Refractory Blog Archives - Rongsheng Refractory Castable Manufacturer

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.

Lightweight High-Strength Castable for Steel Ladle

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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.

Rongsheng Refractory Castable Manufacturer

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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.

High-Quality High Alumina Castable of Rongsheng

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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.

Thermal Insulation Acid Resistant Refractory Castable for High Temperature Chimney

July 2, 2022 by rsrefractorycastable

Lightweight Thermal Insulation acid-resistant refractory castables are usually used for the lining of the chimney wall of the circulating fluidized bed boiler. On the lining of the chimney wall of the circulating fluidized bed boiler, the castable is used not only as an acid-resistant lining, but also as a refractory and heat-insulating layer, and no insulation layer is added.

The light acid-resistant castable is composed of light aggregate, powder, binder, and additives, and the main component of the binder is water glass. The lightweight aggregate structure has a large porosity, a rough surface, and a particle size of about 5mm, and the aggregate and powder have high water absorption and hygroscopicity.

Lightweight Acid-Resistant Castable For Chimney Wall Lining

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Lightweight acid-resistant castables have the characteristics of low bulk density, fast solidification, high service temperature, increased compressive strength with the increase of temperature and acidity, small thermal conductivity, and a small coefficient of linear expansion. However, lightweight Thermal Insulation acid-resistant castables have relatively high requirements for transportation and storage. This is because the manufacturer has prepared the aggregate and powder into a mixture when leaving the factory, and then packed it in a woven bag. When transported to the site, it needs to be temporarily stored in a warehouse with good drainage measures, rain-proof, moisture-proof, and dry.

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Features of Lightweight Thermal Insulation Acid-Resistant Castables

Lightweight Thermal Insulation acid-resistant castables are unshaped refractories that can be directly cast into linings as needed, and can also be made into prefabricated bricks.

Lightweight heat-insulating acid-resistant castables have the characteristics of high compressive strength, acid and acid gas corrosion resistance, light volume, and low water absorption. Thermal Insulation acid-resistant refractory castables fully play a role in thermal insulation in tall chimneys, high-temperature flues, and pipe linings. The light acid-resistant castable can ensure the compactness of the masonry when it is used in places with severe acid corrosion. It can also be used in acid-resistant projects such as acid-resistant pools and tanks in petroleum, chemical, non-ferrous metallurgy, and other industries.

Lightweight Thermal Insulation acid-resistant castables are easy to construct, have strong cohesion, and have a long initial setting time and construction operation time. The strength of the castable increases rapidly, the impermeability is strong, and no acid treatment is required. It is convenient to ensure the dense and full masonry ash joints, and can significantly improve the air tightness and integrity of the chimney lining wall and the anti-corrosion ability of the lining.

Lightweight Thermal Insulationacid-resistant castables need to be poured in layers, and the layered vibrating time should be shorter than the vibrating time of the castable. The amount of water added to the castable also needs to be strictly controlled, and the amount of water determines the performance and strength of the castable. Therefore, attention must be paid to the construction of the castable, and the mixed water should be added according to the construction standards of the castable.

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Matters needing attention in the construction of light acid-resistant castables

In the construction of castables, it is necessary to choose a more suitable construction environment, and a suitable temperature is a key to the construction of refractory materials. How much should the construction temperature of acid-resistant castables be controlled? Let’s find out together.

In the preparation of lightweight thermal insulation and acid-resistant castables, the main raw materials used are aluminate cement and light aggregates. Raw materials such as perlite aggregates are made by adding various additives such as high alumina fine powder and silicon powder. The product has the characteristics of light volume, high compressive strength, alkali resistance, acid gas resistance, heat insulation, heat preservation, and low water absorption. The lightweight Thermal Insulation acid-resistant refractory castable has the characteristics of convenient construction and convenient construction in the preparation process and is an ideal product for the construction of high-temperature acid-resistant components.

After talking about the characteristics of so many lightweight Thermal Insulation acid-resistant refractory castables, according to the structural characteristics of acid-resistant castables, what temperature should the construction temperature be controlled at? In the construction of castables, the construction temperature can be flexibly selected according to seasonal changes. In the summer construction environment, the construction temperature is about 20 to 30 ℃. When the temperature is too high in summer, the setting speed of the acid-resistant castable will be accelerated, but the strength of the castable will be affected. When the castable is prepared, a small amount of retarder can be added to slow down the setting process of the castable. In the winter construction environment, the construction temperature should be between 5°C and 10°C at room temperature, and the construction temperature should not be lower than 0°C. When the temperature is too low, an accelerator needs to be added to accelerate the setting of the castable.

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Thermal Insulation Acid Resistant Refractory Castable for High-Temperature Chimney Wall Lining. High-quality lightweight heat-insulating acid-resistant refractory castables, free samples, and quotations, please contact us.

Industrial Kiln Insulation Refractory Castable for Sale

June 10, 2022 by rsrefractorycastable

With the development trend of the integration of the global economy, resources, and environment, industrial kiln technology and equipment level are facing great challenges, and it is imperative to save energy and reduce emissions. Therefore, the development of industrial kilns must take a sustainable development path with high technological content, good economic benefits, low resource consumption, and less environmental pollution. Therefore, more and more industrial kilns now put forward higher requirements on the thermal insulation layer of the kiln body. This is also a great challenge for refractory manufacturers. Rongsheng refractory castable material manufacturer, through years of accumulated experience in the use of industrial kiln lining refractory materials, is more careful and perfect in the configuration and design of materials for the thermal insulation layer of industrial kilns. Rongsheng has made greater breakthroughs in the production of unshaped monolithic refractory castables for industrial kilns. Industrial Kiln Insulation Refractory Castable for Sale, contact Rongsheng for free samples and prices.

High-Quality Lightweight Insulation Castables for Industrial Kilns

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Industrial Kiln Insulation Refractory Castable for Sale

The design of the thermal insulation layer of the industrial kiln slows down the loss of temperature in the kiln, reduces thermal energy consumption, and saves fuel costs. On the one hand, it ensures the safety of production, and on the other hand, it is of great help to save production costs and prolonging the operating life of kiln furnace equipment. So, how is the thermal insulation layer of industrial kilns generally designed?

In the design of the thermal insulation layer of industrial kilns, the materials generally used are ceramic fiber products, thermal insulation bricks, and thermal insulation refractory castables. These materials, according to the different working conditions of different industrial kilns, choose different materials of thermal insulation bricks and thermal insulation refractory castables for industrial kilns and configure different indicators.

Insulation refractory castable is also called lightweight refractory castable, thermal insulation refractory castable. The Industrial Kiln Insulation Refractory Castable is mainly composed of light thermal insulation aggregate, added with refractory powder, together with bonding material and admixture. A hydraulic unshaped thermal insulation material is prepared by dry mixing according to the optimum ratio. It has the characteristics of low bulk density, low thermal conductivity, and high thermal insulation performance, and can be constructed and poured on-site. Lightweight refractory castables, also known as lightweight insulating castables, are widely used in the thermal insulation layer of boilers, industrial kilns, and other equipment bodies. It is mainly used for heat preservation of kiln and to prevent the loss of heat energy.

Industrial Kiln Insulation Refractory Castables for Sale in Rongsheng — Industrial Kiln Insulation Refractory Castables for Sale

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Classification of Industrial Kiln Insulation Refractory Castables

Insulation castables are used for boiler linings and are generally used as insulation linings. The use temperature is generally under 1000 ℃. Thermal insulation refractory castables are classified into the following three categories according to the operating temperature.

Low-temperature lightweight castable, the operating temperature is 600℃-900℃.
Medium temperature light castable, the operating temperature is 900℃-1200℃.
High-temperature lightweight castable, the operating temperature is >1200℃.

Lightweight castables with bulk densities of 0.8 and 1.0 are common for thermal insulation castables. Lightweight castables with a bulk density of 0.8 or 1.0 can also be used for thermal insulation refractory castables for industrial kilns. In the refractory industry, thermal insulation castables can also be divided into 3 categories according to their bulk density.

Semi-light castable (1.0-1.8 g/cm3)
Lightweight castable (0.4-1.0 g/cm3)
Ultra-light castable (less than 0.4g/cm3)

Industrial Kiln Insulation Refractory Castables Construction

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Properties of thermal insulation castables for industrial kilns

The selection of the thermal insulation layer lining of the industrial kiln generally refers to the operating temperature and thermal conductivity. In the end, it is necessary to select an insulating castable with a suitable bulk density. The smaller the bulk density of the Industrial Kiln Insulation Refractory Castables, the smaller the thermal conductivity, and the better the thermal insulation performance. During the production of thermal insulation castables, high-index thermal insulation castables can also be customized according to requirements. Insulation castables of different materials are used in thermal insulation layers of boilers and high-temperature kilns at different temperatures.

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Buy High-Quality Insulation Castables for Industrial Kilns

Rongsheng refractory castable factory can provide unshaped monolithic refractory castables for thermal insulation layers for various industrial kilns. Moreover, Rongsheng Environmental’s advanced monolithic refractory castable production line provides a production guarantee for refractory castables of various raw materials used in industrial kilns. Please use it in strict accordance with the construction and storage instructions of the unshaped refractory materials when you use the unshaped refractory castable. The quality of our monolithic refractory castables products is guaranteed, and our perfect after-sales service system can also provide reliable solutions for your refractory lining problems. To purchase high-quality Insulation Castables for Industrial Kilns, please contact us.

The Differences Between the Three Different Monolithic Refractories

April 19, 2022 by rsrefractorycastable

Refractory mortar, refractory cement, and refractory castables are all monolithic refractories, and they are commonly used in the refractory industry. So, what are the differences between these three different monolithic refractories? Simply put, refractory mortar is used for masonry refractory bricks. Therefore, refractory mortar is also known as refractory mortar or joint compound. Refractory cement is one of the materials for making refractory concrete and is generally used as a binder. Refractory castables are sometimes referred to as refractory concrete. It is made of refractory aggregates, powders, and binders, and is also called refractory castables because of its pouring construction.

The Difference Between Three Different Amorphous Refractories

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Refractory Mortar

Refractory mortar can be divided into fireclay, high alumina, silica, and magnesia refractory mortar according to the material. It is composed of refractory powder, binder, and admixture. The general refractory mortar is made of refractory clinker powder and an appropriate amount of plastic clay as a binder and plasticizer. Its normal temperature strength is low, and it has high strength only when it constitutes a ceramic bond at a high temperature. The particle size of refractory mortar varies according to the application requirements, and its limit particle size is generally less than 1mm, and some are less than 0.5mm or finer.

The material of refractory mortar should be considered together with the material of masonry refractory products. In addition to being used as a joint material, refractory mortar can also be used as a maintenance coating for the lining body by the modification method or the spray method.

refractory castable cement — High-Temperature Refractory Cement

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Refractory Cement

Refractory cement is also called aluminate cement. Aluminate cement is a hydraulic cementitious material obtained by calcining bauxite and limestone as raw materials, clinker with calcium aluminate as the main component and alumina content of about 50%, and then grinding. Aluminate cement is often yellow or brown, but also gray. For the lining of industrial kilns.

Refractory Castables (Refractory Concrete)

What is refractory concrete? What is refractory concrete composed of? Refractory concrete is composed of refractory aggregate, refractory powder, and cement or admixture in a certain proportion. After stirring (the cement should be mixed with appropriate water), molding and curing, it can be used directly. Generally, it is also called refractory castable.

Refractory castable is a kind of monolithic refractory that is widely produced and used. It is mainly used to construct the overall structure such as the lining of various heating furnaces. Certain high-quality varieties can also be used in smelting furnaces. For example, aluminate cement refractory castables can be widely used in various heating furnaces and other thermal equipment without slag and acid and alkali corrosion. The parts that are corroded by molten iron, molten steel, and slag have a high working temperature, such as tapping groove, ladle and blast furnace shaft, tapping ditch, etc. In some parts of metallurgical furnaces and other vessels that are in direct contact with slag and molten metal, repairing with high-quality phosphate refractory castables also has excellent results.

castable refractory concrete — High-Alumina Castables Refractory

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Refractory concrete can generally be divided into two categories, shaped refractory products, and bulk refractory materials.

Shaped refractory products. Including prefabricated components, prefabricated blocks (unit weight less than 30 kg), and unburned bricks produced by vibration, machine pressing, ramming, and vibration pressing. Such products are generally factory-produced, with stable quality, regular size, and less template consumption.
Bulk refractory materials. Including refractory aggregate, refractory powder, cement, etc., as well as the mixture of the above-mentioned several raw materials in proportion, and leaves the factory in bulk form. During construction, appropriate water or liquid binder should be added to the bulk material, which can be formed by any method.

An important feature of refractory concrete is that it does not require pre-calcination, and can be used to directly build a furnace, or it can be assembled with prefabricated components and used after baking. Therefore, refractory concrete has many advantages over fired refractory bricks.

Advantages of Refractory Concrete

The production process of refractory castable concrete is simple, usually, only construction equipment such as concrete mixers and vibrators are used, and there is no need for huge brick presses and firing equipment. Therefore, the construction of refractory concrete plants requires less investment, a quick start, and great results. And it can save a lot of fuel and electricity, the production cycle is short, and the production efficiency is high.
The refractory concrete is easy to construct and manufacture, can be arbitrarily shaped and can meet the various requirements of production for thermal equipment. Some special parts of thermal equipment are difficult to be made of fired bricks, and refractory concrete can be used. In addition, refractory concrete can be made into a composite lining that is light and heavy. This reduces the thickness and reduces the overall weight of the kiln. It not only saves materials and fuel but also uses less steel. Refractory concrete can also be equipped with a small number of steel bars, which are both used as linings and load-bearing. The steel envelope can be partially or completely removed.
In addition to the commonly used vibration molding process, refractory concrete can also be constructed by various process methods such as spraying, ramming, or machine pressing according to engineering characteristics and production needs. Suitable for new construction, renovation, and hot and cold repair of furnaces and thermal equipment. Especially when using prefabricated components and spraying, the furnace construction can be mechanized, greatly shortening the construction period and speeding up production and construction. In the process of kiln and thermal equipment production, the damaged prefabricated components can be replaced without stopping, and the furnace lining can be thermally repaired by spraying a new process, thereby improving the operation rate of the kiln.
Kilns and thermal equipment made of refractory concrete have strong integrity and good airtightness. The reasonable application can increase its service life by 30~150%, and some are as high as 8~5 times. This not only improves the operation rate but also reduces the consumption of refractory materials and saves the cost of building the furnace.
The raw materials used in refractory concrete, in addition to the raw materials for making bricks, can also use some industrial slag, waste refractory bricks, and local or natural materials. That is to say, it uses a wide range of materials, which is convenient for comprehensive utilization of resources, and opens up a broadway for the refractory industry.
The production and construction of refractory concrete furnaces have good working conditions, low labor intensity, and high efficiency. Furnace builders can get rid of the tile knife, creating conditions for the realization of mechanized furnace construction.

From the above, we can see that although the three products are all monolithic refractories, their uses are quite different. And each product is divided into different models and types. Therefore, when purchasing, you can consult professional technicians and choose suitable products, so as not to delay the construction period and cause unnecessary losses.

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In a word, the development and adoption of new refractory concrete materials can promote the technological innovation of refractory production and kiln structure, save fuel, power, financial resources, and manpower, and realize mechanization of production and construction. Achieve the purpose of prolonging the life of the kiln, reducing the consumption of materials, and increasing production. Therefore, refractory concrete is a new type of refractory material with broad development prospects. Rongsheng refractory manufacturer has rich experience in the production and design of various unshaped refractory materials. Provides high-quality, long-life refractory lining materials for a variety of furnace types. Rongsheng refractory manufacturer will become your best choice for purchasing unshaped refractory materials.

Refractory Mud VS Refractory Cement?

November 23, 2021 by rsrefractorycastable

High alumina refractory mud is different from high alumina cement.

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The difference between them is: high alumina refractory clay is a refractory material used in the joints of refractory bricks, and the sheet material is high aluminum powder plus a certain proportion of binding agent and coagulant. After adding water or adding liquid binder, stir it into a slurry, and apply it on the surface of the refractory brick to adjust the size deviation. It can make the refractory bricks form a tight whole to prevent the damage of high temperature and external force. In other words, it is the fire clay for bricklaying. It is a finished solid powder.

High alumina cement is a kind of binder in the application of refractories. High alumina cement is also called aluminate cement. It is clinker with 50% alumina content calcined with bauxite and lime. Aluminate cement is yellow or Brown, high grade high alumina cement is white. The labels are 625#, 725#, 925# and CA70, CA80.

High alumina cement is closely related to refractory materials and can be used as a binder for various castables. In addition, some 525# and 425# refractory cements are equipped with gypsum bauxite for construction and special projects. High alumina cement has a good coagulation effect in the castable, which will make the castable have high temperature resistance and good strength. It is a raw material for refractory materials.

The high alumina refractory clay cement is also divided into multiple grades, and is used for building a variety of multi-material refractory bricks. It is divided into high alumina refractory mud and phosphoric acid refractory mud.

Although both high alumina refractory mud and high alumina cement are powdered materials, there is a big difference between high-alumina refractory mud and high alumina cement. High alumina refractory mud is processed into powder with high-alumina particles smaller than 180 mesh, plus some binders. , A synthetic material made of coagulant. The high alumina cement is the finished material after calcining bauxite and lime.

Therefore, high alumina cement and high alumina refractory mud are completely different products, but they are closely related to refractory materials. It is also one of two varieties with a large proportion among refractory products.

What is the Damage Form of the Refractory Castable for Ladle?

July 31, 2021 by rsrefractorycastable

The castable for ladle, in terms of material, was originally based on “Zirconia-Silicon” stone. However, with the requirement of clean steel and the increase of secondary refining, the high-durability alumina spinel is gradually adopted. During this period, tests were also done on magnesia-based alkaline materials, but they were not put into practical use due to the inability to suppress structural peeling. Therefore, in terms of extending the service life of the ladle, understanding the damage mechanism of the castable for the ladle is a very important link. Refractory manufacturers and steel mill customers have conducted a series of studies on the damage pattern of the castable for ladle.

Steel Ladle Working Conditions — Steel Ladle

The Damaged Appearance of Castable for Ladle

Regardless of shaped or unshaped refractories for ladle, the slag line, molten steel parts, and the bottom of the ladle will be damaged to varying degrees.

Damage to the slag line

At the position equivalent to the “slag-steel” interface, the damaged surface is smooth and deep with a clear outline. The reason for making it smooth is that the damage is mainly corrosion, but there are also cracks. Recently, due to the use of alumina spinel castables, satisfactory durability has not been obtained. Therefore, magnesia carbon bricks are mostly used. The damage rate is 1~2mm/furnace, and it needs to be repaired after about 100 furnaces are poured.

Damage to the molten steel

The corrosion damage is very small under the current materials and uses conditions, and the cracks and the peeling caused by their expansion are the main damages. Repeated peeling affects the life span. On average, the damage rate of “zirconium-silica” stone is 1 mm/furnace, and alumina spinel is 0.3~0.5mm/furnace. Now the most durable alumina spinel has a life span of 250 to 300 furnaces. Since the molten steel part is the main part that determines the life of the ladle, the damage of this part needs to be paid attention to.

The bottom of the package is damaged by the steel part

Due to the impact of molten steel, the steel parts during pouring steel wear and then develop into cracks, where molten steel penetrates to affect the service life. Use alumina castable prefabricated block, which needs to be repaired after about 100 times of pouring.

Damage Patterns of Refractory Materials for Ladle

The characteristics of the damage of the castable are that although there is no damage to the brick joints, cracks of varying sizes and seldom occur hot spalling instead. The damage of ladle castables is also the same as before, which can be divided into the following three aspects.

Corrosion, continuous loss caused by surface or internal melting.
Mechanical wear, loss caused by the impact of molten steel, etc.
Spalling, falling of refractory lining caused by high temperature, machinery, structure, etc.

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It is rare that corrosion is the main factor in molten steel. At the part of the molten steel where the working face is spalled in layers, the structural spalling caused by slag penetration, that is, the cracking caused by the structural thermal stress is the main cause of damage. However, for alkaline materials and some alumina spinel castables, cracks also occurred in the original layer, and thermal spalling occurred, mainly due to the cracks caused by the concentration of thermal stress.

The temperature of molten steel, the composition of slag, and the residence time of molten steel have a great influence on the damage of refractory materials. After discovering the damage of the refractory layer of the ladle, the analysis of the related damage mechanism will be of great help to prolong the service life of the ladle. To purchase refractory castable for ladle, please contact the refractory castable manufacturer.

Two Questions and Answers about Refractory Castables Used in Furnace Lining

June 16, 2021June 10, 2021 by rsrefractorycastable

With the increase in the use temperature and service life of various high-temperature kilns and thermal equipment, refractory castables are widely used in production and use as unshaped refractory materials. In the modern era of rapid industrial technology, there are many types of refractory castables. Compared with refractory bricks, the advantages of using refractory castables are simple to process, energy-saving, low cost, and easy mechanized construction. It has been widely used in various types of thermal equipment such as cement, steel, glass, and electric power. As a result, the use of refractory castables in high-temperature kilns often encounters some problems. Experienced unshaped refractory castable manufacturers will take you to understand these problems and provide you with the most suitable refractory castable lining solution for your production needs.

Question 1: The operating temperature of the kiln is 1500℃, what refractory castable should be used?

When the temperature of the working part of the kiln is 1500℃, corundum castable should be selected according to the use temperature of the refractory castable. Many users do not understand but think that the price is high, so they choose general high-aluminum castables.

However, if the direct use temperature is 1500°C, the general high-aluminum castable is not acceptable. The brown corundum castable must be selected to meet the application requirements. There are also users who propose to use steel fiber castables, which is not acceptable. Because steel fibers begin to melt at temperatures above 1300°C. Therefore, steel fiber castables cannot be used.

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However, some customers choose to use stainless steel. The answer given by refractory manufacturers is still no. Because the stainless steel used for the lining only serves as an anchor, it cannot resist high temperature and corrosion. The characteristics of corundum castable are the highest bulk density, lowest apparent porosity, high-temperature resistance, corrosion resistance, and thermal shock resistance. And at 1500℃, the characteristics of corundum castable can be fully reflected. If steel fiber castable is used, it cannot withstand the high temperature of 1500℃. The general high-aluminum castables can be used at a temperature of 1300℃-1400℃.

Refractory castable manufacturers pointed out that if it is a different kiln, the working atmosphere inside the kiln is different and the degree of erosion is different, corundum wear-resistant castable or high-strength wear-resistant castable can also be selected. In this way, it is resistant to both high temperature and corrosion. For example, waste incinerators have low temperatures, but strong corrosion, sometimes with acid and alkali corrosion. At this time, the choice of corundum castable is not acceptable, the temperature is not high, and the corundum cannot be fully used. Wear-resistant castables with clean raw materials can be used to resist acid or alkali corrosion. Moreover, the price is lower than that of corundum castable, and it is also suitable for the special use of incinerators.

In short, no matter what kind of refractory castable is selected, the appropriate refractory castable must be selected according to different kilns, different temperatures, and different degrees of erosion.

Question 2: How much is a ton of corundum steel fiber refractory castable for the rotary kiln?

Corundum steel fiber refractory castable is a high-quality refractory castable. It uses special grade bauxite clinker and sintered corundum as refractory aggregates and admixtures, and calcium aluminate cement as a binder. Unshaped refractory material mixed with a small amount of water reducing agent and a certain proportion of wear-resistant and heat-resistant steel fibers of different sizes and diameters using micro-powder technology. It is castable with good fluidity, high strength, good wear resistance, and good thermal shock resistance.

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The corundum steel fiber refractory castable has a good effect. Corundum steel fiber castables with different physical and chemical indicators are used in different industrial furnaces, such as steel-making electric furnaces, tundishes, heating furnaces, rotary kilns, and other thermal equipment. So, how much is a ton of corundum steel fiber refractory castable for the rotary kiln?

Generally, the price of corundum steel fiber castable is about 6,500 yuan per ton. However, there are many factors affecting the price of castables, and the details need to be determined based on the actual kiln situation and the use of castables.

The price of corundum steel fiber castable is a reference factor when customers purchase. But what you pay for is what you pay for. Refractory castables are different from other refractory products. Its quality is not only about the price, but also about the application. The better the effect of the application in high-temperature kilns, the more expensive it is. When purchasing high-quality corundum steel fiber refractory castables, it is best to provide refractory castable manufacturers with the working conditions of the furnace, such as operating temperature and service life. Then the refractory manufacturer will have a technical team to provide corresponding castable solutions to ensure the use of corundum steel fiber castables and calculate the cost of purchasing refractory castables.

To learn more about refractory castables for furnace refractory linings, please continue to follow our blog. For the price of high-quality refractory castables, please contact us.

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The Damaged Appearance of Castable for Ladle

Damage to the slag line

Damage to the molten steel

The bottom of the package is damaged by the steel part

Damage Patterns of Refractory Materials for Ladle

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Question 1: The operating temperature of the kiln is 1500℃, what refractory castable should be used?

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Question 2: How much is a ton of corundum steel fiber refractory castable for the rotary kiln?

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