| 摘要 |
<p>An improved process for preparing a fluid cracking catalyst is disclosed. A slurry of microspheres of kaolin clay calcined to undergo the characteristic exotherm, microspheres of kaolin clay calcined to metakaolin condition and sodium hydroxide solution is formed. The weight ratio of microspheres of kaolin calcined to undergo the exotherm to microspheres of kaolin calcined to metakaolin condition is in the range of about 9/1 to 4/1; the sodium hydroxide solution is of about 16% to 20% concentration and is present in amount such that the molar ratio of Na<Sub>2</Sub>O/AI<Sub>2</Sub>O<Sub>3</Sub> in said slurry is in the range of about 0.6 to 0.7. The slurry is aged and an additional quantity of microspheres of kaolin clay calcined to undergo the characteristic exotherm is added. The quantity of microspheres of clay calcined to undergo the exotherm added is such that the total weight ratio of such microspheres to microspheres of metakaolin is in excess of 9/1. Also added is an additional quantity of sodium hydroxide to produce a slurry having substantially the same sodium hydroxide concentration and substantially the same Na<Sub>2</Sub>0% Al<Sub>2</Sub>O<Sub>3</Sub> molar ratio as that of the original slurry. The reconstituted slurry is heated until crystals of zeolite of the faujasite type form in the microspheres in said slurry, and the crystallized microspheres are ion-exchanged to produce a fluid cracking catalyst.</p> |
