α-β alumina block is the compact structure formed from α-Al2O3 and β-Al2O3 alumina acicula and in a most ideal proportion, it has good erosion resisting and good stability, its feature is that when touching melting glass, it produces little stone or bubble. So, α-β alumina brick may be widely used to the position of touching melting glass of refiner, and may be used to the upper structure including crown