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.

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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.

RS Magnesium Bricks Manufacturer

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.

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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