Alumina bubble brick is made of alumina hollow ball and alumina powder as the main raw materials, combined with other binders, and fired at a high temperature of 1750°C . It belongs to a kind of ultra-high temperature energy-saving thermal insulation material.
Alumina hollow ball is a new type of thermal insulation material with high temperature resistance, high strength and stable pores. As a high temperature heat insulating material for energy saving, alumina hollow balls can be directly used as adiabatic fillers for high temperature kilns, and can also be further processed into alumina hollow sphere products, or formulated as lightweight castables. Alumina bubble bricks are made of alumina hollow balls, corundum powder, calcined powder, etc. as raw materials, which are homogenized, shaped and sintered at high temperature. In the production process, the firing temperature also has a great influence on the thermal insulation performance of the product. With the increase of the firing temperature, the thermal conductivity increases due to the improvement of the sintering degree. Compared with other lightweight thermal insulation materials, alumina hollow sphere thermal insulation materials are characterized by high safe use temperature, high strength and low thermal conductivity. Their bulk density is 50%-60% lower than that of dense products of the same composition, and can be directly used as the lining of high-temperature kilns with the impact of high-temperature flames.
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The production method of alumina hollow ball
The production methods of alumina hollow balls include rolling ball burn-off method and melt blowing method. The rolling ball method is to first use organic resin or low-melting material to make core pills, put them in a rotating disk, and then sprinkle moist alumina fine powder containing a certain amount of moisture on the disk and adhere to the core pills to form a shell, like a sugar coating around a pill. Then the pellets are fired at a high temperature, the core pellets are burned out and volatilized, and the outer shell is sintered to form a hollow ball. The disadvantage of this method is that the efficiency is low, the spherical surface is not smooth, and the wall thickness and size are not easy to control, so it is not used much in industrial production.
Production ingredients and technology of alumina hollow balls for making thermal insulation bricks
Alumina bubble bricks with anti-stripping properties were prepared by using alumina hollow balls, fused corundum powder, a-Al2O3 micropowder, SiO2 micropowder, sillimanite and clay powder as raw materials.
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Alumina hollow balls are light aggregates, which can ensure high temperature resistance and reduce density; corundum powder is an inert filler; sillimanite is an expansion agent, which can reduce sintering shrinkage and improve thermal shock resistance; alumina Micro-powder, silica micro-powder and clay powder are binding materials, which can reduce the sintering temperature, form a mullite binding phase, and improve the high temperature resistance and thermal shock resistance of refractory materials.
The bricks were prepared according to the set batching plan. After mixing, molding, and natural drying for 24 hours, they were then dried at 110 ° C for 24 hours and fired at 1600 ° C for 4 hours to obtain thermal insulation bricks. The amount of sillimanite added was 12 %, the properties of the thermal insulation bricks are: bulk density 1.48g/cm3, compressive strength 26MPa, load softening temperature 1710°C, 1600°CX2h reburning line change +0.3%, thermal shock resistance (1100°C water cooling ) 17 times, the thermal insulation material has the characteristics of light weight, high strength, high temperature resistance and thermal shock resistance.
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Application of alumina bubble brick
Alumina hollow balls and their products are lightweight refractory materials with high temperature resistance and excellent energy saving, which are very stable in various atmospheres. Especially in high temperature furnaces up to 1800°C. Hollow balls can be used as high temperature and ultra-high temperature insulation fillers, high temperature refractory concrete lightweight aggregates, high temperature castables, etc. Alumina bubble bricks can be used in high temperature and energy saving inverted flame kilns, shuttle kilns, aluminum wire furnaces, pigeon rod furnaces, induction furnaces, nitriding furnaces, etc. For reducing the weight of the furnace body, transforming the structure, saving materials and saving energy, obvious effects will be achieved.
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Zhengzhou Shennan Refractory Co., Ltd. specializes in the production of alumina bubble bricks, which effectively guarantees the normal operation of high-temperature equipment, reduces heat loss, and can reduce heat loss by 25% , effectively improving the utilization rate and improving product quality.Any demands of the alumina bubble bricks ,please don’t hesitate contact with us.
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+86-15238007351 |
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+86-371-86039318 |
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annie@snrefractory.com |
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www.snrefractory.com |
