Author: KilnRefractory

Preparation of 65% Zircon Brick

KilnRefractory

Zircon (ZrSiO4) belongs to the tetragonal system. The theoretical composition is 67.2% of Zr02 and 32.8% of SiO2, which is the only compound in the binary system of Zr02-Si02. 65% Zircon Brick. The thermal expansion coefficient is small, the load softening temperature is high, the thermal shock stability is good, and the thermal conductivity decreases with increasing temperature. Therefore, As the refractory materials manufacturer said, the zircon refractory brick is an indispensable material for industrial kilns such as building materials, light industry, electronics, metallurgy, and so on.

In recent years, with the advancement of glass industry technology and the application and promotion of kiln insulation technology, the amount of machined 65% Zircon Brick has been increasing. Mainly used in the gap, upper partition wall, fire observation hole, temperature measurement hole, and other parts of the glass kiln. The temperature of this part is high and it is eroded by flying materials and eroded by hot airflow, so the environment is very engraved.

RS Zircon Refractory Bricks Manufacturer
RS Zircon Refractory Bricks Manufacturer

Preparation of 65% Zircon Brick

To produce zircon bricks with a Zr2O3 content greater than 65%, the content of the raw material Zr2O3 used must be greater than 66%. The decomposition temperature of the zircon is 1676℃. As the content of impurities increases, the decomposition temperature decreases. The high purity of the raw materials is the primary condition for the production of zircon refractory bricks with 65% zirconium with excellent properties.

The raw material of zircon is granulated and cannot be directly used for making bricks, but must be ground into a fine powder. Because zirconite has a large wearability index, the fine powder is obtained by vibrating mill and air-jet mill.

Due to the use of 65% zircon brick containing ZrO2. The material should have good high-temperature physical properties, and the aggregate is closely related to it. The zircon sand is ground first, then made into a green body, which is crushed into different particle sizes after high-temperature calcination. Because the zircon material is brittle, the broken particles are in the form of flakes. The normal temperature compressive strength of sheet materials is about 50% higher than that of granular materials. On the contrary, under the same conditions, the bulk density of granular granules is 0.12g/cm³ higher than that of flakes on average. Taking into account the compressive strength and density performance, the crushed material must be properly treated before it can be used.

The batch materials are mixed on a wheel mill mixer, and the materials are trapped for 16 hours, and then formed on a large-tonnage friction brick press. The forming pressure is 700~1000Kg/cm³. Applying large pressure can cause the average distance between adjacent particles to decrease and the contact area to increase, which is beneficial to sintering. But after increasing to a certain level, the effect is extremely insignificant. Appropriate pressure and pressurization methods are the keys to solving the formation of barren materials.

The sintering of zircon is more difficult, and its speed is slow due to solid-phase diffusion at high temperatures. Adding MgO, CaO, Y2O3, TiO2, ZnO2 can reduce the sintering temperature and promote its sintering. In this sintering, 1.5% to 2.75% of Y2O3 and TiO2 were added as sintering accelerator, sintered in a shuttle kiln, and the firing temperature was 1580 to 1650℃.

RS High Quality Zircon Bricks
RS High-Quality Zircon Bricks

Use Performance of Zircon Brick in Steel Ladle

The use performance of zircon bricks in steel Ladles is also called zircon bricks in steel Ladles. It is made of zircon as the main raw material and participates in the combination of a certain amount of fused alumina, high-silica content of clay soil, clay, and chromium oxide. This kind of steel barrel lining bricks has been developed abroad for a long time. In order to improve the uneven erosion of semi-silicon brick steel lining bricks, it gradually expanded from strengthening local lining to all lining bricks. As a result, the service life of large steel Ladles is increased by 2 to 3 times. In order to meet the use of the first phase of Baosteel in China, this brick has been developed and used.

The defects of zircon bricks are slag, steel, and spalling. The main reason is that it is not easy to reduce the porosity due to the zircon brick, and it is affected by the infiltration and the glass property generated in the matrix part. The advantage is that the service life can reach more than 100 times, which is conducive to the turnover of the steel drum. The high cost of this kind of brick is also limited by the source of domestic raw materials, which restricts its development.

Detailed Information of Alumina Silicate Refractory Mortar

KilnRefractory

Alumina Silicate Refractory Mortar includes clay, mullite, and high alumina refractory mortar. All alumina silicate refractory mortar is added with clay, the main purpose is to improve its adhesion.

Castable Refractory Mortar

The alumina silicate refractory mortar is made of 160-200 mesh powder. In general, different grades of refractory mortar are based on the grade of alumina silicate fire brick built with a refractory lining. For example, 75 high-alumina bricks, the refractory mortar with the aluminum content of 65 is used, and the 65-high-aluminum bricks are prepared with 55-60 high-alumina mortar. High alumina bricks with an alumina content of 55 are formulated with a slurry content of 45-50. Some refractory bricks with high alumina content also need to add corundum powder when configuring brick fire clay to meet the needs of brick distribution.

If it is used in the blast furnace hearth and other parts, phosphate combined refractory mortar is also used. In this way, the service life can be more guaranteed, and the gray seam does not shrink during use.

RS Castable Refractory Mortar Manufacturer
RS Castable Refractory Mortar Manufacturer

Some of the refractory mortar used in large-scale blast furnaces, many of which are added with andalusite, quartz powder, or kyanite, is to ensure that the crevice does not shrink when sintered.

Some refractory mortars with low aluminum content generally do not add a binder. However, in order to improve the bonding strength, a certain proportion of bonding agents will be added, such as phosphoric acid, water glass, polyphosphate, etc. With the change of the addition of the binding agent, the bonding strength also changes after firing, but the strength at the high temperature and hot state is opposite. Adding the binding agent will cause the liquid phase in the refractory mortar to increase at high temperatures. Sodium polyacrylate and methylene naphthalene sulfonate are added to the binder to prevent solid-liquid separation of the prepared refractory mortar during standing. The addition of methylcellulose can also be prevented.

Aluminum silicate refractory mortar belongs to a water-based refractory mortar and cannot be built with carbon bricks or the like. Because the water vapor volatilized by the water-based mortar in the oven and use has a destructive effect on the carbon brick masonry. Therefore, the non-aqueous refractory mortar is used. learn more from Rongsheng Refractory mortar manufacturer.

Volume Stability of High Alumina Castables

KilnRefractory

For a long time, high silica bricks have been used for tundish refractory. Today, low-cement and high alumina castables have widely replaced high-silica bricks by increasing life to reduce costs and improve working conditions. Because MgO coating must be applied to the tundish permanent castable. For high aluminum castables, volume stability is very important.

Although high-alumina refractory castables have higher mechanical strength and better corrosion resistance, cracks occur due to insufficient volume stability. Metal attachments penetrate through the cracks, resulting in a reduction in their life and an increase in local maintenance.

High Alumina Refractory Castable
High Alumina Refractory Castable

Performance of Light-weight High Alumina Castable

High-performance light-weight high-aluminum castable improves its strength and reduces thermal conductivity. The castable has better construction performance and higher medium-high temperature strength. The compound combination method of hydration combination and coagulation combination can improve the normal temperature and high-temperature performance of the castable. The developed high-performance light-weight high-aluminum castable has low thermal conductivity, high high-temperature strength and volume stability. It is used in high-temperature parts of various industrial furnaces from 1200 to 1500 ℃ and has achieved good results. The energy-saving effect is obvious.

Experiments have shown that:

(1) The method of adding ultra-fine alumina powder can improve the construction performance of high-aluminum castables. However, as the ultrafine alumina content increases, the volume stability after firing decreases.

(2) If mullite is added to the matrix instead of alumina, the volume change after firing will decrease, but the construction performance will also decrease with the increase of mullite content.

(3) When andalusite is added to the matrix, the construction performance is reduced a lot, but the volume stability is greatly improved. Therefore, if the plasticity of andalusite is improved, andalusite is a good material of choice for the matrix of high-alumina castables that require high volume stability.

The high-performance light-weight high alumina castables are fully considered, and various related factors that affect the castables are fully considered. In the case of reducing production costs and meeting the conditions for the use of castables, optimize the composition and configuration of castables, formulate a reasonable production process, and strengthen process control. Castable manufacturers have produced a series of high-performance light-weight high-aluminum castables with a bulk density of 1.30 g/cm3, 1.50 g/cm3, and 1.80 g/cm3 to meet various working conditions.

High Alumina Castable Construction
High Alumina Castable Construction

Application of Lightweight High Alumina Castable

The performance of lightweight high-aluminum castables determines the energy-saving effect of thermal kilns. With the rapid development of various industries, the number and scope of light-weight castable applications are gradually expanding. From the permanent layer, the heat insulation layer to the working layer, from the low-temperature part to the high-temperature part, the transition from low load environment to high load environment. insulating castable. At present, the technology of lightweight high-alumina castables used in the working layer in the middle and low temperature (<1 200 ℃) and high temperature (>1 500 ℃) parts has basically matured performance. However, the performance of lightweight castables used in the medium and high-temperature range (1 200 to 1 500 ℃) needs to be improved to meet the new requirements for the use of lightweight high aluminum castables.

Rongsheng Refractory Castable Manufacturer

Rongsheng refractory castable manufacturer has a fully automatic refractory castable production line. The high-performance light-weight high alumina castables produced by Rongsheng are characterized by high strength, low thermal conductivity, and excellent construction performance in the working environment above 1200 ℃. And it has great significance in the research and application of energy-saving technology, energy-saving equipment, and energy-saving materials.

Refractories for Regenerators

KilnRefractory

The regenerators chamber is a waste heat recovery device that exchanges heat through medium heat storage and heat release. The main structure includes wall, lattice, bottom flue, grate arch-supporting lattice, etc. Therefore, it is also called the regenerator checker chamber. Its internal structure, lattice structure and material are the key factors that affect heat recovery efficiency and process characteristics. Refractories for Regenerators, as it is listed in the following text, will help you understand more.

Checker Bricks for Hot Blast Stoves Regenerators
Checker Bricks for Hot Blast Stoves Regenerators

Selection of Checker Bricks for Regenerators of Hot Blast Stoves

The regenerator of the hot blast stove is a space filled with checkered bricks. Its main function is to use the internal checker bricks to participate in the heat exchange between high-temperature smoke and combustion air.

Therefore, the checker brick as heat storage and heat transfer medium should have a larger heat receiving area, higher thermal conductivity and quality to facilitate heat exchange and heat storage. The method of increasing the heating area is to increase the number of holes in the checker brick per unit area. Therefore, the number of holes in the lattice brick of the regenerator tends to increase. Refractories for regenerators.

In order to improve the thermal conductivity of the material, black silicon bricks are commonly used in lattice bricks inside regenerators in Europe. Because the content of iron oxide in the black silica brick is high, the density is large, the thermal conductivity is large, the heat storage capacity is strong, and the heat exchange efficiency is high.

Therefore, the upper part of the regenerator is made of silicon lattice brick. Low creep high alumina brick, mullite brick, sillimanite brick, andalusite brick, etc. are used in the middle of the regenerator. Clay bricks are generally used in the lower part of the regenerator.

Refractories for Coke Oven
Refractories for Coke Oven

Coke Oven Regenerator

The single vertical wall, partition wall, bottom, and lattice bricks of the small coke oven regenerator can be built with clay bricks. Refractories for regenerators. The large and medium-sized coke oven regenerators are all made of silicon bricks in the upper and middle masonry, so that the whole coke oven can be evenly expanded.

The small flue is located at the bottom of the regenerator and communicates with the flue. The small flue is made of clay bricks.

Refractories for Glass Kiln
Refractories for Glass Kiln

Refractory Material for Glass Kiln Regenerator

At present, there are two main options for the selection of checker bricks used in the regenerators of glass kilns:

(1) Alkaline brick scheme

The lattice bricks on the top layer of the regenerator of this scheme use directly combined high-purity magnesium bricks. The upper layer is made of ordinary fired magnesium brick. The middle layer is made of magnesia chrome brick or forsterite brick which is resistant to sulfate attack. The lower layer uses low porosity clay bricks. The transition material between magnesia brick and clay brick is made of anti-stripping high-alumina brick.

(2) Scheme of fused zirconium brick

The entire lattice body of the regenerator is made of the same cross-shaped fused zirconium corundum lattice brick (ER-1681). According to reports, recently, fused β-alumina material has been selected as the top checker brick.

The top of the regenerator is often made of fused AZS brick, directly combined with magnesium brick or silicon brick. The upper layer of the sidewall and the partition wall is made of magnesia brick, the middle layer is made of magnesia brick or low porosity clay brick, and the lower layer is made of low porosity clay brick. Grate bricks with low porosity are used for the grate.

After choosing a scheme suitable for the kiln regenerator, the quality of its refractory materials, the construction quality of the refractory bricks, and the subsequent oven, maintenance, and daily operations are also the key factors that affect the safe operation of the kiln. Therefore, these steps must be completed in accordance with the design requirements. Avoid economic losses caused by kiln problems.

Rongsheng Refractories for Regenerators Manufacturer

Rongsheng is an experienced manufacturer, who is a professional at refractories. The refractory products of Rongsheng refractory manufacturers have been sold to more than 60 countries and regions around the world. Such as Malaysia, South Africa, India, Indonesia, Pakistan, Netherlands, Kuwait, Kenya, Russia, United States, etc. Rongsheng’s experienced refractory brick production line, as well as the fully automated production line of unshaped refractory castables, are the symbol of Rongsheng’s strength. Rongsheng’s unshaped refractory materials production line, with an annual output of 80,000 tons. If you need to purchase refractories for regenerators, Please contact us or by mail with your specific needs. We will reply to you in the shortest time.

Refractories for Carbon Baking Furnaces

KilnRefractory

The Carbon Baking Furnaces adopt silicon-alumina refractory materials as a whole. Refractories for Carbon Baking Furnaces. The furnace body of the Carbon Baking Furnace is made of high-quality fire clay bricks or high alumina bricks, and the furnace cover is integrally prefabricated with high-alumina refractory castables.

The brick piers and pit-faced masonry at the bottom of the closed Carbon Baking Furnaces bear the weight of the upper masonry and calcined products. The masonry of the upper electrode box’s heating wall, firebox and burner are subjected to a high temperature of 1400 ° C. At the same time, during each Furnace’s cycle, it is also affected by temperature changes. Therefore, fire clay bricks with high mechanical strength, high load softening temperature, and good thermal stability are used for masonry. The removable furnace cover can be built with heat-resistant refractory materials.

Low Creep Low porosity fire clay bricks
Low Creep Low Porosity Fire Clay Bricks

Refractories for Carbon Baking Furnaces

In the construction of a Carbon Baking Furnace, the following refractory materials are required. For example, fire clay bricks, fire clay insulation refractory bricks, special-shaped fire clay bricks, clay refractory mortar, fire clay insulation refractory particles, refractory fiber felt, asbestos rope, fire hole, burner bricks, etc. Among them, the amount of fire clay bricks are the largest.

Fire clay bricks are one of the main varieties of aluminum silicate products. It is made of clay clinker as aggregate and refractory soft clay as a binder with Al2O3 content of 30% ~ 48%. Clay refractory bricks have the following characteristics:

  • The properties of clay refractory bricks products can fluctuate in a large range, which is due to the large fluctuation range of the chemical composition of the product and the difference in the production process. (AL2O3 content fluctuates between 30% and 48%).
  • The refractoriness fluctuates between 1580 ~ 1700 ° C;
  • Its products have good thermal shock resistance and a large fluctuation range, generally more than 10 times (1100 ° C water cooling);
  • Coefficient of linear expansion of fire clay products. The average linear expansion coefficient from 20 to 1300 ° C is (4.5 to 5.8) * 10-6 ° C-1.

Fire clay products are kinds of weakly acidic refractory products, which increase their acidity as the SiO2 content increases. It has a certain erosion resistance to acidic slag, but a poor erosion resistance to alkaline slag. Therefore, clay products are suitable for the refractory lining of the acid slag furnace.

Refractories for Carbon Baking Furnaces
Refractories for Carbon Baking Furnaces

Construction of Refractories for the Carbon Baking Furnaces

When the Carbon Baking Furnace is constructed, the furnace body is built first. The flue and “Π” shaped regulators on both sides are built together. As for the bricklaying of the furnace cover and the outer flue (or flue pipe), it will be carried out after the furnace body is completed, and they can also be constructed along with the furnace body under the conditions allowed by the site.

The masonry construction of refractory materials for Carbon Baking Furnaces is often the key to the safe operation of the entire kiln. Therefore, in the masonry construction of the Carbon Baking Furnaces, it is necessary for the construction personnel to carry out the construction in an orderly, and high-quality manner.

RS Refractory Manufacturer
RS Refractory Manufacturer

Rongsheng Refractory Bricks Manufacturer

Rongsheng is an experienced refractory bricks manufacturer, Rongsheng’s customers have more than 60 countries and regions around the world. Our technical engineers can customize refractory materials for customers according to their production conditions. For refractory bricks that are used in large quantities, such as fire clay bricks, high alumina bricks, and silica bricks, Rongsheng competes with its peers by quality. For thermal furnaces with harsh production conditions, Rongsheng can customize refractory materials for customers. Last year, RS have customized fused silica bricks for a customer. This is also the first time of us to use such refractory, said by the customer. If you need to buy refractory bricks to build refractory lining. Please contact us and we will reply to you as soon as possible, and perfectly solve the refractory linings’ problems.  by RS Kiln Refractories Blog.

Detailed Explanation of Semi Silica Refractories

KilnRefractory

Semi-Silica Refractories generally use silica as the main component and a glassy matrix as a binder. The silica content is about 75% to 93%. The raw materials are silicon-containing clay, sand and refractory mortar. According to the Kiln Refractories Blog, it can resist slag erosion and is used in open hearth furnaces.

Semi Silica Refractory Bricks
Semi Silica Refractory Bricks

Brief Introduction of Semi-Silica Refractories

The Semi-Silica Refractories have an A12O3 mass fraction less than 30% and a SiO2 mass fraction greater than 65%. It is a kind of refractory material that is made of wax stone, siliceous clay or primary kaolin and its tailings, coal gangue and other main raw materials, combined with clay as a binder.

Whether in China or international standards, there is no definition of Semi-Silica Refractories. However, refractory materials with a SiO2 mass fraction greater than 85% and less than 93% are defined as silica refractory materials. It also defines Al2O3, aluminum-silica refractories with a mass fraction of 30% to 48% as clay refractories. Traditionally, aluminum-silicon refractory materials with Al2O3 mass fraction between 15% and 30% are called semi-silica refractory materials. The crystal phases are cristobalite, mullite, and a certain number of glass phases. Its typical representative is wax stone brick.

Semi-Silica Refractories
Semi-Silica Refractories

  1. Raw Material of Wax Stone

The most commonly used raw material for producing semi-silica refractory materials is wax stone. The wax stone mine is composed of pyrophyllite, quartz, kaolinite, mica and so on. The ore is dense and massive, with a waxy luster. Different colors due to different impurities, such as gray, wax yellow, light brown, meat red, etc. It has a greasy feel, very similar to talc. China is rich in waxstone resources, mainly distributed in the volcanic rock development area on the southeast coast, of which there are many mining sites in Fujian and Zhejiang.

1.1 Chemical mineral composition of pyrophyllite

Pyrophyllite is a water-containing silicate mineral. In theory, A2O3 accounts for 28.3%, SiO2 accounts for 66.7%, and H2O accounts for 5%. A complex layered structure is formed by two layers of hexagonal silicon-oxygen tetrahedral mesh layer sandwiched by a layer of “aluminum hydroxide” octahedron (aluminum oxyhedron). Pyrophyllite is also known as Qingtian stone, Shoushan stone, seal stone, wax stone, etc. Can be divided into pyrophyllite wax stone, siliceous wax stone, kaolinite wax stone and diaspore wax stone. Often contains a certain amount of Fe2O3, CaO, R2O and other impurities.

1.2 Basic properties of wax stone

Due to the different mineral composition of wax stone, their differential heat curves are obviously different, and there are different endothermic and exothermic peaks. It can be seen that the sample will expand in a certain temperature range before being sintered. The reason is that the lattice expands and the aluminum oxide and silicon oxide layers are separated. Vigorous expansion began at about 700 ° C, dimensional changes at 900 ° C tended to be gentle, and 1100 ° C began to shrink. This expansion characteristic is the basis for the wax brick’s micro-expansion characteristic. Raw wax stone has very low hardness and is a commonly used engraving material, but its hardness and strength have been greatly improved after calcination. In addition, pyrophyllite has good chemical stability and can only be decomposed by sulfuric acid at high temperature.

  1. Key points of production process of semi-silica brick

The manufacturing process of semi-silica brick is basically similar to that of clay bricks. The biggest difference is that semi-silica bricks can be made of raw materials. The main points of its production process are as follows.

(1) When using natural silica clay and wax stone, it is necessary to decide whether to add clinker according to the nature of the raw material and the use conditions of the finished product. Raw materials can be used to make bricks directly. It is also possible to add part of the wax stone raw materials to the mature materials after calcination, or add% to 20% of clay clinker to replace natural silica clay.

(2) If quartz sand or silica is added as barren material, the particle size should be determined according to the product performance requirements. In general, if there are many raw material impurities and fine quartz particles, the fire resistance of the resulting product is low, the thermal shock stability is reduced, but the strength is increased. If the quartz particles used are large, the strength of the product is low, but the thermal shock resistance is enhanced and the load softening temperature is increased.

(3) The water content of raw wax stone is small (less than 7%). When the whole wax stone or a small amount of combined clay ingredients are added, the mud water is low and the bonding performance is poor. At the same time, in the process of using wax stone bricks, it is generally subjected to repeated heating and cooling, the expansion amount gradually increases, and the bulk density further decreases. Therefore, high-pressure molding should be used, generally the molding pressure is above 50 MPa. Some molding pressure is 50 ~ 100 MPa, or use vacuum degassing brick machine to mold high-density wax stone brick with high volume stability. This wax stone brick has small air permeability and small pore diameter, which can improve durability.

(4) The maximum firing temperature varies with the characteristics of the raw materials used. Low temperature firing is usually used, and the temperature is 150 ℃ lower than that of clay bricks with lower firing temperature, and generally does not exceed 1200 ℃. Cool slowly after firing.

  1. Performance characteristics and application of semi-silica brick

The semi-silica brick produced with pyrophyllite as the main raw material has a refractoriness greater than 1700 ° C. It does not shrink at high temperature but has a slight expansion. It has good thermal shock resistance, can withstand the impact of steel slag and metal, and has strong creep resistance. Its micro-expansion is conducive to improving the integrity of the masonry and weakening the erosion of slag on the masonry along the brick joints. At the same time, glaze-like substances with high viscosity can be formed on the surface of semi-silica  bricks during high-temperature use to prevent the penetration of slag into the bricks, thereby improving the ability to resist erosion of the slag. In order to improve the performance of semi-siliceous bricks, it is sometimes necessary to add some other substances, such as adding mullite, high-alumina clinker, and zircon to increase the heat resistance of refractory bricks.

Semi-silica bricks are mainly used for ladle bottom lining, ladle lining, pouring steel bricks and kiln flue. With the increasing requirements for steel quality, the amount of semi-silicon bricks used in the steel industry has been very small. In addition to wax stone, other semi-silicon materials and minerals can also be used to make semi-silicon refractory materials.

The Difference Between Refractory Mortar and Refractory Cement

KilnRefractory

In the process of building refractory bricks lining, for those who do not know much about refractory materials, the difference between refractory mortar and refractory cement is difficult to distinguish. When should I choose refractory cement and refractory mortar? The technical staff of Rongsheng refractory manufacturer gave the following explanation.

Refractory Mortar for Sale in RS Manufacturer
Refractory Mortar for Sale in RS Manufacturer

The furnace lining material can be made of refractory bricks or directly cast by refractory castables.

When building refractory brick lining, the special joint material or bonding material needed is refractory mortar.

Because the refractory bricks are piece by piece, the complete refractory lining material requires that the refractory bricks are to be tightly linked together and not fall off. Therefore, a kind of binder is used when refractory bricks are used for kiln linings building. This kind of binder is called refractory mortar or seam material. They are refractory slurries reconciled with refractory mortar and water. It is the main auxiliary material for refractory brick masonry and the seam filler for the bonding of refractory bricks.

The choice of refractory mortar material needs to be selected strictly in accordance with the material of the refractory brick used in the construction of the refractory lining. Do not mix! There are as many types of refractory bricks as there are refractory mortar materials. Commonly, high alumina refractory mortar is used for masonry high alumina bricks, magnesium refractory mortar is sampled for masonry magnesiate bricks, and silica refractory mortar is used for masonry silicon bricks.

Refractory Brick Lining Building
Refractory Brick Lining Building

How to use refractory mortar

The supply method of refractory mortar is supplied as dry powder. When used, it is mixed with liquid gelling agent to form a viscous slurry. This kind of mortar is collectively called high temperature refractory mortar, high temperature refractory mud or high temperature binder. According to the combination method of liquid gelling agent, it is divided into: water glass combined refractory mortar, phosphoric acid combined refractory mortar, aluminum phosphate combined refractory mortar, etc. In addition to being used as a bonding material, refractory mortar can also be used as a protective coating for furnace linings by smearing or spraying.

The refractory lining material can also be completed by painting, spraying and pouring.

When the refractory castable is casting, a binder is needed to bond the refractory feedstock together. So that the refractory lining material can be firmly fixed on the lining of thermal equipment. The binder used here is generally refractory cement.

Refractory cement, also called aluminate cement or high alumina cement. Aluminate cement is often yellow or brown, and sometimes gray. The main mineral composition of aluminate cement is calcium aluminate (CaO · Al2O3, CA), other aluminates, and a small amount of dicalcium silicate (2CaO · SiO2). Refractory cement forms eutectics under the action of high temperature. When configuring refractory castables, excessive addition will reduce the high-temperature performance of the castables, usually using silica powder to replace part of the refractory cement.

Furnace Lining Castable Refractory
Furnace Lining Castable Refractory 

In Conclusion

The biggest difference between refractory mortar and refractory cement is that refractory mortar is used for refractory bricks (mixed with water or other liquids). The refractory cement is used as a binder material for various refractory aggregates, and the refractory castables made of it are used as lining materials for kilns.

Application of Corundum Refractory Castable

KilnRefractory

Corundum refractory castables have a higher aluminum content than other castables. Therefore it has higher abrasion resistance and mechanical strength. Speaking of the application of corundum refractory castables, it is mainly used for lining materials of various furnaces such as boilers, blast furnace hot blast stoves, heating furnaces, ceramic kiln and so on. In other words, it is used in parts with more mechanical shock and wear. In addition, this castable is mainly used in thermal equipment such as synthetic ammonia gasification furnaces and carbon black reaction furnaces, and can also be used in repairing furnace linings. RS refractory castable manufacturers will introduce you the application of corundum refractory castable. Rongsheng refractory manufacturer’s refractory castable products have guaranteed quality and strong performance.

Corundum Refractory Castable
Corundum Refractory Castable

The Main Application of High Purity Corundum Refractory Castable

High-purity corundum refractory castables are mainly used in large and medium-sized ultra-high power electric furnace cover triangle areas and LF refining ladle covers. It is mainly used to produce breathable bricks and nozzles. It is widely used in the steelmaking industry, and SH benefits and economic benefits are very good.

High-purity corundum (white corundum, brown corundum) refractory castable is an excellent refractory material, mainly used in the working layer of large ladle. It can be pre-made into bricks or can be cast in one piece. The proportion of the latter construction method is increasing. The damage of high-purity corundum refractory castables during use is mainly thermal spalling. However, if microcracks occur in the ladle material used, it will cause the molten steel to penetrate the molten steel during the cooling process, causing the ladle to peel off.

Corundum Refractory Castable Features

High-purity fused white corundum, plate-shaped corundum and dense corundum are used as aggregates, dense corundum and white corundum are used as powders, and appropriate amounts of active SiO2 fine powder and α-Al2O3 powder are added, and a dispersant and a water reducing agent are added at the same time. With the proper formula and molding process, high-purity corundum refractory castables with a life span equal to or exceeding that of imported similar products can be produced.

The main component of corundum is α-Al2O3, which belongs to the triangular crystal system. The crystals are short columnar, the true density is 3.85 ~ 4.01g / cm ~ 3, the hardness is 9, and the melting point is about 2050 ℃. In addition, corundum itself has high thermal conductivity and insulation, good chemical stability and ability to resist reducing agent action. Therefore, corundum can be used as a raw material for advanced refractories. Adding corundum to the refractory castable can make the aluminum content of the castable reach more than 90%, which improves the hardness and strength of the castable. But adding corundum and mullite to the castable, the aluminum content can reach 99%, the hardness, strength and wear resistance can reach a certain range, and the application effect is also significant.

RS Corundum Refractory Castable Manufacturer
RS Corundum Refractory Castable Manufacturer

Corundum refractory castable manufacturer

Rongsheng refractory manufacturer, specializing in the production of refractory castable, high alumina castable, corundum castable, mullite castable, rigid fiber castable and other castables. The company has passed ISO international 9001 quality system certification. The product quality conforms to international standards and is sold throughout the country and exported to Southeast Asia, South America, Africa and other countries and regions. We provide customers with guaranteed services: reliable quality, timely delivery and reasonable prices. Save your money without affecting product quality.

What refractory material is used in the blast furnace iron channel?

KilnRefractory

The blast furnace iron channel is composed of the main iron channel(main iron channel), iron trough(branch trough) and slag trough. After the molten iron flows out of the blast furnace tap hole, it passes through the molten iron channel system, after slag and iron separation and pretreatment, flows into the molten iron ladle or torpedo tanker. When the blast furnace is tapped, the temperature of the molten iron is as high as 1450 ~ 1570 ° C. The working lining of the refractory materials working layer of the tapping pit is repeatedly and frequently subjected to erosion, abrasion and corrosion by high temperature molten iron and slag. The refractory lining of the section is even more corroded, becoming the largest part of the refractory consumption of blast furnace ironmaking.

RS baking-free ramming mass
RS baking-free ramming mass

Iron channel is built in steel plate trench or concrete foundation. The permanent layer is generally built with clay bricks or unshaped refractory materials (also called the monolithic refractory), and the working layer uses carbon-containing ramming mass materials or carbon-containing refractory castables. Among them, carbon-containing refractory castables are commonly used refractory materials for iron tapping grooves, such as Al203-SiC-C ramming mass material and castable.

The carbon-containing unshaped refractory at the slag line of the main iron ditch should have the following properties in order to withstand the harsh conditions of use:

  1. Chemical Corrosion Resistance. That is, chemical corrosion resistance and penetration of molten slag and high-temperature molten iron. Especially, it is required to have good corrosion resistance when the temperature is higher than 1500 ° C. At the same time, it also requires good penetration resistance of molten slag and molten iron.
  2. Good High Temperature Mechanical Properties. It has excellent high-temperature abrasion resistance, that is, it must be resistant to the impact and erosion of molten slag and molten iron.
  3. Has a Dense Structure. Better volume stability at high temperatures.
  4.  Good Oxidation Resistance. For carbon-containing refractories, good oxidation resistance is required.
Refractory ramming mass material
Refractory ramming mass material

Experts from Rongsheng Kiln Refractory Factory introduced that in addition to using blast furnace spray paint and blast furnace ramming mass materials, the method of vibration is also used to form iron channel by pouring. When using these methods, the residual trench lining can not be removed and the original trench lining can be fully utilized, thereby reducing the consumption of refractory materials and improving the working conditions of the construction. Also to extend the life of the iron channel.

Rongsheng kiln refractory manufacturer, with more than ten years of production and sales experience, provides high-quality refractory products for blast furnace iron channel. Our products have passed ISO9001: 2005 quality certification and have been sold to more than 60 countries and regions in the world. If your blast furnace iron channel refractory lining needs repair or replacement, please contact us. We will get in touch with you in the shortest possible time.

Advantages and Disadvantages of Silicon Carbide Castable Refractory

KilnRefractory

In the production and sales of unshaped refractories, RS refractories manufacturer has concluded through the accumulated experience of more than ten years. When using silicon carbide castable refractory, not only the Advantages and disadvantages of silicon carbide castable refractory, the refractory castable price, but also the working environment of the refractory material need to be determined.

RS Anti-Crust Refractory Castable
RS Anti-Crust Refractory Castable

Silicon carbide (SiC) is an excellent wear-resistant and refractory raw material. In order to improve the wear resistance when configuring refractory castables, in addition to corundum, an appropriate amount of silicon carbide can be added to improve its wear resistance. Silicon carbide is made of natural silica and coke with SIO2 content greater than 97% as basic synthetic raw materials, and is synthesized at 2000-2500 ° C using an electric furnace. It has the advantages of small thermal expansion coefficient, Mohs hardness 9.0 ~ 9.5, and strong chemical stability.

Silicon Carbide Castable Refractory Advantages

The biggest advantage of silicon carbide refractory castables is that it has high thermal conductivity, low thermal expansion, and does not react with slag. It has been used as a slag reaction and high temperature spalling kiln parts very early.

Silicon Carbide Castable Refractory Disadvantages

  1. The biggest disadvantage is that, it is chemically unstable under certain atmospheres. Silicon carbide castable refractory is easy to be corroded in the atmosphere of oxidizing gas such as (oxygen, water vapor, carbon monoxide, carbon dioxide) and iron oxide. And it is easy to be oxidized and decomposed in the molten iron and vacuum.
  2. Another disadvantage, due to the poor water solubility of silicon carbide, in water-based monolithic refractories such as castables, the silicon carbide refractory castables may have poor fluidity, resulting in poor density of the silicon carbide refractory castables.
  3. The third disadvantage is the lack of sintering and difficulty in obtaining high strength. However, silicon carbide refractory castable are sometimes difficult to cause over-sintering and shrinkage, but they have advantages in unshaped refractories.

In the actual environment of the use of unshaped refractory castables, Advantages and disadvantages of silicon carbide castable refractory may have an impact on specific production. If we can carry out the production operations correctly and carry out the correct construction of refractory castables, we can avoid bad situations. Therefore, the construction party must follow the construction instructions for refractory castables. The production process also requires careful operation. If you want to know more about silicon carbide castable refractory, please contact us. Rongsheng refractory manufacturer is looking forward to cooperate with you.