What are the Mixing Steps of Ladle Refractory Castable

Ladles are used in steelmaking plants and foundries to receive molten steel and carry outpouring operations before open-hearth, electric furnace or converter. 45% of the ladle castables are aluminum-magnesium spinel castables. The alumina-magnesia spinel castables for ladle are mainly used on large, medium, and small ladles. Ladle castable refers to a mixture of granular and powdery materials made of refractory materials and a certain amount of binder for a ladle. This product has a long service life, safety, and stability, and is an ideal refractory material for a ladle. Therefore, it needs to be stirred before the ladle castable is used. Next, Rongsheng monolithic refractory castable manufacturer will introduce the mixing steps of ladle refractory castable for you.

The Mixing Steps of Ladle Refractory Castable

As we all know, the construction process of ladle castables includes construction preparation, mixing, pouring, demolding, baking, etc. The mixing of ladle castables is a very critical step after construction preparation.

1. The mixing of ladle castables must be mixed with a forced mixer. When mixing, do not mix in packaging bags, rope ends, and other sundries, so as not to affect the pouring effect and performance.

2. The ladle castable used for mixing must be unpacked after arriving on site. The mixing capacity of the mixer should be determined according to the capacity of the mixer. The amount of castable used should be accurately measured before being poured into the mixer.

3. When mixing, the process of dry mixing first and then wet mixing is required. After the castable is added to the mixer, first dry mix for 2 minutes, then add about 5.2~5.5% of water, add water while stirring, first add 80% of the total. Then, add as appropriate depending on the consistency of the mixture, and note that the mixing water must be clean tap water, not sewage. Wet mixing for 4 minutes, one-time mixing should not be less than 6 minutes, until the castable is uniform. Discharge after the surface is flooded. Generally speaking, the bottom of the package is slightly dry and the wall of the package is slightly thinner. The above-mentioned water addition is a reference value.

4. When mixing, strictly control the water consumption and mixing time to ensure the consistency required for construction. If the castable is too thin, it will seriously affect the performance and quality of the material. The amount of mixing, mixing time, and the amount of water added each time are uniform and should not be thick and thin. If it is found that the consistency of the mixing material does not meet the requirements, it should be returned to the mixer to add water or dry material to mix properly. It is strictly forbidden to temporarily add water during pouring.

5. The evenly stirred material should be poured within 20 minutes. In order to avoid being hardened for a long time and cannot be poured, it will affect the structural strength of the ladle lining.

6. The mixer should be cleaned every time the construction is completed or the variety of castables is changed.

7. It is strictly forbidden to stop the mixing operation halfway and put the materials that have already started mixing in the mixer. If the mixer breaks down during work, if it can be repaired in a short time, you must clear a part of the material before turning on the machine before it can be turned on. Put this part of the material into it after starting up. If it cannot be repaired in time, all the castables in the machine must be cleaned.

The above is the mixing steps of refractory castable for a ladle. Hope to help you with your construction. We are a Rongsheng Alumina Bricks manufacturer. http://www.aluminabricks.com/. Our main products are various types of refractory bricks and monolithic refractory materials. If you want to know our company or want to buy refractory castables for ladle, please contact us. We will provide you with services according to your specific needs. 

 

 

How to Reserve Expansion Joints for Refractory Bricks and Castables?

When refractory bricks or castables are used in the refractory lining of industrial kilns, due to the influence of temperature changes and thermal stresses formed by temperature gradients, the lining structure will deform and expand. Therefore, expansion joints should be left during the construction of refractory bricks and castables.

The raw materials used in refractory bricks and castables are different, and the expansion coefficients produced after heating are also different. During masonry, the size of expansion is mainly determined by the nature of refractory bricks or castables and the temperature it withstands. 

Reserved Expansion Joints for Refractory Bricks in Rotary Kiln

The expansion of refractory brick and castable heating surface at the highest temperature is (unit: mm):

• Clay brick masonry: 5-6
• High alumina brick masonry: 7-8
• Corundum brick masonry: 9-10
• Silica brick masonry: 12-13
• Magnesia brick masonry: 10-14
• Clay castable masonry: 4-6
• Phosphorus salt castable: 5-8
• High alumina cement castable: 6-8
• Water glass castable: 4-6

Rules for reserved expansion joints

Clay bricks and lightweight brick masonry whose temperature is lower than 800°C do not need to leave expansion joints. However, expansion joints are still required for clay bricks with too long dimensions. The location of the expansion joint must avoid the stressed part. If there are holes in the furnace body frame and lining, the expansion joints should be separated and the spacing should not exceed 2m.

The expansion joints of refractory bricks or castables at the bottom of the furnace should be staggered in the upper and lower bricklayers and the furnace bottom of the same layer. When building the furnace wall, the left expansion joints can also be left in a staggered pattern between the inner and outer layers and in the upper and lower layers. When the circular wall is constructed, a gap should be left between the shells to compensate for expansion.

In the vault construction, the expansion joints of the refractory bricks and the castable should be left straight at both ends. Consider the vertical expansion of the vault and the upward expansion of the furnace wall when setting it aside. When the length of the dome is greater than 5 meters, in addition to leaving expansion joints at both ends, expansion joints must be set in the middle of the dome according to the segmentation of the arch length. The expansion joints of the staggering vault are left straight through.

The expansion joints of each layer of the multi-layer vault should be staggered, and the expansion joints should be covered with a layer of flat bricks. If it is a dome made of silica bricks, cardboard of 1-2mm should be inserted every 3-5 bricks in the radial joint of the dome to compensate for expansion.

If refractory bricks or castables are used for suspended furnace roofs, expansion joints should be left around the furnace roof.

Rongsheng refractory material manufacturer provides high-quality refractory brick lining and castable lining for various thermal furnace equipment. For detailed price information, please contact us, http://www.aluminabricks.com/contact-us/.

Application of Refractory Plastics in the Top of Heating Furnace

The top of the heating furnace is the place where the temperature of the heating furnace is high and the airflow is severely scoured. Regardless of the preheating section, heating section, or soaking section, the roof of the heating furnace has different defects from the early refractory brick hanging furnace to the refractory castable furnace roof of previous years. Considering different usage requirements, the refractory materials for the top of the heating furnace can be selected, as well as refractory castables and refractory plastics.

RS High-Quality Refractory Plastics for Sale

Application of different refractory materials on the top of the heating furnace

The roof of the heating furnace adopts the hanging roof of refractory bricks, which has poor air-tightness and large heat loss. Due to the uneven surface of the brick, it will increase the airflow resistance and is not conducive to heat radiation, and the heat utilization is low. The overall performance of the refractory brick hanging furnace roof is poor, and the phenomenon of local brick falling is very easy to appear. The high-temperature resistance is poor, and the high-temperature zone of the soaking section is difficult to reach in a year of use.

Based on the above-mentioned shortcomings, now the top of the heating furnace generally uses refractory castables or refractory plastics(http://www.aluminabricks.com/refractory-castable/plastic-refractory/). Although refractory castables overcome many shortcomings of refractory bricks. However, the castable has a serious weakness, that is, its poor thermal shock resistance. The spalling and erosion phenomenon in the heating furnace is more serious, especially the roof of the heating furnace, which sometimes causes large-area laminar shedding. The reason is that the castable itself is poor in thermal shock resistance, and its resistance to rapid cooling and heating is not as good as that of clay bricks. The second reason is that the castable construction is horizontally layered pouring, sometimes due to the failure of the construction equipment or other reasons, the pouring interval is too long. Artificially created laminar gaps and destroyed the overall performance of casting.

Corundum SiC Wear-Resistance Refractory Plastic

However, the construction method of plastics completely avoids the lack of integrity of refractory castables. The advantage of plastics compared with castables is that it has good thermal shock resistance. This is also an important reason why it is applied to the top of the heating furnace.

Application of Refractory Plastics in the Top of Heating Furnace

1. From the perspective of construction, the construction of refractory plastics(http://www.aluminabricks.com/refractory-castable/plastic-refractory/) is more complicated. From the ramming of the anchoring brick and wood mold to the shaving after removing the mold, piercing the ventilation holes, and anchoring the bottom of the brick with the sleeves until the expansion line is hit. The construction process is complicated, the technical level is high, and the quality requirements of the construction personnel are also high.

2. It is also important to complete the plastic refractory construction to the curing stage before the oven. Since plastics are afraid of water, they cannot be wet from the rain. Be careful to protect the storage before use.

3. Due to the characteristics of the plastics, the shrinkage joints must be processed after the oven. Where the shrinkage seam is large, fill it with plastic to meet the sealing requirements.

The main products of Rongsheng refractory material manufacturers include high alumina bricks, clay bricks, refractory castables, refractory plastics, refractory mortar, and other refractory materials. Rongsheng's refractories have been trusted by customers in more than 60 countries and regions all over the world. If you want to know about the Rongsheng refractory material manufacturer or Rongsheng refractory project, please contact us by email: info@aluminabricks.com. Our team will provide you with services according to your specific needs.

 

The Advantages of Using Magnesia Bricks

The use of magnesia bricks is mainly used in steelmaking alkaline open-hearth furnace, electric furnace bottom, and furnace wall. The permanent lining of oxygen converter. Non-ferrous metal smelting furnace, high-temperature tunnel kiln, calcined magnesium brick, and cement rotary kiln lining. The bottom and wall of the heating furnace, the lattice brick of the regenerator of the glass kiln, etc. The advantages of using magnesia bricks can be perfectly reflected in these refractory linings. If you want to know more about the advantages of using magnesia bricks, you need to first understand magnesia bricks.

Definition of magnesia brick

Magnesia bricks are basic refractory materials with magnesium oxide content above 85% and cristobalite as the main crystal phase. Magnesia bricks are refractory bricks made of fused magnesia and sintered magnesia at high temperatures. Generally, it can be divided into two categories: sintered magnesia brick (also called fired magnesia brick) and chemically combined magnesia brick (also called unfired magnesia brick). Magnesia bricks with high purity and high firing temperature are called directly bonded magnesia bricks due to the direct contact of the periclase grains. Bricks made of fused magnesia as raw materials are called fused and combined magnesia bricks, and are suitable for large and medium-sized lime kilns such as various rotary kilns, sleeve kilns, and shaft kilns.

Magnesium brick characteristics

It has a high degree of refractoriness, good resistance to alkaline slag, high temperature at the beginning of load softening, but poor thermal shock resistance. Sintered magnesia bricks are made of magnesia bricks. After crushing, batching, kneading and molding, it is fired at a high temperature of 1550 to 1600°C, and the firing temperature of high-purity products is above 1750°C. Unburnt magnesia bricks are made by adding appropriate chemical binders to magnesia, mixed, shaped, and dried.

Magnesium bricks have the advantages of strong alkali resistance, strong erosion resistance, good thermal stability, high compressive strength, and high load softening temperature. The fired magnesia brick uses high-quality sintered magnesia as the main raw material and uses pulp as the binding agent. After mixing and high-pressure molding, it is fired in a high-temperature tunnel kiln above 1550℃. Has good thermal stability, anti-erosion, and anti-stripping properties. It is widely used as lining refractories in industrial furnaces such as converters and electric arc furnaces.

The advantages of using magnesia bricks

Unburned alumina magnesia brick for ladle refers to non-fired refractory products made of high-alumina bauxite clinker and magnesia for lining bricks in the steel drum. With the development of new steelmaking technologies such as oxygen blowing in the converter, continuous casting, and refining outside the furnace, the temperature of the molten steel increases, and the residence time in the steel drum increases. The use conditions of the inner lining of the steel drum are harsh, which causes serious erosion of the clay brick. The use of this kind of lining brick has a better use effect.

The fused magnesia brick has the advantages of the dense brick structure, high mechanical strength, and low impurity content. Mainly used for heat storage of large glass kiln. Dense refractory bricks have certain shapes and sizes of refractory materials, with unit volume weight and high density. Dense refractory brick is a kind of siliceous clay rich in hydrated aluminum silicate. It has the ability to not deform, crack, soften or paste at high temperature. The basic quality requirements of refractory bricks are higher than 38% alumina and low iron and low alkali metal content. These products may not be calcined or calcined, such as refractory clay, plastic materials for overload, high alumina plastics, refractory clay and high alumina castables.

Learn more by email: sales@hy-refractory.com

What are the Performance and Use of Magnesia Brick?

Magnesia bricks have good high-temperature performance and strong resistance to alkaline slag. It is widely used in steelmaking furnace lining, ferroalloy furnace, mixed iron furnace, nonferrous metallurgical industry furnace, and limestone kiln in the steel industry. Heat exchangers for lattices of regenerators in the glass industry, high-temperature calcination kilns, and tunnel kilns in the refractory industry. The performance of magnesia bricks is greatly different due to the different raw materials, production equipment, and technological measures adopted.

High-Quality Magnesia Bricks

The refractoriness of magnesia bricks is as high as 2000℃, and the load softening temperature does not change greatly with the melting point of the bonding phase and the liquid phase produced at high temperatures. Generally, the load softening starting temperature of magnesium bricks is 1520～1600℃, while the heavy softening starting temperature of high purity magnesium bricks can reach 1800℃.

The load softening start temperature of the magnesia brick is not much different from the collapse temperature, because the main phase composition of the magnesia brick is periclase.

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The brucite crystals do not crystallize the network skeleton in the magnesia brick, but are cemented by the combination. In ordinary magnesium bricks, silicate phases of low melting point, such as calcium magnesium olivine and magnesite, are generally used as a combination. Although the granite of the magnesite constituting the magnesia brick has a high melting point, there is a silicate phase melted at about 1500°C, and its liquid phase viscosity is very low at high temperature. Therefore, the load deformation temperature of ordinary magnesium bricks is not much different from the collapse temperature, but there is a big difference from the refractoriness. The load softening starting temperature of high-purity magnesium bricks can reach 1800℃. The main reason is that the combination between the perovskite grains is forsterite or dicalcium silicate. Moreover, the melting temperature of the eutectic formed with MgO is high, the lattice strength between crystals is large and the plastic deformation at high temperature is small, and the crystal particles are well bonded.

RS Magnesia Serious Bricks

The linear expansion rate of magnesia brick at 1000～1600℃ is generally 1.0%～2.0%, and it is approximate or linear.

In refractory products, the thermal conductivity of magnesium bricks is second only to carbon-containing bricks, which decreases with increasing temperature. Under the condition of 1100℃ water cooling, the number of thermal shocks of magnesia bricks is only 1-2. Magnesia brick has strong resistance to alkaline slag of CaO and ferrite, but weak resistance to acid slag containing SiO2. Therefore, it can't be in direct contact with silicon bricks during use. Generally, it should be separated with neutral bricks.

At room temperature, the conductivity of magnesia bricks is very low, but at high temperatures, its conductivity will not be ignored.

Refractories for Electrode Furnaces

MgO-C Bicks for EAF
Manesia carbon brick for electric furnace uses eletro-fused magnesia, high-carbon graphite as the main raw materials, in which an adequate amount of anti-oxidant is added, using phenolic resin as the bonding agent, the product is characterized by good erosion resistance and thermal shock stability and it is widely applied in electric-arc furnace.

MgO-C Bicks for EAF

Gunning Repair Mix for EAF Slag Line
The product uses quality dead burnt magnesia and other basic compound materials with a rational grain gradation composition. It has a good sintering property and erosion resistance, a small rebound rate in construction and a high adhesion to facilitate gunning repair operation. It is applicable to hot repair to such locations as hot zone, slag line, hearth slope, side wall,tap hole, etc. In an eletric furnace, an electric furnace with a super high power, being an ideal complementing material to achieve a uniform damage from erosion for furnace liner, increase service life.

Gunning Repair Mix for EAF Slag Line

Taphole Flling Mass for EBT EAF
The tap hole filling is an essential material for eccentric bottom tapping from electric furnace. The product is characterized by non-floating up, high self -opening rate, being easy for operation ,being safe for using，etc.

Taphole Flling Mass for EBT EAF

Hot Repair Mix for EAF Bottom
The material is prepared based on the principle of the most compact particle piling by selecting quality synthetizing raw materials and additives, bonding agent and sintering agent, which is characterized by a strong ability to resist permeation of molten steel, erosion resistance, being easy to get sintered at a low temperature, being convenient for construction, etc.


Precast Roof Cover for EAF and LF, Nozzle Well Block
Precast EAF roof Delta blocks are produced by combined casting from extremely fine powder by carefully selecting high bauxite, electro-fused corundum, chromium fused alumina, electro-fused spinel, etc. as main raw materials and adding efficient water reducing agent and efficient dispersing agent. It is characterized by such advantages as high strength, good thermal shock stability, resistance to high-temperature erosion, long service life, etc. It applies to large size electric furnace, LF refining furnace, VOD furnace, etc.

Precast Roof Cover for EAF and LF, Nozzle Well Block

Ramming Mix for EAF Bottom
The product uses high quality synthetic MgO-CaO- Fe2O sand as the raw material and is formed with a rationa grain gradation. It has a good sintering property, high resistant erosion, convenient for construction and strongly integral. It can be used for initial placing and also for hot repairing, being applicable to such locations as bottom, hearth slope, etc. In an electric furnace with a high power, an electric furnace with a super high power.

Ramming Mix for EAF Bottom