Fused alumina brick is a kind of product which is made by melting alumina into a specific shape model in an electric arc furnace, annealing and heat preservation, and then processing diamond abrasive tools. The product can be divided into three types according to the different crystalline forms and quantity of alumina. The first one is mainly composed of α - Al2O3, which is called α - corundum brick; the second is mainly composed of α - Al2O3 and β - Al2O3, with the content of 1:1, and the content of α phase is slightly higher, which is called α, β corundum brick; the third one is mainly composed of β - Al2O3 crystal phase, which is called β - corundum brick
When fused brown corundum or white corundum is used as the raw material, the frit shall be broken and selected to remove ferrosilicon or other impurities contained in the brown corundum. The white corundum block should be sorted out from the high sodium aluminate and other low melting substances, which are flake crystal. Due to their small density, these impurities usually float on the surface of the corundum block and are easy to identify. Corundum contains a small amount of harmful components, which will lead to poor sintering or cracking of products, so it should be calcined in advance before use. The final sorted ferrosilicon alloy is oxidized and decomposed into Fe2O3 and SiO2 at 500-1000 ℃, and the titanium bearing minerals are oxidized into TiO2 (Jin Hongshi), etc., all of which produce large volume expansion. After pre firing, the destructive stress caused by these decomposition and oxidation reactions is eliminated in the pre firing process, so as to avoid the cracking of the product caused by the expansion of the reaction of these impurity minerals during the firing of the product.

Project indicators	fireclay	High alumina	High aluminum  poly light	siliceous	Mullite	Diatomite  brick
	0.5~1.3	0.6~1.0	0.8~1.0	0.8~1.0	| 1.0~1.2	0.8
A1203(%)≥	48	48	65		70	≤16
Fe203(%)≤					≤1.5	≥5.0
Si02(%)<				≥88~91		≥70
Ca0(%)						≥2.0
Mg0(%)						≤2.0
bulk densityg/cmBD≥	0.8~1.3	0.6~1.0	0.8~1.0	0.8~1.0	1.0~1.2	0.8
Normal temperature compressive strengthMPa›	2.5~3.0	3.0~4.0	3~7	1.8~2.0	5.0~6.0	≥2.0
Load softening  temperature℃				≥1400	≥1400
Change rate of  reheating line,%(℃Xh)	1250~1350 ±2	1400 ±2	1450 ±2			0.2
Thermal expansion  rate(%)
thermal conductivity1000℃	0.35~0.5	0.5	0.5		0.6~0.7
Fire resistance℃						≥1280
Apparent porosity%						≥75
Product features	High load softening point, heat insulation, heat preservation and energy saving,  good thermal stability, erosion resistance and erosion resistance.
purpose	Widely used in metallurgy, building materials, petroleum, chemical industry, glass furnace and other industries