Spherical cerium-activated catalyst for ammonia synthesis and process for its manufacture

A process for the production of a highly porous, non-brittle, spherically shaped, cerium activated catalyst for ammonia synthesis which demonstrates high catalytic efficiency, high resistance to thermal stresses and to chemical poisons, low pressure drop, and uniform synthesis gas distribution comprising:

• mixing magnetite in proportions by weight, based on the weight of the magnetite, of:
• 2.0-3.5% aluminum oxide,
• 0.8-2% potassium hydroxide,
• 2.0-3.5% calcium oxide,
• 0.1-0.4% magnesium oxide, and
• 0.2-0.5% silica;
• melting the mixture so formed in a furnace at a temperature of at least 1600.degree. C.;
• air cooling the melted mixture and removing the melted slag;
• crushing the melted mixture;
• pulverizing the crushed mixture in a rod mill to form a porous powder;
• mixing the porous powder with a solution of cerium nitrate in such proportions as to produce a metallic cerium concentration of 0.5-2.5% by weight in the final catalyst;
• pelletizing the porous cerium-containing powder in a tray pelletizer to obtain non-brittle, spherical granules which absorb continuously additionally supplied powder;
• drying the spherical granules at a temperature of from 100.degree. C. to 200.degree. C.;
• sintering the dried spherical granules in an argon atmosphere at a temperature of from 1250.degree.-1350.degree. C.