High alumina refractory brick, an aluminum silicate refractory material having an alumina content of 48% or more. It is formed by bauxite or other raw materials with higher alumina content. High thermal stability, refractoriness above 1770 . Good slag resistance.
Usually divided into three categories:
I, etc.: Al2O3 content ≥ 75%;
II, etc.: Al2O3 content 60%~75%;
III, etc.: Al2O3 content is 48%~60%;
https://refractoriesmaterials.com/alumina-silica-fire-brick-for-sale/ can also be classified according to its mineral composition, generally divided into: low mullite (silica), mullite, mullite – corundum, corundum – mullite and corundum.
One of the important working properties of high alumina refractory bricks is the structural strength at high temperatures, which is usually assessed by the load softening temperature. The high temperature creep is also measured to reflect its high temperature structural strength. The test results show that the load softening temperature increases with the increase of Al2O3 content.
For high alumina refractory bricks with an Al2O3 content of less than 70%, the load softening temperature depends on the proportion of the mullite crystal phase and the liquid phase, which increases with the increase in the amount of mullite. The amount and nature of the liquid phase have a significant effect on the load softening temperature. Therefore, reducing the content of impurities in the raw material is advantageous for improving the load softening temperature and high temperature creep.
The production methods of high alumina refractory bricks and clay bricks are basically the same. Only some process parameters are different. There are also processes such as pulverization, kneading, molding, drying, firing, inspection, and packaging. The compressive stress is better at low temperatures but slightly lower at high temperatures, so the stacking in the kiln is less than 1 meter.
The production process of high alumina refractory bricks and multi-crop clay bricks is similar in that the proportion of clinker in the batching is as high as 90% to 9%. The clinker needs to be sorted and sieved before crushing. For example, high-alumina refractory bricks such as I and II are fired in tunnel kiln at 1500 to 1600 .
The production practice proves that the high-aluminum clinker is strictly sorted and graded before being crushed, and the grading storage adopts the bauxite clinker and the combined fine grinding method of the clay to improve the quality of the high-alumina refractory brick.
Species separation, based on chemical properties
A sign of this classification is the composition of the refractory stone, the substances involved. There are 3 categories:
•acidic group. This includes dinas and quartz-clay stones, which are able to interact with an acidic medium without any damage.
•The main group consists of dolomite, magnesite, chromomagnesite. For them, contact with alkaline medium will be problem-free. Most often they are used for the erection of structures, in which there are constant sharp changes in temperature.
•Neutral group is represented by chamotte fireproof, carbon and graphite stone materials. They are characterized by resistance to alkaline and acidic environments.
Among a number of positive properties, we distinguish the main:
•comparatively low weight.
•Ability to withstand temperatures up to 1690 C inclusive.
•Good heat capacity and inertia, manifested in rapid heating and slow cooling.
•Variations in shape and size.
•Excellent cope with temperature changes.
•It withstands the influence of aggressive external factors.
•Attractiveness of appearance and satisfaction of any requests due to different shades and textures.