Silicate refractory fiber with colloidal silica as the main raw material is widely used in industrial furnace and other thermal and industrial equipment because of its excellent energy saving and high temperature resistance. Other amorphous refractories and ceramic products with colloidal silica as binder have the advantages of high demoulding strength, stable high temperature volume and good thermal shock resistance because they do not bring into various low melting point oxides.The type of GS, LS, NS colloidal silica, has been widely used in this industry. Especially the type of NS-30, is excellent raw materials for spraying mullite fibers, which are slender and soft and do not drop powder.