Unshaped Refractories Archives - Rongsheng Refractory Castable Cement for Sale Manufacturer and Supplier

Application Advantages of Refractory Precast Shapes

April 27, 2024April 26, 2024 by rsrefractorycastable

Application cases of RS refractory prefabricated parts. Refractory prefabricated parts are most commonly used in small high-temperature kiln equipment. The products required at the construction site are produced in advance by the manufacturer to facilitate customer construction. Used for special-shaped or special-shaped refractory products. Refractory prefabricated parts are widely used in various industrial kilns due to their irreplaceable advantages. Its biggest advantage is that it can be pre-baked and directly hoisted, so the construction period is greatly shortened, and the quality is stable and easy to control.

Application Solutions for Refractory Precast Shapes

Refractory prefabricated parts are an important variety of refractory materials, and their applications account for an increasing proportion. Refractory prefabricated parts are made by dividing the parts of the high-temperature kiln to be constructed into small pieces in advance. And design it into a special shape, and make the mold according to the shape. In the factory, refractory castables and other materials are pre-cast, cured, and baked before being transported to the site for hanging and assembly before use.

Ultra Low-Cement Castable Precast Shapes for Iron Trough

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Castable precast shape refractories can be preformed into various shapes at will, with good thermal shock stability, high strength, and good spalling resistance. No joints, good air tightness, less heat loss, and energy saving. It can quickly repair the kiln and improve the furnace operation rate. It can realize direct hoisting and mechanized furnace construction, and the construction efficiency is high. It can solve technical problems in furnace construction for users and can be customized according to user requirements and furnace-type conditions. Consider lining body design and multiple construction options for users.

There are the following solutions for the shaping of unshaped refractory materials in cement kilns. As a result, the unshaped refractory materials used in special parts of the cement kiln are customized and produced. The product has the following characteristics:

(1) There is no need for on-site pouring construction or formwork pouring, which reduces labor costs and material costs.
(2) Heat-resistant anchors are not required, eliminating the material and construction costs of anchors.
(3) The pouring, curing, drying, and baking steps of prefabricated parts have been completed when delivered, saving a lot of construction time.
(4) It is not restricted by environmental and climatic conditions, which solves the problem that castable materials cannot be constructed on-site under natural conditions during hot summer and severe winter.
(5) It can be made into various special products with different sizes and shapes. Such as grate cooler low wall, tertiary air duct elbow, lifting gate valve, kiln tail smoke chamber, coal injection pipe, kiln mouth, and other refractory materials.
(6) Maintenance is easy to replace, has little waste loss, and saves labor and time. Corundum, fused mullite, special grade bauxite aggregate, and special wear-resistant materials are added to the material, and a certain proportion of special additives are added. Vibration forming. Therefore, the product has high strength, wear resistance, corrosion resistance, good mechanical impact resistance, and excellent thermal shock resistance. It has excellent peeling resistance and cracking resistance, long service life, convenient construction, safety, and reliability, and greatly shortens the construction period.

Application Advantages of Refractory Prefabricated Parts

Refractory Preforms refer to components with a certain shape and size made of refractory materials according to specific ratios and process conditions. The main raw materials of refractory precast shapes usually include refractory castables, refractory bricks, refractory fibers, and other special refractory materials. Refractory prefabricated parts are prepared under certain process conditions, which usually include mixing, molding, curing, and drying.

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Refractory Precast Shapes have the Following Advantages

stable quality. During the production process of prefabricated components in the factory, raw materials, proportions, and process conditions are strictly controlled. Therefore, product quality is stable and reliable.
Save construction time. The use of refractory prefabricated parts can significantly shorten the construction period and improve construction efficiency.
Reduce on-site labor. Prefabricated components are produced in factories, reducing the workload of construction workers and material handling on-site.
Good performance. Because the production process of prefabricated components is strictly controlled, their performance is often better than that of refractory materials constructed on-site.

Refractory prefabricated parts are widely used in various industrial furnaces and equipment in petrochemicals, metallurgy, building materials, electric power, and other industries. Such as heating furnaces, smelting furnaces, converters, gas generators, glass kilns, etc. Depending on the actual application environment and needs, refractory prefabricated parts can be customized with different shapes, sizes, and properties. When selecting refractory prefabricated parts, factors such as the working environment, usage conditions, performance of refractory materials, and construction requirements should be considered.

When using refractory prefabricated parts, you need to pay attention to the following points.

Storage and transportation. During storage and transportation, prefabricated parts should be protected from moisture, heat, and external force damage. It is recommended to store prefabricated parts in a dry, ventilated, and cool warehouse. And pay attention to reasonable stacking to avoid extrusion and deformation.
Install. When installing refractory prefabricated parts, design requirements, and construction specifications should be strictly followed. For different types of prefabricated parts, corresponding installation methods and connection methods need to be adopted. During the installation process, it should be ensured that the position of the prefabricated parts is accurate and that good connection and sealing properties are maintained.
Seam treatment. Seams between precast parts should be kept clean and tight to prevent heat loss and the penetration of aggressive gases. Depending on the actual working conditions and precast material, appropriate filling materials can be used for joint treatment. Such as refractory mud, refractory fiber, etc.
temperature control. During the initial heating and operation of the furnace, the heating rate and temperature should be strictly controlled. To prevent the refractory prefabricated parts from being damaged due to thermal stress caused by excessive heating. At the same time, regularly check the use of prefabricated parts to detect and deal with potential problems in a timely manner.
Maintenance and overhaul. During use, the refractory prefabricated parts should be inspected and maintained regularly. If damage, cracks, and other problems are found, they should be repaired or replaced in time. For prefabricated parts with a long service life, timely cleaning and maintenance can be carried out to extend their service life.
With proper selection, installation, and maintenance, refractory prefabricated components can provide efficient and stable performance for industrial furnaces. Save construction time and cost at the same time. In the continuously developing industrial field, the application of refractory prefabricated parts will continue to expand to meet the needs of various working conditions and environments.

Precast Shapes with Refractory Anchor Bricks for Heating Furnace Top

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What Should We Do if These Problems Arise with Refractory Castables and Castable Precast Shapes?

Unshaped refractory castables and castable refractory precast shapes have the advantages of convenient and fast construction and low labor intensity. It has been widely used in more and more high-temperature industrial kilns.

However, many corporate users have discovered some abnormal phenomena in refractory castables or prefabricated parts during storage or maintenance. For example, some have chalking, some have white hair, etc. In fact, these are caused by the contact between the high alumina cement hydration products in the refractory castable and the acidic gases in the atmosphere. As the water in the castable evaporates, salt substances continue to migrate and precipitate to the surface, and then slowly intensify the damage process of the refractory castable. Powdering occurs during the storage of prefabricated parts made from cement-containing refractory castables. Some of them have “white hair” growing on the surface, commonly known as white alkali, which causes the surface of the castable to become powdery. In severe cases, the strength of the castable will decrease.

Solution

Dry the castables as soon as possible after construction to remove moisture. Eliminate the carrier of sodium salt in the pouring body, so that the alkali stays in the construction body and no longer migrates to the surface.
When the construction conditions do not allow for timely drying, the castable environment must be sealed and the surface covered with plastic film to prevent moisture from carrying alkali from migrating to the surface.
Use refractory raw materials with low alkali content in the refractory castable to increase the viscosity and rapid hardening of the refractory castable, which can reduce the migration speed of sodium salt. Strengthen quality management and strictly control the amount of water added during construction.

Tips: Leave a message to ask your questions about kiln refractory castables, and we can provide solutions for free.

Steel Fiber Refractory Castable Precast Shapes

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RS Unshaped Refractory Castable Manufacturer

RS unshaped refractory castable manufacturer is a powerful manufacturer of refractory materials production and sales. Our environmentally friendly, fully automatic unshaped refractory material production line customizes unshaped refractory lining materials for high-temperature industrial furnaces. Extend the service life of the kiln lining, save the cost of production energy, and improve economic benefits. Customize refractory precast shapes, wear-resistant refractory castables, insulation castables, refractory plastics, refractory ramming materials, etc. from Rongsheng unshaped refractory material manufacturer. Contact us to get a free customized plan and quote.

Functional Mechanism and Use of Water Reducing Agent for Unshaped Refractory Materials

November 20, 2023 by rsrefractorycastable

A commonly used additive for unshaped refractory materials is water reducing agent. It can reduce water consumption without affecting the workability of monolithic refractory materials. Or it can increase the workability of unshaped refractory materials without affecting water consumption. Additives that combine the above two properties are called water-reducing agents, also known as dispersants.

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The mechanism of action of water-reducing agent

Change the physical and chemical properties of powder

In the unshaped refractory material industry, solid particles (such as cement, clay, ultrafine powder, etc.) are usually used as dispersants, water is used as the dispersion medium, and additives are treated as solutes. In this system, the particles have a certain surface energy, which has the tendency to absorb electrolytes and surfactants from the solution to reduce the surface energy and cause the system to be in a stable state. It is the powder that selectively and preferentially adsorbs water-reducing agent ions, making it easy for water to disperse on its surface.

Due to this effect, the water-reducing agent is adsorbed on the interface of liquid-gas, liquid-solid, etc. Reduce the interface energy, destroy the agglomeration of particles, and reduce the frictional resistance of relative movement of particles, thereby improving the fluidity of the mud.

Change the electrical properties of the interface

When solid particles are stirred and coagulated with water, they have an attraction due to the opposite charge of the solid particles. Or the angular collision, adsorption and van der Waals force between particles caused by the thermal movement of solid particles in the solution cause a flocculation-like structure, wrapping a large amount of water. After the water-reducing agent is added, the hydrophobic groups of the water-reducing agent are directionally adsorbed on the surface of the particles, and the hydrophilic groups are directed toward the solution to form a monomolecular film or a multimolecular film. The particle-water system is placed in a relatively stable suspended state, the floc structure is dispersed, and free water is released. Because it can release free water in the condensed structure. Therefore, while maintaining the rheology (workability) of the castable, the unit water consumption can be reduced, or the workability can be improved without changing the unit water consumption, making the material easy to construct and shape.

Peptization of colloidal particles

The colloidal particles are transformed from the flocculation state to the sol state, thereby reducing the flow resistance of the mud and improving the fluidity. This can be achieved by adding appropriate electrolytes or water-reducing agents.

Therefore, the water-reducing agent of monolithic refractory materials is either an interface active substance or contains an interface active substance, or a substance that chemically interacts with the surface of the refractory material to change the surface properties. For the former category, the water-reducing agent must have both hydrophobic and hydrophilic groups.

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Classification of water-reducing agents

Depends on the type of binder used. Water-reducing agents can be divided into water-reducing agents for clay bonding, cement bonding water-reducing agents, sol-gel bonding water-reducing agents, ultrafine powder bonding water-reducing agents, and phosphate and silicate bonding water-reducing agents.

Classified by function: ordinary type, retarding type, accelerating type, air-entraining type, etc.

Classified by chemical properties: anionic surfactants, cationic surfactants, nonionic surfactants, polymer surfactants, and inorganic salt surfactants.

Aluminate cement binding water-reducing agent

There are many water-reducing agents used in aluminate cement, but the following five categories are commonly used. Lignins, naphthalene series, water-soluble resins, salts of hydrocarbyl carboxylates and modifications and derivatives, alkanes, aromatic sulfonates, inorganic salts, and polymers.

In aluminate, cement refractory castables, MF, sodium lignin, alkyl sulfonate, etc. are added. It has a good water-reducing effect, but the retardation is heavy and affects the early strength. When tartaric acid, citric acid, and sodium tripolyphosphate are used alone, the water will bleed significantly, which can improve the compactness of the castable, but the water reduction effect is not great. Therefore, for aluminate cement castables, water-reducing agents should be used in combination as much as possible.

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Water-reducing agent for low cement castables

In low-cement refractory castables, the commonly used admixtures are mainly high-efficiency water-reducing admixtures and dispersants. Its varieties include NNO, MF, NF, JN, SM, humic citric acid, tartaric acid and their salts, sodium tripolyphosphate, sodium hexametaphosphate boric acid, etc. The dosage is generally 0.03~1.0%. When selecting admixtures, they should match the ultrafine powder, and at the same time, the source of the material, ease of use, and cost should be considered. Generally speaking, the water-reducing and dispersing effects of organic admixtures are better than those of inorganic admixtures. In addition, kyanite and sillimanite are also added to make the low-cement refractory castable slightly expand at high temperatures.

However, in practice, water-reducing agents are very beneficial in improving the performance of castables. However, you should still pay attention to the following points when using it:

Use standard dosage to avoid material separation and bubbles;
Pay attention to the quality of the water-reducing agent to avoid affecting the performance of the castable;
The post-mixing method should be used during use to improve the use effect and be easily adsorbed by cement;
Stirring time: It is necessary to mix thoroughly and to introduce less air, and the two must be coordinated;
After adding admixtures, the cement dosage and water consumption should be adjusted in time.