As a special type of refractory brick, checkered bricks are excellent in heat storage and heat insulation because of their special structure. However, checkered bricks are not the same. The situation requires the selection of bricks made of different materials. The following is a small series to introduce to you the characteristics and scope of use of checkered bricks.
Checker bricks are generally used for hot blast stoves. The function of checker bricks for hot blast stoves is to insulate heat and withstand high temperature loads. Therefore, when determining the material and thickness of lining materials for each part, it should be based on the temperature, load and thermal insulation of the masonry. Requirements, as well as the physical and chemical effects of the flue gas on the masonry and other conditions. The main requirements of the checkered bricks in the high temperature area of the regenerator are good high temperature volume stability, corrosion resistance and creep resistance. Silica bricks have these characteristics and are cheap. It is widely used in blast furnaces.
When the design temperature of the top of the hot blast stove is not less than 1400°C, on the premise of good combustion of blast furnace fuel and high operation level, the preferred refractory material in the high temperature area of the hot blast stove should be silica brick, and the residual quartz of the silica brick must be controlled at not more than 2%. For hot blast furnaces using silica bricks, it is necessary to carefully determine the lower limit of the use of silica bricks, and set up a reliable temperature detection device here to ensure that the minimum use temperature of silica bricks during production operations (including wind shutdown) is not lower than 800 °C.
When the design temperature of the top of the hot blast stove is not higher than 1400°C, it is more suitable to use low-creep, high-density high-alumina refractory bricks, and can make full use of my country's rich bauxite resources. At present, the creep resistance index of foreign high-alumina refractory materials has reached a better level. For example, the creep rate of HD bricks in Hogovin, the Netherlands, is not more than 0.2% under the conditions of 1350°C 0.2MPa and 50h.
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The AC-8M brick index of Shinagawa, Japan is 1300°C, 0.2MPa, and the 50h creep rate is not more than 0.2%; at present, the creep rate index of high-alumina refractories in my country is not more than 1% under the corresponding conditions, which is the same as the world's advanced There is still a large gap compared with the level. At the same time, in view of the current situation of low-creep high-alumina brick production in my country, while strictly assessing the creep index of bricks, it is also necessary to control the impurities contained in the products, especially the content of alkali metals and alkaline earth metals. .
For the checker bricks in the middle and lower part of the regenerator, high alumina and clay refractory materials are usually used. With the increase of the height of the regenerator of the large-scale hot blast stove, the pressure of the upper lattice bricks on the lower refractory materials is also increasing. In addition, according to the damage investigation of the lattice bricks of the large-scale high-temperature hot blast stove abroad, the lower lattice bricks are caused by periodic temperature fluctuations. The cracking and breaking of checkered bricks are increasing, so in addition to continuing to control the creep characteristics of the lower clay bricks, the compressive strength at room temperature and the number of thermal shock stability (resistance to rapid cooling and rapid heating) of the products are put forward. high demands.
The effect of checkered bricks on the hot blast stove is undoubtedly very powerful. The checkered bricks can help the hot blast stove to effectively increase the heat storage capacity and effectively convert heat energy. Zhengzhou Shennan Refractory specializes in the production of all kinds of bricks for hot blast stoves. Welcome to call for product information.
High-alumina bricks are refractory bricks made of bauxite clinker as refractory aggregate. Bauxite clinker and many types of high-alumina bricks produced by different types of bauxite clinker are naturally different. , Bricks of different materials have different effect characteristics and refractoriness uses and methods of use are also different. The following is a detailed explanation for you.
What is high aluminum? It has high aluminum content, here refers to alumina (AL2O3), the main component is high alumina bauxite clinker, soft clay and waste pulp and paper liquid are used as binders, and the mud is composed of multi-level particles. , Refractory bricks made of high pressure molding, drying and high temperature firing. High-alumina bricks are divided into four grades according to the aluminum content. The aluminum content of the third-grade high-alumina bricks is not less than 55%, the aluminum content of the second-grade high-alumina bricks is not less than 65%, and the first-grade high-alumina bricks are not low. At 75, the aluminum content of super high-alumina bricks is above 80. As for the shape of high-alumina bricks, in addition to standard high-alumina bricks, there are also general-purpose high-alumina bricks, also called special-shaped high-alumina bricks. If the shape is very irregular, it is usually called special-type high-alumina bricks. to order.
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What are the types of high alumina refractory bricks?
1. Heavy-duty high-aluminum products are classified according to the content of aluminum oxide, as described above;
2. Lightweight high-alumina bricks, high-alumina polylight insulation bricks, are lightweight refractory bricks used for thermal insulation layers, and the product has good thermal insulation effect;
3. Anti-spalling high-alumina refractory bricks are due to the introduction of ZrO2, and their microstructural characteristics determine their anti-spalling properties;
4. Low creep: It is made by adding other beneficial auxiliary minerals to the ordinary high alumina brick production process to improve the creep resistance. With the development of large volume, high air temperature and longevity of iron-making blast furnaces, the proportion of low-creep high-alumina bricks used in hot blast furnaces is getting higher and higher.
5. High-alumina sillimanite bricks, grade III high-alumina refractory bricks produced with natural sillimanite raw materials are called sillimanite bricks. This kind of refractory brick has the characteristics of high softening temperature under load, good thermal shock stability, good wear resistance and slag resistance;
How to identify high quality high alumina bricks?
Appearance color: When purchasing high-alumina bricks, the first thing to look at is the color. Excellent high-alumina bricks have a smooth surface, yellowish white, flat sides, no broken corners, and no cracks.
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The weight of a brick: to weigh the weight of a single brick, according to the weight specification, the weight of a high-alumina brick is 4.5 kg. The weight of the second-grade high-alumina brick is 4.2 kg, and the weight of the third-grade high-alumina brick is 3.9 kg. The same grade and the same parameter type can reach this standard. It can be regarded as an excellent high-alumina brick. If it is found that there are cracks, uneven corners, broken corners, etc., it is an unqualified product.
The above are some tips for identifying high-alumina bricks. Refractory specializes in the production of various refractory products. Different refractory products have different use environments. Be sure to understand the environment you want to use and know various types of high-alumina bricks. Aluminium brick performance, welcome to inquire about refractory products.
Zhengzhou Shennan Refractory Co.,Ltd are professional in producing high quality checker bricks ,any demands,please don't hesitate contact with me.
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