Alumina bricks
Alumina brick English: High-alumina brick
Alumina bricks are aluminum oxide (Al2O3) content higher than 48% of the aluminosilicate refractory products. Such as Al2O3 content higher than 90%, known as corundum bricks. Because different resources, national standards are not entirely consistent. European countries such as high alumina refractories required minimum of 42% Al2O3 content. In China, according to alumina bricks are usually divided into three classes Al2O3 content: Ⅰ, etc. ─ ─ Al2O3 content> 75%; Ⅱ, etc. ─ ─ Al2O3 content of 60 ~ 75%; Ⅲ etc. ─ ─ Al2O3 content of 48 to 60%. More than 48% alumina content of a neutral refractories. Bauxite or alumina by a high content of other raw materials by molding and calcination. Thermal stability, high refractoriness at 1770 ℃ or more. Slag resistance is better. For masonry steelmaking furnace, glass furnaces, cement rotary kiln, etc. lining.
High-load soft. Low creep high alumina bricks are super bauxite. Fused corundum, fused mullite as the main raw material of high-grade refractory. The product has a high-temperature creep. Corrosion resistance. Good thermal shock resistance, etc., suitable for large and medium-sized stove, stove needed it for our new high-quality, high-grade refractory localization of imports under an open road to success has been included in the national "Spark Program "project.
Resource conditions and products according to different requirements, can use the following types of materials: a hydrous aluminum oxide minerals (a boehmite, gibbsite, etc.) high alumina brick
As the main component of bauxite; sillimanite group minerals (including kyanite, andalusite, sillimanite, etc.); synthetic materials, such as industrial alumina, mullite, fused corundum and so on. China alumina bauxite resource-rich, fine texture, origin mainly in Shanxi, Henan, Hebei, Guizhou, Shandong and other places. High alumina bauxite produced mainly one diaspore (α-Al2O3 · H2O) and a mixture of two minerals kaolinite.
Feature
a, high alumina brick refractoriness refractoriness than clay and semi-silica brick refractoriness to be higher, up to 1750 ~ 1790 ℃, belonging advanced refractories. b, load softening temperature because of Al2O3 high alumina products, less impurities, forming fusible vitreous less, so load softening temperature than clay bricks high alumina bricks, mullite crystals but did not form a mesh tissue, so the load silica softening temperature is still not high. c, slag resistance of Al2O3 high alumina bricks are more close to neutral refractory materials, resistant to acidic and alkaline slag slag erosion, because it contains SiO2, so the ability of anti-alkaline slag slag than weak acid resistance more. Production process
Alumina brick and clay clinker production process more similar, except that the ingredients in the clinker higher proportion of up to 90 ~ 95% of clinker required before the crushing and screening classification iron chosen, the firing temperature higher, such as Ⅰ, Ⅱ and other high alumina brick tunnel kiln firing with generally 1500 ~ 1600 ℃. Chinese production proved, alumina clinker crushing strict selection before classification and grading storage, use and integration of bauxite clinker grinding clay common method, can improve product quality.
Use mainly for masonry furnace, stove, furnace roof, blast furnaces, reverberatory furnace, rotary kiln lining. In addition, high alumina brick also
Widely used open-hearth regenerative checker bricks, pouring system using plug head, nozzle brick. However, high alumina brick clay than the price, it is able to meet with the requirements of the local clay do not have to use high alumina bricks.