How to build a round refractory brick furnace lining? How many options are there for building a round refractory brick furnace lining? Arc brick? Curved mother-in-law buckle brick? Knife brick? The following suggestions are given by experienced manufacturers and sales of refractory bricks, as well as the construction team of refractory brick linings.
Arc High Alumina Bricks
Arc High-Alumina Refractory Bricks for Ladle Lining
The arc of the arc brick is a semicircle, and the other end is a groove, which can be flexible no matter how thick it is. Because it has no axis and the size is slightly deviated, it can also be built into a circle, so it is called arc brick. This kind of brick is used more in ladles. Curved high-alumina refractory bricks are mainly used as the lining of steel drums. In the past, it was mainly clay, but now it is gradually replaced by high alumina bricks. High-alumina arc brick is an aluminum silicate refractory material with an alumina content of more than 48%. It is formed and calcined from bauxite or other raw materials with high alumina content. High thermal stability, and refractoriness above 1770°C. Good slag resistance.
According to the usage, we believe that high alumina arc bricks have the following advantages.
High service life, more clinker clay bricks increase by 210%.
The reduction of unit consumption also shows the characteristics of high alumina arc bricks. The reduction of unit consumption can explain the corresponding reduction of non-metallic inclusions in molten steel.
Check that the cross-section of high-alumina bricks has better corrosion resistance to slag and molten steel than multi-clinker clay bricks.
Due to the roundness at both ends of the arc-shaped refractory brick, it can be moved back and forth to adjust the roundness when laying bricks. Therefore, it is convenient to build refractory bricks, and the brick joints can generally reach 1 mm.
The vertical joints of arc bricks are smaller, which is 70% less than that of standard refractory bricks. In this way, the erosion of the molten iron layer moving up and down and deep into the brick joints is corrected.
Due to the improvement of the quality of refractory bricks, the thickness of the lining bricks can be reduced, and the capacity of the steel drum can be increased accordingly.
Due to the long service life and the convenience of bricklaying, the labor required for laying steel drums behind the furnace is reduced, and the utilization rate of steel drums is increased.
Option 2: Masonry with arc-shaped mother-in-law buckle bricks
The arc-shaped letter buckle refractory brick has a small semicircular protrusion at one end and a small groove at the other end. Compared with arc bricks, the masonry is stronger and the gaps are smaller, but the disadvantage is that there is no arc bricks that can change the arc at will. There is no arc brick for the masonry of circular furnace linings with different inner diameters. The curved letter buckle is also made of clay or high alumina, and the performance of high alumina is the overall clay refractory brick.
Knife Bricks also Called Ax Bricks for Refractory Lining
Option 3: Laying bricks with knife bricks or ax bricks
It can be built with knife bricks T38 and T39, or with ax bricks T19 and T20.
Rongsheng refractory brick manufacturers can provide high-quality masonry refractory bricks for circular refractory linings in various materials. Free consultation, info@aluminabricks.com.
High-aluminum low-cement castable is a castable with a large number of monolithic refractories. That is to say, the addition of calcium aluminate cement is about one-half or one-third of the ordinary cement castable.
Compared with ordinary high-alumina castables, high-alumina, and low-cement castables use ultra-fine powder to reduce the amount of cement and greatly improve the strength and erosiveness of low-cement castables. While increasing the bulk density and reducing the porosity, the service life is increased.
High-alumina and low-cement castables are used in industrial furnaces such as metallurgy, petroleum and petrochemical, electric power, and building materials. A large part has replaced refractory bricks, but as a manufacturer of low-cement castables, we still use different furnace types and temperatures according to users. According to the requirements of different use environments, some high-alumina and low-cement castables with different levels and different body densities are produced. Of course, the prices of different levels, different body densities, and low-cement castables are also different.
The characteristics of high-alumina and low-cement castables are also based on different grades of refractory micro-powder, different grades of main materials, and different grades of bonding agents to determine the quality of the product. In order to facilitate smaller particles, larger specific surface area, and better sintering ability, the castable is more suitable for the working needs of the user’s high-temperature kiln.
In the practical application of low-cement castables, especially in construction, it is also very important to control the amount of water added. Generally, when leaving the factory, the manufacturer will attach the construction instructions for the castable. During construction, it is necessary to strictly follow the construction instructions, and pour and maintain the castable well, so as to exert its maximum effect.
All in all, regardless of production or application, it is necessary to take into account the different effects of temperature, erosion, erosion, etc. on the refractory lining material according to the actual use. Only in this way can the refractory castables used be selected correctly, and with the appropriate construction technology, the service life of the refractory lining can be greatly extended. Save production costs.
The Difference between LCC Refractory Castable and Ordinary Refractory Castable
Low-cement castables, ultra-low or no-cement castables replace most or all of the cement with superfine powders that have the same or similar chemical composition as the main material. It is formulated by scientifically optimizing particle gradation, micro-powder, particle shape, and other factors, and adding a small amount of dispersant (water reducer) and an appropriate amount of retarder and other compound admixtures.
Compared with ordinary refractory castables, the low cement castable series has many excellent properties.
(1) Less water consumption. The water consumption of LCC low-cement castables is only 1/2-1/3 (about 5-7%) of ordinary refractory castables. Therefore, the bulk density is high, the porosity is low, and there is no obvious dehydration stage during baking. Good thermal shock performance, comparable to fired products.
(2) Because the amount of cement is greatly reduced, the high-temperature performance and slag resistance of the material are improved.
(3) There are few or no hydrates after forming and curing, and there is no hydration bond damage during baking to affect the medium temperature strength. Therefore, no matter at medium temperature or high temperature, its strength does not decrease but increases.
The main application of LCC low cement castable is suitable for petroleum, metallurgy, the chemical industry, and various silicate kilns. Such as some components of the refining device outside the furnace, the cover of the refining ladle outside the furnace, the integral spray gun for molten iron, the treatment of molten steel, and the roof lining of the electric furnace. Soaking furnace, heating furnace, annealing furnace lining, tapping trough. Tundish lining, high-temperature burner, blast furnace tapping ditch cover, ladle lining, etc.
The refractoriness of low-cement refractory castables is greater than 1790°C, and the load softening temperature (4% deformation) at 0.2MPa is 20-100°C higher than that of CA50 cement refractory castables. Therefore, the service temperature of low-cement refractory castables is generally about 100°C higher than that of CA50 cement refractory castables of the same material. The thermal expansion coefficient of low cement refractory castables shows the characteristics of expansion during the whole heating process. It can be seen that as the heating temperature increases, the thermal expansion rate increases, and reaches the highest value at 1250 ° C, which is about 0.68%. Then it began to shrink slowly, and the thermal expansion rate was 0.43% at 1400°C. When the temperature was 1500°C, the thermal expansion rate returned to 0.5%.
Low cement and ultra-low cement refractory castables refer to castable refractory materials with calcium aluminate cement added less than 8%. According to the US ASTM regulations, the CaO content in low-cement castables is required to be less than 2.5%, generally 1.0-2.5. When the CaO content is less than 1%, it becomes an ultra-low cement castable. The materials of low-cement and ultra-low-cement castables include clay, high alumina, mullite, corundum, carbon and silicon carbide, etc. Its ingredients are composed of refractory aggregate, refractory powder, an appropriate amount of superfine powder, an appropriate amount and small amount of calcium aluminate cement (delayed coagulation accelerator), and a trace amount of dispersant (high-efficiency debonding agent). Generally, multi-level ingredients are used, which are divided into 5~3mm, 3-1mm, 1~0.2mm, 0.2~0.074mm, 0.074~0.044mm, and less than 1 micron.
Mullite low-cement castables can be used as inner linings of various high-temperature burners, dressing linings of water-cooled pipes of heating furnaces, etc. Corundum and chromium-containing corundum low-cement refractory castables can be used as the lining of the triangular area of the top of the steelmaking electric arc furnace and the lining of some parts of the refining device outside the molten steel furnace. Such as integral spray gun lining for spray metallurgy, RH and DH vacuum degassing device and dipping tube lining, power frequency induction furnace lining, the high-temperature wear-resistant lining of a petrochemical catalytic cracking reactor, etc.
Al2O3-SiC-C low-cement castables are used as linings for blast furnace tapping troughs, iron furnace tapping troughs, and integral spray guns for molten iron pretreatment.
MgO-Al2O3 or Al2O3-MgO·Al2O3 low-cement castables are used as linings for ladles and tapping troughs.
Blast furnace technology is a critical aspect of the iron and steel production process. This highly specialized technology requires various components, including checker bricks, to operate at optimal performance. Checker bricks are a unique type of refractory material that plays a vital role in enhancing the performance of blast furnaces. In this essay, we will explore the importance of using high-quality checker bricks to maximize blast furnace performance.
Checker bricks are named after their unique checkered pattern. They are typically used in the lower portion of the blast furnace where they serve as a lining material. Checker bricks consist of a combination of carbon, silicon carbide, and alumina, which gives them high-temperature resistance and durability. They are designed to withstand extreme temperature and pressure conditions in the lower portion of the furnace and play a crucial role in enhancing the efficiency and productivity of blast furnace operations.
How to Maximize Blast Furnace Performance with Quality Checker Bricks?
One of the key benefits of using quality checker bricks in blast furnace construction is their ability to improve thermal efficiency. The lower portion of the blast furnace experiences some of the highest temperatures and pressures in the entire iron production process. Checker bricks help to regulate and control the flow of hot gases and materials through the furnace, ensuring optimal heating and combustion conditions. By regulating the flow of materials, checker bricks help to minimize heat loss and maximize thermal efficiency. This results in significant energy savings and improved overall blast furnace performance.
Another important benefit of using quality checker bricks is their ability to reduce downtime and maintenance costs. Blast furnace downtime can be costly, resulting in lost production and revenue. Checker bricks that are of poor quality or not designed for the specific conditions of the blast furnace can fail prematurely, requiring frequent replacement and maintenance. High-quality checker bricks are designed to withstand the extreme conditions of the blast furnace, minimizing the risk of failure and reducing downtime and maintenance costs.
Furthermore, quality checker bricks can help to improve the overall quality of iron production. The checker brick lining plays a vital role in ensuring that the blast furnace operates at optimal conditions, which results in high-quality iron production. Checker bricks help to regulate and control the flow of materials through the furnace, ensuring that the iron produced is of consistent quality and purity.
Checker Refractory Bricks Used in Blast Furnace
Checker bricks, checker refractory bricks blast furnace, is a checker brick with many advantages such as strong heat exchange ability, large heat storage area, smooth ventilation, and low resistance, which is generally recognized and accepted by the ironmaking industry in the world. Checker brick is a heat transfer medium used in the blast furnace regenerator. It is usually arranged in an orderly manner in the regenerator, plays a heat storage role during the “burning period”, and heats the cold air into hot air through convective heat exchange and radiation heat exchange during the “air supply period”.
At present, checker bricks, checker bricks blast furnaces, and checker bricks are mainly used in blast furnaces hot blast stoves, and flame furnaces. Checker bricks are mainly used in the regenerator of the hot blast stove. Checker bricks with grid holes in a certain structure are arranged in an orderly manner, and the upper and lower through holes of the checker bricks allow gas to pass through. According to the technical requirements of different temperature regions, silicon checker bricks, and clay bricks are generally used. In some hot blast stoves, there are also high alumina bricks, mullite bricks, sillimanite bricks, etc. to choose from. The function of the hot blast stove is to heat the cold air sent by the blower to the blast furnace into hot air. Then, the hot air is sent to the blast furnace through the hot air pipe for a combustion reaction. The blast furnace hot blast stove has a furnace firing period and an air supply period, and the rotation of the two task periods. During the firing period, the extinguished low-temperature flue gas passes through the holes of the checker bricks of the hot blast stove and transfers heat to the checker bricks. During the air supply period, the cold air from the blower enters the hot blast stove, is heated by the checker bricks to become hot air, and is sent to the blast furnace through the hot air pipe.
Clay bricks for hot blast stoves belong to a secondary category of silicon-aluminum series products. They are refractory products with an Al2O3 content of 30-48% made of clay clinker as aggregate and refractory clay as a binder. The refractoriness of clay bricks is comparable to that of silica bricks, as high as 1690-1730°C, but the load hardening temperature is more than 200°C lower than that of silica bricks.
In conclusion, maximizing blast furnace performance requires the use of high-quality checker bricks. These specialized refractory materials play a crucial role in improving thermal efficiency, reducing downtime and maintenance costs, and ensuring high-quality iron production. The use of quality checker bricks can result in significant energy savings, increased productivity, and improved overall blast furnace performance. It is essential to select the right type of checker bricks that are designed for the specific conditions of the blast furnace and to ensure that they are properly installed and maintained. By doing so, blast furnace operators can ensure optimal performance and maximize the efficiency of their iron production process. Buy refractory bricks used in blast furnace from Rongsheng.
High Alumina Anchor bricks are one of the most efficient materials used in high-temperature furnace linings. These materials are highly durable and provide an excellent heat-resistant environment for the operation of the furnace. High alumina anchor bricks are also called hanging bricks. It is mainly used to connect and support the structure of refractory bricks and ordinary fired bricks. It is used for heating the furnace top, furnace wall, or other parts.
High alumina anchor bricks are composed of special alumina-containing clay, followed by a high alumina anchor brick with an alumina content above 55%. The high aluminum content ensures excellent insulation and thermal shock resistance. Rongsheng high-alumina anchor bricks use natural high-grade bauxite as the main refractory raw material, add soft or semi-soft clay as a binder to the high-alumina clinker to start batching, mixing, then molding, drying, and finally firing. Shaped high alumina refractory bricks. High alumina anchor bricks can be customized for production and processing according to customer needs. The load softening temperature of the high-alumina anchor brick reaches 1550°C, which can meet the performance requirements of the furnace roof lining.
Benefits of Using High Alumina Anchor Bricks in High-Temperature Furnace Linings
High alumina anchor brick is a special-shaped high alumina refractory brick. The benefits of high aluminum anchor bricks compared to other materials are numerous. First of all, judging from the shape of the high-alumina anchor brick, it is a column composed of the hanging end and the anchor. Grooves are distributed at intervals on the surface of the anchor body. In addition, ribs are provided along the length direction on at least one surface of the anchor. Due to the reinforcement and pulling effect of the ribs, the tensile and flexural strength of the anchor body is significantly improved. Therefore, the stress generated at the groove is blocked at the rib and cannot continue to be transmitted, so the high-alumina anchor brick in High-Temperature Furnace Linings is not easy to break.
The benefits of high alumina anchor bricks compared to other materials are numerous. Firstly, they have excellent refractory properties, meaning they can withstand extremely high temperatures and provide the necessary insulation for the furnace. In addition, their compressive strength is very good, enabling them to withstand the huge loads in the furnace linings. Furthermore, their chemical composition helps retain their dimensional stability, making them excellent for linings with long service life. Such as the following listed characteristics.
Characteristics of High Alumina Anchor Brick for Heating Furnace
High-alumina anchor bricks refer to high-alumina refractory bricks with a specific shape that is installed on the steel structure of the industrial kiln shell or supporting the furnace lining and embedded in the refractory lining for anchoring and connection. At room temperature, a bar-shaped sample with a certain size is loaded according to the specified conditions, and the ultimate tensile stress per unit area can withstand it before fracture.
In summary, high alumina anchor bricks are a great choice for creating high-temperature furnace linings. They are highly durable, resistant to corrosion and thermal shock, and environmentally friendly. They are ideal for applications requiring extended service life and reduced maintenance costs. And, since they are made of natural materials, they are an excellent choice for implementing environmentally friendly construction methods.
High Alumina Anchor Bricks for Wall and Top of Industrial Furnace
High Alumina Anchor Bricks from Rongsheng Manufacturer
Rongsheng high aluminum anchor bricks use in high-temperature furnace linings. High-alumina anchor bricks are refractory bricks for the furnace roof and wall of the heating furnace. Rongsheng alumina refractory brick manufacturers can customize processing according to the size of high alumina anchor bricks provided by customers, also the refractory anchors with different shapes. In order to meet the high alumina bricks furnace lining requirements of the heating furnace and ensure the service life of the heating furnace lining, the index parameters can also be customized according to the actual working conditions of the customer’s kiln. In order to finally meet the economic benefits of improving the heating furnace.
The working temperature in the furnace of the incinerator burning hydrogen sulfide is about 1150 ℃, and the working conditions are harsh. It belongs to an acidic combustion atmosphere, but the temperature of the furnace will reach 1400 ℃ due to the fluctuation of materials and air volume in actual production. The amount of hydrogen sulfide gas is very unstable, and every combustion fluctuation in the furnace is a big thermal shock to the furnace lining.
And this kind of acid gas furnace lining is made of refractory materials, so it is very important to resist acid corrosion and thermal shock stability. The main body of the furnace can adopt a three-layer structure. Corundum mullite bricks should be used for parts that are in direct contact with the flame. It is characterized by strong wear resistance and corrosion resistance. The middle layer can choose three grades of high alumina bricks. Because the working layer does not directly contact the flame, the flexibility of the three-grade high-alumina brick is relatively good. The outer layer can be used as an insulation layer, and high-aluminum heat-insulating refractory bricks are used to keep the temperature down and reduce the temperature of the outer wall of the steel shell.
Corundum mullite brick is a refractory product composed of mullite as the main crystal phase and corundum phase, which is sintered at a high temperature of 1650-1750 °C. It has good high-temperature strength, high-temperature creep resistance, thermal shock resistance, and corrosion resistance.
The third-grade high-alumina brick is a series of aluminum products made of high-alumina raw materials and clay as a binder fired at a temperature of 1400°C. High thermal stability, and strong flexibility.
Lightweight high alumina brick. It has the characteristics of small bulk density, large porosity, low thermal conductivity, and specific heat capacity, and has good thermal insulation performance for heat insulation layers. In the case of slow heat dissipation, it can save fuel and reduce the temperature of the steel shell.
The incinerator burning hydrogen sulfide is one of the rare furnace types, so the corundum mullite brick in the refractory brick used for its refractory lining is a high-grade refractory material. High-alumina bricks are neutral materials, and lightweight high-alumina bricks are used as a three-layer masonry lining to effectively improve the corrosion resistance of the incinerator. The refractory mortar of the same material is used for masonry during construction to ensure the long-term safe and reliable operation of the incinerator.
The steel ladles are the necessary equipment for receiving molten steel and for continuous casting. Because many steel grades need to be refined in the ladle, including argon blowing temperature adjustment, alloy composition fine-tuning, powder spray refining and vacuum treatment, etc. The working conditions of the ladle lining are getting worse and worse, and its working environment is.
(1) The temperature of molten steel is higher than that of the die-casting ladle.
(2) The residence time of molten steel in the ladle is prolonged.
(3) The inner lining of the ladle volatilizes itself under a high-temperature vacuum and undergoes the stirring effect of molten steel.
(4) The impact of the lining when it accepts molten steel.
(1) High-temperature resistance. Can withstand high-temperature molten steel for a long time without melting and softening.
(2) Thermal shock. Can withstand repeated loading and unloading of molten steel without cracking and peeling.
(3) Corrosion is resistant to slag. Can withstand the erosion effect of slag and slag basicity changes on the lining.
(4) It has sufficient high-temperature mechanical strength. Can withstand the stirring and scouring of molten steel.
(5) The lining has a certain degree of expansion. Under the action of high-temperature molten steel, the inner linings are in close contact and become a whole.
Commonly Used Refractory Materials for Ladles
The bottom layer of the ladle. Clay bricks, also known as fired bricks. Clay bricks are made of clay (including shale, coal gangue, and other powders) as the main raw material, which is processed, shaped, dried, and fired with mud. There are solid and hollow.
Ladle working layer, high alumina brick. Among the refractory materials produced with aluminum-silicon-based raw materials, the bricks with Al2O3 as the main component are high-alumina bricks, mullite bricks, and corundum bricks.
The main body of the ladle is poured. Castable refers to the mixture composed of refractory aggregate, binder, and admixture, which is mixed with water (or liquid binder) to form mud that can be constructed by the pouring method. The difference from other unshaped refractories is that refractory castables have a certain setting and hardening time after construction. Therefore, after casting and molding, it needs to be cured for a certain period of time before it can be de-molded, and then it can be put into baking after an appropriate period of natural curing.
Ladle wall. Unburned bricks are also known as chemically bonded bricks. It refers to the refractory material that can be directly used for masonry without firing. The production process is relatively simple, it is made of refractory materials of different materials, and the combination of powder and granules in the product is mainly formed by the chemical action of the binder.
If the ladle is also used for refining, refractory materials that can also be used include zircon bricks, magnesia carbon bricks, magnesia carbon bricks, magnesia chrome bricks, magnesia chrome aluminum bricks, and the like.
Improvement of High Alumina Bricks Used in Refining Ladle
Modern refining ladles use natural andalusite and bauxite to produce high-alumina bricks. Compared with bauxite, the former has higher purity and thermomechanical stability (such as thermal strength). Because it contains more SiO2, it has poor corrosion resistance. Especially under the condition of alkaline slag, the lining of high-alumina brick masonry refining ladle produced with bauxite clinker as the main raw material has the following shortcomings and is being eliminated.
①Due to the volume shrinkage, the molten steel and slag are seriously penetrated and eroded, especially a thick slag layer formed at the brick joints.
②Due to the inherent brittleness of the brick itself and its structure, the ladle lining forms a thicker erosion zone and a slag layer.
③ Due to the inherent wettability of the lining to molten steel and slag, the erosion and penetration of the slag are more serious, and flake spalling occurs.
In order to overcome the above shortcomings of high-alumina bricks lined with a refined ladle, Al2O3-MgO-C bricks were developed to replace them. Compared with high alumina bricks, Al2O3-MgO-C bricks have the following advantages:
(1) Good high-temperature resistance and tissue peeling resistance;
(2) Good corrosion resistance to molten steel and slag;
(3) Good residual expansion, even at higher temperatures, no cracks appear at the joints of the bricks.
Because, when the temperature is higher than 1650°C, the high-alumina bricks show obvious shrinkage, which will lead to the penetration of molten steel and slag into the brick joints. Different from high alumina bricks, Al2O3-MgO-C bricks will not shrink in the continuous casting temperature range (1650~1670℃).
Ladle Refractory Materials Manufacturers
Rongsheng refractory material manufacturer is a manufacturer of technical refractory lining material solutions with rich production and sales experience. Our excellent technical team specializes in solving the problem of refractory lining of high-temperature furnaces, including various ladle refractory problems. At the same time, our refractory brick production line and monolithic refractory production line are also the strong support of our team. From our customer base in more than 80 countries around the world, it is not difficult to see the strength of our team. Become a customer of Rongsheng Refractory Factory for free, our customer service will not let you down.
There are many types of refractory castables, and the uses of each refractory castable are also different. Such as corundum wear-resistant refractory castables, low-cement refractory castables, lightweight heat-insulating refractory castables, and steel fiber refractory castables. Castables refractory for circulating fluidized bed boilers are mainly high-strength wear-resistant castables. Among them, corundum refractory castable has the characteristics of high strength and good fluidity, which is convenient for construction. It is mainly used for the parts that are easy to be washed and wear, such as the combustion chamber, separator, and flue of a circulating fluidized bed boiler.
Selection of Castable Refractory for Circulating Fluidized Bed Boilers and Precautions for Use
Selection of refractory castables and refractory plastics for circulating fluidized bed boilers. Taking the 75t/h circulating fluidized bed boiler as an example, the main refractory materials used are corundum wear-resistant plastics, diatomite thermal insulation castables, high-strength wear-resistant castables, phosphate refractory castables, lightweight thermal insulation bricks, diatomite thermal insulation bricks, refractory bricks, etc.
Among them, the wear-resistant layer at the lower part of the furnace and the outlet of the furnace are mainly made of corundum wear-resistant plastic. The inlet flue and target area of the separator use high-strength wear-resistant castables. The separator cylinder and cone are made of lightweight thermal insulation bricks, and the surface is made of high-strength wear-resistant castables. Phosphate refractory castables are used for air distribution devices, ignition air ducts, and furnace doors. Diatomite insulation bricks and refractory bricks are mainly used for the heating surfaces of the tail.
Precautions when using refractory castables and refractory plastics for circulating fluidized bed boilers.
Clean water must be used, and the amount of water added is 6% ~ 8%.
Use a forced mixer, and all mixing tools must be cleaned. Mix until homogeneous. When stirring, the amount of material added should not be less than the whole package. Dry mix for 15min before adding water to achieve the purpose of mixing evenly.
The castable is reinforced with a large number of anchoring nails and the metal surface of the boiler. The anchoring nail is a metal material, and the thermal expansion coefficient is much larger than that of the refractory material, so the anchoring nail needs to be preheated before installation.
The pouring surface of all molds should be coated with a layer of oil.
Each batch of materials must be poured within 10 to 30 minutes after mixing. It needs to be poured to the specified thickness at one time and then vibrated until it is completely sealed.
The mold is demolded 24 hours after pouring, and the total curing time is 3 days.
How to remedy the falling off and cracking of castable refractory for circulating fluidized bed boilers?
During the operation of the circulating fluidized bed boiler, some castable refractory for boiler will fall off and crack. This part of the pipe is more prone to wear than other places because most of it occurs in the dense phase area such as the refeeder and below the water cooling screen. When this happens, the usual approach is to repair with refractory castables or plastic refractories. When repairing, the repairing materials should be mixed and stirred first, and then suitable templates and molds should be made at the repaired part. Finally, pour and repair. The repaired material should be basically cured and formed, and then gradually baked according to the heating curve. This repair method is time-consuming, labor-intensive, and quite uneconomical. If it is repaired with blue mud, it can be ignited immediately after construction, which saves time and effort, and is convenient and quick.
Monolithic Refractory Construction for CFB Boiler
Use special tools to repair the dropped boiler refractory castable to right-angle subsidence of not less than 20 mm, that is, the repair thickness is not less than 20 mm. Clean the repaired area with a brush, slice the blue mud, and stick the new side on the repaired area. Then ram it with a rubber hammer to make it firmly combine with the original refractory castable to form a flat surface.
If the refractory castable falls off and exposes the pin, it can be repaired by cutting it into pieces with blue mud and tamping and compacting. If the drop area is not large, it can be completed in ten minutes before and after. The practice has proved that repairing refractory castables with blue mud is much better than repairing refractory castables with other methods.
What boiler linings are refractory castables generally used for?
The main application scenarios of castable refractory for boilers, power generation boilers, heating boilers, waste incinerators, and other industrial kilns. Specific applications of refractory castables for boilers are as follows.
Water-cooled wall, cyclone separator, furnace, economizer, water-cooled air chamber, slag removal machine, cold ash bucket, etc. in the power generation industry.
In the lining of boiler equipment such as civil boilers, biomass boilers, steam boilers, chain furnaces, pulverized coal furnaces, etc.
Heating furnaces, soaking furnaces, forging furnaces, ladle furnaces, trolley furnaces, etc. in the foundry industry.
Rongsheng refractory material manufacturer, environmentally friendly and advanced automatic unshaped refractory castable production line, with an annual output of tons. Can provide refractory castable lining materials for various industrial boilers. In addition, we can also provide high-quality refractory and wear-resistant plastics, refractory ramming materials, etc. It is matched with the high-quality refractory castable binder produced by Rongsheng, aluminum dihydrogen phosphate. Unshaped refractory lining materials can be formulated with the advantages of strong wear resistance, corrosion resistance, air erosion resistance, high strength, and stable performance. Improve the service life of boiler refractory castable lining. Rongsheng can also design various economical and practical unshaped refractory linings for boiler linings according to the needs of customers and the actual working conditions of boilers. Contact us for free samples and quotes.
In the refractory castable combined with calcium aluminate cement, the castable with CaO content less than 2.5%, that is, the castable with calcium aluminate cement added about 1/2 to 1/3 of the ordinary calcium aluminate cement castable, It is called low cement castable. Low cement castable materials are clay, high alumina, mullite, corundum, chromium corundum, zircon mullite, zirconium corundum, alumina-spinel, and carbon and silicon carbide, and many more. According to its operating performance, it is divided into vibrating castable and self-flowing castable. Rongsheng refractory manufacturer will introduce the above two different types of low-cement refractory castables for you.
Two Different Types of Low Cement Castable Composition
The ingredients of vibrating low cement castables are generally: refractory aggregate 60% ~ 70%, refractory powder 18% ~ 22%. Calcium aluminate cement 3% to 7% (low cement type) or 1% to 2% (ultra-low cement type). Silica (soot silica) micro powder (or reactive alumina micro powder) 3% ~6%. Trace dispersant. The particle size composition can be according to Andreassen’s particle size distribution equation, and the q value is 0.26 ~ 0.35.
The batching composition of the self-flowing low-cement castable is similar to that of the vibrating low-cement castable, but the particle size composition and fine powder content are different. Generally, the maximum critical particle size of aggregate is not more than 6 mm, and the particle size distribution is in accordance with the Andreassen or Dinger-Funk particle size distribution equation. The value of the particle size distribution coefficient q should be controlled between 0.21 and 0.26, and a larger self-flow value (greater than 180) can be obtained between this value. When the q value is greater than 0.26, the flow value becomes smaller, and it is difficult to cause self-flow. When the q value is less than 0.21, the powder content is too large, which will affect the physical properties of the castable. The content of micro powder (silica micro powder) in the particle size composition is generally 5% ~ 6%. At the same time, high-efficiency dispersants must be used.
Low Cement Castable Refractory Material Application
Low cement castable refractory materials have a wide range of applications. In metallurgy, petrochemical, machinery manufacturing, electric power, building materials, and other industrial kilns, such castables have been widely used to replace some traditional fired refractory brick products as linings. Vibration-type low cement castable refractory materials are mainly used as thick-sized linings. Such as heating furnace, various heat treatment furnace electric furnace cover shaft kiln, rotary kiln, blast furnace tapping channel, ladle, hot metal ladle, etc. The self-flowing low cement refractory castables are mainly used as thin linings and linings for high-temperature refractory components with metal anchors. Such as the outer lining of the water-cooled pipe of the heating furnace, the lining of the integral spray gun for jet metallurgy, the lining of the immersion pipe of the RH and DH vacuum degassing device, and the air supply element of the ladle (breathable brick). And the high-temperature wear-resistant lining of the petrochemical catalytic cracking reactor.
Rongsheng Refractory Castables Manufacturers’ Production Line
As one of the refractory castables, the unique advantages of low cement castables play an important role in refractory lining materials. Rongsheng refractory castable manufacturers have rich experience in production and sales. Its advanced environment-friendly and fully automatic unshaped refractory castable production line have an annual output of 80,000 tons. To provide our customers in more than 60 countries with high-quality refractory lining materials. For example, Russia, South Africa, Kazakhstan, Philippines, Chile, Malaysia, Uzbekistan, Indonesia, Vietnam, Kuwait, Turkey, Zambia, Peru, Mexico, Qatar, etc. Rongsheng used to customize low cement castables for customers, ultra-low cement castable, and high customer return rate. To obtain free refractory lining material configuration solutions for high-temperature kilns and solve difficult refractory lining material problems, please contact us. We will customize the refractory lining scheme for you according to your actual production situation.
Wear-resistant refractory materials are usually used under high-temperature conditions. Under high-temperature conditions, the erosion and abrasion of the materials produced by the kiln is an important factor that causes damage to the refractory materials in the lining of industrial kilns. Therefore, it is necessary to understand and master the erosion and wear resistance of the refractory materials selected. First, let us start to understand the wear resistance of refractory materials.
Wear Resistance of Refractory Materials
Many changes in the high-temperature wear resistance of refractory materials vary with temperature and material. It is also believed that the “higher strength, the more wear-resistant” of refractory material, this relationship will exist in similar materials, but this relationship does not necessarily exist between different types of refractory materials. For example, the wear resistance of corundum bricks with a compressive strength of 100MPa is weaker than that of high alumina bricks with a compressive strength of 86MPa. There is also the relationship between the wear resistance of refractory castables and their compressive strength and flexural strength. Some people believe that the higher the strength of high-aluminum castables, the smaller the wear. In practice, it is not found that such a relationship. In short, these are to give users a more comprehensive and in-depth understanding of the wear resistance of refractory materials.
Wear Resistance of Different Types of Refractories
Rongsheng refractory manufacturers have mastered some rules for their wear resistance in the production of refractory materials and studied the possible influencing factors through the wear resistance of refractory materials of different materials.
The wear resistance of different refractory materials is quite different. According to the abrasion resistance of various refractory materials, it can be roughly divided into three gradients. Silicon carbide refractories have the strongest wear resistance, high-alumina refractories and corundum refractories have intermediate wear resistance, and alkaline refractories, siliceous, and clay refractories have poor wear resistance.
Due to the large difference in alumina content of high-alumina refractories, the wear distribution range is wide. The higher the hardness of the mineral, the stronger its wear resistance. It can also be said that silicon carbide refractories have the least amount of wear. Therefore, wear-resistant and refractory materials are selected for some key corrosion parts. The bonding phase of silicon nitride combined with silicon carbide material has high hardness and high strength, and the bonding phase of refractory clay combined with silicon carbide material has a lower hardness of mullite and glass phase. Therefore, silicon nitride bonded silicon carbide materials have better wear resistance than clay bonded silicon carbide materials.
The wear resistance of high-alumina castables prepared with the same high-alumina bauxite material is better than that of high-alumina bricks, and the difference in wear between the two is about 60%-90%. Similarly, the wear resistance of clay castables will be better than that of clay bricks. The castable adopts micro powder technology and the density of low-cement castables is usually greater than that of the corresponding refractory bricks. Because the castable uses a larger particle size aggregate, and the proportion of the aggregate of the castable is larger, and the aggregate is usually denser and more wear-resistant than the matrix. In order to improve the wear resistance of the castable, the wear resistance of the castable is generally improved by adding silicon carbide.
Analysis of the Reasons for the Different Wear Resistance of Different Types of Refractories
Factors such as the type of crystal structure of different mineral phases and the size of the lattice energy cause the hardness of their minerals to be different. Atomic crystals of diamond, silicon carbide, and corundum have high Mohs hardness, while ionic crystals of spinel, mullite, periclase, and other hardnesses decrease in order. Graphite has the lowest Mohs hardness due to its layered structure composed of weak intermolecular forces. The higher the hardness of the mineral, the stronger its wear resistance. Therefore, silicon carbide material has a small amount of wear and is the most wear-resistant. Magnesia bricks, magnesia spinel bricks, and magnesia-chrome bricks with periclase as the main phase have a large amount of wear, most of which exceed 10cm³. The wear of graphite-containing aluminum-silicon carbide carbon bricks is relatively large, while that of aluminum-carbon materials with low graphite content or without graphite is relatively small.
The bonding phase of silicon nitride combined with silicon carbide materials has high hardness (Mohs hardness 9~9.5) and high strength. The mullite and glass phases of clay-bonded silicon carbide materials have a lower hardness. Therefore, silicon nitride bonded silicon carbide materials have better wear resistance than clay bonded silicon carbide materials. For the high alumina brick with 76% AL2O3 content and the third-grade high alumina brick with 58% AL2O3 content, the former has high corundum phase content, while the latter has high mullite phase content and low corundum phase content, so the former is more wear-resistant.
Rongsheng Unshaped Refractory Materials Production Line
To learn more about refractory materials, please continue to follow our blog. If you need to buy high-quality refractory castables, such as wear-resistant refractories, silicon carbide castables, corundum castables, please contact a strong and experienced refractory manufacturer. Rongsheng refractory material manufacturer has rich experience in the production and sales of refractory materials. Rongsheng has customers in more than 70 countries around the world, and customers continue to return orders. Moreover, Rongsheng Environmental Protection’s advanced and fully automatic monolithic refractory castables are produced first, with an annual output of 80,000 tons. The quality of Rongsheng’s refractory castables is guaranteed, and it has customer service that satisfies customers. Look forward to working with you.
For coke ovens that have been produced for many years, the single and main walls of the regenerator will crack, melt, deform or even collapse under the action of temperature and other factors. The checker bricks are easy to be blocked, and even deform and melt at high temperatures. When these defects seriously damage the heating system, the regenerator should be renovated.
Refurbishment of the regenerator will cause the increase and expansion of cracks in the single and main walls due to cold air entering the room, so this is generally not done. In the case of forced renovation, the internal masonry should also be protected from damage, and corresponding insulation measures should be taken. It is also necessary to insist on the continuous operation to shorten the refurbishment time, and when conditions permit, coke oven gas should be used to supply heat to the furnace.
Sampling View of Checker Bricks in the Regenerator
Due to the long-term workload, the checker bricks in the regenerator of the coke oven will melt and creep. When the situation is serious enough to affect the normal production of the coke oven, it needs to be replaced.
First of all, from the perspective of the creep checker bricks taken out of the coke oven regenerator, the damaged checker bricks have expanded volume, the loose internal structure of materials, and blocked holes. The severely damaged parts are concentrated in the upper part of the gas regenerator, generally, no more than three layers of bricks and the upper layer is the most serious. Moreover, the upper part of each checker brick is more creeping than the lower part. A factory sampled and inspected the clogged checker bricks, and the changes are shown in Figure 1.
Figure 1 Sampling of Clogged Checker Bricks
Figure 1 Sampling of clogged checker bricks in a factory
Replacement Measures of Checker Bricks in the Regenerator
Before construction, prepare all necessary tools and refractory materials and install temporary low-voltage lights. Use a special iron plate to cover the upper surface of the waste gas pan connected to the refurbished regenerator to prevent the scrapped bricks from blocking the exchange equipment.
In terms of production organization. During the repair, there will be one buffer furnace number adjacent to each other, and the furnace will not be drawn during the repair. The actual coking time of the repaired furnace number depends on the length of the repair time, the maturity of the coke cake, and the temperature of the combustion chamber. The coking time of the buffer furnace number is set at 36h, the second buffer furnace number is set at 30h, and the coking time difference between adjacent furnace numbers is more than 4h. In terms of furnace temperature management, the standard temperature for repairing furnace numbers and buffering furnace numbers should be lowered accordingly. If it is blast furnace gas heating, it needs to be temporarily stopped. In order to ensure that the furnace body in the combustion chamber area is not damaged, the adjacent units and coke sides are used at the same time, and the coke oven gas is intermittently heated, and the temperature should not exceed 1200°C. After the checker bricks are replaced, the coke oven gas is used to heat up for 2 to 3 hours when the temperature is raised, and then converted to blast furnace gas for heating. If there is no coke oven gas, the supply of blast furnace gas will be temporarily suspended during the maintenance period. The specific measures for the replacement of checker bricks in the regenerator are as follows.
①Before construction, compare the plan to be released. Select the coking time in the middle heat number, and remove the pressure measuring hole with a crowbar. For regenerators with heat shields and single (main) wall small furnace columns, the small furnace columns, beams, and heat shields should be removed before the masonry is removed. And close the corresponding blast furnace gas valve and the blast furnace gas valve on the adjacent machine and coke side. Disengage the mound rod from the exhaust gas stroke and adjust the opening of the exhaust plate flap.
②Pick off the wall tiles from the horseshoe cover, take out part of the checker tiles and continue to remove the sealing wall to the end. Hang the windshield above, insert an iron plate into the gap between the two layers of checker bricks under the replaced checker bricks, and block the chute with a thermal insulation fiber cloth.
③Use a single hook to remove the checkered bricks. If the checker bricks are tightly packed with the single and main walls or the checker bricks are melted together, the furnace head can be smashed with a crowbar and then pulled out, and the deep checker bricks can be smashed and taken out with a live joint flat shovel. As the checker bricks are pulled out, the iron plate gradually moves to the depths of the regenerator.
④ There is one layer of checkered bricks on the burner and fire channel, and wooden planks are laid on it, which is convenient for people to enter and remove. The checker bricks are stripped into a ladder shape, with 4 to 5 checker bricks per layer. All three layers of checker bricks above are required to be replaced.
⑤Before installing the checker bricks, clear out the broken pieces in the holes of the checker bricks. Gunning and repairing the cracks of the single and main walls, and using a multi-section blower to blow the checker bricks until the blower inspection is unblocked. When blowing, pay attention to the blowing hole not to face the single (or main) wall, but to move slowly from the outside to the inside and from the inside to the outside of the checkered brick channel. Strip off the checker bricks at the bottom of the burner and clean the dirt in the grate bricks and the small flue.
⑥ Put the slideway into the heat storage room and push the checker bricks in. The checker bricks are required to be close to each other without skewing or falling over. Strive to align the holes up and down, and do not lean against the furnace wall on both sides.
⑦After the checker bricks are installed, build the inner sealing wall first, and apply the grout to the outer surface to seal, and then build the outer sealing wall. After the temperature of the regenerator is normal, joint again, install the protective cover, restore the small furnace column spring tonnage, etc.
Safety Precautions for Checker Brick Replacement
① When stopping and replacing the heating of the furnace number in the regenerator of the furnace number, it is necessary to determine whether the furnace number with the addition and subtraction cock is closed or not, and confirm that the furnace number is correct.
② During the construction period, the fans in the corridor of the regenerator and the temperature measurement platform of the storage roof should be kept running to maintain ventilation.
③ Prevent scalds during the process of peeling off the wall or checker bricks.
④During the construction period, a dedicated person should be assigned to wear a carbon monoxide alarm to monitor the gas concentration on site.
⑤ When working on the storage roof operating platform, prevent the first-class parts from being bumped. After taking out the checker bricks, they should be stacked to prevent them from falling.
⑥ It is strictly forbidden for idlers to walk in the corridor of the regenerator near the construction to prevent injuries from falling objects.
Measures to Prevent Clogging of Checker Bricks
In order to prevent the checker bricks of the coke oven regenerator heated by blast furnace gas from clogging, the following preventive measures should be adopted.
①Purge the gas regenerator with compressed air regularly.
② The dust content of blast furnace gas should be controlled below 15mg/m3.
③The physical and chemical indexes of clay checker bricks for coke ovens should establish standards. The content of Al2O3 and low melting point substances should be appropriately reduced with reference to foreign standards.
④ Semi-silica checker bricks should be used on the top 3~5 layers of the regenerator of the newly built coke oven.
⑤The checker bricks that have been found to be blocked should be replaced immediately and replaced with semi-silica checker bricks.
