The main purpose of insulating refractory materials made of heat-insulating refractory is to reduce heat dissipation in high-temperature furnaces, reduce the self-weight of the kiln, and reduce the exterior temperature of the kiln. Insulating refractories are crucial in the position of high-temperature kilns and are generally used in conjunction with heavy refractories to form a multi-layer composite structure that effectively improves the service life of the kiln, while also saving energy and protecting the environment.
01. Hollow Ball
Hollow spheres are made by melting raw materials such as alumina or zirconia into liquid form and blowing the high-temperature molten liquid into small droplets with compressed air, forming hollow spheres under the action of surface tension and centrifugal force. Common materials include alumina hollow spheres, zirconia hollow spheres, إلخ. These materials are widely used in refractory materials and can be used to produce hollow sphere bricks and insulation castables. Because of the high purity, low impurity content, قوة عالية, and low thermal conductivity of these material hollow balls, they are generally used in the production of high-grade insulation materials with good high-temperature performance and insulation performance, and can also be in direct contact with flame.
02. Drifting Beads
Drifting beads are hollow microbeads of fly ash that can float on the water surface, separated from the coal fly ash discharged from the burning pulverized coal furnace, mostly off-white. The chemical composition of drift beads fluctuates greatly, which is closely related to the composition of pulverized coal. The particle size is usually between 20~250μm, the specific surface area is 3000~3200cm2/g, and the bulk density is generally 250~400kg/m3. drifting beads are generally used in insulation castables, and the purpose of introducing them is mainly to improve the strength and reduce the thermal conductivity of insulation castables due to their larger cylinder pressure strength and lower thermal conductivity.
03. Diatomaceous Earth
Diatomaceous earth is a kind of siliceous sedimentary rock with a biological origin. The size of the diatom shell is about 5-400μm, containing a large number of tiny pores, and the porosity reaches more than 80%, so it has excellent heat insulation performance. تعد الكثافة الظاهرية معيارًا مهمًا لقياس جودة التراب الدياتومي, أصغر الكثافة الظاهرية, كلما كانت الجودة أفضل. يستخدم التراب الدياتومي بشكل شائع في إنتاج بلاط التراب الدياتومي, والتي لها خصائص عزل حراري جيدة, ولكن لا يمكن أن تكون درجة حرارة الاستخدام أعلى من 900 درجة مئوية, خلاف ذلك, سيتم تحويل السيليكا الموجودة في التراب الدياتومي إلى كوارتز مربع وتفقد خصائص العزل الحراري. فضلاً عن ذلك, يستخدم الدياتوميت أيضًا كمواد حشو في المواد غير المنتظمة.
04. البيرلايت
البيرلايت عبارة عن حمم حمضية ناتجة عن الانفجارات البركانية, الذي يمتد عند 1,180-1350 درجة مئوية, تشكيل البيرلايت الموسع الغني بالمسام المغلقة والمفتوحة, مع مضاعفات التوسع 7-30 مرات أو أكثر. البيرلايت الموسع صغير, عمومًا, بين 40-200 كجم/م3, الموصلية الحرارية منخفضة جدا, the safe use temperature is below 800 ℃, and has a certain degree of refractory properties. لذلك, expanded perlite is used in a large number of insulation refractory materials, the amount in the insulation castables is very large, mainly to reduce the thermal conductivity of insulation materials, while the block expanded perlite can provide a certain strength, widely used in the petrochemical industry kiln and pipe insulation. فضلاً عن ذلك, also use expanded perlite to make some stereotyped products.
05. Ceramic Pellets
Ceramic pellets are spherical porous materials made of low melting point clay, shale, fly ash, or coal gangue as raw materials by calcination. It has a smooth and hard surface, honeycomb shape inside, الموصلية الحرارية المنخفضة, and high strength, it is a high-quality artificial lightweight raw material, mainly used as aggregate in thermal insulation and refractory castables.
06. Vermiculite
Vermiculite is a typical layered silicate mineral composed of black mica, gold mica, and other minerals, and its chemical composition fluctuates widely, mainly depending on the composition of the mica. Vermiculite has the characteristic of heating and expanding, which makes it used in the field of refractory materials. Vermiculite starts to expand in volume when heated to 200°C, and the volume weight decreases to between 600 و 900 kg/m3, and the volume weight can be reduced to 100-130 kg/m after complete cauterization, and the thermal conductivity is also very small, possessing good thermal insulation properties. Vermiculite can be used at a maximum temperature of 1100°C, لذلك يمكن إدخاله على شكل حبيبات أو مسحوق ناعم وصناعته من طوب الفيرميكوليت أو قوالب عازلة للحرارة لاستخدامها في الأجزاء ذات درجات الحرارة المرتفعة قليلاً.
