High-alumina fire brick, that is, an aluminum silicate refractory material with an alumina content of more than 48%. It is formed and calcined from bauxite or other raw materials with high alumina content. High thermal stability, refractoriness above 1770℃. Good slag resistance.

Classification of Fire high alumina brick
Usually divided into three categories: [1]
Class I: Al2O3 content ≥75%;
Ⅱ and so on: Al2O3 content 60%~75%;
Class III: Al2O3 content 48%~60%;
It can also be classified according to its mineral composition, generally divided into five categories: low mullite (sillimanite), mullite, mullite-corundum, corundum-mullite, and corundum.

Nature of Fire high alumina brick
One of the important working properties of high alumina refractory bricks is the structural strength at high temperature, which is usually evaluated by the softening deformation temperature under load. Its high-temperature creep property was also measured to reflect its high temperature structural strength. The test results show that the softening temperature under load increases with the increase of Al2O3 content.

For Fire high alumina brick with Al2O3 content below 70%, the softening temperature under load depends on the quantity ratio between the mullite crystal phase and the liquid phase and increases with the increase in the quantity of mullite. The quantity and nature of the liquid phase have a significant effect on the softening temperature under load. Therefore, reducing the impurity content in the raw material is beneficial to improve the softening temperature under load and the creep at high temperatures.

Production Process of Fire high alumina brick
The molding 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 crushing → mixing → forming → drying → firing → inspection → of packaging. Its compressive stress is better at low temperature but slightly reduced at high temperature, so the stacking in the kiln is less than 1 meter. The production process of high-alumina refractory bricks and multi-clinker clay bricks is similar. Such as I, II, and other high alumina refractory bricks are generally 1500 ~ 1600 ℃ when fired in a tunnel kiln.
Production practice has proved that high alumina clinker is strictly selected and graded before crushing, and graded and stored. The fine grinding method of bauxite clinker and combined clay can improve the quality of high alumina refractory bricks.

Use of Fire high alumina brick
Fire high alumina brick Mainly used for masonry blast furnaces, hot blast stoves, electric furnace roofs, blast furnaces, reverberatory furnaces, and rotary kiln lining. In addition, high alumina refractory bricks are also widely used as open-hearth regenerative checker bricks, plugs for pouring systems, nozzle bricks, etc.