KilnRefractory, Author at Kiln Refractories Blog

Refractory Castable for All Kinds of Coal-Fired Boilers in Power Plants

June 5, 2023June 5, 2023 KilnRefractory

With the development of modern large power plant boilers, the requirement for refractory material for boiler wall structures has changed greatly. The refractory materials of furnace walls are developed from traditional firebrick to refractory concrete, refractory castable, plastic refractory, refractory ramming material, smearing material, spray coating, and so on. With the development of refractory materials for large power generation equipment and boilers, the use of these materials has promoted the development of refractory materials for domestic boilers. castable refractory for the boiler. Power plant boiler due to different parts of the temperature and use requirements, a boiler has 610 kinds of refractories with different performance requirements.

Refractory Castable for CFB Boilers in Power Plants

Refractory Castables for All Kinds of Coal-Fired Boilers in Power Plants

The furnace type of coal-fired boiler in power plants is related to the coal type. At present domestic refractories can basically meet the needs of various boilers.

The liquid slag-discharging furnace and cyclone furnace are used for burning coal with low melting point ash. Because of the high temperature of the furnace, the refractory should have the characteristics of high-temperature resistance, wear resistance, thermal shock stability, high thermal conductivity, and slag resistance. Generally use silicon carbide ramming material.

The combustion of low-volatile coal generally adopts a “W” flame, and the furnace is equipped with a backburner belt. Adopt wear-resistant, high thermal conductivity, and good thermal shock stability of refractory materials. General selection of silicon carbide, chromium coating material, and high aluminum plastic.

The circulating fluidized bed boiler burns coal with low calorific value and high sulfur content. High ash concentration, high flow rate, and serious wear. General selection of corundum, silicon carbide wear-resistant, refractory castable.

The incinerator of the waste power plant is affected by the burning condition, and the refractory material is required to have fire resistance, volume stability, heat shock resistance, corrosion resistance, high strength, and wear resistance. Therefore, spray coating, castable, silicon carbide brick (board) is selected.

The selection of refractory materials for the boiler, refractory materials with good performance, remarkable effect, and reasonable price. Such as boiler tube furnace wall, furnace top, and flue equipment lining, promote the application of fast hard (micro expansion) refractory castable plastic. The double arch “W” flame furnace flame belt is made of high aluminophosphate combined with refractory plastic and silicon carbide coating. Circulating fluidized bed boiler and HR collection box selection of jade, silicon carbide castable, and plastic.

Strengthen the research and development of new refractories. For example, the development of high-temperature resistance, high strength, and wear resistance of the refractory coating, ramming, and spray coating without heat treatment. To simplify the process and improve the quality of the project. The lightweight castable with fibrous, expanded perlite, and vermiculite gradation was studied.

Refractory Castable Material for Circulating Fluidized Bed Boilers in Power Plants

In the fluidized bed boilers of the power plant, high temperature, high pressure, and erosion are very serious. It requires high-quality refractory castables, resulting in longer life and more efficient vulcanization furnaces in power plants. The specific type and performance requirements should be adjusted according to the actual situation of the boiler and should be used with a firebrick. Please contact Rongsheng Refractory for high-quality monolithic castable refractory for the power plant.

The following information about the use of refractory castables for circulating fluidized bed boilers in power plants is for reference only. Case by case analysis, Rongsheng refractory manufacturers, according to your actual work needs, for you to customize the formulation of amorphous refractory. Burner: refractory castable refractory 120mm +215mm +lightweight castable refractory. Top: Refractory castable, refractory plastic 48mm ~60mm. Manhole door: refractory castable and water-cooled wall flat. Test hole: refractory castable and water wall flat. Boiler roof: refractory insulation slips. Smoke Angle: The refractory castable is water-cooled wall flat. Burner wall: refractory tamping material, refractory plastic. Top of heat seal cover: 20 ~ 40mm aluminum silicate felt + 50 ~ 60mm refractory plastic.

Expansion joint of ceiling pipe: filled with aluminum silicate cotton. Non-thermal seal cover top: 20mm aluminum silicate felt +100mm refractory plastic. Furnace top and top tube: aluminum silicate cotton felt, aluminum silicate tube shell, or silicate composite insulation products. E Gas, water connection box, all kinds of pipe baffle: refractory castable. Sanitary belt: tamper. Slag funnel lining, which requires high strength and good thermal shock resistance. 900 ~ 1200℃, steel fiber high alumina refractory castable. High-temperature furnace smoke pipe lining: aluminum silicate cotton felt insulation layer, refractory layer water glass fast refractory plastic or steel fiber high aluminum cement castable.

RS Steel Fiber Refractory Castable Manufacturer

Special castable for burner; Easy to burn parts: free roasting quick supplement, quick drying castable, outlet pipe, tube wall inner layer: expansion high aluminum castable, fast hard micro expansion plastic; Combustion chamber furnace: wear-resistant castable, slag resistant and wear-resistant castable, steel fiber reinforced castable, far infrared radiation coating, high temperature filling joint pressed into cement; Steering flue: wear-resistant castable; Cyclone separator: wear-resistant castable, corundum high strength wear-resistant castable; Coal nozzle.

Steel fiber reinforced castor refeeder: wear-resistant castable; Diaphragm wall: wear-resistant castable; Water-cooled chamber: wear-resistant castable; Ignition duct: wear-resistant castable; Furnace collection: wear-resistant castable in the furnace.

Rongsheng factory is a strong refractory manufacturer. Professional refractory technical team, environmental protection of automatic amorphous refractory production line. Specializing in the production of various castable refractory for boiler, such as lightweight castable refractory, refractory plastics, refractory ramming materials, high strength wear resistant refractory materials, etc. Please also contact the refractory castable manufacturer to compare RS Refractory Castable with Calderys castable. After all, you can shop around for affordable refractory products. If you also want to obtain better customer service, please choose the strength of Rongsheng refractory manufacturers, +86 185 3831 2977.

How to do High Temperature Industrial Kiln Insulation?

May 16, 2023 KilnRefractory

Insulation materials commonly used in industrial kiln equipment include insulation bricks, insulation castables, aluminum silicate fiber series, ceramic fiber series, calcium silicate series, etc. The outstanding performance of this kind of thermal insulation material is that it can play the role of heat preservation and heat insulation. There are many kinds of high-temperature-resistant insulation materials, and their economy and performance should be considered when used in the insulation layer of kilns, so as to achieve energy saving, conservation, and environmental protection. How to do high-temperature industrial kiln insulation?

Rongsheng K23 Insulating Firebricks for Kilns

What are kiln insulation materials?

High-temperature kiln insulation materials, and refractory materials for industrial boilers are divided into two categories: heavy refractory materials and light refractory materials. Heavy refractory materials mainly include refractory bricks, refractory castables, etc. Lightweight refractory materials mainly include ceramic refractory fibers, thermal insulation materials, etc. Lightweight refractory materials require lightweight and good heat insulation performance, which helps to reduce the quality of the furnace wall and heat loss. Rongsheng is a supplier of lining materials for high-temperature industrial kilns and can provide various light and heavy insulation materials for high-temperature industrial kilns. Such as aluminum silicate insulation materials, k23 insulating firebrick, various lightweight insulation bricks, refractory insulation castables, etc.

Ceramic Fiber Insulation Aluminum Silicate Fiber Blanket

Aluminum silicate insulation material

Aluminum silicate thermal insulation material is widely used in the field of high-temperature refractory at present, and there are many types of products. Aluminum silicate needle-punched blanket, aluminum silicate felt, aluminum silicate loose cotton, aluminum silicate board, aluminum silicate module, and other products.

Aluminum silicate wool is made of selected high-quality coke gemstones that are melted in an electric furnace above 2000°C, blown into fibers by mechanical spraying, and uniformly added with special binders, oil-repellent agents, and water-repellent agents, and cured by heating. Mainly used in the electric power industry, electric boiler, steam turbine, and nuclear power heat insulation, fireproof heat insulation in the shipbuilding industry, construction industry, and fireproof heat insulation of fire doors. Wall lining of high-temperature reaction equipment and heating equipment in the chemical industry, automobile and train manufacturing, fire prevention, heat insulation, kiln lining, furnace door, and top cover. Among them, aluminum silicate needle-punched blankets are widely used. Its temperature range is generally between 600 and 1600 degrees.

Electric Furnace Accessories – Three Insulation Materials for High-Temperature Electric Furnaces

The heart of the high-temperature electric furnace has refractory materials and insulation materials. Everyone should know about refractory materials, so what are the insulation materials? There are three main types of insulation materials for high-temperature electric furnaces.

Insulation cotton. High-purity clay clinker, alumina powder, silica powder, chrome sand, and other raw materials are melted at high temperatures in an industrial electric furnace to form a fluid. Then use compressed air to spray or use a spinning machine to spin the silk into fibers, and collect the cotton through the cotton collector to form thermal insulation cotton.
High alumina brick. Usually, high-alumina bauxite clinker is used to add a small amount of clay, after being ground, it is cast and formed in the form of mud by gas generation method or foam method and fired at 1300-1500 °C. Sometimes industrial alumina can also be used to replace part of the alumina clinker. It is used for the inner lining and heat insulation layer of masonry kilns, and the parts without strong erosion and erosion of high-temperature molten materials. When in direct contact with the flame, the surface contact temperature shall not be higher than 1350°C.
Silicon carbide (SiC). Quartz sand, petroleum coke (or coal coke), wood chips (salt needs to be added when producing green silicon carbide), and other raw materials are smelted through resistance furnaces at high temperatures. Silicon carbide also exists in nature as a rare mineral, moissanite. Silicon carbide is also called moissanite. Among the non-oxide high-tech refractory raw materials such as C, N, B, etc., silicon carbide is widely used and economical, and can be called corundum or refractory sand.

How to do insulation for kilns?

The insulation layer material mainly plays the role of heat preservation and heat insulation through heat transfer. The ways of heat transfer are convection, conduction, and radiation, and the mutual help between them. Since the thermal insulation and heat insulation refractories of Rongsheng Refractories (https://kilnrefractory.com/) are composed of gas and solid phases, heat is also transferred through the phase interior and phase interface. The key to the heat preservation effect of insulating and insulating refractory materials lies in its organizational structure, and solid-phase heat transfer is still the main way of heat transfer, even at 1500 °C. Therefore, compared with dense refractory materials, the porous structure of thermal insulation materials can be regarded as a solid phase separated by a gas phase, which changes from gas-phase conduction to gas-phase conduction, thereby reducing thermal conductivity.

Thermal conductivity is an intuitive indicator of the performance of insulation materials. Factors affecting the thermal conductivity of thermal insulation materials include material, porosity, opening state, humidity, and ambient temperature. Various materials have different thermal conductivity. Rongsheng refractory insulation materials with different performances require different thicknesses of insulation layers to meet the design thermal resistance requirements. The thermal conductivity of the same material is different, and the bulk density is also different. The material has a high porosity and a good thermal insulation effect.

The quality of thermal insulation performance depends on the thermal conductivity of the thermal insulation material. The smaller the heat conduction, the better the heat preservation and insulation effect. Thermal conductivity is related to the composition of the material itself, apparent density, internal structure, average temperature, and moisture content of the material during heat transfer. In general, the lighter the surface density, the lower the thermal conductivity. However, for loose fiber materials, when the apparent density is less than the optimal limit value, the thermal conductivity increases with the decrease of the apparent density.

When the apparent density, average temperature, and water content of the material are exactly the same, the more pores per unit volume of the porous material, the smaller the thermal conductivity. The thermal conductivity of loose granular materials decreases as the number of particles increases. The thermal conductivity of loose fiber materials decreases as the cross-sectional area of the fibers decreases.

The design and construction of good insulation layer refractory materials can not only prolong the service life of industrial kilns and save production costs, but also an important guarantee for safe production.

What Kind of Refractory Castables Can be Used When the Working Temperature is 1300℃?

April 27, 2023April 27, 2023 KilnRefractory

What kinds of refractory castable should be used when the refractory castable is used at a temperature of 1300°C? This is determined according to the different working conditions of different furnace types. But no matter what castable you choose, the ultimate goal is to save energy, reduce production costs, and prolong the service life of the refractory lining.

When choosing castables for high-temperature industrial furnaces, whether it is to choose castable manufacturers or distributors of monolithic refractory materials. First of all, the fuel used in the high-temperature industrial furnace and the material of the raw materials required in the production process must be considered. And whether there are highly corrosive substances in the raw material composition, it is also necessary to determine whether the corrosive substances are acidic or alkaline. In addition, there are external factors of the furnace type to be considered, whether there is wind speed, erosion and wear caused by mechanical stress, etc.

RS Monolithic Refractory Castable Factory

The furnace temperature of 1300°C is the direct contact temperature of the flame, not the refractoriness. This temperature definition is very important. High alumina castables are also divided into different grades and different substrates. If the castable solidifies too quickly in the early stage, it proves that the amount of cement added is too large, or there is a problem with the control ratio of the binder and the micro-powder, which will affect the strength of the castable later.

If the setting time is too slow, the construction temperature should be considered, and the amount added should be well controlled when adding water. When the temperature is low, the drinking water should be heated to 30°C, and then added to the material and mixed for use. If congealed within 40 minutes. Then bake according to a reasonable baking system to ensure the service life of the refractory castable.

Generally, high-alumina castables can be used for the furnace temperature of 1300°C, but if the corrosion is severe, it is necessary to choose acidic or alkaline corrosion-resistant castables according to the nature of the corrosion. If it is acidic corrosion, you can choose water glass bonded castable or phosphoric acid bonded refractory castable, if it is alkaline corrosion, you can choose high wear-resistant castable. Because the high wear-resistant castable is added with silicon carbide, it can resist erosion and play a role in wear resistance.

Application Advantages of Low Cement Castables

The prominent feature of low-cement castables is their dense and high strength, which brings benefits to use but brings troubles to baking, that is, improper baking, prone to peeling or bursting. Therefore, it is very important to formulate a reasonable oven curve and use an excellent explosion-proof admixture, so that the moisture in the molded refractory castable can be removed smoothly without causing any side effects.

The thermal expansion coefficient of low cement refractory castables shows the characteristics of expansion during the whole heating process. It can be seen that as the heating temperature increases, the thermal expansion rate increases, reaching a value of about 0.68% at 1250 °C. Then it began to shrink slowly, and the thermal expansion rate at 1400°C was 0.43%. When the temperature is 1500°C, the thermal expansion rate returns to 0.5%.

Low-cement refractory castables have a wide range of applications. In industrial kilns such as metallurgy, petrochemicals, machinery manufacturing, electric power, and building materials, such castables have been widely used to replace traditional fired refractory products as linings. Low-cement and ultra-low-cement refractory castables are mainly used as linings of thick dimensions, such as linings for heating furnaces, various heat treatments, electric furnace covers, shaft kilns, rotary kilns, blast furnace tapping hooks, ladles, ladles, etc. The self-flowing low and ultra-low cement refractory castables are mainly used as thin linings and linings of high-temperature refractory components with metal anchors, such as outer linings of water-cooled pipes for heating furnaces, and integral spray gun linings for spray metallurgy.

As the heating temperature rises, the cement stone is gradually sintered, and the crystal form of the castable body begins to transform into mullite crystals. As the temperature continues to rise, the mullite crystals continue to grow, and the matrix glass phase in the castable is in a liquid state, forming a high-temperature ceramic sintered shape, and the strength is significantly improved.

Low-calcium high-alumina cement is a hydraulic material like ordinary cement, and it undergoes hydration reaction and hardening after contact with water. Low cement castable, its main feature is high early strength, 3-7 days room temperature compressive strength can reach more than 30MPa. The disadvantage is that the medium temperature volume stability is poor, and the strength is reduced, and the decline can reach about 40%. Therefore, it is required that the compressive strength at room temperature must meet the requirements of design and national standards. The main factor for the decrease in medium temperature strength is. When the low-calcium and high-alumina cement of the castable body reaches a certain temperature (about 350°C) during the heating process of the heating furnace, the hydrates begin to dehydrate and transform to reduce the cement stone structure, compactness, and strength of the hydrates. The volume of the castable changes and the strength of the castable body drops to a low point at this time and then tends to be stable.

For high-quality refractory manufacturers, please choose RS Kiln Refractory Factory, at sales@kilnrefractory.com to purchase refractory materials with high-temperature resistance of 1300℃.

Construction and Repair of High Temperature Castable Refractory Linings

April 4, 2023April 4, 2023 KilnRefractory

The construction technology of refractory castables is an important aspect that affects the use effect of High Temperature Castable Refractory Linings. Therefore, the construction of high temperature castable refractory is also the key to the service life of refractory castables in kilns. This is related to the service life and maintenance cycle of the refractory lining of the high-temperature kiln.

Rongsheng High Temperature Castable Refractory

Construction Technology of High Temp Castable Refractory

1) Preparation of High Temp Castable Refractory

◇The ratio of raw materials for High Temp Castable Refractory must be strictly in accordance with the design or manufacturer’s technical instructions. It can only be applied to the construction project after being confirmed by the trial matching test, and all kinds of materials should be measured accurately.
◇Mixing method adopts forced mixer. The mixing water should be drinking water, and the amount of water added should be strictly controlled during the stirring process. The feeding sequence and mixing time are in accordance with the instructions or technical requirements of the supplier. When sporadic materials are used, manual stirring can be used, and at least 4 back and forths should be stirred.
◇Adopt the principle of a small amount of frequent stirring. The High Temp Castable Refractory has rapid hardening after mixing, and the mix should generally be used up within 30 minutes. For this reason, the mixer should be as close to the place of use as possible to shorten the transportation distance and time. Mix the ingredients for the second time after each mixing is used up. It is better to wait for the ingredients than to wait for the ingredients. The remaining material that has been initially set shall not be used.

2) The construction ambient temperature should be >5°C according to the specifications. When the temperature is lower than 5°C, it is generally not recommended to carry out the construction of castable refractory lining projects.

3) Casting molding. Pay attention to the compactness of the slider and corners, and do not use mechanical vibration to avoid segregation. The thickness of the lining is controlled by the side mold, and the thickness can be measured by a probe in the middle. Pat the molding surface densely and evenly, and rub it with a wooden trowel. The construction joints should be left as stepped joints, cleaned up and fully moistened before continuing construction. Pay attention to adding slurry and vibrating at the seams to ensure the tightness of the seams.

4) Conservation. Generally, it is cured in a humid state for 24-72 hours, and the curing temperature is 5-30°C. According to the manufacturer’s technical instructions, the maintenance stipulates that the ambient temperature should be ≤25°C and the natural curing should be done for 3 days. When the temperature is >25°C, carry out humid curing. According to the construction experience, the lining will be cured after 2 hours of construction. If the ambient temperature is 20-25°C, use a sprayer to spray once every 2-3 hours, and spray once every 1.5 hours if the temperature is >25°C. It is maintained for 48 hours, and it is advisable to control the amount of water spray so that it does not flow.

5) Test block production. During the construction of each ingredient, according to the specification, every 20m3 is a batch of indwelling test blocks, and the inspection items are bulk density, compressive strength, flexural strength, and line change after burning.

Retention of expansion joints in high temperature castable refractory construction

During the construction of high temperature castable refractory, expansion joints should be reserved according to the design. When there is no provision in the design drawings, well-shaped expansion joints can be left at a distance of 800-1200mm. The general seam width is 2-3mm. It can also be cut into slits after forming, and the slit depth is 20-30mm in thickness.

Construction of Refractory Castables in Furnace Bottom Lining

The furnace bottom lining should be carried out after all the work in the furnace is completed and the scaffolding is completely removed. Specific requirements for the Construction of Refractory Castables in Furnace Bottom Lining are as follows.

1) The surface should be flat and free from pockmarks, and cracks.

2) The lining should be dense. Use a 0.5kg hand hammer to lightly tap every 200mm for inspection. The sound should be sonorous and crisp, and serious “husky” or hollow drumming is not allowed. Otherwise, it should be chiseled off and poured again.

High temperature castable refractory lining repair

After baking, if the high temperature castable refractory lining has cracks or penetrating network cracks with a width greater than 5mm, it must be repaired.

1) Partial chisel removal. Chisel off all the defective parts to expose the solid surface or steel surface. For the lining with insulation nails, at least two insulation nails should be exposed. The chiseled place should form a pit with a large inside and a small outside. The minimum area of the pit mouth is 300×600mm for the outer opening and 400×700mm for the inner opening.

2) Partial repair. ①Clean up the joint surface, remove loose material and floating ash, soak it with water first, then carefully tamp it with the same proportion of lining material, and smooth it. ② Cracks with a width greater than 5mm or penetrating network cracks should be filled with high-temperature adhesive + refractory fiber.

Precautions in the construction of high temperature castable refractory

The suitable construction temperature is 10°C-30°C. When the temperature is too low, conditions should be created.
When the relative humidity of the air exceeds 85%, it is not suitable for construction.
When the surface temperature of the steel plate is lower than 3°C above the atmospheric dew point or higher than 60°C, it is not suitable for construction.
It is not suitable for construction on windy and sandy days, rainy and foggy days.

Rongsheng Kiln Refractory Manufacturer

Rongsheng Kiln Refractory Manufacturer is a refractory manufacturer with rich experience in production, sales, and construction. The refractory lining materials provided by Rongsheng include not only monolithic refractory castables but also various types of refractory bricks. For monolithic refractories and refractory bricks, we support product customization to meet the working needs of thermal kilns. At the same time, the design and construction of our refractory insulation layer are also excellent. The design and construction of the thermal insulation refractory project of the rotary kiln we have served has greatly reduced the temperature of the outer wall, providing a reliable guarantee for safe production and cost savings. contact us for more, at sales@kilnrefractory.com.

Ceramic Fiber Insulation Zr-Al Insulation Blanket Furnace Insulation Blanket

March 17, 2023March 17, 2023 KilnRefractory

In the modern steel industry, in order to improve the thermal insulation performance of ladle, increase the service life of lining and reduce the consumption of refractory materials, new ladle has appeared. The so-called new ladle is a widely used ladle calcium silicate plate and aluminum silicate fiber blanket. furnace insulation blanket, there are a lot of different kinds, there are a lot of different names, zr-al insulation blanket, furnace insulation blanket, ceramic fiber insulation, ceramic insulation blanket, ceramic fiber blanket insulation, furnace blanket insulation, etc. Ceramic insulation blanket, ceramic fiber blanket insulation, furnace blanket insulation, etc. Contact us to purchase a high-quality furnace zr-al insulation blanket.

What is an Aluminum Silicate Fiber Blanket?

An aluminum silicate fiber blanket is a kind of refractory insulation material. Aluminum silicate fiber blanket is mainly divided into aluminum silicate fiber blowing blanket and aluminum silicate fiber spinning blanket. Aluminum silicate casting blanket because of the long fiber, small thermal conductivity, and thermal insulation performance is better than aluminum silicate blowing blanket. Most insulation pipe construction uses ceramic fiber swing silk blankets.

Common sizes for aluminum silicate fiber blankets (mm)

10*610*15000
20*610*7200
30*610*5000
40*610*3600
50*610*3600
60*610*3000

Aluminum silicate fiber blanket density: 55kg/m3-160kg/m3

Classification and service temperature of aluminum silicate fiber blanket

Ordinary type aluminum silicate fiber blanket 1100℃
Standard type aluminum silicate fiber blanket 1260℃
High purity aluminum silicate fiber blanket 1260℃
High aluminum type aluminum silicate fiber blanket 1360℃
Zirconium aluminum type aluminum silicate fiber blanket 1360℃
Zirconium-containing aluminum silicate fiber blanket 1430℃

Characteristics of aluminum silicate fiber blanket products

1, high-temperature resistance, low volume weight, and small thermal conductivity.
2, corrosion resistance, oxidation resistance, thermal shock resistance, etc.
3, high-temperature condition fiber elasticity is good, shrink.
4, good sound absorption.
5, easy to secondary processing and installation.

In summary, combined with the physical and chemical properties of aluminum silicate fiber blanket has a good thermal conductivity of 0.03 at 200℃. 400℃ is 0.06. 600℃ is 0.09. 800℃ is 0.1. It is widely used in furnace lining, boiler, gas turbine, and nuclear power heat insulation welding to eliminate stress heat insulation, fire insulation, sound absorption, insulation, high-temperature filter medium, and kiln door seal.

1400 Model Ceramic fiber blanket with zirconium

1400 ceramic fiber blanket model meaning, that is, 1400 belongs to the classification temperature, also known as the classification temperature.

Ceramic fiber blanket material classification, according to the long-term working temperature from low to high divided into ordinary, standard, high purity, high aluminum, zirconium aluminum, and zirconium containing 6 grades. The zirconium ceramic fiber blanket corresponding long-term operating temperature is 1280℃.

Application of ceramic fiber blanket containing zirconium. Zirconium ceramic fiber blanket is generally used in the long-term working temperature between 1150℃-1300℃ industrial kiln wall lining, and backing material. Industrial kiln masonry expansion joint material, furnace door, top cover insulation seal. Thermal insulation sealing material for high-temperature pipelines. High-temperature insulation gasket with long-term operating temperature below 1280℃. Raw materials for processing zirconium ceramic fiber modules/folding blocks.

Characteristics of zirconium-containing (zircon-quartz) aluminum silicate fiber blanket

Zirconium-containing aluminum silicate fiber blanket is a high-temperature resistance grade of ceramic fiber conventional models. Strictly speaking, a zirconia-containing aluminum silicate fiber blanket is divided into low zirconium type and high zirconium type.

Low zirconium type, theoretical classification temperature 1400 degrees, 24-hour operating temperature 1200 degrees. The content of zirconia is 5%-7%.
High zirconium type, theoretical classification temperature 1430 degrees, 24-hour operating temperature 1260 degrees. The content of zirconia is 15%-17%.

Properties of zirconium containing refractories

Zircon refractory products are made of natural zircon sand and are acidic materials. Zirconium refractory has good slag resistance, low thermal expansion rate, and thermal conductivity decreases with increasing temperature. High softening temperature under load, high wear resistance, and good thermal shock resistance have become important materials in various industrial fields.

Zircon refractory has high resistance to acid slag and glass but also has the property of non-penetration of aluminum, and aluminum oxide slag. Therefore, good results have been obtained on the bottom of the aluminum smelting furnace.

Zirconium-containing Aluminum Silicate Fiber Blanket

1430℃ Zirconium Aluminum Silicate Blown Fiber Blanket

The production process of zirconium-containing aluminum silicate-blown fiber blanket. Zirconium-containing aluminum silicate fiber blanket is made of fiber cotton through needling, heat setting, cross – and – cross-cutting, winding, and other processes. All kinds of needled blankets have the same excellent properties as the corresponding loose aluminum silicate fiber cotton and have excellent tensile strength. The needled blanket has a uniform texture and a flat surface.

The needled blanket with different bulk densities and thickness provides users with a wide range of materials to obtain the best heat insulation structure and energy-saving benefits.

The working temperature of a zirconium-containing aluminum silicate blown fiber blanket depends on the material use condition, the type of heat source, and the environment atmosphere.

Technical characteristics of zirconium-containing aluminum silicate-blown fiber blanket

Low thermal conductivity and low heat capacity
Excellent thermal stability and thermal shock resistance
Excellent tensile strength
Excellent heat insulation, fire prevention, and sound absorption

Application of zirconium-containing aluminum silicate-blown fiber blanket

Industrial building materials kiln, heating device, high-temperature pipelining
Electric boiler, gas turbine, and nuclear heat insulation
Wall lining of high-temperature reaction equipment and heating equipment for the chemical industry
Fire prevention and heat insulation of high-rise buildings
Heat insulation of furnace door and top cover
High-temperature filter material

Zirconium-containing Aluminum Silicate Fiber Blanket Price

Aluminum silicate needled blanket adopts advanced equipment, a double-sided needled blanket assembly line. Its equipment and production technology are at a higher level. All kinds of aluminum silicate fiber blankets, using different materials of raw materials (such as coke gems, SiO2, Al2O3, zirconium sand, etc.) into the fiber by settling acupuncture, heat setting, cross and cross-cutting, roll, and other processes made. Uniform texture, flat surface, excellent tensile strength, solid aluminum silicate needled blanket itself does not contain a binder, so greatly improves the degree of heat resistance. For free zirconium-containing aluminum silicate fiber blanket prices, please contact Rongsheng refractory manufacturers.

Where to Buy Refractory Insulation in China?

February 3, 2023 KilnRefractory

Refractory insulation materials are generally used in industrial kilns, metallurgy, pipelines, and thermal equipment to slow down the loss of heat. Most of the refractory insulation materials for the walls of general industrial kilns are made of lightweight refractory insulation materials, such as lightweight clay bricks, lightweight high-alumina bricks, and lightweight refractory castables. Walls have a certain mechanical strength. Where to buy refractory insulation in China? In most cases, an Internet search for “refractory insulation in China” will quickly bring up countless entries. If you want to buy refractory insulation materials economically and economically, we still recommend that you buy them from the manufacturer.

Kiln Insulation Refractory Bricks from Rongsheng

At present, there are various types of furnace-building refractory insulation materials that have been maturely used. Manufacturers of refractory materials generally classify refractory insulation materials according to the standards in the industry. Generally, according to the structure, material and use temperature, etc. Refractory insulation materials can be divided into low-temperature insulation materials (below 600°C), medium-temperature insulation materials (600~1000°C), and high-temperature insulation materials (above 1000°C) according to the use temperature. Combined with many years of production and sales experience, in the selection of thermal insulation lining for high-temperature kilns, there are many kilns that use aluminum silicate fiber refractory thermal insulation materials to save energy.

This is a fact that spread like wildfire. The basic requirements for furnace-building refractory insulation materials are low heat capacity, light bulk density, small thermal conductivity, high strength, and easy construction. The fiber refractory insulation material has its main characteristics of light bulk density, low heat capacity, small thermal conductivity, and easy construction, so it is widely used. For refractory insulation in China, why do most high-temperature industrial furnaces choose fiber refractory insulation materials?

Ceramic Fiber Insulation Refractory Products

First, the thermal conductivity of fiber refractory insulation materials is low. Thermal conductivity is a very important thermal index of refractory insulation materials. It marks the material’s ability to transfer heat. At the same operating temperature, the thermal conductivity of aluminum silicate refractory fiber is only 1/5 of that of ordinary refractory clay bricks, and less than 1/2 of that of lightweight clay bricks.

Due to the small thermal conductivity of aluminum silicate fiber, using it as a furnace lining or insulation layer can reduce heat loss and save energy compared with commonly used refractory materials. When the volume of the furnace and the temperature inside and outside the furnace wall remain unchanged, the outer surface area of the furnace body can be reduced by about 30% and the heat dissipation loss can be reduced by 15-30% after using aluminum silicate fiber. Therefore, the small thermal conductivity of fiber refractory insulation materials is one of the main reasons for the energy saving of industrial kilns.

Second, the fiber refractory insulation material has a light bulk density. For example, the bulk density of aluminum silicate fiber and its products is 40~220Kg/m³, only less than 20% of light clay bricks, and about 6~8% of ordinary clay bricks. Since the aluminum silicate fiber has a small bulk density and a thinner thickness in use, using it in an industrial furnace can not only reduce the weight of the furnace body but also reduce the heat storage loss of the furnace. Moreover, due to the strong heat storage capacity of the aluminum silicate fiber furnace wall, the temperature rise in the furnace body is fast, which can improve the working efficiency of the kiln. For periodic or discontinuous industrial kilns, using aluminum silicate fiber lining or insulation layer, the energy-saving effect is more significant.

To sum up, fiber refractory insulation materials create good conditions for improving the performance of thermal equipment and are widely used. As long as we choose refractory insulation in China reasonably according to its operating temperature, furnace atmosphere, and other working conditions, we will definitely get good economic benefits.

Refractory insulation in China. The refractory insulation material used for high-temperature industrial kiln masonry is a kind of refractory insulation material with high-temperature resistance, low thermal conductivity, and flame retardancy, and can slow down the heat loss caused by heat conduction and heat convection. It slows down heat loss by restricting air heat convection with low thermal conductivity through the special structure of the material. Refractory materials that can realize such functions include refractory insulation bricks, castable refractory insulation, etc. Rongsheng refractory material manufacturer is a manufacturer and sales company of refractory materials in China. Provide you with free samples and quotations. Contact us, to buy refractory insulation in China, to provide the most suitable solution for your kiln insulation.

Zirconium Refractory Material for the Slag Part of the Steel Drum

July 7, 2022 KilnRefractory

Zircon-based and ZrO2-based refractories made from zirconium-based refractory raw materials have excellent resistance to chemical attack and high-temperature performance. For example, zircon bricks are used for the slag part of the steel drum, ZrO2 brick linings are used for the nozzle holes of the sliding nozzles, and ZrO2 quality sizing nozzles are used for horizontal continuous casting. At the same time, zirconium-based raw materials are introduced into other refractory materials, and the performance of the original materials, especially the thermal shock stability, is greatly improved by using the phase transition of ZrO2.

The Effect of Adding Zirconium-Based Raw Material to the the Slag Part Refractories of the Steel Drum

Adding ZrO2 substances to refractory materials has the following two functions:

①The main crystalline phase or the secondary crystalline phase is generated so that the material has special properties.

For example, the most well-known fused corundum bricks. It is a mass-produced 33# fused cast zirconium corundum brick. Its composition is near the eutectic point of the Al2O3-SiO2-ZrO2 ternary system, and its molecular formula is equivalent to 2Al2O3-SiO2-ZrO2, abbreviated as AZS fused cast brick. Its main crystal phase is the eutectoid of baddeleyite and corundum (Z+C), or baddeleyite, corundum and mullite (Z+C+M). The presence of (Z+C) eutectoid makes AZS bricks 15 times more resistant to chemical attack by glass solution than high alumina materials made by sintering. The (Z+C) eutectoid of independent components is an important structural unit to maintain the structural stability of the AZS brick body in the middle and later stages of the erosion of the glass molten pool.

In the iron and steel industry, the use of stable ZrO2 has the ability of oxygen ions to move between two phases with an oxygen potential difference, that is, the deoxidation ability and the use of stable ZrO2 bushings suppresses the precipitation of oxides. The clogging degree caused by Al2O3 deposition in the immersion nozzle for continuous casting is reduced by half.

② Modification of the original material.

High alumina and basic refractory products have good chemical stability and high-temperature performance, but poor thermal shock stability. Adding ZrO2 to corundum bricks, high alumina bricks, and magnesia bricks can significantly improve the thermal shock stability of these refractory products by using the toughening effect of ZrO2. Anti-spalling high-alumina bricks for cement kilns are made by adding zircon powder to the ingredients of high-alumina bricks. After firing, many microcracks are formed around the ZrO2 particles, so that the thermal shock stability (1100℃-water cooling) of this brick can reach more than 40 times. Good results have been achieved in the upper transition zone of the cement rotary kiln and the side wall of the grate cooler. As early as the early 1930s, some people developed magnesium-zirconium products, whose thermal shock stability and resistance to iron furnace slag and open-hearth slag are better than those of magnesia bricks. After adding ZrO2, the strength of magnesia zirconium brick is also higher than that of ordinary magnesia brick. This product is expected to be used in cement rotary kilns, which can partially replace magnesia-chrome bricks to reduce chromium pollution and protect the environment.

For free samples and quotations of refractory zircon bricks for ladle slag, please contact us.

Why do Some High Temperature Kilns Use Alumina Bubble Bricks?

June 16, 2021 KilnRefractory

Alumina Bubble Bricks belong to the category of lightweight bricks, and the use ratio is currently not very wide. But why some high-temperature kilns use alumina hollow ball bricks? Refractory manufacturers with rich production and sales experience often provide customers with refractory materials that are most suitable for production needs based on customer requirements and the actual working conditions of high-temperature kilns. This will not only extend the service life of the kiln but also save production costs.

The production process of alumina hollow ball brick. Lightweight hollow sphere bricks are made of alumina hollow spheres as the main raw material, adding ultra-fine powder and other process ingredients to dry and form. It is to add alumina raw material into a dumping electric furnace to melt it into a liquid state, and the furnace is dumped at a certain angle to make the solution flow out of the pouring tank. Then the hollow alumina spheres, sintered alumina fine powder, and binder are mixed according to a certain proportion, formed and fired in a shuttle kiln at a high temperature of 1750°C. Alumina hollow ball brick is a high-grade lightweight refractory material. Its lightweight, high-temperature resistance, small line change, and excellent thermal shock resistance. It can be used as an insulation layer and can be used directly on the working layer.

Why do some high-temperature kilns use alumina bubble bricks? Now in high-temperature kiln equipment, the proportion of heavy refractory bricks used will be larger. However, in order to optimize the structure of some furnaces, it is necessary to reduce the weight of the furnace. The bulk density of high temperature resistant heavy refractory bricks is above 2.6g/cm, and the bulk density of alumina bubble bricks is only 1.1~1.5g/cm. Therefore, in the case of the same cubic meter volume, the use of hollow ball bricks can reduce the weight of the kiln body by 1-2 tons.

From the perspective of cost, the price of heavy bricks and hollow ball bricks are similar. The price of alumina bubble bricks for special areas may be slightly higher than that of heavy bricks. But in terms of weight, the use of hollow ball bricks can reduce 1-2 tons per cubic meter. Moreover, there is no need to make an insulation layer, which reduces the number of use and saves fuel. Not only the use effect is good, but the cost is also reduced a lot.

In addition, because alumina hollow spheres have good thermal insulation properties, reducing heat dissipation improves thermal efficiency, and the energy-saving effect reaches 30%. Therefore, some high-temperature kiln lining high-temperature zone or shuttle kiln lining all use hollow ball bricks, which is light in weight and has a significant effect.

Alumina bubble bricks have high aluminum content, low iron content, and low bulk density. It can be used in the working layer of the shuttle kiln and the tunnel kiln in the high-temperature area, and can also be used as the insulation layer in the high-temperature area.

The above is the reason why some high-temperature kilns use alumina bubble bricks. It can be seen that the choice of refractory materials for certain kilns not only saves costs but also needs to reduce the weight of the furnace body, as well as a good insulation effect. At this time, alumina hollow ball brick is a good choice. If you need to buy high-quality alumina bubble bricks, please contact the refractory manufacturer. Buy directly from the manufacturer, the product quality is reliable, and you can enjoy perfect customer service.

What is the Bulk Density of Refractory Castables?

April 29, 2021 KilnRefractory

What is the bulk density of refractory castables? This is mainly based on the specific construction site and high-temperature resistance requirements. The preparation of refractory castables is customized according to the index requirements provided by users. These indicators mainly include refractoriness, material chemical composition, bulk density, compressive strength, flexural strength, and so on. Bulk density or bulk density is one of the important indicators, which intuitively reflects the compactness of refractory products and characterizes the mass of refractory materials per unit volume. It is an important measure of the quality level of refractory raw materials and dense refractory products.

The Significance of the Bulk Density of Refractories

Bulk density is the ratio of the dry mass of the refractory material to the total volume. The higher the volume density, the higher the density. The bulk density of the material has a significant effect on many other properties, such as porosity, strength, corrosion resistance, load softening temperature, wear resistance, thermal shock resistance, etc. For lightweight thermal insulation materials, such as thermal insulation bricks, light weight castables, etc., the bulk density is also closely related to its thermal conductivity and heat capacity. Generally speaking, the bulk density of the material is high, which is beneficial to its strength, corrosion resistance, wear resistance, and load softening temperature.

Therefore, with regard to the volume density of refractory castables, each manufacturer has its own standards. In order to increase the bulk density of refractory castables, a reasonable ratio of multi-stage particles should be adopted, which should meet the requirement of “large at two ends and small in the middle”. That is, under the premise of not affecting the performance of refractory castables, adding fine powder matrix or using silicon powder to replace part of the binder material, reducing the amount of water added to increase its bulk density.

Bulk Density of Refractory Castables

The bulk density of refractory castables is different depending on the location of use. It is mainly divided into two parts, namely dense refractory castable and light refractory castable. Dense refractory castables are used for parts that are exposed to high temperature, molten slag, scouring, and thermal shock stress. The use of castables with high bulk density can improve structural strength, wear resistance, slag penetration resistance, thermal shock resistance, etc. Lightweight refractory castables are only used for the material of the thermal insulation layer close to the furnace shell, with the main purpose of thermal insulation. Its strength is low, density is small, porosity is high, and it can’t touch slag or chemically corroded parts.

The density of dense refractory castables configured by different materials is different. For example, the bulk density of clay refractory castables is 2.1~2.2 g/cm3. The bulk density of high-aluminum refractory castables is generally 2.5~2.85 g/cm3, which increases with the increase of aluminum content. The bulk density of clay low cement castable is 2.2~2.3g/cm3. The bulk density of corundum low cement castable is 3.0~3.1g/cm3, etc.

The lightweight refractory castables configured by different materials are different. For example, the bulk density of lightweight floating bead castables is 0.6~1.0g/cm3. The bulk density of the castable prepared with clay porous clinker is 0.8~1.3g/cm3. The volume density of the castable configured with mullite porous clinker is 1.2~1.6g/cm3, etc.

In short, the bulk density of refractory castables depends on the temperature and location of use. For example, the bulk density of high alumina refractory castable is 2.5g/cm3 or 2500kg/m3, which means that a cubic high alumina refractory castable weighs about 2.5 tons. The bulk density of lightweight castables is 0.8g/cm3 or 800kg/m3, representing a cubic weight of 0.8 tons. The volume density of refractory castables is the specific manifestation of bulk density, and the weight of materials required for construction parts can be calculated through this index. Refractory castables will inevitably be lost during the construction process. In order to prepare all the materials at one time, the total quantity can be increased by about 0.5 tons to avoid suspension due to insufficient construction materials.

Refractory Castable Manufacturer and Sales Manufacturer

This is the introduction about the appropriate density of the castable. I hope it will be helpful to you. If you have any other questions, please feel free to contact us. Purchasing suitable refractory materials for the kiln lining, and looking for a suitable refractory lining material solution, the strength of the Rongsheng refractory manufacturer is your reliable guarantee. Our experienced technical team and our advanced refractory production line have won us many return customers and long-term cooperative customers. If you have any questions about refractory materials or refractory lining materials, please contact us or follow our blog.

Can the Price of Refractory Bricks be Determined by Color?

April 7, 2021 KilnRefractory

Can the color of refractory bricks determine the price of refractory bricks? is this real? Among the customers I have contacted in the past, I have encountered customers who left messages saying that they want to buy red or black refractory bricks from our manufacturer, as well as those who buy white smooth refractory bricks. Similarly, some purchasing managers are obsessed with buying refractory bricks of a certain color. So can the price of refractory bricks be judged by the color?

Rongsheng Kinds of Refractory Bricks for Sale

After specific communication with customers, they found that some of them are looking at the color of our refractory bricks that are very suitable for the color of their crafts, so they want to buy a certain color of refractory bricks. Their needs are not in line with our goal of serving refractory linings for industrial kilns. And when customers learned that we were providing refractory brick materials for the lining of industrial kilns, they stopped insisting. Among the refractory bricks lined with industrial kilns, the color of the refractory bricks reflects the proportion of the refractory raw materials added to a certain extent and has a certain influence on the properties of the refractory materials. Similarly, it also affects the price of refractory bricks.

The Colors of Some Common Refractory Bricks

People who are often exposed to refractory materials can basically judge the material of refractory bricks based on the color. The color of fireclay refractory bricks is generally light yellow or brownish yellow, dark yellow, and there will be brown or black spots on the surface of the brick. This is generally a spot formed by impurities in the refractory raw material after being fired at a high temperature. The color of high-alumina bricks is mostly beige, and even a little whitish. Refractory brick products made of magnesia, graphite, and silicon carbide are mostly blue. Corundum and mullite are mostly white.

High alumina bricks are often used to judge the quality and grade of bricks by color. In fact, the color of refractory bricks with the same index content will also appear inconsistent. This is because there are many factors that affect the color of refractory bricks.

① The bricks are unreasonably stacked when loading the kiln car, and the sparseness and unevenness cause the flame to not uniformly heat all the bricks. The bricks are heated unevenly during preheating, and the moisture of the refractory bricks cannot be completely eliminated and enters the firing zone, causing some refractory bricks to appear different in color and light.
②The processing temperature of refractory bricks is not well controlled, resulting in too much fluctuation of the firing temperature, which will make some parking spaces have high temperatures and some low temperatures.
③If the pulling force of the smoke exhauster is too large, when the flame cannot reach the top of the kiln, it will be pulled out of the high-temperature zone by the pulling force in a horizontal direction, causing the temperature difference between the top and the bottom to be too large. The temperature difference of the fired refractory bricks can reach 50 degrees so that sometimes the lower part sticks and deforms to produce waste products, but the upper part still does not reach the sintering temperature.

In addition to the influence of the process during the firing process, after the refractory bricks are discharged from the kiln, with the influence of the storage time and storage environment, some chemical reactions will gradually occur on the surface of the refractory bricks, which will eventually cause the color difference of the refractory bricks.

There are more factors affecting the appearance and color of fused-cast refractory bricks, such as the oxidizing atmosphere and reducing atmosphere when the batch material is melted, and the degree of solubility of impurities during the conversion process.

How Can I Buy High-Quality Refractory Bricks?

Having said that, what should be the standard when buying refractory bricks? First of all, we must know that there are corresponding national standards for the appearance of refractory brick products. “GB/T 10326-2016 Inspection Method for Dimensions, Appearance, and Section of Shaped Refractory Products”, this standard is required from the appearance of refractory bricks.

Secondly, when we buy refractory bricks, we must look at the content of the material, the main material, and the content of impurities. Because generally, shoddy manufacturers will make a fuss about the ratio of raw materials and materials, such as materials with a low main material content, such as the wrong proportion of materials, such as materials with more impurities, and so on. After this type of brick is produced, the surface will generally be rougher and the color will be uneven. The purchaser may require the supplier to provide the inspection report or quality certificate of the goods at the time of purchase. The test report of refractory bricks can reflect the content, porosity, refractoriness, load softening temperature, compressive strength, and other values of this batch of bricks.

Finally, in addition to the content detection, because refractory bricks also involve bulk density, specifications, and dimensions. Therefore, some manufacturers also have unit weight or body density requirements when purchasing. Because, based on the unit weight, we can also make a rough judgment on the quality of refractory bricks.

To learn more about the recognition and identification of the color of refractory bricks, please start with the basic knowledge of refractory materials. Our blog not only introduces our products to you but also introduces you to the relevant knowledge of refractory materials at any time. Please pay attention to our blog to know why there are black spots, black hearts, or cracks in refractory bricks at any time? You can also understand the requirements of binders and additives in the production of refractory bricks of different materials, and so on.