Refractory Blog Archives - Rongsheng Refractory Castable Manufacturer

What is the Proper Bulk Density of Refractory Castable?

April 28, 2023 by rsrefractorycastable

What is the bulk density of the refractory castable? Generally, this technical index will be given before the refractory castable leaves the factory. The unit of castable bulk density is usually g/cm3. The bulk density of the castable can range from 0.8g/cm3 (or even lower) to 3.2g/cm3 (or even higher). Which castable to choose depends on the production conditions of the high-temperature industrial furnace.

What is the Proper Bulk Density of Refractory Castable? — Kinds of Refractory Castables in Rongsheng

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The bulk density of refractory castables refers to the mass per unit volume after adding a specified amount of water or liquid binder to the castables, stirring, pouring, curing, and hardening, and then drying at 110°C. It is one of the commonly used physical and chemical indicators of refractory castables. The difference between the unit volume dosage and bulk density of refractory castables. A test method for testing the dosage per unit volume of refractory castables is introduced. The test results intuitively reveal the difference between the unit volume dosage of refractory castables and their bulk density, and the differences between different types of castables. Taking the hydraulic refractory castable as an example, the reasons for this difference are analyzed.

What is the Proper Bulk Density of Refractory Castable?

The density of the castable affects the wear resistance, strength, service life and thermal insulation, and energy-saving effect. So, what is the appropriate density of the castable? Is the higher the density of the castable, the better? The density of the castable we use has a great influence on its performance, and some people think that the denser the castable, the better, which is wrong. It should be determined according to the occasion you use and the type of castable.

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Now refractory castables are used in many industries, and different industries have different standards for the use of castables. The density of the castable is one of the most critical factors. The density of the castable has a great influence on its performance, so the requirements for the density of the castable are different in different situations.

The different industries used have different requirements for the wear resistance of castables. For example, tunnel kilns, such as mechanical equipment, have different requirements for wear resistance. Therefore, the density requirements for refractory castables are also different. In addition, different types of refractory castables also have great differences in construction density.

What is the appropriate density of castable? For parts that need to be exposed to flames and require high wear resistance, it is recommended to use corundum series products or corundum plastics with high density and good wear resistance. For those who require good heat preservation and heat insulation effect and have requirements on weight, light castables with low density and light weight are used.

Bulk Density and Apparent Porosity of Refractory Castables

In addition to the solid body, the prepared refractory castable sample also has many pores of different sizes and shapes, that is, the sample is a porous body. There are three types of pores: open pores that are closed on one side and open to the outside world, closed pores that are closed in the sample and not connected to the outside world, and penetrating pores that penetrate through several sides of the sample. The total porosity, that is, the true porosity, refers to the percentage of the total volume of the pores in the sample to the total volume of the sample; in general, the through pores are combined with the open pores, and the closed pores are less and difficult to measure directly. Therefore, the porosity is expressed by the open porosity, that is, the apparent porosity. Apparent porosity refers to the percentage of the total volume of open pores in the sample to the total volume of the sample.

Bulk density refers to the ratio of the amount of castable to the total volume of the sample after drying, that is, the ratio of the amount of castable to the total volume of the porous body, expressed in Kg/m3 or g/cm3.

Apparent porosity and bulk density are one of the basis for controlling the amount of castable in the construction of refractory castable. The two performance indicators can be measured with the same sample. The followings are the bulk density and apparent porosity of commonly used refractory castables.

CA-50 cement high alumina castable bulk density 2.3–2.6g/cm3, apparent porosity 17-20%
CA-50 cement clay castable bulk density 2.2-2.35g/cm3, apparent porosity 18-22%
Clay combined with high alumina castable bulk density 2.25–2.45g/cm3, apparent porosity 16-21%
Low cement high aluminum castable bulk density 2.4–2.7g/cm3, apparent porosity 10-16%
Ultra-low cement high aluminum castable bulk density 2.3–2.6g/cm3, apparent porosity 10-16%
CA-70 cement corundum castable bulk density 2.7–3.0g/cm3, apparent porosity 12-16%
Water glass clay castable bulk density 2.10–2.35g/cm3, apparent porosity 15-19%
High aluminum phosphate castable bulk density 2.3–2.7g/cm3, apparent porosity 17-20%
Aluminum phosphate high alumina castable bulk density 2.3–2.6g/cm3, apparent porosity 16-20%

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What is the Density of Low Cement Refractory Castables?

Before understanding the density of low cement refractory castables, it is necessary to understand the composition of low cement refractory castables. Low-cement castables use calcium aluminate cement as the binder, and castables with a CaO content of less than 2.5% are collectively referred to as low-cement castables. Different from traditional castables, low-cement castables are used to replace most or all of the high-alumina cement with coagulated ultrafine powder (particle size less than 10 microns) with the same or similar chemical composition as the main material. Optimize particle gradation, fine powder, particle shape, and other factors. At the same time, it is formulated by adding a small amount of dispersant (water-reducing agent) and an appropriate amount of retarder and other compound admixtures.

The density of clay low cement refractory castable is about 2.26g/cm³.
The density of high alumina low cement refractory castables is around 2.3~2.6g/cm³.
The density of corundum low cement refractory castable is about 2.65~2.9g/cm³.

The density of low-cement castables is that if the content of alumina is 51%, its density is 1.3g/m3; if it is 60%, its density is 1.52g. The alumina content is 63%, its density is 1.51g; 65%, its density is 1.78g. The smaller its volume density, the lower its thermal conductivity and absorption, and the better its thermal insulation performance. Its scope of use plays a role in heat preservation and heat insulation in industrial kilns and thermal equipment, and its withstand temperature is 600 °C. It can be divided into low-temperature lightweight low-cement castables that can withstand below 900 °C. Medium-temperature lightweight low-cement castables can withstand temperatures between 900-1200°C. High-temperature lightweight low-cement castables can withstand temperatures above 1200°C.

This product is formulated by adding a small amount of dispersant (water reducer) and a certain amount of slow-acting retarder. Because the cement content of this product is low, the eutectic phase is reduced, thereby improving refractoriness, high-temperature strength, and slag resistance. And when heated, the strength can also increase with the increase of heat treatment temperature. The small amount of cement also allows low-cement castables to achieve the corresponding effect without pouring too much water. The service temperature of low cement castables and ultra-low cement castables is higher than that of ordinary refractory castables of the same material. In the glass kiln tin tank bottom, cement kiln front and rear kiln door cover cooler front and other high-temperature resistant parts, front and rear kiln mouth, coal injection pipe, etc. Heating furnaces, soaking furnaces, and other heat treatment furnaces. The lining of the intermediate frequency induction furnace, the high-temperature wear-resistant lining of the petrochemical catalytic cracking reactor, and the lining of other industrial kilns have been fully applied.

Regarding the appropriate density of castables, Rongsheng monolithic refractory castable manufacturers provide refractory castables with various volume densities(lightweight refractory castables 0.5g/cm3、0.6g/cm3、0.8g/cm3、1.0g/cm3、1.2g/cm3、1.5g/cm3; dense refractory castables 2.0g/cm3、2.2g/cm3、2.3g/cm3、2.4g/cm3、2.5g/cm3、2.6g/cm3、2.7g/cm3、2.8g/cm3, etc. ), which can be selected for high-temperature industrial kilns. Purchase kiln lining refractory bricks and monolithic refractory castables find suitable refractory manufacturers, high-quality construction teams for refractory lining materials, and perfect customer service from Rongsheng manufacturers. Help you solve all-around services from refractory production and construction after-sales. Let your high-temperature kiln run smoothly on the road of high efficiency and long life. Look forward to working with you.

Acid-Resistant Castables for Chemical Plant Chimneys and Pipes

April 28, 2023April 4, 2023 by rsrefractorycastable

Castable refractory castable light acid-resistant castable, lightweight castable manufacturer, light acid-resistant castable, acid-resistant castable for chemical plant chimneys, acid-resistant castable for pipelines, Rongsheng refractory castable manufacturers. Acid-resistant castables are easy to construct and have good acid corrosion resistance, and are widely used in chimneys and other parts of the power industry. Because acid-resistant refractory is suitable for acidic environments, they can be used for a long time at 800 ° C ~ 1200 ° C, and are a monolithic refractory material that can resist acid corrosion.

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Acid-resistant castable is a kind of monolithic refractory material, which has excellent fire resistance and acid resistance, so acid-resistant castables for chemical plant chimneys and acid-resistant refractory for pipes are widely used. Acid-resistant castables use water glass as a binder, and acid-resistant refractory materials as aggregates and powders, which can have a good coagulation effect with the assistance of a coagulant. There are two kinds of acid-resistant castable products: heavy and light. The light heat preservation effect is good, and the compressive strength of the heavy is higher than that of the light.

Acid-Resistant Castables for Chemical Plant Chimneys and Pipes

Acid-resistant castables are stable in various concentrations of organic acids and inorganic acids. Especially in dilute acid, industrial water, and neutral aqueous solution, no crystalline salt is produced, and it has high impermeability.
Good heat resistance, the lining of titanium dioxide rotary kiln, the service temperature is as high as 800°C-1000°C.
The curing agent used in acid-resistant castables is harmful to operators and construction personnel. Appraised by the health department, it can be used in various equipment anti-corrosion projects.
Compared with organic acid-resistant refractory materials, acid-resistant castables are cheaper. In addition to having the same performance as an organic acid and corrosion resistance, it also has the characteristics of corrosion resistance to strong oxidizing media.
Curing at room temperature, simple construction, and convenient use. Easy to transport, moisture-proof storage.

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Acid-resistant castables have a wide range of raw materials and low prices. Commonly used aggregates are silica, diabase, andesite, and wax stone. These kinds of stones have relatively strong acid resistance, especially silica, and cast stone are the most commonly used. Of course, it is not possible to use it in any situation if it is acid-resistant, and it should be selected according to the requirements of the construction site.

In addition, it should be noted that silica will change to polycrystalline when quartz is heated, and its volume will shrink and become larger during this process, in order to avoid this phenomenon. Therefore, we usually use discarded silica brick materials to replace part of the silica raw materials. The powder used in acid-resistant refractory castables is mostly silicon powder, high-silica clay powder, porcelain powder, etc. Due to the polycrystalline shrinkage characteristics of silica, it is used on a smaller scale than cast stone, which is also a common acid-resistant castable aggregate.

The commonly used components of acid-resistant castables can be divided into three types, namely aggregate, powder, and binder. According to the specific requirements and the situation of the construction site to formulate the appropriate preparation ratio. The acid-resistant refractory aggregate is between 60% and 70%, the powder is between 30% and 40%, and the water glass solution with a density of 1.4g/cubic centimeter is used as a binder.

Precautions for the Use of Acid-Resistant Castables

The acid-resistant castable itself has excellent fire-resistant and acid-resistant functions. However, its impermeability is average. Therefore, try not to use acid-resistant castables in wet and liquid conditions. If it is necessary to construct under such circumstances, preparations must be made before construction, and waterproof and moisture-proof materials should be laid in the wet place.
Try not to use light acid-resistant castables as refractory materials. Since the castable will add a certain amount of binder during the distribution process, direct contact with the flame may destroy the adhesive additive in the acid-resistant castable.
The characteristics of acid-resistant castables are somewhat similar to those of cement, and both require a certain setting time. If the temperature difference of the refractory lining is too large, it will affect the condensation process of the acid-resistant castable. There may even be cracks, which should be paid special attention to.
Requirements for the construction environment temperature of acid-resistant castables. Acid-resistant castables are actually very picky about the construction environment. When using acid-proof castables, the construction temperature should be between 5 degrees Celsius and 30 degrees Celsius. If the temperature is too low during construction, then we should store the dry material in a room with a suitable temperature. During construction and stirring, the temperature of the acid-resistant castable can be kept at more than ten degrees Celsius by heating the water or adding an appropriate amount of coagulant. If the construction of acid-resistant castables is carried out in areas with high temperatures, and the temperature exceeds 30 degrees Celsius, then some methods are required to cool down. Containers and pipes can be placed in a cool place to prevent the material from being exposed to sunlight, perhaps mixed with ice water, or a cooling fan can be used to cool the surrounding environment, so as to prevent the acid-resistant castable from being affected by high temperature.

Lightweight Acid-Resistant Castable For Chimney Wall Lining

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Application of Acid-Resistant Castables for Chimneys and Pipes

Acid-resistant castables are mainly used as anti-corrosion flue and chimney linings, acid storage tanks, pickling tank linings, and nitric acid shrinkage tower linings. Acid recovery furnace lining and other container linings corroded by acidic high-temperature gas, etc. The acid-resistant castable is flexible in use and can be poured and constructed. It can also be used by Rongsheng refractory castable manufacturers to make acid-resistant refractory prefabricated parts (precast blocks). The use of prefabricated refractory castables greatly improves construction efficiency and saves construction time. Rongsheng refractory castable manufacturer is located in Xinmi, Henan. The refractory castables produced include steel fiber castables, lightweight castables, iron trench castables, high-aluminum castables, lightweight thermal insulation castables, wear-resistant castables, refractory ramming materials, refractory plastics, unshaped prefabricated blocks, etc. Contact us for free samples and quotes.

Refractory Castables Materials for Rotary Kiln Insulation

March 18, 2023 by rsrefractorycastable

Due to the structure and working characteristics of the rotary kiln, as well as the diversity and complexity of the materials it handles, the requirements for the temperature of the outer wall of the rotary kiln are also different. From the perspective of environmental protection and energy saving, reducing the temperature of the outer wall of the rotary kiln as much as possible, doing a good job in the insulation layer of the rotary kiln, and the configuration of the refractory lining material of the rotary kiln are all the enterprises that operate the rotary kiln expect. Rongsheng monolithic refractory manufacturer has rich experience in the production, sales, and application of monolithic refractory materials. We have served various types of rotary kilns, which can help you solve the problem of rotary kiln insulation lining. Get pricing information for free.

Lightweight High-Strength Castable for Steel Ladle — Lightweight High-Strength Castable Refractory

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There are also various designs for the thermal insulation lining of the rotary kiln, and the types of refractory materials used are also various. According to the specific needs of customers, we can provide customers with insulating castables, lightweight castables, lightweight plastics, dense refractory plastics, heavy wear-resistant castables, phosphate-bonded composite insulation bricks, ceramic fiber products, etc.

Working Layer and Thermal Insulation Layer of the Rotary Kiln Lining

When the rotary kiln lining refractory material is selected, the next step is to evaluate the heat loss of the rotary kiln body.

When we realize that the working temperature in the rotary kiln is high, and the material has serious erosion and wear on the inner lining, then the inner lining design must consider the double-layer inner lining, and the two inner linings are respectively called the working layer and the thermal insulation layer.

The working layer is made of heavy refractory materials to meet the resistance to high-temperature flames and material erosion and wear; the heat insulation layer is made of light refractory materials to improve the thermal insulation performance of the inner lining and reduce the heat loss of the rotary kiln body.

The inner lining of the rotary kiln has a thermal insulation layer, which can effectively reduce the heat loss of the rotary kiln and also help protect the rotary kiln shell and other shell components.

Generally speaking, the rotary kiln lining with a thermal insulation layer is often used for rotary kilns with high operating temperatures. The refractories of the inner lining of the thermal insulation layer and the inner lining of the working layer have similar chemical compositions, and the difference between Rongsheng refractory materials lies in their respective strength and thermal conductivity. The refractory material lining the thermal insulation layer has a low density and low strength, but its thermal resistance is relatively large, which can effectively reduce the heat loss of the rotary kiln body.

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What Refractory Castables are Used for Each Part of the Cement Rotary Kiln?

Refractory castables are used as the main insulation material for the new dry-process rotary kiln. If it is properly configured, it can protect the normal operation of production equipment at high temperatures and effectively reduce system energy consumption.

Cement Rotary Kiln Refractory Castable

Kiln mouth with refractory castables. At the kiln mouth in front of the rotary kiln, the clinker outlet temperature is around 1400°C, and the temperature of the secondary air entering the kiln changes frequently due to kiln conditions. With the expansion of the scale of the cement plant, the amount of clinker at the kiln mouth is also increasing, and the thermal stress and mechanical stress on the refractory castable at the kiln mouth increase accordingly. For this reason, the kiln mouth refractory castable should have sufficient refractoriness, mechanical strength, thermal shock stability, and alkali resistance under high-temperature environments. It is recommended to use high-performance kiln mouth special refractory castable or improved kiln mouth special refractory castable. The product has excellent anti-stripping performance, high temperature and alkali resistance, and cement clinker erosion resistance.
Refractory castables for burners. The working environment of the burner is about 1400°C, the flame temperature is about 2000°C, and it works in an alkaline atmosphere for a long time. Compared with the front kiln mouth, the temperature changes more frequently and the temperature difference is larger. Therefore, the requirements for its thermal shock resistance are higher. The front end of the burner is always scoured by the high-temperature airflow entrained with clinker dust, especially the lower part is more severely scoured. Therefore, burner refractory castables need sufficient wear resistance. It is recommended to use special castables for burners or special refractory castables for improved burners. The product has excellent spalling resistance and thermal shock stability.
Refractory castables for kiln hood and grate cooler. For some large rotary kilns, the heat load on the lower part of the kiln hood is relatively high. If the general high-alumina refractory castable is not well controlled for curing and temperature rise, it is prone to bursting and falling off. The top of the kiln hood is close to the tertiary air duct, and the erosion of the dusty airflow is relatively serious, and the construction of the top castable is relatively difficult, and the requirements for the fluidity and early strength of the material are relatively high. The working temperature at the top of the front end of the grate cooler is high, and the temperature changes greatly. The low walls on both sides of the front end have been worn by the high-temperature clinker coming down through the kiln mouth for a long time, and they are also damaged by certain mechanical stress and thermal stress. It is recommended that these two parts use high-strength wear-resistant castables with good high-temperature performance, strong thermal shock resistance, and wear resistance.
Refractory castables for tertiary air pipe elbows and air valves. This part has a large change in heat and cold and is washed by high-temperature clinker particles. The castable is prone to loosening and peeling, and it is the most prone to wear and tear during the operation of the cement plant. It is recommended to use wear-resistant refractory castables.
Refractory castables for C4 and C5 cones and their discharge pipes, calciner cones, and smoke chambers. These areas are prone to crusting and are difficult to remove. Cleaning needs to be done manually with iron tools, which will inevitably cause mechanical damage to the refractory castable. Once severe skinning occurs, the kiln needs to be stopped for treatment. It is recommended to use high-strength anti-skinning silicon carbide castables.
Refractory castables are used for other parts of the cement rotary kiln. It is recommended to use high-strength alkali-resistant castables for C1~C3, high-temperature high-strength alkali-resistant castables for C4 and C5 (except for the cone), and high-strength wear-resistant castables for the decomposition furnace.

Rongsheng Insulation Castable Manufacturer

The application and development of refractory and insulating castable refractory should conform to the concept of environmental protection and circular economy. Reasonable selection of thermal insulation castables can prolong the service life of the rotary kiln castable lining, effectively protect equipment, reduce system heat loss, reduce system crust blockage, reduce kiln shutdown times and maintenance time, and improve system operation rate. To achieve the purpose of stable production, high production, and low energy consumption of the kiln system. For a case study on the configuration of thermal insulation and refractory materials for the rotary kiln project, please contact us. We will provide you with the most suitable thermal insulation refractory solutions for your production needs according to your working conditions.

How to Use Insulating Castables to Reduce the Surface Temperature of the Kiln Skin?

March 3, 2023 by rsrefractorycastable

The temperature of the shell of industrial kilns varies, and the higher the operating temperature, the higher the temperature of the shell of the kiln. In recent years, due to the requirements of environmental protection and the advocacy of energy conservation, industrial kiln enterprises have paid more and more attention to the temperature of the outer wall of the kiln skin. So how to reduce the temperature of the outer wall of the kiln skin? To reduce the surface temperature of the kiln skin, how to use insulating castables?

Generally, if you want to lower the temperature of the kiln skin, you must improve the use of insulation materials, or thicken the insulation layer. There are many light clay bricks and light fiberboards, cotton wool, and blankets used for the insulation layer. If you use fiber insulation materials, you don’t need lightweight clay bricks, and you can’t use fiber insulation materials if you use lightweight clay bricks. However, if it is required to reduce the temperature of the kiln skin, it is necessary to do multi-layer insulation to reduce the degree of heat diffusion and reduce the temperature of the outer wall of the kiln.

What kind of material should be used as the insulation layer when the kiln skin temperature is required to be 50°C?

When the temperature of the kiln skin is required to be 50°C, insulating castable refractory can be used, and fiberboard can also be used as the insulation layer.

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The kiln skin temperature is required to be 50°C, and the temperature requirement is relatively low. If you choose fiberboard, it is not enough to use ordinary aluminum silicate fiberboard, you have to use nanometer board as an insulation layer. And it doesn’t work if it’s too thin, the minimum thickness should be 100mm. It is uncertain whether the final kiln skin outer wall temperature reduction effect will reach 50°C on the outer skin. If it is winter, it should be able to meet expectations. If it comes to summer, the temperature of the outer wall of the kiln skin may be 50℃ higher due to the influence of sunshine and weather temperature. This is affected by certain weather factors. If you use a 150mm nanoplate, there is no big problem.

If you use lightweight castable refractory, some costs will be reduced, but the thickness should not be too small. Under normal circumstances, the thickness reaches 300mm, and the temperature of the outer skin can also be lower than 50 degrees Celsius. However, the thickness of the lightweight castable is too thick, which will affect the kiln diameter. Because the insulation layer with a thickness of 300mm, a total thickness of 600mm must be occupied on both sides of the kiln. Therefore, the usable kiln diameter will become smaller. However, from the perspective of heat preservation alone, if it is expected to reduce the temperature of the kiln skin, the temperature required by the kiln skin can also be achieved by pouring 300mm thick lightweight heat-insulating castables.

If the height of the kiln is too high, it is unlikely to use refractory bricks for the insulation layer or the working layer. Because there may be string joints in the middle, the working layer is most likely to be poured with dense castables as the working layer. It is possible to use nano-sheets or lightweight castables for the pouring working layer. Because the outer layer of the nano-plate is wrapped with plastic, no moisture will enter, and even if the castable discharges a certain amount of water, the thermal insulation layer will not be affected. If light heat insulation castables are used and dense castables are used in the working layer, they are all constructed by pouring, and there is no problem of water discharge affecting the use of the heat insulation layer.

Therefore, when the external temperature of the kiln skin is low, it is possible to use nano-plates and lightweight insulating castables. Only the thickness has certain requirements. The thickness of the nano-plate should not be less than 100mm, and the thickness of the lightweight castable must be constructed to a thickness of 300mm to meet certain usage requirements.

Can Lightweight Insulating Castables be Used Outside the Furnace Shell?

Lightweight insulating castables are used on the outside of the furnace shell and are not recommended. Because the lightweight insulating castable refractory plays the role of heat preservation and heat insulation, the main function is slowing the heat dissipation, which can save fuel and protect the furnace shell.

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If the furnace lining is not used as an insulation layer during construction, it is not recommended to use it in this way. If there is a user unit that has not made an insulation layer and has been put into production, under such conditions, in order to avoid overheating of the furnace shell, it is not advisable to make an insulation layer on the outside of the furnace shell, and then add a layer of the iron sheet on the outside.

The reason is that there is no insulation layer and the temperature of the furnace shell is high. The insulation layer can be used for the next maintenance. If an insulation layer is made on the outside of the furnace shell and a layer of iron sheet is added, the furnace shell will also be attacked by high temperature and the service life will be shortened.

There is a furnace type with heat-insulating material coated on the outside of the furnace shell. Due to the high temperature of the boiler, heat-insulating castables or heat-insulating bricks are used as heat-insulating layers on the inner lining. Some manufacturers also apply a layer of fabric on the outside of the furnace shell, which also slows down the temperature and heat dissipation process. This saves fuel and protects the furnace shell. There are also manufacturers who use a layer of epoxy paint on the outside of the furnace shell, but not many use this method. On the contrary, more fabrics are used.

If the inner lining is made of light-weight insulating castable or light-weight bricks as the insulation layer, if the insulation layer is made outside the furnace shell for remedy, it will not play any role in the protection of the furnace shell, and it is of little significance to make the insulation layer. Even doing it with nanoplates doesn’t make much sense.

Therefore, the selection of lining materials must be determined according to the temperature of the lining. Whether to use lightweight insulating castables refractory or lightweight refractory bricks or use insulation cotton and boards as insulation layers. If the furnace lining temperature does not exceed 200°C, there is no need to make an insulation layer. If the temperature exceeds 1000 ℃, it is necessary to make an insulation layer. If the temperature exceeds 1400°C, high-grade lightweight materials should be used as the insulation layer.

Rongsheng Refractory Castable Manufacturer

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Solutions to Reduce Kiln Skin Surface Temperature

Rongsheng refractory material manufacturer is a manufacturer with rich production and sales of refractory materials. Our monolithic refractory materials offer reliable performance. It has a long service life on the refractory lining of various industrial kilns. Extend the service life of the refractory lining. Recently, our technical team is also working on the research of refractory materials that reduce the surface temperature of the kiln skin, providing cooling solutions for industrial kilns. Contact us for a free solution.

How Much Water Should be Added During the Construction of Refractory Castables?

January 3, 2023 by rsrefractorycastable

The amount of water added to the refractory castable is very important, and directly affects the service performance and service life of the castable. How much water should be added during the construction of refractory castables? Different binders are used in castables, and the prepared refractory castables are also different. Even the same kind of refractory cement can be used as a binder to prepare various refractory castables. The amount of water added to the castable is also different during construction. The strength and service life of castables are inseparable from water consumption.

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During the construction of castables, the increase in water consumption will generally lead to a large decline in various properties. When the amount of water is large, the water will escape after heating, and the pores will increase accordingly, forming a loose structure, resulting in an overall decline in the performance of the castable and affecting the service life of the castable. Therefore, during the construction of castables, it is necessary to minimize the amount of water used during mixing.

According to the current use of castables, basically, the amount of cement is increasing, and the amount of cement added is basically canceled. Because the amount of low-cement castable high-alumina cement added is small, the amount of water added during construction is also small, and the situation of low medium-temperature strength is also overcome. If the amount of water added to the castable is too large, it is not only a coagulation problem, but the biggest reason is to affect the later use strength.

When the ratio of refractory castables and the production process are basically the same, water consumption has the best value. Generally, after the castable is produced, the manufacturer will make a sample block and do certain chemical and physical tests. Then, according to different situations, determine the optimal value of water consumption for each pouring material. Sometimes it is necessary to do certain tests or equip some binders according to the temperature on the spot during construction so that the water consumption of different castables during construction can be used at different temperatures.

Therefore, when making cement-bonded refractory castables, they should be mixed to the best fluidity. Then, according to the size of the normal temperature strength, determine the optimal amount of water.

The main points of adding water during the construction of refractory castables

Refractory castables are divided into neutral, alkaline, and acidic. The materials are divided into high aluminum, magnesium, acid, light series, and so on. Regardless of the series, the amount of water added is different for different models and materials.

Mixing of Refractory Castables Water Addition

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During the construction of refractory castables, drinking water with pH = 6-7.5 must be used. In general, the water content of the high aluminum series is 10-15%, the water content of the low cement series is 6-8%, and the water content of the wear-resistant series is controlled at 5.5-6.5%. The amount of water added to the spray paint is 10-15%, and the amount of water added to the corundum series is 5-6%. If it is the refractory mud for brick matching, the water addition is 20-25%, and the water added for the light series is 20-25%. Be sure not to add too much water. Adding too much water will prolong the setting time of the castable and affect the strength of use.

The amount of water added to the refractory castable also has a great influence on the internal structure. If you add too much water, the internal performance will gradually decline. As the amount of water added increases, the strength decreases, the porosity increases, and the anti-scouring ability also decrease, which seriously affects the service life.

During the construction of refractory castables, the amount of water added is determined according to the particle gradation and the ratio of the binder. The castable does not have a large amount of water and good performance. If too much water is added, the aggregate will be separated from the base material, which will affect its performance and reduce its density and corrosion resistance.

However, the amount of water added is insufficient, the fluidity cannot be achieved, the air bubbles cannot be discharged, and the internal structure cannot form density accumulation, which will still affect various performances.

Therefore, in the construction, it is necessary to follow the instructions provided by the manufacturer, add water and stir the construction reasonably, so that the performance of the refractory castable can be fully utilized.

How to judge the appropriate amount of water added to monolithic refractory castables?

Why do castables that add water in strict accordance with the construction instructions still have problems? This problem is often encountered in actual use. Most people will say that I added water strictly according to the construction instructions, why is it still too wet (too dry)? In fact, the amount of water added in the construction instructions is only a theoretical reference, and the specific amount of water added should be determined according to actual construction needs.

After determining the raw materials of castables, qualified refractory castables are produced after a series of processes. Users can use it by adding water and stirring it, but it is precisely the step of adding water that stumps many construction workers. Either the mixing is too dry, or it is too wet. I have summed up a method in many times of practices, which can well control the amount of water added so that the performance of the castable can be better exerted.

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the appropriate amount of water added to monolithic refractory castables

The reference water content of general refractory castables is 8%-10%. When actually adding water, you can add water according to the principle of “small amount and many times”. Control the time well, and the mixing time of the pouring material should not be too long. After the mixing is finished, grab a handful of castables with your hands and hold them into balls (balls). If the dough disperses immediately after holding the ball, it means that the amount of water added is too small. If the spherical castable flows down from the fingers after holding the ball, it means that the amount of water added is too large. The amount of water added is appropriate only if the spherical castable does not disperse or flow out.

The amount of water to be added to the castable during construction is not only related to the raw materials, but also factors such as the construction site environment, dryness and humidity, and seasons. Only by controlling the amount of water added can the performance of the castable be maximized.

Alkaline Castables and Magnesia Refractory Castables for Rotary Kilns

December 28, 2022 by rsrefractorycastable

As a component part of the kiln body, the cement kiln mouth is the most vulnerable part of the cement kiln and the weakest link in the whole kiln lining. The kiln mouth has the shortest service life of the refractories used in cement kilns. When the refractory material in this part is corroded, it will often cause serious deformation of the kiln mouth shell, or even crack. Finally, the cylinder has to be replaced, which seriously affects normal production and brings great economic losses to the enterprise. Alkaline castable magnesia refractory castables for rotary kilns and new alkali-resistant castables, compared with traditional refractory materials, can increase the service life of the kiln mouth by more than double (up to 180 days or more). It has broad promotion prospects and obvious economic benefits.

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Alkaline castable magnesia refractory castable for rotary kiln

Magnesia refractory castable is made of fused magnesia or sintered magnesia aggregate and fine powder. The binder uses periclase cement, magnesium chloride, magnesium sulfate, water glass, polyphosphate, etc.

(1) The magnesia castable with periclase cement as the binder has the characteristics of high purity, small line change after burning, and high load softening temperature.
(2) Magnesium castables using water glass as a binder have the advantages of high strength, and strong corrosion resistance to alkali and sodium salt melts.
(3) The magnesium castable combined with polyphosphate has the characteristics of high load softening temperature, high strength, and excellent thermal shock resistance.

What is the composition of magnesia refractory castable?

Magnesia refractory castable is prepared from fused magnesia or sintered magnesia aggregate and its fine powder. The binder uses periclase cement, magnesium chloride, magnesium sulfate, water glass, polyphosphate, etc. The magnesia refractory casting material combined with periclase cement has the advantages of high purity, a small change of line after burning, and high softening point under load. However, as the heat treatment temperature increases, especially between 400 and 1200 °C, the cementation will be lost due to the dehydration of the magnesium hydroxide generated by the hydration of magnesia. The combination of refractory aggregate and powder is very loose, and the solid phase reaction is very weak, resulting in a sharp drop in the strength of the refractory castable. It is prone to loosening and peeling.

Magnesia refractory castables using water glass as a binder have the advantages of high strength, corrosion resistance to alkali and sodium salt melts, etc. However, due to the use of water glass as a binder, a large amount of Na2O (or K2O) and SiO2 are brought in. Therefore, the refractoriness and load softening point of magnesia refractory castables are greatly reduced, thereby limiting the maximum use temperature of water glass bonded castables.

The magnesia refractory castable combined with polyphosphate has the advantages of high strength after firing, a small decrease in strength with the increase of heat treatment temperature, high softening point under load, and good thermal shock stability. However, at high temperatures (above 1400°C), the strength of magnesium castables decreases due to the large amount of volatilization of P2O5. In general, sodium polyphosphate is often used as a binder in magnesium castables, such as sodium tripolyphosphate, sodium hexametaphosphate or sodium polyphosphate. The degree of polymerization of polyphosphate and the content of P2O5 has a great influence on the strength of castables. When the average degree of polymerization of polyphosphate is 24, the castable has the highest strength.

In addition, in order to improve the high-temperature strength of magnesia refractory castables, an appropriate amount of calcium-containing materials (such as calcium carbonate, etc.) is added to the components to form Na2O2CaOP2O5 phases with high bonding strength and stable existence at high temperatures. However, no matter what kind of binder is used, it is difficult to overcome the problem of easy hydration of magnesium refractory castables and the phenomenon of cracks in the drying process. For this reason, the method of adding an appropriate amount of silicon oxide ultrafine powder can overcome the problem of hydration.

Magnesia Refractory Castable for Rotary Kiln

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Mixing ratio and properties of magnesia refractory castable

Magnesia refractory castables usually use sintered and fused magnesia as refractory aggregate and powder. Its particle gradation is 5~2.5mm, 33%; 2.5~1.2mm, 1.2~0.6mm, 25%; 0.6~0.15mm; magnesia powder fineness <0.09mm is greater than 85%. Sodium hexametaphosphate solution with a concentration of 30% or an equivalent concentration of 4N is used as a binder, and aluminate cement is used as a coagulant. Some are mixed with a sintering machine, such as iron phosphorus or clay powder. The preparation process is to mix the refractory aggregate with two-thirds of the sodium hexametaphosphate solution, and then add the refractory powder after the surface of the aggregate is completely wet, and stir evenly. Finally, add the remaining sodium hexametaphosphate solution and continue to stir for 1-2 minutes; after vibration molding, it should be cured naturally for 3 days without water. The ambient temperature should not be lower than 10°C, the higher the better.

The refractoriness of magnesia refractory castables is >1830°C, and the load softening temperature of 4% deformation is greater than 1400°C. The temperature of fused magnesia aggregate can reach 1520°C; the drying bulk density is larger and the apparent porosity is smaller. The use of aluminate cement coagulant does not reduce the refractoriness but increases the load-softening temperature. At the same time, the compressive strength after firing at 1000°C increased from 19.1MPa to 26.5~34.8MPa, which was caused by the formation of Na2O·2CaO·P2O5 minerals. From the perspective of strength change characteristics, the medium temperature strength has a large decrease, but the absolute value is still greater than 25MPa. Therefore, it does not affect the use of magnesia refractory castables. The reason for the decrease in strength can be seen from the petrographic analysis, which is caused by the change in the structure of sodium hexametaphosphate during the heating process and the lack of sintering of the base material.

The relationship between concentration and strength of sodium hexametaphosphate solution. With the increase of its concentration, the compressive strength after burning at 1000°C is peak-shaped, that is, when the concentration of sodium hexametaphosphate solution is 23%~30%, the strength is the best, which can reach more than 30MPa. When preparing sodium hexametaphosphate refractory castable, its concentration should be selected as 25%~30%.

In alkaline refractory castables, under the premise of ensuring the workability of the mixture, the amount of sodium hexametaphosphate solution should be used as little as possible to ensure its high-temperature performance. In addition, the type of refractory aggregate, particle gradation, amount of bone powder, type and amount of aluminate cement, etc. also affect the performance of refractory castables and should be selected reasonably.

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Rotary kiln refractory castable manufacturer

Rotary kiln refractory castable manufacturer is a powerful manufacturer and seller of refractory castables. Rongsheng’s monolithic refractory castable production line has an annual output of 80,000 tons. Moreover, it is equipped with an advanced and environmentally friendly fully automatic production environment and production equipment. Our production line has served the supply of monolithic refractories for many turnkey projects. And received praise from customers. If you are looking for a manufacturer of monolithic refractory materials and buy rotary kiln refractory castables, please try to contact us. We will provide you with the most suitable refractory castable products according to your specific production needs.

Solutions for Aluminum-Magnesium Castables in Use

December 5, 2022 by rsrefractorycastable

Alumina Magnesite Refractory Castable is a refractory castable with corundum as the aggregate, spinel and corundum powder as the matrix and pure calcium aluminate cement as the binder. Its chemical composition is Al2O3 89%~93%, MgO 5%~8%. It has good corrosion resistance and slag penetration resistance and can be used as a large ladle lining for continuous casting.

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Application of aluminum-magnesium refractory castable

Aluminum-magnesium refractory castables have been widely used in ladles for medium and small die-casting. The average package age is 60 to 80 times. Compared with clay ladle bricks, the refractory material consumption per ton of steel is reduced by about 70%.

The raw materials of aluminum-magnesium castables for ladles are basically the same as that of aluminum-magnesium refractory ramming materials. In order to obtain normal temperature strength, sodium fluorosilicate should be added as coagulant. The load softening temperature of the ladle aluminum-magnesium castable is low, which is due to the combination of some low-baking substances formed by adding magnesia powder and the joint action of water glass and sodium fluorosilicate.

The solution to cracks in aluminum-magnesium castables during use

Aluminum-magnesium castables crack during use, which reduces the service life. The specific manifestation is: when the ladle is used for 5 heats, cracks begin to appear on the inner wall of the ladle, covering the entire ladle wall. As the number of uses increases, the cracks become deeper and wider. When more than 20 furnaces were used, they had to be forced to stop using them. In order to solve the problem of castable cracks, the following methods have been tried.

(1) Replace the bauxite clinker calcined by the shaft kiln with the bauxite calcined by the downdraft kiln, so that the sinterability and bulk density of the bauxite are increased. The theory was that this might reduce volume shrinkage caused by incomplete calcination of alumina and re-sintering during use, but without success.
(2) It is believed that the cracks are related to the total amount of fine powder in the castable. Try to reduce the fine powder in the castable to less than 30% (mass fraction), the lowest to 25%. Didn’t solve the problem either.
(3) Start to solve the crack from the chemical reaction. Because Al2O3 and MgO can generate aluminum-magnesium spinel under high temperature, accompanied by large volume expansion. After a series of experiments, adjusting the ratio of Al2O3/MgO did not achieve satisfactory results. Even when the MgO content is too high, peeling occurs instead.

Solution: Finally, the following method was adopted to basically solve this problem.

(1) The upper limit of the aggregate particle size was raised from 15 mm to 5 mm, of which 20-25 mm accounted for 7.2% (mass fraction) of the total. This is due to the existence of super-large particles, which not only act as a skeleton, but also can change the direction of long cracks, helping to prevent the expansion of internal cracks.
(2) Add zircon powder into the matrix. This zircon powder is produced in Australia, and the ZrO2 content is about 66%. Since ZrO2 itself has a high melting point, it can absorb CaO in slag during use to generate CaZrO3 with high melting point and high corrosion resistance, which can close pores and cracks and strengthen the matrix. At the same time, due to the existence of zircon, micro-crack structures can also be formed in the castable, improving the high-temperature performance of the castable.
(3) Reduce the amount of active silica fume powder as much as possible. Since the quality of silica fume powder is unstable, if the amount added is large, there will be many impurities brought in, which is unfavorable for use. It is better to control the amount of silica fume in the castable below 1.5% (mass fraction).
(4) When pouring, it is also critical to strictly control the amount of water added and ensure uniform vibration.

Rongsheng Refractory Castable Manufacturer

Rongsheng refractory castable manufacturer is a powerful monolithic refractory manufacturer. Rongsheng Environmental Protection’s advanced fully automatic monolithic refractory production line has an annual output of 80,000 tons. Provide high-quality monolithic refractory products for thermal equipment of various furnace structures such as circulating fluidized bed boilers, gasification furnaces, fluidized furnaces, and waste incinerators. Our refractory products have been sold to more than 70 countries all over the world, such as South Africa, the Philippines, Chile, Malaysia, Indonesia, Vietnam, Kuwait, Turkey, Zambia, Peru, Mexico, Qatar, Egypt, Russia, Kazakhstan, etc. To purchase high-quality aluminum-magnesium refractory castables and get free refractory castable lining configuration solutions, please contact us. We will provide you with the configuration of refractory lining material that best suits your production needs.

Low Cement Refractory Castable for Cement Kiln Lining

September 30, 2022 by rsrefractorycastable

With the continuous progress of the production and use technology of monolithic refractories, especially the development of low-cement refractory castables, self-flowing castables, and wet injection technology. The refractory lining used in the new dry-process cement kiln system has gradually developed into a castable-based lining structure.

Multifunctional refractory castables have many functions such as high early strength, high thermal strength, alkali resistance, wear resistance, and heat insulation. For the vulnerable parts in the new dry process cement kiln system. Such as the kiln mouth, the top of the kiln door cover and the blanking slope, the low wall of the grate cooler, and the high-temperature area on the top of the grate cooler. Coal injection pipe, tertiary air pipe elbow, and other parts. Various refractory castables have different damage mechanisms under different conditions of use parts. Because the vulnerable parts in the new dry-process cement kiln system are in harsh environments such as high temperature, cement clinker erosion, abrasion, rapid cooling, rapid heating, etc. And it is located in special parts of the port, and the service cycle of these parts seriously restricts the life of the kiln lining of the whole kiln. According to the specific use characteristics of each part of the kiln, the development trend of refractory castables for the cement industry is as follows.

Improve the wear resistance of wear-resistant castables.
Improve the thermal shock resistance of wear-resistant castables.
Reduce Fe2O3 content.
Reduce the bulk density of the castable. Reducing the load on the equipment Reduce the bulk density of the castable on the premise of ensuring wear resistance and thermal shock resistance.

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Low Cement Refractory Castable for Cement Kiln Lining

Low cement refractory castables for cement kilns mainly include high alumina, mullite, and corundum refractory castables. This series of products has the characteristics of high strength, erosion resistance, wear resistance, and excellent performance. At the same time, the material can be made into a quick-baking explosion-proof castable according to the user’s baking time requirements.

Rongsheng monolithic refractory castables are the first to produce low-cement products with reliable quality and stable performance. It is widely used in blast furnace tap ditch, cast iron furnace tap trough, integral powder spray gun for molten iron pretreatment, high-temperature burner lining, heating furnace water cooling tube wrapping lining, etc.

Corundum and chromium-containing corundum low-cement castables are used for the lining of some parts of the refining device outside the molten steel furnace. It is also used in the lining of power frequency induction furnaces, the high-temperature wear-resistant lining of the petrochemical catalytic cracking reactor, etc. The low-cement refractory castable has the properties of high strength, alkali resistance, and wear resistance, which is obvious to all who have used it.

Corundum Self-flowing Wear-resistant Castable

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Index of low cement refractory castable for cement kiln

There are three common low-cement refractory castables, where low refers to less cement content in the product. The cement content of castables is as high as 10-30%, and the cement content of low-cement castables is between 3%-8%, so there are also 1% of ultra-low cement castables.

How to cure and bake low cement castable in the rotary kiln?

Low cement castables are widely used in new dry process cement rotary kilns. It is mainly used in the rear kiln mouth, kiln door, decomposition furnace, cooler and other parts. As we all know, the construction of refractory castable is mainly composed of three links, namely mixing, pouring, and curing. So how to maintain and bake it?

Maintenance

The tools that low-cement castables need to use in the curing process are polyethylene plastic film, straw bags, etc.

Ambient temperature requirements and controls. The curing temperature of the casting body is preferably between 15-35 ℃. Outside this temperature range, corresponding heating or cooling measures should be taken. Otherwise, the performance of the product will be degraded.

conservation. After the castable is hardened, the surface of the construction body must be covered with polyethylene plastic film immediately. A wet straw bag is added on top to prevent water evaporation and promote cement activation. After hardening, it is forbidden to beat and vibrate within one day. According to the hardening situation, the mold can be removed after 24-30 hours of hardening, or it can be removed in 3 days. After de-molding, continue curing for 2 days. Continue to cover with polyethylene film and wet straw bags during maintenance. After 3 days of curing, remove the polyethylene plastic film and a wet straw bag. Let the cast body dry naturally in the air for 1 day before baking.

Baking

One of the most critical aspects when using castables during baking. Because the casting body is relatively thick and dense, the water is not easy to discharge. Therefore, it is absolutely forbidden to heat up too fast during baking, otherwise, it will cause the casting body to crack.

Process of Lightweight High Strength Castable for Ladle Insulation Layer

September 21, 2022September 19, 2022 by rsrefractorycastable

The process of using lightweight and high-strength castables for ladle insulation. The choice of insulation layer material, the traditional insulation layer is built with clay bricks, which is cumbersome in process, frequent maintenance, easy to penetrate the brick seam, low life, and high cost. The technology of unshaped refractories is becoming more and more mature, and the lightweight and high-strength castables have the characteristics of low bulk density, low thermal conductivity, and high compressive strength, and are widely used.

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Preparation and Characteristics of Lightweight and High Strength Castables for Ladle Insulation Layer

The aggregate of the castable is made of floating beads, high alumina porous clinker, and alumina hollow sphere composite aggregate. The castable has the properties of low bulk density, low thermal conductivity, good thermal insulation performance, high refractoriness, and high compressive strength. Clay clinker powder and industrial alumina powder are used as powders so that the mass fraction of Al2O3 in the castable reaches 45% to 50%. Pure calcium aluminate cement is used as a binder to ensure high strength after casting without reducing the mass fraction of Al2O3. Adding an appropriate amount of fused magnesia to maintain the volume stability of the product, reduce the cracking and peeling phenomenon in use, enhance the resistance to rapid cooling and rapid heating, and improve the service life of the insulation layer.

Table 1 Performance indexes of the light-weight and high-strength castables for ladle

Operating Temperature / ℃	Bulk Density g/cm3	Thermal Conductivity / w·(m·K)^-1	Compressive Strength / MPa	Line Change Rate After Heating / % (1400 ℃)	W(Al2O3)
1200 ~ 1400	1.5 ~ 1.7	0.41 ~ 0.52	7 ~ 15	+0.3 ~ (-1.0)	45 ~ 50

Thickness Design of Ladle Insulation Layer

The refractory lining of the ladle requires a working layer thickness of 180mm, a minimum use thickness of 60mm, and service life of not less than 25 times. Considering the thermal insulation performance of the ladle and the service life of the working layer, the thickness of the thermal insulation layer of the clad wall is determined to be 80mm. The thickness of the bottom insulation layer is 140mm.

Production of tire molds

Design the insulation layer mold according to the designed insulation layer size and the size of the cladding. In order to facilitate the vibrating and ramming of the castable, so that the castable fills the entire insulation layer and facilitates de-moulding, the tire mold is made into a split structure of upper and lower layers. The taper is the same as that of the cladding, the outer diameter of the lower mold is 190mm smaller than the inner diameter of the cladding (10mm to 20mm for the thermal insulation layer), and the outer diameter of the upper mold is 180mm smaller than the diameter of the inner wall of the cladding (10mm to 20mm for the thermal insulation layer). The welding of the tire mold steel plate should be smooth and flat, with a support plate inside to prevent deformation of the tire mold, and hooks are welded on the support plate to facilitate lifting.

Pouring Construction of Castables for Ladle Insulation Layer

The overall knotting process of lightweight and high-strength castables is adopted. The process is carried out in stages, and each batch of castables should be fully stirred in the mixer. The amount of water added is controlled at 10% to 15%.

① Knot the bag wall and evenly coat the outer wall of the lower mold with a layer of release agent put it in the bag, and fix it, and the gap between the mold and the insulating layer is uniform. Then pour the stirred castable into the gap between the mold and the heat insulating layer, taking care not to peel off the heat insulating castable material or roll it into the castable. Then use a vibrating rod to vibrate the castable evenly and densely. After the lower layer is knotted, put the upper layer of the mold in and tie the knots in turn.
②Dry naturally for 24h-48h, and the mold will come out. Install the seat brick and the breathable brick mold, and then use the evenly stirred castable to tie the bottom insulation layer.
③ Natural drying for 12h ~ 24h, the mold comes out. Then natural curing for more than 72h, and finally baking.

Baking of ladle insulation

The water content of the poured insulation layer is relatively large, and the water in the castable needs to be discharged by baking to increase the strength of the insulation layer. In order to prevent the thermal insulation layer from bursting due to the excessive heating speed, the baking is carried out in strict accordance with the heating speed and holding time specified by the process. The total baking time shall not be less than 15h.

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Rongsheng Unshaped Refractory Castable Manufacturer

Rongsheng Unshaped Refractory Castable Manufacturer is an unshaped refractory manufacturer with rich experience in production and sales. Our environmentally friendly fully automatic monolithic refractory castable production line has an annual output of 60,000 tons. Our refractory materials have been sold to more than 80 countries all over the world, eg, South Africa, Philippines, Chile, Malaysia, Indonesia, Vietnam, Kuwait, Turkey, Zambia, Peru, Mexico, Qatar, Egypt, Russia, Kazakhstan, etc. Moreover, our technical team is also keeping pace with the times, providing high-quality materials for the refractory lining of high-temperature industrial furnaces. Including light and high-strength castables for ladle insulation, ladle wear-resistant refractory castables, etc. Contact us for free quotes and samples.

Differences between Dense Castable Refractory and Lightweight Refractory Castable

September 5, 2022 by rsrefractorycastable

What are the commonly used refractory castables? What is the difference between dense castables refractory and lightweight refractory castables? Castable refractory, also known as refractory castable, is an unshaped refractory material, also called monolithic refractory castable. The refractory castable is easy to construct and has good integrity. It can be used for the lining of various industrial kilns and can also be used to manufacture prefabricated parts.

High-Alumina Refractory Castables Manufacturer — High-Alumina Refractory Castables – Dense Refractory Castable

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Classification of Commonly Used Refractory Castables

There are many types of refractory castables, which can be distinguished according to different dimensions.

1) According to the characteristics of refractory castables, they can be divided into high-strength wear-resistant castables, high-temperature-resistant castables, low-cement castables, steel fiber castables, acid-resistant, and heat-resistant castables, etc.
2) According to refractory raw materials, it is divided into clay castable, high alumina castable, silicon castable, mullite castable, corundum castable, silicon carbide castable, etc.
3). According to the applicable industrial kiln environment, including aluminum-silicon carbide castables for ladle ditch, aluminum-magnesium spinel castables for ladle, etc.
4) According to the density, it is divided into lightweight castables and dense castables refractory.
5) According to the composition of the binder, organically bonded castables and inorganic bonded castables, such as resin bonded castables and cement bonded castables;
6). According to chemical properties, refractory castables can be divided into acid-resistant castables, neutral castables, and alkali-resistant castables.

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What is the difference between dense castables refractory and lightweight insulation castables?

Analyze the difference between dense castables refractory and lightweight insulation castables. The main difference between dense refractory castables and lightweight castables is the difference in bulk density. Lightweight castables with a density lower than 1.6 and dense castables with a density higher than 1.8.
The characteristics of dense castables differ from lightweight insulating castables. Dense castables have high-temperature resistance, erosion resistance, erosion resistance, thermal shock resistance, spalling resistance, etc. Lightweight castables have low thermal conductivity and a good thermal insulation effect.
Dense refractory castables and lightweight insulating castables are also used differently, that is, they are used in different environments. The dense refractory castables are wear-resistant, high-temperature-resistant, and corrosion-resistant, and are used in kilns with harsh environments. Lightweight castables are generally used for heat insulation layers to avoid heat loss from the kiln and have the effect of heat insulation. And because the kiln skin temperature is low, fuel can be saved.
The raw materials used for dense castables and lightweight castables are also different. Bauxite particles and powders with high density are generally used for heavy castables, and materials with low specific gravity such as floating beads and alumina hollow spheres are used as raw materials for lightweight castables.
The amount of water added to heavy castables and light castables is different, and the amount of water added to lightweight castables is larger than that of dense castables. Because lightweight castables have higher water absorption than dense castables.
The addition of binders for heavy castables and light castables is different. Lightweight castables are added more than heavyweight castable binders, the purpose of which is to increase the initial strength of lightweight castables.

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How to choose refractory castable?

Heavy castables and light castables are selected according to the characteristics of the castables. Dense refractory castables can exert the maximum performance of castables at different positions, different temperatures, and different degrees of erosion in the kiln, and different castables are used. Lightweight castables are made of materials with different bulk densities according to different kilns and different temperature requirements to play the role of heat insulation.

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Rongsheng refractory castable manufacturer

Castable is a kind of amorphous refractory material that does not need to be formed and has fluidity. It is composed of aggregates, powders, and binders according to technological proportions. Under certain conditions, it can replace the refractory brick products with complex shapes and a high degree of irregularity. It has the advantages of convenient construction, a short construction period, and light labor intensity. For more product information about refractory castables, please contact Rongsheng refractory castable manufacturer. Based on your specific needs, we will provide you with the product that best suits your thermal kiln production needs. Contact us for free samples and quotes.

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What is the Proper Bulk Density of Refractory Castable?

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Bulk Density and Apparent Porosity of Refractory Castables

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What is the Density of Low Cement Refractory Castables?

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Acid-Resistant Castables for Chemical Plant Chimneys and Pipes

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Precautions for the Use of Acid-Resistant Castables

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Application of Acid-Resistant Castables for Chimneys and Pipes

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Working Layer and Thermal Insulation Layer of the Rotary Kiln Lining

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What Refractory Castables are Used for Each Part of the Cement Rotary Kiln?

Cement Rotary Kiln Refractory Castable

Rongsheng Insulation Castable Manufacturer

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What kind of material should be used as the insulation layer when the kiln skin temperature is required to be 50°C?

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Can Lightweight Insulating Castables be Used Outside the Furnace Shell?

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Solutions to Reduce Kiln Skin Surface Temperature

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The main points of adding water during the construction of refractory castables

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How to judge the appropriate amount of water added to monolithic refractory castables?

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the appropriate amount of water added to monolithic refractory castables

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Alkaline castable magnesia refractory castable for rotary kiln

What is the composition of magnesia refractory castable?

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Mixing ratio and properties of magnesia refractory castable

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Rotary kiln refractory castable manufacturer

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Application of aluminum-magnesium refractory castable

The solution to cracks in aluminum-magnesium castables during use

Rongsheng Refractory Castable Manufacturer

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Low Cement Refractory Castable for Cement Kiln Lining

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Index of low cement refractory castable for cement kiln

How to cure and bake low cement castable in the rotary kiln?

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Preparation and Characteristics of Lightweight and High Strength Castables for Ladle Insulation Layer

Thickness Design of Ladle Insulation Layer

Production of tire molds

Pouring Construction of Castables for Ladle Insulation Layer

Baking of ladle insulation

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Rongsheng Unshaped Refractory Castable Manufacturer

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Classification of Commonly Used Refractory Castables

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What is the difference between dense castables refractory and lightweight insulation castables?

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How to choose refractory castable?

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Rongsheng refractory castable manufacturer

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