Adopting tabular alumina, emery, chromium oxide green and magnesia alumina spinel as main raw materials, using cement as binder. Numerous designs are available based around high purity refractory materials. They can be designed and produced types of straight hole, directional slit, directional labyrinth, girth shape and interior and exterior integral split etc according to users’ request. With precisely formed slot/channel for the optimum gas flow rates and stirring efficiency