| 摘要 |
A self-supporting monolithic body comprises an amorphous alumina-silica skeleton of inter-connecting cells, e.g. a honeycomb, with crystalline synthetic zeolite integral with and exposed at the cell walls. In its preparation, for example, hydrated kaolin is mixed with a binder to form a solid self-supporting honeycomb by extrusion. The binder is removed and the residue is calcined to dehydrate the clay. The rigidized honeycomb is immersed in a solution of sodium hydroxide or other base(s) and heated to form a crystalline zeolite in situ. The base extracts a portion of the silica and/or aluminia in the calcined structure, whereby the nonzeolitic portion of the structure is porous and the zeolite crystals are accessible when the structure is used as a catalyst, catalyst support or adsorbent. Such structures are peculiarly suited to high space velocity processes such as reduction of nitrogen oxides. |
