics of large-crystal fused magnesia are more prominent, so the production of magnesia-carbon bricks begins to shift. Fused magnesia. The fused magnesia-sintered magnesia may also be used in combination in consideration of the bonding state of carbon and the wett ability of the binder. The results of the use of magnesia-carbon bricks show that the best effect is on the production of magnesia-carbon bricks with magnesia with high MgO content, large magnesia phase crystal particles and calcium-silica ratio greater than 2. 2. Graphite Graphite is another essential component in magnesia carbon bricks. Graphite has good basic properties of refractory materials. The main physical and chemical indicators are: fixed carbon 85%～98%, ash 13%～2% (main component SiO2, Al2O3, etc.), relative density 2.09～2.23, melting point 3640K ( Volatile). Since graphite is very easily oxidized, it has not attracted much attention for a long time. There are three reasons for the oxidation of graphite during the use of magnesia carbon bricks: (1) Oxidation of graphite by oxygen in the air; (2) Oxidation of graphite by oxides in the slag; (3) Oxidation of graphite by impurity oxides contained in graphite itself. These oxides mainly refer to SiO2 and Fe2O3. After the impurity oxide and graphite in the magnesia carbon brick react, the structure of the brick body is loose, the gas permeability is increased, and the strength is decreased, which is the internal cause of the damage of the magnesia carbon brick. Therefore, most of the magnesia carbon bricks used are graphites with high purity and large crystals of phosphorus. 3. Bonding agents Bonding agents are essential for magnesium carbon bricks and other carbon-containing refractory products. There is no mutual solubility relationship between graphite and refractory oxide, and it is impossible to sinter each other. They are cured by bonding at room temperature. The binder is coked and carbonized, and carbon is combined with graphite at high temperatures. Generally, the binder refers to organic substances such as resins and asphalt. The high-temperature coking of the binder forms about 3% of carbon after carbonization. Although this amount is not much, it is the most dynamic component in magnesia-carbon bricks or other carbon-containing products, and has an important influence on the high-temperature performance of the product. Magnesia-carbon brick binders can be generally divided into three types: phenolic resin, modified asphalt, and petroleum cracking by-products. Among them, phenolic resin is the best used and the most used. 4. Additives The oxidation of graphite is one of the most important causes during the destruction of magnesia carbon bricks. Due to the loss of carbon from oxidation, the structure of the brick body is loose and the strength is lowered. The damage process follows the path of oxidative carbon loss → structural looseness → erosion → erosion and dissolution. In order to improve the oxidation resistance of the ladle magnesia carbon brick, a certain amount of additives may be added, including silicon powder, aluminum powder, FeSi alloy, CaSi alloy, SiC, Si3N4, B4C and the like. Another effect of the additive is to "bridge" between the refractory oxide and the graphite to form a strong bond between the graphite and the refractory oxide, which is facilitated by the formation of a new mineral phase at a certain temperature.?For further details, please feel free to contact us, we would be your reliable partner.

We Changxing Refractory Material Co.,LTD is professional manufacturer and supplier of refractory materials for more than 30 years. Our high quality changxing refractory products are good sold to many countries say South Africa, Bangladesh, Indonesia, Malaysia, etc. Shall any interests, welcome to contact us. Our team would make best to be your reliable partner!

Article Source:Factors influence MgO-C bricks quality Company name: Henan Changxing Refractory Materials Co.,Ltd More refractory products:https://www.cxrefractories.com/en-product-solution Email:[email protected] Website:https://www.cxrefractories.com

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Brief introduction of magnesia-carbon brick raw material

1. Fused magnesia sand: it is an alkaline refractory made of natural magnesite, light fired magnesia or sintered magnesia fused by an arc furnace. Fused magnesia main crystal phase of periclase, melting point is 2800 ℃, 1600 ℃ sublimation in vacuum, in reducing atmosphere above 2000 ℃ sublimation, is greater than 3.40 g/cm3 density, porosity of 0% to 10%, 5.5 mohs hardness, resistance to basic slag erosion is very strong, stable chemical properties, under the high temperature of 1500 ℃ and other than the silica brick no or weak reaction between all kinds of refractory materials. The appearance should be clear after the complete melting crystallization, do not allow mixing with other magnesia or sundries.

2, Graphite: is a carbon as the main component of the natural mineral, it has high temperature resistance, heat conduction, electricity, lubrication, plastic and corrosion resistance and other properties. It is the main material containing carbon resistant material. The graphite used in refractory is flake graphite, which is divided into high purity, high carbon, medium carbon and low carbon graphite according to the fixed carbon content. The color is iron black, steel gray. The density is 2.09-2.23g/cm3 with a melting point of 3700℃±100℃(in vacuum), high thermal conductivity, small expansion coefficient, small elastic modulus, good lubricity, good conductivity, stable chemical properties, no reaction with acid, alkali and organic solvents at room temperature, and steel solution is difficult to wet, with good anti-erosion performance. 3. Phenolic resin: it is a non-aqueous organic binder for refractory materials. It is prepared by condensation of phenol (or cresol, dicresol, or resorcinol) with formaldehyde (or glycolaldehyde) under the action of catalyst.?

The main advantages are

(1) high carbonization rate (52%);

(2) good adhesion, high strength of the formed body;

(3) high bonding strength after burning;

(4) the rate of hardening can be controlled at room temperature;

(5) less harmful substances, can improve the operating environment.

According to heating properties or structural morphology classification, there are thermosetting phenolic resin and thermoplastic phenolic resin, according to product morphology classification, there are liquid phenolic resin and solid phenolic resin (granular and powder), according to the curing temperature classification, there are high temperature solidified type 130℃-150℃; There are medium temperature fixed type 105℃-110℃; There are room temperature solidified type 20℃-30℃.g material.

We Changxing Refractory Material Co.,LTD is professional manufacturer and supplier of refractory materials for more than 30 years. Our high quality changxing refractory products are good sold to many countries say South Africa, Bangladesh, Indonesia, Malaysia, etc. Shall any interests, welcome to contact us. Our team would make best to be your reliable partner!

Article Source:Brief introduction of magnesia-carbon brick raw material Company name: Henan Changxing Refractory Materials Co.,Ltd More refractory products:https://www.cxrefractories.com/en-product-solution Email:[email protected] Website:https://www.cxrefractories.com

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The four most common damage mechanisms of magnesia carbon brick

1. Slag causes melting and dissolution of magnesia 2. The oxidation of carbon (1) Direct oxidation The carbon in the MgO-C brick is directly oxidized by oxygen in the environment, generally occurring below 1400℃. (2) Indirect oxidation Indirect oxidation generally occurs above 1400℃, and indirect oxidation is divided into intrinsic oxidation and external oxidation. 3. Corrosion caused by molten steel flow (1) The slag layer formed on the working surface of the magnesium carbon material could be washed away by the flow of the molten steel, or the slag is insufficient. (2) Repeated heating and cooling during the production process and the stirring force of the molten steel may cause the structure of the material to relax. 4. Hot peeling and mechanical peeling.

We Changxing Refractory Material Co.,LTD is professional manufacturer and supplier of refractory materials for more than 30 years. Our high quality ladle magnesia carbon bricks are good sold to many countries say South Africa, Bangladesh, Indonesia, Malaysia, etc. Shall any interests, welcome to contact us. Our team would make best to be your reliable partner!

Ladle Magnesia Carbon Brick:Magnesia carbon brick is made of fused magnesia and high carbon graphite, with antioxidant was added, and the phenolic resin was used as the binder for high pressure molding. MgO-C refractory bricks are widely used in steel industry.

Ladle Purging Plug:Ladle purging plug has been in the leading position in domestic and abroad over years. We have developed the series of corundum, chromium corundum, low silicon chromium corundum and corundum spinel one after another.

Ladle Slide Gate Plate:Slide gate plate is preferred products for big/medium ladle and continuous casting tundish. Alumina-carbon slide gate plates can meet the requirement of different steel grades.

Ladle Castable:Ladle castable has good workability, high strength, good volume stability, good abrasion resistance and thermal shock resistance, etc.

Article Source:The four most common damage mechanisms of magnesia carbon brick Company name: Henan Changxing Refractory Materials Co.,Ltd More refractory products:https://www.cxrefractories.com/en-product-solution Email:[email protected] Website:https://www.cxrefractories.com

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4 solutions for serious damage to refractory materials used in ladle lining

Ladle turnover process: converter/electric furnace tapping once and twice refining process, continuous casting and pouring steel, ladle preparation work, and waiting for tapping. The normal turnaround time depends on the steel type and the continuous casting machine, and it takes 100 to 140 minutes. The tapping temperature of the ladle is 1680-1700℃, and the holding time is 100~120min. If the ultra-low carbon steel process such as silicon steel, bridge steel, automobile plate steel, etc must be vacuum treated, argon blowing and stirring at the bottom of the ladle and LF furnace are used at the same time. Arc heating, reducing atmosphere in the furnace, white slag refining, gas stirring, etc., strengthen the comprehensive refining effects of thermodynamics and kinetic conditions, desulfurization, alloying, and heating, so the slag alkalinity range is large, and the temperature of molten steel and slag is higher. The residence time of molten steel in the ladle is prolonged, the thermal shock is strong, the stirring force is large, and the damage to the inner lining of the ladle is aggravated.

The reasons for the damage of the ladle refractories are as follows:

First, the ladle is used to transport high-temperature molten steel. During transportation, high-temperature molten steel and molten slag at around 1680°C will erosively corrode it, especially at the slag line. The scouring erosion is more serious, which is an important factor in determining the service life of a tank.

Second, the refining treatment outside the furnace such as LF seriously damages the unburned bricks.

Third, the inner lining is subjected to severe temperature changes when the converter is tapped and molten steel flows out, which causes cracks and peeling of the inner lining material.

Fourth, when the ladle is filled with molten steel during the tapping of the converter, the high-temperature molten steel has strong mechanical erosion on the bottom of the ladle, which makes the lining material of this part prone to damage due to thermal shock. According to the above analysis, the ladle lining refractories should have the following characteristics: compact and uniform structure; high temperature micro-expansion, good volume stability; High strength, small ratio of medium temperature strength to high temperature strength.

In addition to the above-mentioned two chemical and physical reasons, there is another reason that cannot be ignored is man-made:

(1)Improper selection and collocation of refractory materials;

(2)Improper use of refractory materials, such as unreasonable masonry and baking methods;

(3)Too long ladle turnover period causes cold ladle;

(4)Improper unpacking will damage the permanent layer of the ladle;

(5)Failure to take repair measures in time. The method to reduce the structural spalling of refractory materials is to reduce the depth of slag penetration.

It is recommended to start from the following aspects:?

(1)Improve the slag penetration resistance of refractories;

(2)Reduce the porosity of?refractory materials?and reduce the erosion channel of slag;

(3)The slag reacts with the refractory material to form a high melting point compound retaining wall to prevent the penetration of the slag;

(4)Increase the viscosity of the slag. The greater the viscosity of the slag, the worse the corrosiveness to refractory materials;

(5)Understand the properties of the refractory materials used, and reasonably formulate the use conditions of the ladle;

(6)Speed up the use cycle of ladle as much as possible, and achieve "red envelope" work;

(7) The damaged parts of the lining refractories should be repaired or replaced in time.

We Changxing Refractory Material Co.,LTD is professional manufacturer and supplier of refractory materials for more than 30 years. Our high quality ladle magnesia carbon bricks are good sold to many countries say South Africa, Bangladesh, Indonesia, Malaysia, etc. Shall any interests, welcome to contact us. Our team would make best to be your reliable partner!

Ladle Magnesia Carbon Brick:?Magnesia carbon brick is made of fused magnesia and high carbon graphite, with antioxidant was added, and the phenolic resin was used as the binder for high pressure molding. MgO-C refractory bricks are widely used in steel industry.

Ladle Purging Plug:Ladle purging plug has been in the leading position in domestic and abroad over years. We have developed the series of corundum, chromium corundum, low silicon chromium corundum and corundum spinel one after another.

Ladle Slide Gate Plate:Slide gate plate is preferred products for big/medium ladle and continuous casting tundish. Alumina-carbon slide gate plates can meet the requirement of different steel grades.

Ladle Castable:Ladle castable has good workability, high strength, good volume stability, good abrasion resistance and thermal shock resistance, etc.

Article Source:4 solutions for serious damage to refractory materials used in ladle lining Company name: Henan Changxing Refractory Materials Co.,Ltd More refractory products:https://www.cxrefractories.com/en-product-solution Email:[email protected] Website:https://www.cxrefractories.com

[cxrefractories]

Nanotechnology improves the thermal shock resistance of low-carbon magnesium-carbon refractory materials

In addition to good slag resistance, low-carbon magnesia-carbon refractories also require products with a certain degree of thermal shock resistance. This is due to the sharp decline in thermal shock resistance due to the reduction of carbon content. Thermal shock resistance is not only an important index to measure refractory materials, but also a key research direction in the low-carbon use of magnesia-carbon bricks.

Nano powder particles have the characteristics of small size, large surface energy and large dispersion, which are conducive to the relative slip between particles and can improve their thermal shock resistance. Therefore, the use of nanotechnology to improve the thermal shock resistance of low-carbon magnesium-carbon refractories has attracted much attention. The use of nanotechnology to improve the thermal shock resistance of low-carbon magnesium-carbon refractories is essentially to increase the fracture toughness of the material. The microstructure of the material can be adjusted to further increase the crack propagation resistance of the material. There are two main toughening methods for low-carbon magnesium-carbon refractories.

?(1) Crack deflection toughening, nano-powders are introduced in the form of refractory raw materials or additives, and the introduced nano-powders are dispersed and distributed in or between particles. A large number of sub-interfaces are formed and play a role in pinning dislocations, making the crack propagation path more tortuous, extending the crack propagation path, resulting in an increase in the ability of the crack to be consumed during the propagation process, and an increase in the fracture toughness of the material.

(2) Crack bridging and toughening, introducing nanoparticles into the refractory aggregates can form bridging components of fibers, whiskers and ceramic phases in situ. When larger bridging components are encountered in the process of crack propagation, their existence is relatively high. The bridge connecting element is equivalent to erecting a bridge between two opposing crack surfaces, which increases the resistance of crack propagation. If the cracks continue to expand further, the bridging component is destroyed by pulling out from the matrix. This pulling out process will consume a lot of energy and increase the fracture toughness of the product, thereby improving its thermal shock resistance.

We Changxing Refractory Material Co.,LTD is professional manufacturer and supplier of refractory materials for more than 30 years. Our high quality refractory products are good sold to many countries say South Africa, Bangladesh, Indonesia, Malaysia, etc. Shall any interests, welcome to contact us. Our team would make best to be your reliable partner!

Article Source：Nanotechnology improves the thermal shock resistance of low-carbon magnesium-carbon refractory materials Company name: Henan Changxing Refractory Materials Co.,Ltd More refractory products:https://www.cxrefractories.com/en-product-solution Email:[email protected] Website:https://www.cxrefractories.com