| 摘要 |
PURPOSE:To smoothly perform extrusion molding without generating a curing phenomenon at the time of kneading, by using type-II anhydride, which is obtained by baking gypsum dihydrate and/or gypsum hemihydrate under a specific condition, in preparing a catalyst using gypsum. CONSTITUTION:In preparing a catalyst for removing nitrogen oxide in combustion exhaust gas, type-II anhydrous gypsum obtained by heating and baking gypsum dihydrate and/or gypsum hemihydrate at 500 deg.C or more for 10hr or more is used. When the catalyst is prepared using this type-II anhydrous gypsum, no curing phenomenon is generated when gypsum is shrunk because of the removal of combined water at a heating time or kneading is performed while water is added and smooth extrusion molding is performed. |
