| 摘要 |
Shaped zeolites are made by (a) forming the shapes with a binding solution which comprises an aqueous solution of an alkali metal silicate or aluminate and an organic nitrogen compound in a 0.05 to 0.1 molar excess of the amount required to form in step (b) an alkali metal carbonate with the aluminate or silicate; (b) heating the shapes at a temperature and for a time sufficient to decompose the organic nitrogen compound and to form the alkali metal carbonate; (c) aging the shapes in air for at least 18 hrs.; (d) washing the shapes with water until the pH of the wash water is in the range from 8.8 to 9.4; and (e) drying the shapes by heating to remove the water there-from. The organic nitrogen compound may be urea ammonium carbonate, potassium cyanate, hexamethylene tetramine, acetamide or formamide. The heating may be at 130-270 DEG C. for 2 to 24 hours, the drying may be at 100-240 DEG C. for 6 to 24 hours. After drying the shapes may be activated by heating at 370 DEG to 485 DEG C. for 2 to 24 hours. |
