The characteristics and classification of magnesia refractories

 The melting point of MgO is as high as 2800℃, and the refractoriness of magnesia bricks is generally high, reaching above 2000℃. Therefore, magnesia bricks have good high temperature resistance, high temperature vacuum stability is good, and strong resistance to alkaline slag , but magnesia bricks have poor resistance to sulfate erosion, poor thermal shock stability, and are easy to hydrate. In addition to traditional magnesia bricks, magnesia refractories also include forsterite refractories and magnesia alumina spinel high-quality refractories, magnesia-chrome refractories, white jade refractories, etc.

Magnesium chromium refractory material. It is a refractory material made of magnesia and chromite, and with magnesia as the main component. According to the chemical composition, magnesia-chrome refractory products include chrome bricks and chrome-magnesia bricks. Magnesium-chromium refractory products have high refractoriness, high-temperature strength, good thermal shock stability, strong corrosion resistance to alkaline slag, adaptability to acidic slag, and good kiln-hanging properties. Magnesium-chromium refractory products are mainly used in RH ovens, AOD furnaces, non-ferrous metal smelting furnaces and glass kiln regenerators, cement rotary kilns, mixing furnaces, lime kilns and high-temperature kiln linings, etc.

However, due to the environmental impact of hexavalent chromium ion harm to the human body. Magnesium aluminum spinel refractory material. It is a refractory composed of magnesia and spinel with a magnesium oxide content (mass fraction) of not less than 20%. However, due to the large variation range of A12O3 and MgO content, we will use A12O3 and MgO as the main chemical composition of the refractory. It is called magnesia-aluminum spinel refractory. Magnesium-aluminum spinel refractories are mainly used in large cement rotary kilns, glass kiln regenerators, electric furnace tops, refining furnaces outside the furnace, ladle and other thermal equipment for enhanced operations.

Dolomite refractory material. The main component is white jade clinker. White jade clinker refers to calcining natural magnesium calcium salts or hydroxides to form a uniform and dense mixture of calcium oxide and magnesium oxide. According to the chemical mineral composition, it can be divided into the following two categories.

Article Source:The characteristics and classification of magnesia refractories
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Refractory products for AOD refining furnace

 The AOD furnace is an argon-oxygen blown converter for two-step steelmaking. It is an atmospheric refining furnace. Its appearance is similar to that of a converter. It is mainly used for smelting stainless steel.

The working characteristics of AOD furnace are:

1.High working temperature. In order to reduce the carbon content in steel to a very low level, the refining temperature needs to be increased to over 1700 degrees Celsius.

2.The molten steel is stirred vigorously. The spraying of a large amount of high pressure caused the molten steel to agitate violently.

3.The alkalinity of the slag changes greatly.

4.Intermittent operation.

The working process of the AOD furnace is to first blow oxygen to decarburize, then add ferrosilicon or aluminum to reduce the chromium in the slag, and then add lime for desulfurization. During the whole smelting process, the slag changed from acidic to alkaline, and the atmosphere changed from silicon oxide to reducing atmosphere. Due to the above working characteristics, refractory materials for AOD furnaces are required to have high refractoriness and high temperature strength. Good thermal shock resistance and strong slag resistance. Especially for the tuyere and the area around the tuyere, it is more necessary to use refractory materials with good corrosion resistance and peeling resistance. The refractory materials commonly used in AOD furnaces are magnesia chrome bricks, magnesia carbon bricks, and magnesia dolomite bricks. In order to form a balanced furnace lining, the upper part of the tuyere is fused and then combined with magnesia chrome bricks, the other parts are directly combined with magnesia chrome bricks, or the tuyere part uses pre-reacted magnesia chrome bricks, and the rest are magnesia dolomite bricks. The top of the furnace can be made of high-aluminum refractory castables and refractory plastics, or can be built with magnesia bricks.

Article Source:The development and function of long nozzle
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The development and function of long nozzle

 The invention of long nozzle started from the demand for the protection of molten steel pouring. Its use played a good role in preventing the secondary oxidation and slag entrapment of molten steel, and played an important role in the development of molten steel continuous casting. Tundish liquid steel pollution in different periods of continuous casting are almost related to the long nozzle, which has attracted the attention of more and more metallurgical workers.

In recent years, long nozzle has been continuously upgraded in terms of materials, structure and process operations. The new designed long nozzle structure realizes the immersion pouring, which effectively alleviates the serious entrapment and air suction during pouring. With the development of continuous casting technology, refractories are taking on more metallurgical tasks, and the metallurgical functions of the long nozzle are becoming more diversified, such as detection of slag under the ladle, formation of dispersed bubbles, and prevention of filling compound pollution. But the primary task of long nozzle is still protect the pouring of molten steel.

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!

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Lining method of EAF bottom ramming mass

 After feed in EAF bottom ramming mass, use a shovel or a nail rake to level it, and then use an aluminum alloy long ruler and a level to level it, taking the baseline released in advance as the standard, and then spread a canvas on the leveled ramming material, and the canvas will ramming the furnace bottom cover it all.

Put two vibrators on the canvas and keep a certain distance between the two vibrators. At the beginning, the two vibrators are best placed on the two ends of the furnace diameter inside the furnace shell. This will not only avoid mutual interference, but also enable the operator to reduce dust damage.

After the vibrator is activated, it starts to vibrate from the outer ring and ramming from the outside to the inside. The next circle should overlap the previous one by one third to prevent missed beating. Continuously vibrate from the inside of the brick wall until the center of the furnace is regarded as-times. After the ramming is completed, the ramming is repeated several times from the outside to the inside, and each layer of ramming material is simultaneously rammed multiple times with two vibrators.

After each layer of ramming is finished, remove the dust-proof canvas, and use a homemade nail rake to pull the surface of the ramming material in the same direction and comb into grooves to help increase the contact area of the upper and lower adjacent layers to form a seamless overall ramming stove bottom.

The density of the ramming material after compaction should reach 2.8g/cm2 or more. At this time, the vibrator jumps up and down, the amplitude is larger, and the vibration sound is louder than the previous few times. These phenomena indicate that the material layer is basically solid.

Knotting quality inspection method: use a 4mm diameter iron rod, such as φ 4mm welding rod, the insertion depth does not exceed 20mm.

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The development of low creep high alumina brick

 Low creep high alumina brick is an acquainted product for refractory material and steel making workers. In 1985,in order to realize the nationalization of refractory material for Baosteel second-stage construction, metallurgy organization pay more attention to the research the low creep high alumina brick reaching the Japanese level.

Until now, many factories can produce the higher quality low creep alumina brick for the blast furnace and cowper stove. The burdening of the most of homebred low creep alumina brick is to add the family of sillimanite materials, whose process is complicated and cost is higher.

Early guidance Tangshan Iron and Steel author refractory plant for Bao steel to develop low creep high alumina brick, but with pure silica powder as a secondary mullitization provenance, products in 1550 ℃ 0.2 MPa 50 h creep rate index level over Japan. There was no disclosure of the technical know how to add quartz. In fact, this is a lesson to be learned from an article in the Russian data. A Ukrainian Institute refractory low creep high alumina brick submitted on paper entitled. High alumina refractories with high creep resistance at temperatures. At first glance, the title seems to be no novelty, but its high-performance products. The technology index of industrial scale produced by this share company :w(Al2O3)>73%, show porosity ≥18%,compression strength >100Pa, Heavy softening temperature (0.5MPa)> 1750 ℃, the creep rate (1600 ℃ 1.5MPa24h) <0.09%.Here note load softening temperature and pressure values creep rate tests.

Low creep high alumina brick is generally cannot afford such high stresses. The products used in the lower temperature hot stove brick dome, more than 9.5 years of continued operations. Speaker did not introduce technical points, did not explain the materials used, but no mention of the addition of quartz. But between the lines describe a little trace impurities in the raw material properties, the industry can determine its so-called "purity of 99% SiO2" is quartz, quartzite and general purity. In fact, the use of fused alumina, activated alumina, and a quartz-based raw materials to manufacture non-uniform state technical essentials multiphase quartz reaction product is so fully realized mullite bonded corundum microstructure to achieve excellent high temperature performance.

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The main elements for controlling electric furnace steel-making

 The main elements for controlling electric furnace steel-making are the supply and quality of steel scrap. Adopting DRI which is also called sponge iron steel becomes the most efficient and economic processing measure. In 2000, Sponge iron production reach 43 million ton in the world, the main country are Venezuela, Mexico and India. For India, it tried to produce sponge iron steel in 1980 and could not reach 10 million ton in 1990, while it reached 54 million ton. The processing measure for smelting sponge iron steel is not complicated. It is to mix mineral flour and coke equality, balling, roast in the ring kiln and reduced iron to get sponge iron and impurities product.

The surface temperature of rotary kiln lining is 1000 degree centigrade or so and, it can bear mechanical stress, slagging, washout and heat shock function . In preheating zone, about 900 degree centigrade , it happened C+CO2---2CO reaction, the mine partly and slowly is reduced and then it happened Fe2O3+CO---2Fe0+CO2 reaction. The temperature of material, but in the zone of reduction, it happened Fe2O3+CO---2FeO+CO2, this reaction absorbs the heat , the reactant material temperature is lower than 100 degree centigrade, the refractory lining bear the sudden change for temperature of fuel burning and material cooling.

Article Source: BOF furnace classification and related refractories
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BOF furnace classification and related refractories

 BOF is a vertical cylindrical furnace that does not require an external heating source and mainly uses liquid pig iron as raw material for steelmaking. According to the nature of refractory lining, it can be divided into acid BOF and alkaline BOF. According to the position where the gas is blown into the furnace, it is divided into bottom blowing, top blowing, side blowing and top and bottom combined blowing BOFs.

Because of the different components of molten iron and refractory resources in different countries in the world, the choice of furnace lining bricks is also emphasized. The United States mainly uses tar-combined magnesia bricks, periclase bricks, and tar impregnated and fired periclase bricks. Magnesia carbon bricks have also been used since the 1990s. France mainly uses dolomite bricks, magnesia dolomite bricks, dolomite carbon bricks, asphalt bonded magnesia bricks and magnesia carbon brick. The United Kingdom once used tar dolomite bricks and fired dolomite bricks. After 1989, a large number of MgO C bricks were used.

Russia mostly uses tar dolomite bricks, and a few factories also use tar magnesia bricks and periclase spinel bricks. Japan is the first country to move magnesia-carbon bricks from electric furnaces to BOFs, and its use effect is in a leading position in the world. The development of BOF lining in China has gone through the process of tar combined with dolomite bricks, tar combined with magnesia bricks, magnesia dolomite bricks, high calcium magnesia bricks, magnesia dolomite carbon bricks and magnesia carbon bricks. In summary, all countries in the world are gradually using magnesia carbon bricks to replace other bricks. Magnesia carbon brick has good thermal shock resistance, strong corrosion resistance, excellent stability at high temperatures, good thermal conductivity, good wear resistance and good spalling resistance, plus the improvement and progress of smelting technology and gunning technology Since the 1990s, the service life of furnace lining has been greatly improved, and the consumption of refractory materials per ton of steel generally does not exceed 2kg.

Article Source: BOF furnace classification and related refractories
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The application of cement kiln refractories

 We often use magnesite chrome brick, high alumina brick, clay bricks, silicon mullite brick, phosphate bonded high alumina brick, magnesia spinel brick, high alumina castable, low cement castable, calcium silicate board and ceramic fiber products in the cement rotary kiln.

Changxing factory is located on Xinmi city, Henan Province with abundant raw material resources. Reasonable price and best service providing for you. We also have professional kiln designers help you to do the refractory solution for you. You can discuss with our engineer face to face and visit factory to see the process of steel making.

Changxing refractory provides refractory products, calcium silicate products, castable & mortar, china refractory brick, ceramic fiber felt, ladle & tundish nozzle, ceramic fiber with high quality for you. Such as high alumina refractory bricks, magnesia carbon brick, clay refractory bricks and other refractory products.

Article Source: The application of cement kiln refractories
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The use and composition of ladle purging plug

 In modern steel smelting technology, ladle purging plug is a very important functional element in the out-of-furnace refining technology. Inert gases such as argon are introduced into the molten steel through the ladle purging plug at the bottom of the ladle to provide power for the stirring of the molten steel to achieve uniform steel. Aim to make the alloy composition and uniform temperature are average in the liquid steel. According to the assembly mode, the purging plug can be divided into integrated purging plug and seperated purging plug. Both are composed of purging plug core and well block. Whether integrated purging plug or seperated purging plug, the function of the well block is to protect the brick core and prevent molten steel from corroding to any position of the brick core except the working surface. Usually the bricks will be damaged as follows: Erosion of molten steel, spalling, transversely broken, longitudinally cracked of well block.

Ladle purging plug is a very important functional element in the out-of-furnace refining technology. Inert gases such as argon are introduced into the molten steel through the ladle purging plug at the bottom of the ladle to provide power for the stirring of the molten steel to achieve uniform steel.

Article Source: The use and composition of ladle purging plug
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The refractory design effect for submerged arc furnace’s working performance

Refractory design is the most fundamental factor in furnace construction. Refractory design details and proven technology consideration is of paramount importance to come up with an optimum furnace life and to maintain productivity in the life span of the furnace lining.

The failure to produce a technically or operationally durable refractory design lining could give rise to premature deterioration of the refractory lining and furnace shell.

The premature failure of the furnace lining will lead to extensive heat losses, furnace bath shift, change in taphole orientation and alteration of the Pitch Circle Diameter. In this way, the pre-design of refractory lining is very important, we must pay attention to every details, finding out the most suitable refractories for each part.

If you want to learn more about this, please contact us.

Changxing refractory provides refractory products, calcium silicate products, castable & mortar, china refractory brick, ceramic fiber felt, ladle & tundish nozzle, ceramic fiber with high quality for you. Such as high alumina refractory bricks, magnesia carbon brick, clay refractory bricks and other refractory products.

Article Source: The refractory design effect for submerged arc furnace’s working performance
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Magnesia alumina carbon brick composition and classification

 Broadly speaking, refractories with alumina, magnesia and carbon as the main components can be collectively referred to as aluminum magnesium carbon refractory materials. Alumina magnesia carbon brick are non-fired shaped refractory products combined with high alumina bauxite clinker, magnesia and graphite as main raw materials and combined with asphalt or resin. Aluminum-magnesium-carbon refractory products can be divided into two categories according to the content of alumina or magnesia: one is alumina magnesia carbon brick with alumina as the main component, usually expressed as AMC or LMC; the other is mainly magnesium oxide. The composition of magnesia alumina carbon brick is usually expressed by MAC or MLC.

The new magnesia alumina carbon technology is ideally suited for ladle transition zone (between the AMC barrel brick and the MC slag lines), as it is compatible with both magnesia-carbon (MC) and alumina-magnesia-carbon brick qualities. There will be no transition zone joint erosion due to the incompatibility of some AMC barrel products mating up to magnesia-carbon slag lines. The new magnesia alumina carbon brick technology also performs very well in the steel ladle bottoms, barrels and especially in the lower sidewall slag zones, which do not tend to react with free lime. The new magnesia alumina carbon brick can be used successfully as slag line brick in steel ladles and steel transfer ladles, as long as there is no free lime the slag during tap, after de-skulling and extra additive addition, and during the heat treatment in the LMF.?

Article Source:Magnesia alumina carbon brick composition and classification
Company name: Henan Xinmi Changxing Refractory Materials Co.,Ltd
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The development of refractory material for blast furnace

 Introducing the development of refractory material for the blast furnace lining in China. For the design of blast furnace, it needs to choose refractory raw material reasonably according to the performance for the size of the volume and different parts. In China, with the quality and variety of the blast furnace lining making a great progress, no need to use the imported refractory material.

With the quick development of steel-making industry in recent years, the blast furnace lining refractory material has made great progress. It is pursuing the advanced technology in the world instead of some of importing products to meet the need of the development of steel-making production.

Prolong the blast furnace service life is the important policy in recent ten years in China.

1.The blast furnace refractory material performance
2.The blast furnace lining refractory material quality analysis

Changxing refractory provides refractory products, calcium silicate products, castable & mortar, china refractory brick, ceramic fiber felt, ladle & tundish nozzle, ceramic fiber with high quality for you. Such as high alumina refractory bricks, magnesia carbon brick, clay refractory bricks and other refractory products.

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Refractory bricks used for different parts of blast furnace

 Blast furnace is the main equipment for ironmaking, and clay brick is the earliest furnace lining material used in blast furnace. Blast furnace has the advantages of large output, high productivity and low cost, which is unmatched by other ironmaking methods.

The refractory materials and refractory bricks used in diffreent parts of blast furnace are as follows.

(1) Furnace hearth
One of the main functions of furnace hearth is to hold molten iron safely. The hearth refractory material must be stable enough when the temperature is highter than 1500 ℃. So for furnace hearth bottom, we need to choose carbon brick which has the advantages of anti-molten iron penetration, good melting, alkali resistance erosion, good thermal conductivity. And we can use small carbon brick to take the place of large carbon block, or construct ceramic rings on the carbon bricks.

(2)Tuyere zone and bosh
Temperature in tuyere area and furnace bosh is the highest in the blast furnace. The hot gas temperature produced in front of the tuyere rises at a high speed, the temperature can reach 1600 ℃ and higher. When 1450 ~ 1550 ℃molten iron and slag flow furnace hearth and finally flow to the furnace bosh, there will be a variety of metallurgical reactions happen in this area violently. Those two areas need refractory materials with characteristics of good resistance to high temperature and slag erosion, good alkali resistance, anti carbon dioxide and anti water oxidation. China refractory bricks we can use in this area are corundum brick, alumina carbon brick, hot pressed semi-graphite carbon brick, SiC brick and so on.

(3)Furnace bosh and lower furnace stack
The lower furnace stack is the position of root cohesive zone where the temperature is quite high, but slag layer or stable slag layer self protection can not be formed. This are need ds refractory materials which can bear severe temperature fluctuations, and also has advantages of alkali metal erosion, zinc erosion, carbon monoxide erosion, etc. What’s more, refractory materials used in furnace bosh and lower furnace stack should have good thermal shock stability, high temperature resistance, good alkali resistance and other properties. Refractory bricks can be used in these two areas are high alumina brick, corundum brick, alumina carbon brick, SiC brick and so on.

(4)The middle and upper part of furnace stack
The furnace stack middle part’s temperature is lower than that of furnace stack lower part. People genarally use high alumina brick, corundum brick and silicon carbide in furnace stack middle part. The temperature in furnace stack upper part is relatively lower than other parts, and it mainly affected by the wear and impact of the burden, alkali metal, zinc and carbon deposition erosion. This area requires refractory material has advantages of good wear resistance, good alkali resistance and good thermal shock stability.?Refractory bricks can be used in this area are clay brick, high alumina brick, sillimanite brick, corundum brick. There is a trend that cooling walls are taking the place of refractory bricks used in blast furnace.

Article Source: Refractory bricks used for different parts of blast furnace
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Thermal conductivity of refractory bricks

 The thermal conductivity of refractory fire bricks is represented by the thermal conductivity that has the ability to transfer heat. Thermal conductivity represents the amount of heat per in unit area, unit time and unit temperature gradient in the energy transfer process.

At 1000 ℃The thermal conductivity of various refractory bricks rate as shown below. The thermal conductivity of different materials is often very different. At normal temperature, the thermal conductivity of various refractory bricks can be from a few percent to several tens (w／(m℃), which is nearly a thousand times lowst than the highest value. As the temperature rises, although the difference between the thermal conductivity of various refractory bricks tends to decrease, but the difference is still large. Such as 1000 degrees centigrade, the thermal conductivity of lightweight silica is only about 0.35W, recrystallized silicon carbide products is about 17.5W／(m℃), graphite can be up to 35W / (m℃).

In addition to temperature, the thermal conductivity of refractory bricks is closely related to its chemical composition and structure. When refractory bricks are made of crystal, the properties of crystal have obvious influence on thermal conductivity. As we all know, the thermal conductivity of inorganic nonmetallic materials is generally much lower than that of metal. Because inorganic nonmetallic materials are different from metals with metal bonds, there are very few free electrons. The thermal conductivity caused by free electrons in this material is extremely limited, and the lattice vibration is mainly deviated from the degree of resonance. The greater the degree of deviation from the resonance, the thermal conductivity is smaller. The degree of lattice vibration deviation increases with the difference in the molar mass of the constituent components, so the thermal conductivity of the element is the largest. (So the thermal conductivity of graphite is relatively large).

China refractory bricks have a complex structure of crystals, the thermal radiation of the lattice is greater and the thermal conductivity is smaller, such as MgO, A12O3 and MgAl2O4 Such as MgO, A12O3 and MgAl2O4 are equiaxed, but the structure of MgAl2O4 is complex and the thermal conductivity is low. Non-coherent crystals, in the direction of dense particles along the crystal, thermal conductivity is larger. The quartz along the C axis has a dense accumulation of particles, and its thermal conductivity (13.6W／(m℃)) is about twice as high as that of the C axis. The layered structure of graphite, the thermal conductivity parallel to the direction of the level of about 4 times in the direction perpendicular to plane direction.

If the crystal is defective, the formation of substitutional solid solution, because the rules of the crystal structure of the destruction caused by thermal scattering phenomenon, resulting in a decrease in thermal conductivity. Other crystal defects such as vacancies, dislocations and so on, also has a similar effect. Due to the thermal scattering of the grain boundary, the thermal conductivity of the polycrystalline material is lower than that of the single crystal. The refractory raw material of fine grain is lower than that of coarse grain. The material contains impurities, the thermal conductivity is lowered due to the scattering effect.

When refractory bricks contain glass phase, due to the amorphous structure of the disorder, the probability of collision between atoms. So compared with the crystal, thermal conductivity is low. When the refractory brick contains pores, because the thermal conductivity of the gas is smaller than the solid, so with the increase in porosity, the thermal conductivity of the material decreases. This is the basic reason for the low thermal conductivity of porous materials.

Article Source: Thermal conductivity of refractory bricks
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Thermal Conductivity
1-Silicon Carbide Brick;2-Magnesia Brick
3-Silicon Carbide Brick(SiC70%);4-Corundum Brick
5-Silicon Carbide Brick(SiC50%);6-Sintered Dolomite Brick
7-Zirconia Brick;8-Chrome-Magnesite Brick
9-Corundum(A12O390%);10-Sillimanite Brick
11-Olive Brick;12-Chromite Brick
13-Silica Bricks;14-Dense Clay Bricks
15-Clay Brick

The uses of high purity magnesia

 Because the high purity magnesia has good hot modulus of rupture, slag resistance and corrosion resistance, it can increase the service life of the lining, so it is widely used in lining refractory of the steel furnace; It is a high-quality material for manufacturing refractory bricks and unshaped refractories (high-grade alkaline refractories); It can be used as a filler to make thermocouples insulation materials (household appliances, etc); It also can be used for ceramic raw materials and sintering aids, as well as metallurgy, building materials, chemicals, national defense, medical equipment,etc.

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:The uses of high purity magnesia
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The advantages of high-durability cement-free iron trench materials

 Cement bonded castable for iron runner is widely used in Japanese blast furnace iron runner because of its easy construction and compact structure. However, castables with dense structure are prone to burst during baking, so the development of silica sol-bonded iron groove materials which are easy to dry and resistant to burst has been widely studied. Researchers from Shinagawa Refractory Co., Ltd., Japan, have developed a highly durable cement-free iron trench material, the composition of which is shown in Table 1. The new type of iron trench material uses silica sol as binder, keeps the Al2O3 content unchanged, increases the content of additive X by 10 times, slightly increases the amount of SiO2 and SiC+Si, and correspondingly reduces the amount of other components.

The results show that, compared with cement-bonded iron trench materials, after burning at 1000℃ for 3 h, the weight loss rate and apparent porosity of silica sol-bonded iron trench materials are greatly reduced, and the bulk density is constant the flexural strength, compressive strength and elastic modulus at temperature increased significantly, and the flexural strength at high temperature increased significantly at 1 500℃ in N2 atmosphere. The practical application results in the taphole of blast furnace show that the erosion rate of silica sol bonded iron groove material is reduced to about half of that of cement bonded iron groove material, and the service life is greatly improved.

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!

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The magnesia carbon bricks specification

Magnesia carbon brick is a basic refractory made of magnesia and carbon material with asphalt or resin as binder. Magnesia refractory high refractoriness and carbon refractories are difficult to be slag, steel liquid wetting multiple advantages, because of its high refractoriness, slag erosion resistance is strong, excellent thermal shock resistance, and many other good characteristics and is widely used in steel industry, such as front of converter, electric furnace slag line parts and high temperature in the working layer of ladle, severe mechanical erosion, slag erosion condition of bad environment.

The magnesia carbon brick is easy to oxidize in high temperature and oxidizing atmosphere, which leads to the deterioration and looseness of brick structure, and finally erosion, spalling and failure. Therefore, it is necessary to add various anti-oxidants to inhibit the oxidation of carbon and improve the quality of magnesium carbon brick, such as adding boron carbide, metal aluminum powder, metal silicon powder and their mixtures.

Adding aluminium and silicon into magnesia carbon brick can increase the ability of resisting oxidation notably also, the strength at high temperature and the strength at normal atmospheric temperature with carbonization dealt at 1000℃ all have obvious increasement compared with the strenth of original brick. Now many countries are developing the production technique of magnesia-carbon brick.

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The classification and usage of silica ramming mass

 Intermediate frequency furnace knotted material also calls the intermediate frequency furnace lining material, intermediate frequency furnace, silica ramming mass, intermediate frequency furnace refractory ramming material dry vibrating material, intermediate frequency furnace, tie points acidic, neutral and alkaline materials, knot acidic materials in high purity quartz, fused silica as the main raw material, compound additives for sintering agent; Neutral knot material with high alumina, aluminum material as the main raw material, sintering agent by the composite additive; Knot alkaline materials in high purity fused corundum and high purity fused magnesia, high purity spinel as main raw materials, sintering agent for compound additives.

Knot acidic, neutral and alkaline materials are widely used in the coreless medium frequency furnace, induction furnace, the knot as intermediate frequency furnace to molten gray iron, ductile iron, can be calcined cast iron, vermicular cast iron and cast iron alloy, molten carbon steel, alloy steel, high manganese steel, tool steel, heat-resistant steel, stainless steel, melted aluminum and its alloy, melting copper, brass, copper and bronze, copper alloy, etc.

Our company’s intermediate frequency furnace lining material main be silica ramming mass and medium ramming mass. Silica ramming mass can reach 25 heats, and the medium ramming can be sure at least 60 heats. We?can also provide the workers and designs.?We Changxing Refractory Material Co.,LTD is professional manufacturer and supplier of refractory materials for more than 30 years. Our high quality silica ramming mass are good sold to many countries say South Africa, Bangladesh, Indonesia, Malaysia, etc. Shall any interests, welcome to contact us.

Article Source:The classification and usage of silica ramming mass
Company name: Henan Xinmi Changxing Refractory Materials Co.,Ltd
Email: info@cxrefractories.com
Website:http://www.cxrefractories.com

Causes of erosion of blast furnace body and selection of refractory materials

 

Erosion reason	Requirements for refractory properties
1.Wear of charge drop process	1.High crushing strength
2.Erosion wear of upward gas flow	2.The performance of alkali resistant metal corrosion resistance is good
3.Alkali metal erosion	3.Low porosity
4.Destruction of CO	4.Low iron oxide content
The upper and middle furnace refractories for blast furnace are: clay brick, sillimanite brick, dense clay brick, high alumina brick etc.
The lower part of the shaft, belly erosion causes
Erosion reason	Requirements for refractory properties
1.Chemical erosion of primary slag	1.Slag resistance is good
2.Wear of down charge	2.The performance of alkali resistant metal corrosion resistance is good
3.Erosion of metallic iron	3.High - temperature strength
4.Erosion wear of gas flow	4.Good thermal conductivity
5.Spalling due to thermal shock	5.Low porosity
?	6.Good thermal shock stability
From the waist to the lower part of the shaft lining, thermal shock is decreased by high temperature and high pressure gas charge and increase the wear and temperature changes, but also by the chemical high FeO high basicity slag erosion, more serious is alkali metals and zinc vapor caused by carbon deposition and chemical reaction, the refractory brick organization embrittlement lose strength. And suitable for refractory brick is: aluminum brick, silicon carbide, hot pressing small carbon bricks and semi graphitized carbon - silicon carbide brick.
Lining erosion reason
Erosion reason	Requirements for refractory properties
1.Corrosion and penetration of molten iron	1.Resistance to molten iron corrosion, good permeability
2.Circulating erosion corrosion of molten iron	2.Good thermal conductivity
3.Alkali corrosion	3. The performance of alkali resistant metal corrosion resistance is good
4.Destructive effect of thermal stress	4.Low porosity , microporosity
Hearth wall masonry taphole above by erosion of iron, iron mouth following the "dead iron layer", by the iron soaked, by erosion of molten iron flow in the furnace wall and the bottom of the junction. The masonry has good anti erosion ability of slag, molten iron and mechanical washing. Most of the hearth and bottom of large and medium blast furnace are made of carbon brick and carbon brick ceramic cup composite hearth.

We Changxing Refractory Material Co.,LTD is professional manufacturer and supplier of refractory materials for more than 30 years. Our high quality 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!

Article Source:Causes of erosion of blast furnace body and selection of refractory materials
Company name: Henan Xinmi Changxing Refractory Materials Co.,Ltd
Email: info@cxrefractories.com
Website:http://www.cxrefractories.com

Refractory bricks used for different parts of blast furnace

 Blast furnace is the main equipment for ironmaking, and clay brick is the earliest furnace lining material used in blast furnace. Blast furnace has the advantages of large output, high productivity and low cost, which is unmatched by other ironmaking methods.

The refractory materials and refractory bricks used in diffreent parts of blast furnace are as follows.

(1) Furnace hearth
One of the main functions of furnace hearth is to hold molten iron safely. The hearth refractory material must be stable enough when the temperature is highter than 1500 ℃. So for furnace hearth bottom, we need to choose carbon brick which has the advantages of anti-molten iron penetration, good melting, alkali resistance erosion, good thermal conductivity. And we can use small carbon brick to take the place of large carbon block, or construct ceramic rings on the carbon bricks.

(2)Tuyere zone and bosh
Temperature in tuyere area and furnace bosh is the highest in the blast furnace. The hot gas temperature produced in front of the tuyere rises at a high speed, the temperature can reach 1600 ℃ and higher. When 1450 ~ 1550 ℃molten iron and slag flow furnace hearth and finally flow to the furnace bosh, there will be a variety of metallurgical reactions happen in this area violently. Those two areas need refractory materials with characteristics of good resistance to high temperature and slag erosion, good alkali resistance, anti carbon dioxide and anti water oxidation. China refractory bricks we can use in this area are corundum brick, alumina carbon brick, hot pressed semi-graphite carbon brick, SiC brick and so on.

(3)Furnace bosh and lower furnace stack
The lower furnace stack is the position of root cohesive zone where the temperature is quite high, but slag layer or stable slag layer self protection can not be formed. This are need ds refractory materials which can bear severe temperature fluctuations, and also has advantages of alkali metal erosion, zinc erosion, carbon monoxide erosion, etc. What’s more, refractory materials used in furnace bosh and lower furnace stack should have good thermal shock stability, high temperature resistance, good alkali resistance and other properties. Refractory bricks can be used in these two areas are high alumina brick, corundum brick, alumina carbon brick, SiC brick and so on.

(4)The middle and upper part of furnace stack
The furnace stack middle part’s temperature is lower than that of furnace stack lower part. People genarally use high alumina brick, corundum brick and silicon carbide in furnace stack middle part. The temperature in furnace stack upper part is relatively lower than other parts, and it mainly affected by the wear and impact of the burden, alkali metal, zinc and carbon deposition erosion. This area requires refractory material has advantages of good wear resistance, good alkali resistance and good thermal shock stability. Refractory bricks can be used in this area are clay brick, high alumina brick, sillimanite brick, corundum brick. There is a trend that cooling walls are taking the place of refractory bricks used in blast furnace.

Article Source:Refractory bricks used for different parts of blast furnace
Company name:Henan Xinmi Changxing Refractory Materials Co.,Ltd
Email: sales1@chinafirebrick.com
Website:http://www.chinafirebrick.com/

The advantages and use of chrome corundum brick

 Chrome corundum bricks refer to corundum refractory products containing Cr2O3. At high temperatures, Cr2O3 and Al2O3 form a continuous solid solution, so the high temperature performance of chromium corundum products is better than pure corundum products. The chromium corundum bricks used in the gasification furnace of the petrochemical industry should be of low silicon, low iron, low alkali, high purity, and also have high density and strength. In the most widely used chromium corundum products, the content of Cr2O3 is mostly in the range of 9%~15%. The main mineral composition is α-Al2O3-Cr2O3 solid solution. The secondary mineral composition is a small amount of composite spinel (or no composite spinel), refractory bricks with a chromium oxide content of 1% to 30%. There are two types of cast chromium corundum bricks and sintered chromium corundum bricks. In general, chromium corundum brick refers to sintered chromium corundum brick.

In high purity corundum material add Cr2O3, no matter how much the amount, not only will not reduce the fire performance of materials，can make refractory performance of material improved. We Changxing Refractory Material Co.,LTD is professional manufacturer and supplier of refractory materials for more than 30 years. Our high quality 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!

Article Source: The advantages and use of chrome corundum brick
Company name: Henan Xinmi Changxing Refractory Materials Co.,Ltd
Email: info@cxrefractories.com
Website:http://www.cxrefractories.com

Erosion of magnesia carbon brick in the ladle furnace

In the ladle, due to the complex physical and chemical environment of the slag line, the furnace lining is the most vulnerable to damage. The chemical attack of steel slag on the magnesia carbon brick is mainly through the dissolution of magnesia and the oxidation of the graphite in the brick body. Under the combined action of two factors, the magnesia carbon brick is damaged.

1. The effect of alkalinity: the lower the alkalinity of the slag, the more beneficial it is to the erosion of magnesia-carbon bricks. The increase in alkalinity of the slag will reduce the activity of FeO in the slag, and the decrease of FeO activity will lead to the diffusion capacity of FeO.

2. The influence of MgO: Osbom et al. found that the MgO content in the reaction layer of the residual bricks of the LF slag line is very high. When the MgO content in the slag is low, it will affect the refractory magnesia carbon brick. The erosion rate of bricks is very large, and the lower the alkalinity, the faster the erosion of magnesia carbon bricks.

3. The influence of Al2O3: Al2O3 in the slag will reduce the melting point and viscosity of the slag, which greatly increases the penetration and erosion of the magnesia carbon brick by the slag, and can also corrode the magnesia from the magnesia grain boundary, making periclase Dissociate.

4. The influence of FeO: Firstly, FeO in the slag easily reacts with the graphite in the magnesia carbon brick at high temperature, and produces bright white iron beads to form a decarburized layer as shown in Figure 1. Secondly, the magnesia will interact with the graphite in the slag. FeO will form a low melting point of rich magnesium. AT&S believes that in the process of repeated heating and cooling of the ladle, due to the phase transformation between the magnesium richite and the mafic ore accompanied by the volume change, the magnesia on the working surface will crack, which will lead to the formation of magnesia. Dissolution, foreign studies believe that the increase in iron content in steel slag is detrimental to the life of ladle magnesia carbon bricks. First, iron oxides accelerate the oxidation of graphite, and secondly, it increases the solubility of MgO in the slag and accelerates the dissolution of periclase. The combined effect of the two is the erosion of magnesia carbon bricks.

Article Source:Erosion of magnesia carbon brick in the ladle furnace
Company name: Henan Xinmi Changxing Refractory Materials Co.,Ltd
Email: info@cxrefractories.com
Website:http://www.cxrefractories.com

The greenization of refractories for the cement industry

 Refractory is important, necessary and basic material for high temperature industry. It can’t be health development without the technological progress and innovation of refractory materials.

The state of ministry of industry and informatization. Ministry of Science and Technology and Environmental Protection Department clearly put forward that using the chrome free alkaline refractory to replace of chrome refractory.

America has stopped using the chrome?refractory. Japan also has used other material instead of magnesia chrome bricks. In our country, magnesia alumina spinel, magnesium iron spinel and iron magnesium aluminum spinel brick have successfully used? in large new dry process cement rotary kiln sintering zone and transition zone . The service life of these bricks has reached or exceed the magnesium chrome bricks. The greenization of refractory has become an important development strategy for the sustainable development of the industry.

We Changxing Refractory Material Co.,LTD is professional manufacturer and supplier of refractory materials for more than 30 years. Our high quality 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!

Article Source:The greenization of refractories for the cement industry
Company name: Henan Xinmi Changxing Refractory Materials Co.,Ltd
Email: info@cxrefractories.com
Website:http://www.cxrefractories.com